chapter 5 results and discussion -...
TRANSCRIPT
55
CHAPTER 5
RESULTS AND DISCUSSION
This chapter has following four parts that deals with the results obtained during
present investigation.
1. Standardization of Chhana jalebi
2. Shelf life enhancement by using two following preservatives
a. Sodium benzoate
b. Potassium sorbate
3. Shelf life enhancement by using following four packaging materials
a. Low barrier packaging materials
i. Polystyrene cups covered with aluminum foil
ii. Cardboard box lined with butter paper (generally using for
packaging of sweets)
b. High barrier packaging materials
i. Metalized polyester (MET)
ii. Low density poly ethylene (LDPE) pouches
4. Shelf life enhancement by using following two packaging techniques
a. Modified Atmospheric Packaging (MAP) technique in MET and LDPE
materials with following three modified atmospheric conditions
i. 100% CO2
ii. 100% N2
iii. Combination of 50% CO2 and 50% N2
b. Vacuum packaging technique
56
PART –I: STANDARDIZATION OF CHHANA JALEBI
5.1 STANDARDIZATION PROCEDURE FOR CHHANA JALEBI
PRODUCTION
Standardized procedure for the preparation of Chhana jalebi has not been
available so far. Preparation of Chhana jalebi involves making batter, coil formation and
frying and dipping in sugar syrup. This method is highly variable as followed by small
scale manufacturer or halwais.
In order to produce uniform quality product various processing parameters such as
i. Fat content in milk
ii. Combination of Chhana maida ratio
iii. Level of water addition
iv. Frying time and temperature
v. Sugar Syrup concentration, temperature and time of soaking are needed
to be optimized.
5.1.1 Optimization of fat levels in milk
Fat plays a significant role in determining the quality of Chhana in terms of
consistency, texture and flavor. Increasing of fat level in milk is desirable character for
Chhana making for soft end product. Soft Chhana is preferable for manufacture of
jalebi.
Chhana prepared with milk containing different fat levels such as 1.5%, 3%,
4.5% and 6% was used in batter making by mixing with other ingredients such as
Chhana, maida, baking soda, corn flour and water.
For comparing the effect of fat, all other factors such as level of Chhana- maida
ratio (1:1), hydration time (3 hr), baking soda (0.25%), corn flour (4%), water, sugar
syrup concentration (60°Brix) and soaking time (1 min) and soaking temperature (50°C)
were kept constant whereas frying temperature and exposure time was determined based
on change of desired color of the product through visual observation [65]. The Chhana
jalebi prepared was evaluated through sensory quality such as color and appearance,
57 flavor, body and texture, overall acceptability using 9-point hedonic scale. Ideally good
quality Chhana jalebi should have a golden to yellow color, crispy texture, rich flavor
and sweet taste. The comments of evaluators was recorded and expressed as a mean
value of sensory scores of jalebi on 9 point hedonic scales in Table 5.1.
Table 5.1 Effect of fat level in milk on sensory score *(max 9.0) of Chhana jalebi
Level of fat percentage
Parameters 1.5% 3.0% 4.5% 6.0% CD(P≤0.05)
Colour and appearance 7.31±0.51a 7.33a±0.59a 7.38 ±0.744a 7.36 ±0.74a -
Flavour 7.08±0.44a 7.70±0.46b 7.89±0.45b 8.19±0.50c 0.23
Body and texture 6.6±0.77a 8.12±0.74ab 7.52±0.98a 6.71±0.72a 0.98
Overall acceptability 7.11±0.63a 7.70±0.62d 7.47±0.66c 7.28±0.67b 0.16
*Average three trials; Note: Values with different superscripts are differ significantly at
P≤0.05
Table 5.2. Statistical report (ANOVA) of milk fat level effect in Chhana jalebi
based on the sensory score (max 9.0)
Source dfCA FL BT OA
MSS F MSS F MSS F MSS F
Judges 4 1.570 29.641 1.015 37.233 1.121 2.200 1.663 117.652
Fat level in milk
3 0.005 0.103NS 1.116 40.959* 2.382 4.673* 0.325 23.037*
Error 12 0.052 - 0.027 - 0.509 - 0.014 -
Total 19 - - - - - - - -
* Significant at 5% level; CA-Color and appearance, FL-Flavor, BT-Body and texture,
OA-overall acceptability; NS-Non significant
58 i. Color and appearance
The color and appearance scores for fat levels 1.5%, 3%, 4.5% and 6% were
7.31, 7.33 7.38, 7.36 respectively. Jalebi prepared from 1.5%, 3%, 4.5% and 6% of milk
fat have given same color development. The color of jalebi varied from light yellow to
brown; however, fat level in milk did not show any impact on color and appearance
scores whereas frying time and temperature plays vital role on the same. Brown colour
development during frying is attributed to derivatives of proteins and their interaction
with carbohydrates [75]. The fat content in milk had no significant influence on color
and appearance of the product (Table 5.2). The brown color development of jalebi was
mainly due to frying. The products are mainly protein derivatives and interact with
carbohydrates and developed colour. Hence, fat content showed only less effect on the
colour and appearance of the product.
ii. Flavor
The flavor scores for 1.5%, 3%, 4.5% and 6% milk fat were 7.08, 7.70, 7.89,
and 8.19 respectively and it’s contributes less, optimal, strong and very strong flavors to
the products respectively. The flavor of Chhana jalebi was partly dependent on fat level
in milk as indicated by significantly higher flavor scores (P<0.05). This could be
attributed to the optimal fatty acid balances in butter fat. Milk fat contributes for the
desirable flavor of milk [76]. It observed that the flavor scores were increased when
increases the fat content in milk. It means the product prepared with high fat content
milk had high flavour than that prepared with low fat content milk. Based on our
observation, concluded that milk fat significantly contributes to the flavor of milk
products, the mean value and significantly difference are represented in Table 5.2. For
example the flavor score was 7.08 which significantly increased to 8.2% in case of 6%
fat milk product whereas there was no significant difference among 3 and 4.5% fat milk
samples.
iii. Body and texture
The body and texture of the product was also influenced by fat level in milk. The
jalebi became firmer to more chewy as fat level in the milk increased. The fat generally
contributes to the soft texture to the product; but in the present study the product
prepared with higher fat milk exhibited chewy body. This may be attributed to
59 interaction of proteins (specifically casein) and fats during frying at high temperature
[77]. The body and texture score of the product prepared from 1.5% was 6.69 which
statistically increased to 8.12 for 3% fat milk. When the fat level in milk increased to
4.5%, the scores significantly decreased to 7.52 and thereafter to 6.71 (P≤0.05). There
was no significant difference between 1.5%, 4.5% and 6% of fat milk products in the
body and texture scores (Table 5.1). Because 1.5% fat milk jalebi samples were firmer
and 4.5% and 6% fat milk jalebi samples were chewier. There was significant difference
between 3% fat milk jalebi samples from other fat level samples. The jalebi samples
prepared from 3.0% fat milk showed crispier than other samples.
iv. Overall acceptability
According to evaluators the flavor of the product prepared from 6% fat milk was
better. However, overall acceptability of these product scores was less due to more
chewy body and texture. The overall acceptability scores of jalebi were significantly
different from each jalebi samples prepared from 1.5%, 3%, 4.5% and 6% fat milks.
The highest score was noticed in 3% fat milk jalebi as a 7.70. The overall acceptability
score of the product prepared from 1.5% was 7.11 which increased to 7.70 from 3% fat
milk samples whereas the scores was significantly decreased in 4.5 and 6% milk fat
samples as 7.47 and 7.28 respectively (P≤0.05). As can be seen from the Table 5.1, the
effects of fat on flavor, body and texture there by overall acceptability are statistically
significant (P≤0.05) (Table 5.2). Based on the sensory report, concluded that 3% fat
milk jalebi had a desirable color, body and texture. Hence, further trials were continued
with 3% fat milk.
5.1.2 Water content of batter for Chhana jalebi
Water plays a key role in food preparation. It helps to distribute the particles like
starch and protein to produce a smooth texture. The quantity of water in food creates
impact on texture, consistency and makes comfortable feeling in mouth during chewing
process. In case of jalebi manufacture, water level in batter is very important because it
affects the integrity of coils formed for deep fat frying. The initial study was undertaken
to estimate the optimum water level in the batter for making jalebi coils. The extrusion
behavior of batter was also recorded using plastic container for making jalebi coils.
Hence, the water content used for batter making has been optimized.
60
Water content in the batter has impact on the formation and retention of shape,
size, frying qualities, as well as jalebi quality. During studies different levels of water
was added in to other ingredients such as Chhana and maida for making batter. For
comparing the effect of water level in batter, all other factors such as level of Chhana-
maida ratio (1:1), baking soda (0.25%), corn flour (4%), hydration time (3 hr), sugar
syrup concentration (60°Brix) and soaking time (1 min), soaking temperature (50°C),
were kept constant [65] whereas, frying temperature and time determined based on
color change of the product through visual observation.
In order to optimize the water level, five different levels of water ranges 35%,
40%, 45%, 50% and 55% percent were taken. There was no impact of water level in
batter on color, appearance and flavor of the product, but the body and texture of the
product was highly dependent on water level in the batter. Initially, when 35% of water
was added in the batter, more force required to extrude it through the plastic container.
The batter consistency was found very thick. The final product after dipping in sugar
syrup was showing hard body, very closed texture, firmer texture.
Added 55% of water level showed the batter became thinner. This batter was
easily passed through an aperture of the plastic container but the retention of shape
and size was found to be complex. The final products were not in uniform size,
breakage of coil during extrusion, too soft and sticky in texture, absorbed more oil and
sugar syrup. Hence two extreme levels of water have been rejected due to above
unacceptable batter and end product. Therefore, it was confirmed that water level may
be within 40% to 50%.
At the water level of 40% of batter was observed discontinued flow from an
aperture due to hard batter consistency with application of moderate force. The fried
Chhana jalebi coils were little hard and firmer body and texture. In water content of
50% batter were flows very easily from the aperture, non-uniform shape and breakage
of coil during extrusion. The end product of fried Chhana jalebi was found disintegrated
coils during frying and more sugar syrup absorption during soaking. Both 40% and 50%
water levels are given little better results than the 35% and 55% of water levels, even
though batter and product characteristics were not up to the acceptable level. However
these studies are given more assurance that optimal level water would fall between 40%
and 50%.
61 In batter, 45% of water was added and again tried to make Chhana jalebi. At this
time, the batter passed easily through the plastic containers aperture with application of
very less force and formed the desired shape and as well as retained the shape. The fried
Chhana jalebi coils were sufficiently expanded. They were shown uniform shape,
uniform frying and crispy in texture.
The prepared Chhana jalebi was evaluated for sensory quality such as color and
appearance, flavor, body and texture, overall acceptability using 9-point hedonic scale.
The comments of evaluators was recorded and represented in Table 5.3.
i. Color and appearance
The color and appearance scores for water levels in batter 35%, 40%, 45%, 50%
and 55% were 7.04, 7.06, 7.06, 7.06 and 7.06 respectively (Table 5.3). The results
indicate that the water level in batter had no significant influence on color and
appearance. The color of jalebi was mainly because of the browning products formed
during frying and those products are mainly derivatives of proteins and interaction with
carbohydrates. But the brown color was observed in 35%, 40%, 45%, 50% and 55% of
water level in batter as same. Hence, it is clearly showed that there was no impact of
water level in batter on color and appearance of the product.
Table 5.3 Effect of water level in batter on sensory score *(max 9.0) of Chhana jalebi
Water level in batter* (%)
Parameters 35 40 45 50 55 CD(P≤0.05)
Colour and appearance 7.04±0.26NS 7.06±0.19 NS 7.06±0.19NS 7.06±0.13NS 7.06±0.18NS -
Flavour 7.1±0.29NS 7.14±0.24NS 7.18±0.22NS 7.10±0.28NS 7.12±0.25NS -
Body and texture 6.80±0.14a 7.06±0.19b 8.24±0.18c 7.08±0.19b 6.80±0.20a 0.23
Overall acceptability 6.80±0.14a 7.06±0.19ab 7.24±0.18b 7.00±0.14a 6.88±0.17a 0.20
* Average three trials; ml water for 65 g of batter; Note: Values with different
superscripts are differ significantly at P≤0.05; NS-Non significant
62
Table 5.4 Statistical report (ANOVA) of water level effect in batter based on
sensory score (max 9.0) of Chhana jalebi
Source dfCA FL BT OA
MSS F MSS F MSS F MSS F
Judges 4 0.025 0.599 0.224 7.652 0.052 1.813 0.055 2.529
water level in batter
4 0.000 0.009NS 0.005 0.190
NS 1.794 62.089* 0.144 6.593*
Error 16 0.042 - 0.029 - 0.028 - 0.021 -
Total 24 - - - - - - - -
* Significant at 5% level; CA-Color and appearance, FL-Flavor, BT-Body and texture,
OA- overall acceptability; NS-Non significant
ii. Flavor
The flavor scores for water levels in batter 35%, 40%, 45%, 50% and 55% were
7.10, 7.14, 7.18, 7.10 and 7.12 respectively (Table 5.3). The ANOVA report indicates
that the water level in batter had no significant influence on flavor (Table 5.4). In our
pervious analysis concluded that flavor scores increased as fat content in milk was
increased. However, in this study 3.0% of fat milk was taken for all water levels of
dough making. Hence, it is clearly showed that there was no impact of water level in
batter on flavor of the product.
iii. Body and texture
The average body and texture scores of different water levels such as 35%, 40%,
45%, 50% and 55% in batter were 6.80, 7.06, 8.24, 7.08 and 6.80 respectively. Jalebi
samples were shown very hard, crispy, very firm and soggy texture based on the water
content in batter. Product became firm and soggy as water content increased in the
batter. This is attributed to gelation and water absorption during batter making. The
crust thickness of the product increased with respect to decreasing moisture content
during frying. The mean values of sensory scores obtained from 9 point hedonic scale
are presented in Table 5.4. The sensory score of body and texture of product prepared
from 35% to 45% moisture batter ranged from 6.80 to 8.24, whereas further increase of
63 water level in batter to 50% and 55% decreased scores to 7.08 and 6.80 respectively,
which was statistically significant (P≤0.05). This was due to interaction of water and
protein during frying [75]. There was no significant difference between 35% and 55%
as well as 40% and 50% water level products but there was significant difference in
45% water level products from each other (Table 5.4). Because pour ability of this water
level batter was optimum and the product was crispy in texture compared to other
samples. Hence 45% water level in batter content was given good score of 8.24 on body
and texture of the product.
iv. Overall acceptability
It was observed from the sensory report that the average overall acceptability
scores for water levels in batter 35%, 40%, 45%, 50% and 55% were 6.80, 7.06, 7.24,
7.00 and 6.88 respectively. According to evaluators, the body and texture of the product
prepared from 45% water level in batter was better. The overall acceptability scores of
jalebi were significantly different from each other among 35%, 40% and 45% water
level in batter. The highest score of Chhana jalebi was noticed in 45% water content
batter as 7.24. There was no significant difference between 35% (6.80), 50% (7.00) and
55% (7.29) water level of batter. The mean value presented in Table 5.3 and 45% water
level in batter product was significantly different from each other. The Table 5.4
represented that when water content increases, overall acceptability scores was also
increases upto 45% water level and there after decreased. The results indicate that 45%
of water level in batter gave a desirable body and texture in Chhana jalebi.
Thus, it was concluded that a batter prepared with 45% water level was found to
be optimum for Chhana jalebi preparation which not only facilitates in shape formation
but also yields best quality Chhana jalebi. Therefore, remaining trials were continued
with 45% of water content for making batter. Role of water content in Chhana as well as
dough on the quality of the product has also been reported by several Researchers.
Nawale Pratik (2010) [13] reported that 45 to 50% water level in khoa jalebi was found
to be optimum which not only facilitated shape formation but also yielded good quality.
Chakkaravarthi et al., (2009b) [78] reported that maida jalebi prepared with 53 to 57%
of water content needed additional force to push the batter through an orifice while
gravity flow was possible when water content was between 57 and 61%.. Nath (1992)
[27] reported that pantua made from Chhana with about 58% water level possessed all
64 desirable sensory attributes. Desired water level of 60% in gulabjamun dough has been
reported by Prajapati et al., (1992) [39]. Rajhoria (1989) [54] reported that the softness
of gulabjamun could be increased by increasing the quantity of water content from 60 to
65% in dough preparations. In case of rasagulla, about 55-58% water level was found
to be optimum for good quality and acceptable product which showed a round shape,
soft body and maximum spongy texture reported by Bhattacharya and Des Raj (1980)
[55].
5.1.3 Effect of frying temperature and time combination for Chhana jalebi
Frying temperature determines the nature of the fried product, especially in deep
fat fried foods. Foods fried at the optimum temperature and time which have golden
brown color, crispy and optimal oil absorption [79]. However, under fried foods at
lower temperature or shorter frying time have white or slightly brown color at the edge
and have un-gelatinized or partially cooked starch at the center. Over fried foods at
higher temperature and longer frying time have darkened and hardened surfaces and a
greasy texture due to the excessive oil absorption [80].
In order to optimize the frying temperature and time combination, Chhana
jalebi was made with Chhana obtained from 3% fat milk mixed with other
ingredients such as maida and water (45%). For comparing the effect of frying
temperature and time, all other factors such as level of Chhana-maida ratio (1:1), baking
soda (0.25%), corn flour (4%), hydration time (3 hr), sugar syrup concentration
(60°Brix) and soaking time (1 min), soaking temperature (50°C), were kept constant.
Four different ranges of temperature such as 120-130°C, 140-150°C, 160-170°C and
180-200°C were selected. Development of golden brown color on the product was
taken as the end point and time taken to the end point was recorded for each
temperature ranges. Fried units were then transferred to hot sugar syrup at room
temperatures. The Chhana jalebi prepared was evaluated for sensory quality such as
color and appearance, flavor, body and texture, overall acceptability using 9-point
hedonic scale.
In the preliminary trial, it was found that frying at 120-130°C required 5 min.
The product obtained from frying at this temperature range was prolonged frying time,
hard product, less sugar syrup absorption. It needed more time to fry and the end
product also showed not satisfactory results. Thus 120-130°C of frying temperature was
65 not selected for the further studies. At the temperature range of 140-150°C, the product
obtained optimum color at 4 min. The product became firmer body, chewy texture and
less sugar absorption in this frying temperature range. Hence the frying temperature of
140-150°C was discontinued. At 180-200°C for 40 sec, the dark brown in color was
developed rapidly in the product and very difficult to maintain the color at this
temperature, case hardening and poor sugar syrup absorption. This frying temperature
range also showed not satisfactory results.
However, frying at 160-170°C for 2 min produced a final product with crispy in
texture, good sugar syrup absorption, optimum body and texture and pleasant flavor.
The product obtained from this frying temperature range showed acceptable outcomes.
Consequently, it was concluded that frying at 160-170°C for 2 min found to be optimum
for Chhana jalebi preparation which not only facilitates in golden brown color as well as
produced the best quality of Chhana jalebi. The prepared Chhana jalebi was evaluated
for sensory quality such as color and appearance, flavor, body and texture, overall
acceptability using 9-point hedonic scale. The average sensory scores for color and
appearance, flavor, body and texture and overall acceptability are expressed in Table 5.5
and statistically analysis of the sensory scores is presented in Table 5.6. The comments
of evaluators was recorded and presented in Table 5.5.
i. Color and appearance
It was observed that the color and appearance scores for frying temperatures at
120-130°C, 140-150°C, 160-170°C and 180-200°C were 7.78, 7.88, 7.98 and 7.88
respectively. In this study, jalebies were taken based on the development of golden
brown color and time was noted. It was found that at lower temperatures. i.e, from 120-
130°C the product used to get the optimum golden brown color gradually. As the
temperature increased upto 180-200⁰C the product became dark brown in color within
short time and at this temperature it was very difficult to maintain the color. This is
evident from the ANOVA presented Table 5.6. Color and flavor changes in product
were due to increased rate of non-enzymatic browning (Maillard) reactions between
proteins and reducing sugars during frying [75]. Higher temperature gave dark brown
color and cooked flavor to the product; lower frying temperatures resulted in whiter
color.
66 Table 5.5 Sensory characteristics* of Chhana jalebi fried at different frying
temperatures
Frying temperatures (°C)
Parameters 120-130 for 5min
140-150 for 4min
160-170 for 2min
180-200 for 40sec
CD(P≤0.05)
CA 7.78±0.29NS 7.88±0.16 NS 7.98±0.35 NS 7.88±0.13 NS -
FL 6.80±0.57a 7.10±0.72ab 7.70±0.57bc 6.56±0.84a 0.52
BT 6.30±0.44a 6.95±0.377ab 8.11±0.36bc 6.60±0.54a 0.44
OA 6.50±0.50a 6.95±0.37a 8.00±0.58b 6.60±0.54a 0.5
* Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05; NS-Non significant
Table 5.6. Statistical report (ANOVA) of frying temperatures effect on sensory score (max 9.0) of Chhana jalebi
Source dfCA FL BT OA
MSS F MSS F MSS F MSS F
Judges 4 0.130 3.070 1.446 10.091 0.466 4.555 0.643 4.983
Frying temperatures 3 0.033 0.784NS 1.212 8.454* 3.140 30.693* 2.353 18.217*
Error 12 0.042 - 0.143 - 0.102 - 0.129 -
Total 19 - - - - - - - -
* Significant at 5 % level; CA- Color and appearance, FL- Flavor, BT- Body and texture, OA- overall acceptability; NS-Non significant
ii. Flavor
The flavor scores showed a variation from 6.80 to 7.70. The lowest score was
for the product fried at 120-130°C (6.80) and 180-200°C (6.56) [Table 5.5]. The flavor
profile showed a forward trend as temperature increased to 160-170°C whereas
increasing temperature caused a reduced sensory score due to core of Channa jalebi was
showed case hardening, poor sugar syrup absorption and crust got burnt flavor at high
67 temperature. The statistical scores of flavor revealed that there is no significant (P≤0.05)
difference in the product fried between 120-130°C and 180-200°C, while there was
significant difference between 140-150°C and 160-170°C from each other. Frying of
batter at 160-170°C (7.70) produced a final product which was superior quality of flavor
than those fried at 120-130°C, 140-150°C, and 180-200°C. Flavor changes in product
were due to increased rate of non-enzymatic browning (Maillard) reactions between
proteins and reducing sugars during frying [75]. It is well known that frying temperature
significantly contributes to the flavor of milk products. This could be also attributed that
the typical fatty acids balance in butter fat. During deep-fat frying the food is
completely surrounded by the frying fat or oil and different events occur within a few
minutes: dehydration of food surface, absorption of fat, formation of flavor compounds,
development of surface color, etc [81].
iii. Body and texture
The average body and texture scores of different frying temperatures (120-
130°C, 140-150°C, 160-170°C and 180-200°C) were 6.30, 6.95, 8.11 and 6.60
respectively (Table 5.5). The texture of product is influenced by the type of oil used,
frying temperature and time. Crispiness is an important textural characteristic of fried
foods. Crispiness indicates freshness and high quality [82]. For example, a crisp fried
food should be firm and should snap easily when deformed, emitting a crunchy sound
[83]. Same case was observed in Chhana jalebi fried at 160-170°C. Lower temperature
(120-130°C for 4-5 min and 140-150°C for 3-4 min) of frying resulted in chewy texture,
more oil absorption, hard surface and higher frying temperature (180-200°C for 40-50
sec) resulted in case hardening. The optimal temperature of frying i.e. 160-170°C for 1-
2 min gave crispy texture, light golden color and pleasant flavor. The body and texture
score of the product prepared from 120-130°C, 140-150°C and 160-170°C were
statistically increased from 6.30 to 8.11 whereas further increase of frying temperature
such as 180-200°C was statistically decreasing score to 6.60 at (P≤0.05). Hence 160-
170°C frying temperature was giving good score on body and texture of the product.
iv. Overall acceptability
The overall acceptability of the product was also changed according to frying
temperature. The average scores varied from 6.50, 6.95, 8.00 and 6.60 for 120-130°C,
140-150°C, 160-170°C and 180-200°C respectively. The pleasant flavor, crispy body of
68 the product was obtained at 160-170°C which resulted in maximum acceptability score
of the product. The Chhana jalebi samples fried at 160-170°C scored maximum
followed by the samples fried at 140-150°C, 180-200°C and120-130°C. It was also
observed that the scores differ significantly (P≤0.05) due to the variation of four
different temperatures of frying. However, the overall acceptability scores did not differ
significantly (P≤0.05) between the product fried at 120-130°C, 140-150°C and also
between the product fried at 180-200°C.
Considering the time taken for frying and sensory attributes, the temperature
combination of 160-170°C for 1-2 min was found to be better for the desired crispy
body and texture for frying of Chhana jalebi. Bajaj et al., (2002) [65] found that frying
of maida jalebi at 165-175°C for 2-3 min resulted in good product with uniform brown
colored surface. Nawale pratik (2010) [13] was found that frying of khoa jalebi at 160-
165°C for 2-3 min resulted in good flavor and uniform product.
5.1.4 Optimization of sugar syrup soaking conditions for Chhana jalebi
The concentration of sugar syrup not only provides taste and correct sweetness
of the product but also has an influence on soaking characteristics of sugar syrup, shelf
life and commercial value. In addition, effective soaking depends on temperature of
syrup and time of soaking. Therefore, an attempt was made to find out suitable soaking
conditions for uniform absorption of sugar syrup in a minimum time.
The Chhana made from 3% fat content of milk was used in batter making by
mixing with other ingredients such as maida and water. For comparing the effect of
sugar syrup soaking conditions, all other factors such as level of Chhana- maida ratio
(1:1), baking soda (0.25%), corn flour (4%), hydration time (3 hr), and frying
temperature 160-170°C for 1-2 min were kept constant. The fried units were kept
dipped in sugar syrup of 50, 60, 70 and 80°Brix with the constant time and temperature
of 1 min at 60°C. The product soaked in 50 and 80°Brix had showed less sweet, soggy
body and texture, poor sugar syrup absorption and too sweet, poor sugar syrup
absorption respectively. It was found that 60 to 70°Brix products gave good sensory
scores. Again, 63, 65 and 68°C Brix were taken to find out exact sugar syrup
concentration. It was found that 68°Brix concentrated sugar syrup was given slightly
low sweetness, medium sugar syrup absorption than the other sugar syrup
concentration.
69
Then soaking time was optimized by using 1, 2, 3 and 4 min for 68°Brix
concentrated sugar syrup with constant temperature of 60°C. It was found that 2 min
soaking time had showed optimal sweetness, desirable sugar syrup absorption, optimum
body and texture.
Then temperature was optimized by using 50, 60, 70 and 80°C with sugar syrup
concentration of 68°Brix and 2 min soaking time. It was observed that temperature of
60°C was given good sensory scores. Thus, it was concluded that concentration of
sugar syrup of 68°Brix with 2 min of soaking time at temperature of 60°C showed
optimum sweet and sugar syrup absorption.
The prepared Chhana jalebi was evaluated for sensory quality such as color and
appearance, flavor, body and texture, overall acceptability using 9-point hedonic scale.
Ideally a good quality Chhana jalebi should have a golden brown color, crispy texture,
rich flavor and sweet taste. The comments of evaluators also recorded. The results are
presented in Table no 5.7.
i. Color and appearance
It concluded that the average scores of color and appearance of different
concentration (50, 60, 65, 68, 70, and 80°Brix) sugar syrup was 7.75 and there was no
statistical significant among them (Table 5.7). Based on the sensory score determined
that color and appearance of Chhana jalebi was not dependent on sugar syrup
concentration. The color of jalebi mainly due to browning of products during frying and
those products are mainly derivatives of proteins and interaction with carbohydrates.
The golden brown color was observed in 50, 60, 65, 68, 70, and 80°Brix sugar syrup
concentrations as similar. Hence, it indicates that there is no impact of sugar syrup
concentrations on color and appearance of the product.
ii. Flavor
The flavor scores for sugar syrup concentration 50, 60, 65, 68, 70, and 80°Brix
were 6.90, 7.34, 8.17, 8.70, 7.17 and 6.53 respectively (Table 5.7). It observed that the
sugar syrup concentration had significant influence on flavor of the product (Table 5.8).
The flavor score of the product prepared from 50°Brix was 6.90 which increased to 8.70
for 68°Brix sugar syrup concentration whereas sugar syrup concentration increased to
80°Brix, the scores significantly decreased to 6.53 (P≤0.05).
70
Table 5.7 Effect of sugar syrup on sensory score* (max 9.0) of Chhana jalebi
Sugar syrup concentrations (°Brix)
Parameters 50 60 65 68 70 80 CD
P≤0.05)
CA 7.75±0.36NS 7.75±0.23NS 7.75±0.31NS 7.75±0.23NS 7.75±0.36NS 7.75±0.47NS 0.23
FL 6.90±0.74a 7.34±0.55a 8.17±0.18bc 8.70±0.13c 7.17±0.74ab 6.53±0.84a 0.59
BT 6.96±0.84a 7.30±0.44a 7.34±0.47ab 8.12±0.45bc 7.50±0.50a 7.20±0.57a 0.4
OA 6.93±0.72a 7.10±0.74a 7.14±0.77a 7.92±0.68b 6.90±0.74a 6.80±0.75a 0.44
* Average three trials; Note: Values with different superscripts are differ significantly at P<0.05; CA-Color and appearance, FL-Flavor, BT-Body and texture, OA-Overall acceptability; NS-Non significant
Table 5.8 Statistical report (ANOVA) of the effect of sugar syrup on sensory score
(max 9.0) of Chhana jalebi
Source DfCA FL BT OA
MSS F MSS F MSS F MSS F
Judges 4 0.589 24.348 1.186 6.002 1.300 14.147 2.734 24.415
Sugar syrup concentration 5 0.000 0.000NS 3.336 16.881* 0.843 9.176* 0.852 7.612*
Error 20 0.024 - 0.197 - 0.091 - 0.111 -
Total 29 - - - - - - - -
* Significant at 5 % level; CA-Color and appearance, FL-Flavor, BT-Body and texture, OA-Overall acceptability; NS-Non significant
Based on the observation, there was no significant difference between 60°Brix
and 70⁰Brix sugar syrup concentration for 1 min. But the reasons are 60°Brix had less
sweet, low sugar syrup absorption and 70°Brix had high sweetness, slightly low sugar
syrup absorption. But 68°Brix for 2 min had showed optimal sweetness, desirable sugar
syrup absorption, crispiness and more juiciness. Both increasing and decreasing of sugar
syrup concentrations resulted in less acceptable taste of the jalebi. Hence, in these study
68°Brix sugar syrup concentrations for 2 min was taken.
71 iii. Body and texture
The body and texture scores for sugar syrup concentration of 50, 60, 65, 68, 70,
and 80°Brix jalebi samples were 6.96, 7.30, 7.34, 8.12, 7.50 and 7.20 respectively. The
sugar syrup concentration had significant influence on body and texture. It observed that
the body and texture scores were increased as sugar syrup concentration increased. The
lower sugar syrup concentration of 50°Brix, 60°Brix and 65°Brix for 2 min gave soggy
texture, whereas the product prepared with higher sugar syrup concentration of 70°Brix
and 80°Brix for 2 min resulted in firmer body. The sugar syrup concentration of 50, 60,
65, 68, 70, 80°Brix for 1 min gave poor sugar syrup absorption whereas jalebi samples
of same concentration for 3 and 4 min, resulted high sugar syrup absorption, sweetness
and soggy body and texture.
iv. Overall acceptability
It determined that the overall acceptability scores of jalebi prepared with
different sugar syrup concentration 50, 60, 65, 68, 70 and 80°Brix were 6.93, 7.10, 7.14,
7.92, 6.90, and 6.80 respectively (Table 5.8). It found that the sugar syrup concentration
had significant influence on body and texture. It may be also observed that the overall
acceptability scores increased as sugar syrup concentration was increased from 50°Brix
to 68⁰ Brix. The body and texture score of the product prepared from 50°Brix was 6.90
which increased to 7.92 for 68°Brix sugar syrup concentration when the sugar syrup
concentration increased to 80°Brix the scores significantly decreased to 6.90 and
thereafter to 6.80 (P≤0.05). Based on the observation, there was no significant
difference between 60°Brix and 65°Brix sugar syrup concentrations for 1 min. In
generally in milk products, the low sugar syrup contributes to the soggy texture whereas
in the present study the product prepared with higher sugar syrup exhibited hard body
that was due to interaction of proteins and fats specifically casein and fat during frying
at high temperature. Based on the observation it was concluded that 68°Brix sugar syrup
concentrations for 2 min selected for the jalebi preparation.
5.1.5 Optimization of Chhana maida combination
Maida plays a vital role in Chhana jalebi making by acting as binding agent. The
binding agents affect the composition, rheology and sensory attributes of the
product. It also influences holding capacity of dough with its ingredients taste
72 and binds with moisture. In Chhana jalebi preparation, maida was used as a binding
agent.
Table 5.9 Effect of Chhana and maida combination based on sensory score of Chhana jalebi
Mai
da (g
)
Sensory attributes scored on 9-point hedonic scale
Chhana (g)
Parameters 15 30 45 60
CD
(P≤0
.05)
=0.4
7
Colour and appearance
20 7.00±0.0b 7.44±0.48a 6.71±0.35a 6.80±0.44a
30 6.64±0.41ab 7.64±0.58a 6.86±0.45a 6.81±0.29a
40 6.47±0.33a 7.46±0.45a 6.90±0.54a 7.19±0.41a
50 6.47±0.33a 7.36±0.35a 6.96±0.44a 7.83±0.45b
60 6.14±0.31a 7.32±0.34a 6.77±0.47a 8.10±0.37b
70 6.14±0.31a 7.30±0.34a 6.54±0.33a 7.820.311b
Flavour
20 7.20±0.27bc 7.76±0.43a 6.51±0.36a 6.90±0.37a
CD
(P≤0
.05)
=0.5
4
30 6.60±0.49ab 8.13±0.41ab 6.79±0.35a 6.87±0.18a
40 6.43±0.40a 7.69±0.43a 6.83±0.43a 7.32±0.35a
50 6.42±0.42a 7.55±0.37a 6.91±0.47a 7.92±0.49b
60 6.09±0.35a 7.45±0.30a 6.75±0.51a 8.30±0.43b
70 5.94±0.60a 7.27±0.30a 6.44±0.32a 7.97±0.21b
Body and texture
20 7.18±0.69a 7.86±0.21a 6.47±0.31a 6.76±0.50a
CD
(P≤0
.05)
=0.4
1
30 7.33±0.84ab 8.08±0.51ab 6.71±0.41a 6.93±0.46a
40 7.22±0.89a 7.89±0.21a 7.00±0.58ab 7.19±0.41ab
50 7.18±0.87a 7.76±0.17a 6.83±0.32a 7.71±0.61bc
60 7.07±0.79a 7.59±0.30a 6.82±0.48a 8.10±0.37b
70 6.83±0.77a 7.51±0.40a 6.66±0.37a 7.82±0.31b
Overall acceptability
20 7.18±0.69a 7.84±0.23b 6.68±0.35a 6.90±0.54aC
D (P
≤0.0
5)=0
.24
30 7.02±0.72a 8.27±0.22bc 6.75±0.41a 6.99±0.52a
40 6.88±0.73a 7.98±0.10b 7.20±0.20a 7.23±0.41a
50 6.74±0.66a 7.82±0.10b 6.73±0.33a 7.82±0.67ab
60 6.74±0.66a 7.72±0.30ab 6.72±0.37a 8.31±0.33b
70 6.64 ±0.61a 7.64±0.40ab 6.60±0.34a 7.92±0.21b
Note: Values with different superscripts are differ significantly at P<0.05
In order to select the suitable ratio of binding agent for best quality product,
maida was added as a 20, 30, 40, 50, 60 and 70 g in Chhana obtained from 3% fat milk.
The desirable good quality of Chhana jalebi should have a golden brown color, crispy
73 texture, rich flavor and sweet taste. The comments of evaluators were recorded and
presented in Table 5.9.
i Overall acceptability
Addition of maida and Chhana ratio of 1:1 ratio resulted in best quality product
with crispy body and uniform texture. Addition of lower quantity maida and higher
quantity of Chhana produced a product which was more brittle and coil disintegration
during frying. Higher quantity maida and lower quantity of Chhana resulted chewy and
more firm product. It also influenced syrup holding capacity of fried dough along with
its ingredients during soaking process. It is evident from Table 2 that increase of maida
levels from 20 g to 70 g showed significant difference in scores and increase of Chhana
levels from 15 g to 60 g had also showed significant difference in them. It may be
observed that all the combinations of Chhana-maida ratio had significant influence on
overall acceptance of the product. The ANOVA revealed the same (P≤0.05). Maida is a
common binding agent used in dairy products like gulabjamun [84], Chhana podo [85]
and pantua [86] in which it helps in obtaining the typical shape and texture for which
the products are well known.
Table 5.10 Statistical report (ANOVA) of the effect of Chhana maida combination
on overall acceptance score (max 9.0) of Chhana jalebi
Source of variation SS df MS F P-value F crit CD
p<0.05
Chhana 22.498 3 7.499 33.220* 8.15 2.699 0.24
Maida 0.492 5 0.098 0.436NS 0.822 2.309 0.24
Interaction between Chhana and maida 9.590 15 0.639 2.831* 0.001 1.771 0.60
Error 21.672 96 0.225
Total 54.254 119
* Significant at 5 % level; NS-Non significant
74
The average sensory scores of overall acceptability scores are represented in
Table 5.9. These data were again statistically analyzed and ANOVA of sensory scores
is presented in Table 5.10.
The average minimum score of overall acceptance score was 6.60 and the
maximum score was 8.27. As per the Table, it was clearly showed that increase of
maida levels from 20 g to 70 g on the product had no significant difference. But
increase of Chhana levels from 15 g to 60 g on the product had significant difference. It
may be observed that all the combination of Chhana and maida ratio had significant
influence on overall acceptance of the product. The ANOVA also reveals that there was
significant (P≤0.05) difference between products made by using different combination
of Chhana and maida ratios are presented in statistical Table 5.10.
5.1.6. Optimized process of Chhana jalebi production
Chhana jalebi was manufactured based on the optimized specifications of
individual processing parameters. The flow chart is provided in Figure 5.1 and
photographs of the same are given in Figure 5.2. The optimized process includes
preparation of Chhana from 3% fat level milk (Figure 5.2 – 1), mixing of Chhana
(Figure 5.2 – 3) with equal quantity of hydrated maida, baking soda (0.25%), corn flour
(4%) and water to form a smooth and uniform consistency batter (Figure 5.2 – 5).
The well kneaded batter (Figure 5.2 – 4) was extruded through an aperture of
soft PET bottle to give a coiled shape (Figure 5.2 – 6). Extruded batter coils were fried
in hot refined sunflower oil for deep frying (Figure 5.2 – 7) at 160-170°C for 2 min.
Sugar syrup was prepared by boiling 1:1 ratio (v/v) of sugar and water (Figure 5.2 – 8).
The fried products were then soaked in sugar syrup with 68°Brix for 2 min of soaking
time at temperature of 60°C (Figure 5.2 – 9). Then the soaked jalebi coils were drained
out of sugar syrup and packed in packaging material followed by it (Figure 5.2 – 10)
was analyzed for its physico-chemical, microbial, textural and sensory characteristics..
75
* Parameters were standardized
Figure 5.1 Flow chart for optimized process of Chhana jalebi production
Filtration/Clarification
Packaging and Storage
Mixing of maida (25.5%) and water (44.75%)*
Deep frying(160-170°C for 2 min)*
Soaking in sugar syrup (68ºBrix at 60ºC for 2 min)*
Chhana jalebi
Extrusion through an aperture of a soft PET bottle*
Addition of Chhana (25.5%), corn flour (4%), baking soda (0.25%),
and formation of batter*
Hydration time (3 hr)
Chhana
Straining
Setting of coagulum (15 min)
Cooling to 80°C
Addition of citric acid (2%)
Heating to 90°C
Standardization of milk(3% fat and 8.5% SNF)
Reception of milk
76
Figure 5.2 Standardization of Chhana jalebi
1
6
2
3 4
5
77
Figure 5.2 (Continued)
Figure 5.2 Standardization of Chhana Jalebi
1. Milk (3% fat level)
2. Coagulation of milk
3. Chhana
4. Jalebi batter (After mixing of all ingredients and hydration time)
5. Batter consistency
6. Extrusion of jalebi coils through aperture
7. Frying in oil
8. Sugar syrup
9. Soaking of Chhana jalebi in sugar syrup
10. Chhana jalebi (Standardized product)
7 8
9 10
78 5.2 CHARACTERIZATION OF THE STANDARDIZED CHHANA JALEBI
PRODUCTION
After the production of optimized Chhana jalebi it was analyzed for various
physical characteristics such as weight, thickness, diameter, sugar absorption, oil
absorption, pH, acidity; Chemical characteristics such as moisture content, fat,
carbohydrate, protein, sucrose, ash and water activity; Textural characteristics such as
hardness, fracturability, cohesiveness, adhesiveness, springiness, chewiness,
gumminess; sensory characteristics such as color and appearance, flavor, body and
texture, overall acceptability; color determination by L*, a* and b* values etc. The
mean values of mentioned characteristics are given in Table 5.11.
5.2.1 Physical characteristics of standardized Chhana jalebi
Based on the results, it was concluded that the standardized Chhana jalebi
samples were golden yellow in color and coil shaped, crispy with porous core, slightly
juicy with syrup oozing out when chewed, having high protein and fat content, and
fracturability that is brittle in nature (Table 5.11). The overall acceptability score was
above 8.5, which indicates that the product was ‘liked extremely’ and highly acceptable
[87]. It consists of 2 coils with diameter of each coil being 0.81±0.09. The diameter of
each jalebi unit is 6.51±0.48. Weight of each Chhana jalebi unit before soaking in sugar
syrup after frying was 5.1±0.22g, whereas after soaking in sugar syrup each unit weighs
5.1±0.22g. The final product was crispy with porous core, slightly juicy with syrup
oozing out when chewed. Titratable acidity was found to be 0.310±0.01 expressed as
percentage of lactic acid and pH of Chhana jalebi was 5.05±0.07. It shows that Chhana
jalebi sample was acidic in nature. Similar observations were observed in khoa jalebi
and other jalebi samples [10, 14, 78].
79
Table 5.11 Quality characteristics of standardized Chhana jalebi
Quality characteristicsMean value with SD
Quality characteristics
Mean value with SD
Physical characteristics Proximate composition (%)
Weight of jalebi, g 5.1±0.22 Carbohydrate 67.11±0.19
Thickness of jalebi, cm 0.81±0.09 Protein 5.71±0.202
Diameter of jalebi, cm 6.51±0.48 Fat 12.53±0.17
Sugar syrup absorbed by each jalebi (g)
2.77±0.20 Ash 0.29±0.06
Oil absorbed by each jalebi (g) 1.57±0.04 Moisture 20.23±0.25
Chemical CharacteristicsSucrose 40.21±0.30
pH 5.05±0.07
Acidity (% of lactic acid) 0.310±0.01 Textural characteristics
Water activity 0.825±0.002 Hardness (N) 0.028±0.003
Sensory characteristics (9-Point scale) Fracturability (N) 1.38±0.584
Colour and appearance 8.98±0.16 Cohesiveness 0.438±0.109
Flavour 8.98±0.16 Adhesiveness (Ns) -0.012±0.008
Body and Texture 8.98±0.34 Springiness 0.694±0.101
Overall acceptability 8.98±0.23 Chewiness 0.008±0.003
Color characteristics Gumminess 15.82±1.416
L* 51.04±1.47 Microbial characteristics
a* 10.35±0.29 SPC (log 10 cfu/g) 3.26±0.81
b* 29.97±2.66 Yeast and mold(log 10 cfu/g)
0.41±0.89
80 5.2.2 Proximate composition of standardized Chhana jalebi
Chhana jalebi sample had shown the protein content of 5.71%, fat content of
12.53% and total carbohydrate content of 67.11%. The moisture content was estimated
to be 20.23%. The ash content and water activity was determined as 0.29% and 0.82
respectively (Fig 5.3). Same observations were obtained by Pagote et al., (2012) [10],
Rewa Kumari et al., (2012) [14] and Chakkaravarthi et al., (2009b) [78].
Figure 5.3 Proximate composition of Chhana jalebi
5.2.3 Texture profile characteristics of standardized Chhana jalebi
Textural characteristics analysis is one of the significant analyses for food
products in order to know consumption comfort ability of the food. Various textural
characteristics such as hardness, adhesiveness, springiness, cohesiveness and chewiness
were analyzed for Chhana jalebi (Figure 5.4) [88-90]. Gumminess and chewiness are
mutually exclusive characteristics since gumminess applicable for semi solid food and
chewiness is applicable for solid food. Since Chhana jalebi is considered as solid food,
chewiness was analyzed. Textural analysis was done for fresh samples on 0th day.
Hardness of the product was found as 0.028 ± 0.003 N. This indicates that, 0.028
Newton force is required to compress the Chhana jalebi in order to deform the product.
Protein5.71%
Fat12.53%
Carbohydrate67.11%
Moisture20.23%
Ash0.29%
81
Adhesiveness of the product was measured as –0.012±0.008 Ns and concluded
that -0.012 Newton-seconds energy is required to overcome attractive forces between
food and contact surface. This was due to sugar syrup coating on the product.
Springiness of the product was determined as 0.694±0.101. This denotes that, 0.694
elastic distance was recovered when the compressive force is removed. In other way,
15.82±1.416 was recovered in product’s original shape (gumminess) after the
deformation. It is not 100% recovery of product’s original deformation. It was because
of fried product and total milk solids, but 15.82 distances was recovered due to elastic
product in a maida which is gluten. Similar studies were carried out in khoa jalebi
samples by Pagote et al., (2012) [10].
Cohesiveness of the product was identified as 0.438±0.109. This indicates that,
strength of internal bonds in a Chhana jalebi was 0.438. It is actually very less
compared to other food products. It is due to consistency of batter. Since consistency of
batter was like gel in nature, weaker internal bond was formed during frying of the
product. Moreover, since sugar syrup was also percolated in to the product, strength of
internal bonds was reduced. Chewiness of the product was measured as 0.008±0.003.
This value reveals that, the energy required to chew a Chhana jalebi solid food in to
convert in the state ready for swallowing is 0.0.08. It is actually, energy required to
mellow the product to convert semi solid state from the solid state in order to swallow
the product [88-90].
Figure 5.4 Textural characteristics graph of Chhana jalebi
82
Based on textural characteristics it revealed that, fresh sample of final
standardized Chhana jalebi was little crispy, smooth and soft in nature. In overall
product was suitable and comfortable for human consumption.
5.2.4 Color characteristics of standardized Chhana jalebi
Table 5.11 shows the Hunter parameter (L*, a*, b*) for Chhana jalebi sample.
Color analysis of four jalebi samples was done and the average for ‘L*’, ‘a*’ and ‘b*’
was taken. From the analysis it was observed that all values are in positive .The mean
value of L* value was 51.04±1.47, it indicates that Chhana jalebi samples have bright
colour and a* value for all the samples were 10.35±0.29, which proves that the product
was little orange-ish and ‘b*’ value was 29.97±2.66, which proves that the sample was
brown in colour (Figure 5.5). Similar results were observed in maida jalebi [10, 88-90].
Hence we concluded from this analysis Chhana jalebi samples shown golden brown in
color.
Figure 5.5 Hunter color lab analysis for Chhana jalebi
5.2.5 Sensory characteristics of standardized Chhana jalebi
The final product was given to 15 panel members for sensory analysis according
to 9 point hedonic scale and the scores obtained showed that the final product has all the
desirable characters. The color of the product was golden yellow with the score of
8.98±0.16, taste of the product was also very good with score of 8.98±0.16 and flavor
was also pleasant with score of 8.98±0.16. Texture was crispy and juicy because of
83 syrup with a score of 8.98±0.34 [89-91]. The overall acceptability was good with a
score of 8.98±0.23. Table 5.11 shows the average sensory analysis score given by 15
panel members. The overall acceptability score was above 8.5 out of 9, it indicates that
the product was “like extremely” range and acceptable.
5.2.6 Microbial characteristics of standardized Chhana jalebi
Microbiological analysis for the standardized Chhana jalebi was done by
standard plate count and yeast and mold count. The Chhana jalebi had a standard plate
count of 3.26±0.81 log10 cfu/g and yeast and mold count of 0.41±0.89 log10 cfu/g (Table
5.11). Presently there is no microbiological standard for the products like Chhana jalebi;
however for Chhana (material used for Chhana jalebi preparation) standards are
available [21]. In this regard, the results obtained in this study may be helpful for the
formulating microbiological standards for the jalebi in future. These microbial results
were supported with another research carried out by Nawale Pratik (2010) [13] on khoa
jalebi. Dyuthi (2009) [25] also reported that similar results for Chhana jhili in his
Research work.
5.2.7 Shear thinning efficiency of batter
Shear thinning efficiency of batter was measured by using rheometer. Batter was
prepared and kept required sample on rheometer platform. It was operated, through
which graph with values was received from the monitor [93]. Same analyses were
repeated around 20 times and mean value with standard deviation was taken for arriving
final value. Resultant graph was accomplished by using final mean values. Based on the
graph following values were identified. Viscosity was 2.76±1.27 Pa.S; Shear rate was
55.05±28.01 1/S and Shear stress was 121.5±26.41. This graph was clearly showing the
indirect proportion relationship between viscosity and shear rate, i.e. shear rate increases
viscosity decreases. From these results, it is clearly indicated that the prepared jalebi has
shear thinning rate / shear thinning efficiency which gives exact batter consistency for
making jalebi coils.
84
PART-II: SHELF LIFE ENHANCEMENT BY USING PRESERVATIVES
5.3 PRESERVATIVE STUDIES OF STANDARDIZED CHHANA JALEBI
This part is discussing about shelf life enhancement by preservatives. Three
types of preservatives were utilized in this study viz., potassium sorbate, sodium
benzoate and potassium meta-bi-sulphite. Preservatives treated Chhana jalebi samples
were kept under two different temperature conditions such as ambient and refrigerated
temperatures. Sensory analysis, regression analysis and trend line model parameters
were analyzed in order to determine more suitable preservative.
5.3.1 Effect of preservatives on the changes in Chhana jalebi during storage
Chhana jalebi was manufactured based on optimized process as shown in Figure
1. It was observed that Chhana jalebi packed in low density polyethylene (LDPE) pouch
without preservative could stay in good condition and quality up to 4 days at room
temperature (28°±2°C), whereas it could be stored up to 15 days at refrigerated
temperature (4±2°C). Hence efforts were made to enhance the shelf life using permitted
preservatives. This will pave a way for commercial marketing. Chhana jalebi was
prepared with and without the preservative and packed in low barrier packaging
materials viz., LDPE.
During preliminary trials, three preservatives namely potassium sorbate [13, 25,
56], sodium benzoate [13, 25] and potassium meta-bi-sulphite [94] were tried. During
storage at ambient temperature, the staleness and lack of freshness were observed after
8 days in the samples which contained potassium meta-bi-sulphite (500 ppm) and after
12 days in the samples which contained sodium benzoate (500 ppm), whereas no
abnormal flavor was noticed in the samples containing potassium sorbate (500 ppm)
even after 12 days on the basis of sensory evaluation. This was attributed to the
differences in their mechanism of action. Sodium benzoate is active against yeast and
mold and bacteria at low pH levels, while potassium meta-bi-sulphite is not much
effective against yeast and mold whereas sodium benzoate and potassium sorbate shows
more effective against bacteria, yeast and mold at the low pH levels of Chhana jalebi.
Similar results were observed in other studies. [96-99].
Hence, potassium meta-bi-sulphite was excluded from this study among three
preservatives and remaining two preservatives with different levels were tried for
85 further investigations. Potassium sorbate with 600 ppm, 800 ppm and 1000 ppm levels
and sodium benzoate with 100 ppm, 200 ppm and 300 ppm levels were tried for
enhancement of shelf life of Chhana jalebi [95]. They were added in different
concentrations in sugar syrup. The low density poly ethylene (LDPE) packaging
materials were sterilized by exposing to UV light for 45 min before packaging Chhana
jalebi. About 50g Chhana jalebi was packed in LDPE pouches and stored at both
ambient (28±2°C) and refrigerated temperatures (4±2°C). At the interval of every
alternate day the packets were cut opened and evaluated for sensory acceptance. Finally
it would be determined that more effective and suitable preservative along with its
concentration for giving more shelf life to the product.
5.3.2. Effect of sodium benzoate on standardized Chhana jalebi
In order to enhance the shelf life, a commonly used permitted class II
preservative viz. sodium benzoate was used, which was dissolved in sugar syrup. This
concentration is well below the permitted levels of the preservative in milk based sweets
i.e. 300 ppm [21]. It acts against bacteria, yeasts and molds by alteration of cell
membranes, inhibition of transport systems and key enzymes, creation of a proton flux
into the cell, or more than one of these actions [101]. Hence sodium benzoate was
chosen for studying the preservative effect with three different levels viz. 100 ppm, 200
ppm and 300 ppm.
i. Color and appearance
The color and appearance scores of the jalebi during storage as influenced by
benzoate level are presented in Table 5.12. It was clearly understood from the sensory
report that as storage day increased the sensory score of color and appearance was
decreased irrespective to the preservative level. Similar results were observed in other
Researchers [13, 99]. The means score decreased from the initial value of 8.96 to 1.83 at
the end of 14 days of storage at room temperature. In control without preservative the
score was 7.58 on 4th day and which drastically decreased to 2.2 on 6th day storage. This
was due extensive mold growth was observed inside the package. At 100 ppm, 200
ppm, 300 ppm preservative level the scores were 6.58, 6.53 and 7.2 at the end of 8, 10
and 10 days respectively. It is indicating that the shelf life was 8, 10 and 10 days for 100
ppm, 200 ppm, 300 ppm of sodium benzoate respectively. This was determined by
taking the minimum score of 6.5 as acceptable limit. It concludes that as preservative
86 level significantly increased the color and appearance scores when storage period
increased. The mean scores were 4.36, 5.69, 6.56 and 7.24 respectively for control, 100
ppm, 200 ppm, 300 ppm of benzoate. These scores were statistically significant from
each other. These may be attributed to the effect of benzoate on mold growth. The
ANOVA indicates the significant effect of preservative and storage period and their
interaction (P≤0.05).
Table 5.12 Changes in color and appearance score* of Chhana jalebi samples
treated with different concentrations of sodium benzoate at ambient temperature
(28±2°C)
Sodium
benzoate
Storage days at 28±2°C
0 2 4 6 8 10 12 14 CD=1.54
Control 8.97 8.52 7.58 - - - - - 4.36a
100 ppm 8.99 8.51 8.12 7.71 6.58 - - - 5.69a
200 ppm 8.92 8.82 8.53 8.50 7.21 6.53 - - 6.56ab
300 ppm 8.94 8.72 8.52 8.42 7.52 7.20 - - 7.24b
CD=2.17 8.96cd 8.64c 8.19c 6.71bc 5.88b 4.48ab
*Average three trials; Note 1: Values with different superscripts are differ significantly
at P≤0.05. Note 2: - indicates sample discarded.
The sodium benzoate is a common preservative used normally in high acid foods
to prevent the spoilage from yeast and mold [25]. The pH of Chhana jalebi was around
5.0 at which the benzoate may be effective though may not optimum.
87
Table 5.13 Changes in color and appearance score* of Chhana jalebi samples
treated with different concentrations of sodium benzoate at refrigerated
temperature (4±2°C)
Sodium benzoate
Storage days at 4±2°C
0 5 10 15 20 25 30 35 CD=1.04
Control 8.99 8.94 6.92 6.50 - - - - 4.66a
100 ppm 8.99 8.98 8.95 7.77 7.87 - - - 6.97b
200 ppm 8.98 8.92 8.9 8.59 7.93 6.69 - - 7.35b
300 ppm 8.97 8.96 8.95 8.79 7.92 7.85 - - 7.73b
CD=1.48 8.98b 8.95bd 7.93b 7.41bc 6.85b 5.58ab 4.49a -
*Average three trials; Note 1: Values with different superscripts are differ significantly
at P≤0.05. Note 2: - indicates sample discarded.
Based on observation, the changes observed in the sensory score of color and
appearances of the product stored at 4±2°C are presented in table 5.13. In refrigerated
storage temperature (4±2°C) also, the effect of storage period, preservative level and
their interaction found to be significant as was observed at 28°C. The Color and
appearance score remained 6.5 and above for control, 100 ppm, 200 ppm, 300 ppm
products were 15, 20, 25 and 28 days at 4°C respectively these were observed higher
than at 28°C [13, 25].
ii. Flavor
The flavor scores of the jalebi during storage as influenced by benzoate level are
presented in Table 5.14. It concluded that as storage day increased the sensory score of
flavor was decreased irrespective of the preservative level. Similar reported by other
Researchers [13]. The means score decreased from the initial value of 8.96 to 1.85 at
the end of 14 days of storage at room temperature. The control (without preservative)
score of 4th day was 7.50 which drastically decreased to 2.3 on 6th day. This was due to
extensive mold growth observed inside the package. At 100 ppm, 200 ppm, 300 ppm
preservative level the scores were 6.55, 6.50 and 7.0 at the end of 6, 7 and 10 days
88 respectively. It is indicating that the shelf life was 6, 7 and 10 days respectively. This
was determined by taking the minimum score of 6.5 as acceptable limit. It can also
observe from the Table 5.13 that as preservative level significant increased the flavor
scores irrespective to storage period. The mean scores were 4.31, 5.53, 6.37 and 7.26
respectively for control, 100 ppm, 200 ppm, 300 ppm of benzoate. These scores were
statistically significant from each other. These may be attributed to the effect of
benzoate on mold growth [25]. The ANOVA indicates the significant effect of
preservative and storage period and their interaction (P≤0.05).
Table 5.14 Changes in the flavor score* of Chhana jalebi samples treated with
different concentrations of sodium benzoate at ambient temperature (28±2°C)
Sodium benzoate
Storage days at 28±2°C
0 2 4 6 8 10 12 14 CD=1.46
Control 8.98 8.57 7.50 - - - - - 4.31a
100 ppm 8.99 8.57 8.50 6.55 - - - - 5.53a
200 ppm 8.91 8.84 8.51 8.43 - - - - 6.37ab
300 ppm 8.95 8.87 8.52 8.47 7.51 7.00 - - 7.26b
CD=2.06 8.96c 8.71c 8.26cd 6.44bc 5.49b 4.31ab - -
*Average three trials; Note 1: Values with different superscripts are differ significantly
at P≤0.05. Note 2: - indicates sample discarded.
Based on observation, the changes observed in the sensory score of flavor of the
product stored at 4°C are presented in Table 5.15. At this storage temperature also the
effect of storage period, preservative level and their interaction found to be significant
as was observed at 28°C. In that period within which the flavor score remained 6.5 and
above for control, 100 ppm, 200 ppm, 300 ppm products were 15, 20, 25 and 28 days at
4°C respectively these were observed higher than 28°C storage.
89
Table 5.15 Changes in the flavor score* of Chhana jalebi samples treated with
different concentrations of sodium benzoate at refrigerated temperature (4±2°C)
Sodium benzoate
Storage days at 4±2°C
0 5 10 15 20 25 30 35 CD=1.13
Control 8.98 8.95 6.91 - - - - - 4.54a
100 ppm 8.97 8.97 8.95 7.55 7.85 - - - 6.71b
200 ppm 8.95 8.93 8.92 8.68 7.71 6.69 - - 7.25b
300 ppm 8.96 8.92 8.95 8.60 7.96 7.82 - - 7.65b
CD=1.59 8.97b 8.94bcd 7.93b 7.26bc 6.76b 5.43ab - -
*Average three trials; Note 1: Values with different superscripts are differ significantly
at P≤0.05. Note 2: - indicates sample discarded.
iii. Body and texture
The body and texture scores of the jalebi during storage as influenced by
benzoate level are presented in Table 5.16. It is clearly understood from the Table 5.16
that as storage day increased the sensory score of body and texture was decreased
irrespective of the preservative level, some of the Researchers also reported similar
results in their studies [25]. The means score decreased from the initial value of 8.94 to
1.92 at the end of 14 days of storage at room temperature. Increase of control that is
without preservative the score of 2nd day was 8.53 which drastically decreased to 2.5 on
6th day. It may be due extensive mold growth observed inside the package. At 100 ppm,
200 ppm, 300 ppm preservative level, the scores were 6.50, 6.53and 6.50 at the end of
6, 7 and 10 days respectively. It is indicating that the shelf life was 6, 7 and 10 days
respectively. This was determined by taking the minimum score of 6.5 as acceptable
limit. It can also observe that preservative level significantly increases the body and
texture scores irrespective to storage period. The mean scores were 4.25, 5.52, 6.51 and
7.12 respectively for control, 100 ppm, 200 ppm, 300 ppm of benzoate and scores were
statistically significant from each other. These may be attributed to the effect of
benzoate on mold growth [13]. The ANOVA indicates the significant effect of
preservative and storage period and their interaction (P≤0.05).
90
Table 5.16 Changes in the body and texture score* of Chhana jalebi samples
treated with different concentrations of sodium benzoate at ambient temperature
(28±2°C)
Sodium benzoate
Storage days at 28±2°C
0 2 4 6 8 10 12 14 CD=1.32
Control 8.97 8.53 - - - - - - 4.25a
100 ppm 8.91 8.58 8.01 6.50 - - - - 5.52a
200 ppm 8.94 8.93 8.91 8.90 6.54 - - - 6.51ab
300 ppm 8.94 8.91 8.87 8.73 7.55 6.50 - - 7.12b
cd=1.87 8.94c 8.73cd 7.95c 6.65bc 5.51b 4.25ab - -
*Average three trials; Note 1: Values with different superscripts are differ significantly
at P≤0.05. Note 2: - indicates sample discarded.
Table 5.17 Changes in the body and texture score* of Chhana jalebi samples
treated with different concentrations of sodium benzoate at refrigerated
temperature (4±2°C)
Sodium benzoate
Storage days at 4±2°C
0 5 10 15 20 25 30 35 CD=1.11
Control 8.95 8.93 7.02 6.90 - - - - 4.58a
100 ppm 8.98 8.98 8.95 7.79 7.89 - - - 6.64b
200 ppm 8.99 8.92 8.90 8.69 7.75 6.52 - - 7.20b
300 ppm 8.97 8.91 8.93 8.64 7.91 6.55 - - 7.48b
CD=1.57 8.97c 8.94cd 7.93b 7.26c 6.76bc 4.95ab
*Average three trials; Note 1: Values with different superscripts are differ significantly
at P≤0.05. Note 2: - indicates sample discarded.
91
Based on observation, the changes observed in the sensory score of body and
textures of the product stored at 4°C are presented in Table 5.17. In that period within
which the body and texture score remained 6.5 and above for control, 100 ppm, 200
ppm, 300 ppm products were 15, 20, 25 and 25 days at 4°C respectively which was
higher than 28°C.
iv. Overall acceptability
The overall acceptability scores of jalebi during storage as influenced by
benzoate level are presented in Table 5.18. If the storage day increased, the sensory
score of overall acceptability was decreased irrespective to the preservative level. These
findings are correlated with previous Researchers [13, 25]. The means score decreased
from the initial value of 8.96 to 1.77 at the end of 14 days of storage at room
temperature. The control without preservative the score of 2nd day was 8.54 which was
drastically decreased to 2.4 on 6th day due to extensive mold growth inside the package.
At 100 ppm, 200 ppm and 300 ppm preservative level, the scores were 7.21, 6.81and
6.50 at the end of 6, 10 and 10 days respectively and concluded the shelf life of product.
This was determined by taking the minimum score of 6.5 as acceptable limit. It was
observe that as preservative level increased significant level of overall acceptability
scores also increased irrespective of storage period. The mean scores were 4.32, 5.58,
6.66 and 7.01 for control, 100 ppm, 200 ppm, 300 ppm of benzoate respectively and
scores were statistically significant. These may be due to the effect of benzoate on mold
growth [25, 99]. The ANOVA indicates the significant effect of preservative and
storage period and their interaction (P≤0.05).
The changes observed in the sensory score of flavor of the product stored at 4°C
are expressed in Table 5.19. The effect of storage temperature (28°C), storage period,
preservative level and their interaction found to be significant In that period within
which the flavor score remained 6.5 and above for control, 100 ppm,200 ppm, 300 ppm
products were 15, 20, 25 and 28 days at 4°C respectively.
Based on the observation, it was concluded that control and 100 ppm,200 ppm,
300 ppm of sodium benzoate treated samples had 4, 6,10 and 10 days respectively at
28±2°C and 15, 20, 25 and 28 days at 4±2°C respectively.
92
Table 5.18 Changes in the overall acceptability score* of Chhana jalebi samples
treated with different concentrations of sodium benzoate at ambient temperature
(28±2°C)
Sodium benzoate
Storage days at 28±2°C
0 2 4 6 8 10 12 14 CD=1.40
Control 8.99 8.54 7.14 - - - - - 4.32a
100 ppm 8.98 8.58 8.19 7.21 - - - - 5.58a
200 ppm 8.92 8.97 8.93 8.90 6.81 - - - 6.66ab
300 ppm 8.97 8.85 8.50 8.41 7.55 6.50 - - 7.01b
CD=1.98 8.96c 8.73cd 8.19c 6.73bc 5.64b 4.37ab - -
*Average three trials; Note 1: Values with different superscripts are differ significantly
at P≤0.05. Note 2: - indicates sample discarded.
Table 5.19 Changes in the overall acceptability score* of Chhana jalebi samples
treated with different concentrations of sodium benzoate at refrigerated
temperature (4±2°C)
Sodium benzoate
Storage days at 4±2°C
0 5 10 15 20 25 30 35 CD=1.30
Control 8.98 8.94 6.93 6.50 - - - - 4.07a
100 ppm 8.98 8.98 8.95 7.79 6.58 - - - 6.44b
200 ppm 8.97 8.94 8.95 8.65 7.53 6.70 - - 7.22b
300 ppm 8.96 8.95 8.95 8.77 7.98 7.55 - - 7.72b
CD=1.84 8.97c 8.95cd 7.95bc 6.93bc 6.07b 5.09ab
*Average three trials; Note 1: Values with different superscripts are differ significantly
at P≤0.05. Note 2: - indicates sample discarded.
93 5.3.3 Effect of potasium sorbate on standardized Chhana jalebi
In order to enhance the shelf life, a commonly used permitted class II
preservative viz., potassium sorbate was used, which was dissolved in sugar syrup. The
concentration is well below the permitted levels of the preservative in milk based sweets
i.e. 1000 ppm [21]. It acts against bacteria, yeasts and molds by alteration of cell
membranes, inhibition of transport systems and key enzymes, creation of a proton flux
into the cell, or more than one of these actions [101]. Hence potassium sorbate was also
chosen for studying the preservative effect with three different levels viz. 600 ppm, 800
ppm and 1000 ppm.
i. Color and appearance
The color and appearance scores of jalebi during storage as influenced by
sorbate level are represented in Table 5.20. The sensory score of color and appearance
was decreased when storage day increased irrespective to the level of preservative [13,
25]. The means score decreased from the initial value of 8.99 to 2.05 at the end of 22
days of storage at room temperature. In case of control that is without preservative the
score of 4th day were 6.45 which drastically decreased to 6.45 on 4th day due to
extensive mold growth inside the package. At 600 ppm, 800 ppm, 1000 ppm
preservative level the scores were 6.57, 6.71 and 6.78 at the end of 12, 14 and 16 days
respectively and it indicates shelf life of the product. This was determined by taking the
minimum score of 6.5 as acceptable limit. It can be also observed that as preservative
level, significantly increased the scores of color and appearance irrespective to storage
period. The mean scores were 4.08, 6.26, 6.95 and 7.54 for control, 600 ppm, 800 ppm,
1000 ppm of sorbate respectively. These may be due to the effect of sorbate on mold
growth [100-102]. The ANOVA indicates the significant effect of preservative and
storage period and their interaction (P≤0.05).
The sensory score of color and appearance of the product stored at 4°C are
expressed in Table 5.21. The effect of storage temperature (28°C and 4°C), storage
period, preservative level and their interaction were found to be significant. Similar
results were obtained by other Researchers [56, 95]. In that period within which the
color and appearance score remained 6.5 and above for control, 600 ppm, 800 ppm,
1000 ppm products were 15, 30, 45 and 60 days at 4°C respectively which was higher
than 28°C.
94
Tabl
e 5.
20 C
hang
es in
the
colo
r an
d ap
pear
ance
scor
e* o
f Chh
ana
jale
bi sa
mpl
es tr
eate
d w
ith d
iffer
ent
conc
entr
atio
ns o
f pot
assiu
m so
rbat
e at
am
bien
t tem
pera
ture
(28±
2°C
)
Pota
ssiu
m so
rbat
eSt
orag
e da
ys a
t 28±
2°C
CD
=0.9
70
24
68
1012
1416
1820
22
Con
trol
8.99
7.57
--
--
--
--
--
4.08
a
600
ppm
8.99
8.98
8.92
8.95
8.55
7.80
6.57
--
--
-6.
26b
800
ppm
8.99
8.95
8.94
8.75
8.55
7.95
7.60
6.71
--
--
6.95
bc
1000
ppm
8.99
8.97
8.95
8.85
8.57
8.48
8.35
7.50
6.78
--
-7.
54c
CD
=1.6
98.
99c
8.61
c8.
31b
7.93
b7.
51bc
6.78
ab6.
23ac
5.75
ab4.
82a
*Ave
rage
thre
e tri
als;
Not
e 1:
Val
ues w
ith d
iffer
ent s
uper
scrip
ts a
re d
iffer
sig
nific
antly
at P
≤0.0
5. N
ote
2: -
indi
cate
s sam
ple
disc
arde
d.
95 Table 5.21 Changes in the color and appearance score* of Chhana jalebi samples
treated with different concentrations of potassium sorbate at refrigerated
temperature (4±2°C)
Potassium sorbate
Storage days at 4±2°C
0 15 30 45 60 75 CD=2.03
Control 8.98 - - - - - 3.67a
600 ppm 8.99 7.34 6.67 - - - 4.77a
800 ppm 8.99 8.93 7.43 6.52 - - 5.98ab
1000 ppm 8.99 8.97 8.94 7.97 6.52 - 7.27b
CD=2.48 8.99bc 7.18b 6.36b 4.77ab 3.28a
*Average three trials; Note 1: Values with different superscripts are differ significantly at P≤0.05. Note 2: - indicates sample discarded.
ii. Flavor
The flavor scores of jalebi during storage as influenced by sorbate level are
represented in Table 5.22. It clearly understood from the Table 5.22 that as storage day
increased the sensory score of flavor was decreased irrespective to the preservative
level. Previous findings were correlated with our finding [13, 25]. The means score
decreased from the initial value of 8.98 to 1.92 at the end of 22 days of storage at room
temperature. Increase of control that is without preservative the score of 2nd day was
7.58 which drastically decreased to 1.70 on 22nd day. This was probably due to
extensive mold growth. At level, the scores were 6.58, 6.52 and 6.59 at the end of 12, 14
and 16 days respectively. The shelf life was determined by taking the minimum score of
6.5 as acceptable limit and determined as 12, 14 and 16 days for 600 ppm, 800 ppm and
1000 ppm preservative samples respectively. Based on the observation it concluded that
the preservative level significantly increased the flavor scores irrespective to storage
period. The mean scores were 3.96, 6.18, 6.91 and 7.49 respectively for control, 600
ppm, 800 ppm, 1000 ppm of potassium sorbate. These may be due to the effect of
potassium sorbate on mold growth [100-102]. The ANOVA indicates the significant
effect of preservative and storage period and their interaction (P≤0.05).
96
Tabl
e 5.
22 C
hang
es in
the
flavo
r sc
ore*
of C
hhan
a ja
lebi
sam
ples
trea
ted
with
diff
eren
t con
cent
ratio
ns o
f pot
assiu
m so
rbat
e at
am
bien
t
tem
pera
ture
(28±
2°C
)
Pota
ssiu
m
Sorb
ate
Stor
age
days
at 2
8±2°
C
02
46
810
1214
1618
2022
CD
=1.0
2
Con
trol
8.98
7.58
--
--
--
--
--
3.96
a
600
ppm
8.98
8.96
8.94
8.93
8.57
7.87
6.58
--
--
-6.
18b
800
ppm
8.99
8.96
8.92
8.71
8.57
7.96
7.62
6.52
--
--
6.91
b
1000
ppm
8.98
8.96
8.95
8.84
8.59
8.45
8.32
7.40
6.59
--
-7.
49bc
CD
=1.7
78.
98c
8.61
c8.
28ab
7.82
ac7.
48ac
6.72
ab6.
25ac
5.60
ab4.
66a
*Ave
rage
thre
e tri
als;
Not
e 1:
Val
ues w
ith d
iffer
ent s
uper
scrip
ts a
re d
iffer
sig
nific
antly
at P
≤0.0
5. N
ote
2: -
indi
cate
s sam
ple
disc
arde
d.
97
Based on observation, the changes observed in the sensory score of flavor of the
product stored at 4°C are presented in Table 5.23. At this storage temperature (4°C)
also, the effect of storage period, preservative level and their interaction found to be
significant as was observed at 28°C.
Table 5.23 Changes in the flavor score*of Chhana jalebi samples treated with
different concentrations of potassium sorbate at refrigerated temperature (4±2°C)
Potassium
sorbate
Storage days at 4±2°CCD=2.06
0 15 30 45 60 75
Control 8.97 6.57 - - - - 3.56a
600 ppm 8.98 7.35 6.68 - - - 4.77a
800 ppm 8.97 8.94 7.47 - - - 5.94ab
1000 ppm 8.98 8.97 8.95 7.97 6.53 - 7.23b
CD=2.52 8.98c 7.21bc 6.33c 4.68ab 3.18a -
*Average three trials; Note 1: Values with different superscripts are differ significantly
at P≤0.05. Note 2: - indicates sample discarded.
These results are correlated with previous report [25, 56]. In that period within
which the flavor score remained 6.5 and above for control, 600 ppm, 800 ppm, 1000
ppm products were 15, 30, 45 and 60 days at 4°C respectively these were observed
higher than 28°C.
iii. Body and Texture
The body and texture scores of the jalebi during storage as influenced by sorbate
level are represented in Table 5.24. It was concluded that when storage day increased,
the sensory score of body and texture was decreased irrespective to the preservative
level. The means score was decreased from the initial value of 8.97 to 2.12 at the end of
22 days of storage at room temperature.
98
Tab
le 5
.24
Cha
nges
in th
e bo
dy a
nd te
xtur
e* sc
ore
of C
hhan
a ja
lebi
sam
ples
trea
ted
with
diff
eren
t con
cent
ratio
ns o
f pot
assiu
m so
rbat
e at
ambi
ent t
empe
ratu
re (2
8±2°
C)
Pota
ssiu
m
Sorb
ate
Stor
age
days
at 2
8±2°
C
02
46
810
1214
1618
2022
CD
=1.0
3
Con
trol
8.98
7.55
--
--
--
--
--
3.96
a
600
ppm
8.97
8.95
8.94
8.91
8.58
7.88
6.7
--
--
-6.
25b
800
ppm
8.99
8.97
8.95
8.72
8.58
7.95
7.61
6.63
--
--
6.94
b
1000
ppm
8.97
8.94
8.92
8.81
8.59
8.47
8.34
7.51
6.65
--
-7.
50bc
CD
=1.7
88.
97c
8.60
c8.
31b
7.76
b7.
38bc
6.67
ab6.
26ac
5.68
ab4.
69a
*Ave
rage
thre
e tri
als;
Not
e 1:
Val
ues w
ith d
iffer
ent s
uper
scrip
ts a
re d
iffer
sig
nific
antly
at P
≤0.0
5. N
ote
2: -
indi
cate
s sam
ple
disc
arde
d.
99
The control (without preservative) score was 6.43 on 4thday which was
drastically decreased to 3.8 on 8th day due to the extensive mold growth inside the
package. At 600 ppm, 800 ppm and 1000 ppm preservative level, the scores were 6.70,
6.63 and 6.65 at the end of 12, 14 and 16 days respectively. The shelf life was
concluded as 12, 14 and 16 days for 600 ppm, 800 ppm and 1000 ppm respectively. The
shelf life was determined through base score of 6.5 as acceptable limit. The preservative
level significantly increased the body and texture scores irrespective to the storage
period. The mean scores were 3.96, 6.25, 6.94 and 7.50 respectively for control, 600
ppm, 800 ppm, 1000 ppm of potassium sorbate and were statistically significant from
each other. These might be inhibition effect of benzoate against mold growth [56, 95].
The ANOVA report described the significant effect of preservative and storage period
and their interaction (P≤0.05).
Based on observation, the changes observed in the sensory score of flavor of the
product stored at 4°C are expressed in Table 5.25. At this storage temperature, also the
effect of storage period, preservative level and their interaction were found to be
significant as observed at 28°C. During the storage period, the flavor score remained 6.5
and above for control, 600 ppm, 800 ppm and 1000 ppm products were 15, 30, 45 and
60 days at 4°C respectively these were higher than the 28°C storage period. Similar
results were reported by other Scientists [100-102].
Table 5.25 Changes in the body and texture score* of Chhana jalebi samples treated with different concentrations of potassium sorbate at refrigerated
temperature (4±2°C)
Potassium sorbate
Storage days at 4°CCD=2.00
0 15 30 45 60 75
Control 8.95 6.57 - - - - 3.69a
600 ppm 8.99 7.4 6.65 - - - 4.86a
800 ppm 8.98 8.89 7.46 6.51 - - 5.96ab
1000 ppm 8.97 8.97 8.94 7.96 6.52 - 7.21b
CD=2.46 8.97c 7.21bc 6.36b 4.72ab 3.33a
*Average three trials; Note 1: Values with different superscripts are differ significantly
at P≤0.05. Note 2: - indicates sample discarded.
100 iv. Overall acceptability
The overall acceptability scores of jalebi during storage period which was
influenced by sorbate level are represented in Table 5.26. When storage day increased
the sensory score of overall acceptability was decreased irrespective to the preservative
level and also similarly reported by some Scientists [13, 25]. The score was decreased
from the initial value of 8.98 to 1.80 at the end of 22 days of storage at room
temperature. The score of control without preservative was 6.37 on 4thday which was
drastically decreased to 4.4 on 6th day which was due to extensive mold growth inside
the package. At 600 ppm, 800 ppm and 1000 ppm preservative level the scores were
6.74, 6.73and 6.77 at the end of 12, 14 and 16 days respectively. It is indicating that the
shelf life was 12, 14 and 16 days respectively. This was determined by taking the
minimum score of 6.5 as acceptable limit. It can also observe from the Table 5.26 that
as preservative level increased significant level of body and texture scores irrespective
of storage period. The mean scores were 3.86, 6.02, 6.87 and 7.53 respectively for
control, 600 ppm, 800 ppm, 1000 ppm of sorbate. These scores were statistically
significant from each other. These may be attributed to the effect of benzoate on mold
growth [100-102]. The ANOVA indicates the significant effect of preservative and
storage period and their interaction (P≤0.05).
The changes observed in the sensory score of overall acceptability of the product
stored at 4°C are presented in Table 5.27. The effect of storage temperature and period,
preservative level and their interaction were to be obtained significant as observed as
28°C. In that period within which the flavor score remained 6.5 and above for control,
600 ppm, 800 ppm, 1000 ppm products were 15, 30, 45 and 60 days at 4°C respectively
these were observed as higher than 28°C and similar findings were reported by other
Researchers [56, 95].
101
Tab
le 5
.26
Cha
nges
in th
e ov
eral
l acc
epta
bilit
y sc
ore*
of C
hhan
a ja
lebi
sam
ples
trea
ted
with
diff
eren
t
conc
entr
atio
ns o
f pot
assiu
m so
rbat
e at
am
bien
t tem
pera
ture
(28±
2°C
)
Pota
ssiu
m
Sorb
ate
Stor
age
days
at 2
8°C
02
46
810
1214
1618
2022
CD
=1.
55
Con
trol
8.97
7.65
--
--
--
--
--
3.86
a
600
ppm
8.98
8.96
8.95
8.92
8.58
7.89
6.74
--
--
-6.
02a
800
ppm
8.99
8.97
8.95
8.72
8.58
7.96
7.62
6.73
--
--
6.87
b
1000
ppm
8.97
8.91
8.91
8.85
8.62
8.55
8.36
7.62
6.77
--
-7.
53b
CD
=1.9
98.
98c
8.62
b8.
30b
7.72
bc7.
35bc
6.70
b6.
26ac
5.69
ab4.
38a
4.15
ab2.
99a
*Ave
rage
thre
e tri
als;
Not
e 1:
Val
ues w
ith d
iffer
ent s
uper
scrip
ts a
re d
iffer
sig
nific
antly
at P
≤0.0
5. N
ote
2: -
indi
cate
s sam
ple
disc
arde
d.
102
Table 5.27 Changes in the overall acceptability score of Chhana jalebi samples
treated with different concentrations of potassium sorbate at refrigerated
temperature (4±2°C)
Potassium sorbate
Storage days at 4°CCD=2.09
0 15 30 45 60 75
Control 8.97 6.60 - - - - 3.56a
600 ppm 8.98 7.45 6.67 - - - 4.80a
800 ppm 8.98 8.90 7.50 6.53 - - 5.85ab
1000 ppm 8.97 8.97 8.95 7.97 6.62 - 7.26b
CD=2.56 8.98bc 7.23b 6.33b 4.73ab 3.13a
*Average three trials; Note 1: Values with different superscripts are differ significantly
at P≤0.05. Note 2: - indicates sample discarded.
Based on observation, it was concluded that control and 600 ppm, 800 ppm,
1000 ppm of potassium sorbate treated samples had 4, 12, 14 and 16 days respectively
at 28±2°C and 15, 30, 45 and 60 days at 4±2°C respectively.
Hence, among these two preservatives, potassium sorbate was assumed to be a
better preservative and selected for further investigation on the shelf life of Chhana
jalebi [13, 25, 56, 95]. This was attributed to the differences in their mechanism of
action [100-102]. Sodium benzoate is comparatively less active against yeast and mold
and bacteria at low pH levels. The spoilage of Chhana jalebi was mainly due to yeast
and mold, a preservative which is more effective against yeast and mold at the pH of
Chhana jalebi is needed, hence potassium sorbate was chosen as a suitable preservative
for Chhana jalebi (Figure 5.8-1 and Figure 5.8-2). Most of the other Research studies
were also suggested that potassium sorbate was a suitable preservative for dairy based
products [13, 25, 56, 95, 100-102]
Potassium sorbate contained samples of 800 ppm were showed 14 days without
any adverse effect on its body and texture, flavor, color and appearance. Despite the
longer shelf life (16 days) given by 1000 ppm of potassium sorbate was not preferred
due to the maximum permissible limit for the use of potassium sorbate in food materials
103 [21] and however the difference among the shelf life of 800 ppm and 1000 ppm of
product was just 2 days only. The control sample without preservative was also
analyzed in every 2 days interval and it gave shelf life of 2 days. Hence, 800 ppm of
potassium sorbate was selected for further investigation.
Related observations were found by Scientists that successfully employed the
potassium sorbate for preserving the khoa jalebi up to 15 and 25 days with a
concentration of 500 ppm and 1000 ppm at 30°C respectively [102]. Potassium sorbate
was also found to enhance the shelf life of another milk product, khoa [100].
5.3.4. Linear regression analysis for effects of preservatives on sensory scores of
Chhana jalebi samples stored for 10 days at ambient temperature (28±2°C)
Linear regression analysis was performed to identify preservative and
temperature effect among both sodium benzoate and potassium sorbate preservatives
under both ambient and refrigerated temperatures. Based on the above preservatives
analysis, it was determined that 800 ppm of potassium sorbate has given good
preservative effects than the other preservative and their levels. This was further
confirmed through linear regression analysis using Microsoft excel software and the
values are given in Table 5.28.
Table 5.28 Preservative effects based on linear regression with respect to sensory
scores of Chhana jalebi samples treated with sodium benzoate and potassium
sorbate stored for 10 days at ambient temperature (28±2°C)
Sensory attributes
Sodium benzoate (300 ppm) Potassium sorbate (800 ppm)
Slope value R2 value Slope value R2 value
CA 0.025 0.848 0.001 0.905
FL 0.024 0.863 0.001 0.863
BT 0.021 0.82 0.001 0.837
OA 0.0021 0.696 0.001 0.828
CA-Color and appearance, FL-Flavor, BT-Body and texture, OA-overall acceptability
104 Table 5.29 Temperature effects based on linear regression with respect to sensory
score of Chhana jalebi samples treated with sodium benzoate and potassium
sorbate stored for 10days at ambient temperature (28±2°C) and refrigerated
temperature (4±2°C)
Sensory attributes
Sodium benzoate (300 ppm) Potassium sorbate (800 ppm)
28±2°C 4±2°C 28±2°C 4±2°C
Slope value
R2
valueSlope value
R2
valueSlope value
R2
valueSlope value
R2
value
CA -0.374 0.738 -0.121 0.749 -0.3 0.8 -0.108 0.895
FL -0.376 0.756 -0.128 0.738 -0.306 0.788 -0.11 0.895
BT -0.434 0.813 -0.136 0.82 -0.302 0.804 -0.107 0.911
OA -0.433 0.825 -0.121 0.781 -0.318 0.818 -0.114 0.879
CA-Color and appearance, FL-Flavor, BT-Body and texture, OA-overall acceptability
From the Table 5.28 and 5.29, it was clearly indicated that less slope value and
high R2 value for potassium sorbate than sodium benzoate. Similar results were
observed by Pang et al., (2001) [103], June chan et al., (2012) [104] and Lee et al.,
(2014) [105]. Based on the results, it was concluded that potassium sorbate was given
more effect against microbial growth on Chhana jalebi samples than sodium benzoate.
Similarly, same effect was observed in refrigerated temperature than ambient
temperature of storage conditions.
5.3.5 Trend line analysis for tyrosine values of Chhana jalebi on changes of flavor
scores during storage at ambient temperature (28±2°C)
A graph was drawn between tyrosine value and flavor scores of Chhana jalebi.
Based on the resultant curve, various trend line model parameters such as exponential,
linear, logarithmic, polynomial and power were drawn in order to identify suitable
model through which changes of flavor scores could be addressed. Based on the
analysis it was found that, 118.8, -5.382, - 30.3, 0.548 and 397.0 as ‘a’ values, -0.35,
50.27, 70.31, -11.92 and -1.93 as ‘b’ values and 0.953, 0.975, 0.995, 0.992 and 0.912 as
R2 values for exponential, linear, logarithmic, polynomial and power trend line
parameters respectively (Figure 5.6).
105
Figure 5.6 Model parameters for tyrosine value versus flavor scores of Chhana
jalebi
This analysis reveals that R2 value of logarithmic model parameter was found to
be higher than the other parameters. Moreover, this analysis discovers that logarithmic
model parameter was more suitable than the other model parameters to address the
changes of flavor of Chhana jalebi during storage. Hence it was concluded that, tyrosine
values of the product was increased in terms of one log cycle while increasing of
storage days.
5.3.6 Trend line analysis for tyrosine values of Chhana jalebi on changes of
overall acceptability scores during storage at ambient temperature
Similarly a graph was drawn between tyrosine value and overall acceptability
scores of Chhana jalebi. Based on the resultant curve, various trend line model
parameters such as exponential, linear, logarithmic, polynomial and power were drawn
in order to identify suitable model through which changes of overall acceptability scores
was expressed.
y = -30.3ln(x) + 70.31R² = 0.995
y = 0.548x2 - 11.92x + 67.51R² = 0.992
y = 397.0x-1.93
R² = 0.912
y = -5.382x + 50.27R² = 0.975
y = 118.8e-0.35x
R² = 0.953
0
10
20
30
40
50
60
0 2 4 6 8 10
Tyro
sine
valu
e (m
g/10
0g)
Flavour scores (9-Point hedonic scale)
106
Figure 5.7 Model parameters for tyrosine value versus overall acceptability scores
of Chhana jalebi
Table 5.30 Trend line model parameters for both flavor and overall acceptability
scores of Chhana jalebi
ModelParameters
Flavor scores Overall acceptability scores
‘a’ value ‘b’value R2 value ‘a’ value ‘b’ value R2 value
Exponential 118.8 -0.35 0.953 123.8 -0.36 0.954
Linear -5.382 50.27 0.975 -5.290 49.57 0.978
Logarithmic -30.3 70.31 0.995 -29.9 69.53 0.995
Polynomial 0.548 - 11.92 0.992 0.479 - 11.08 0.993
Power 397.0 -1.93 0.912 431.4 -1.99 0.905
Based on the analysis it was found that, 123, -5.290, - 29.90, 0.479 and 431.4 as
‘a’ values, -0.36, 49.57, 69.53, -11.08 and -1.99 as ‘b’ values and 0.954, 0.978, 0.995,
0.993 and 0.905 as R2 values for exponential, linear, logarithmic, polynomial and power
trend line parameters respectively (Figure 5.7). This analysis reveals that R2 value of
logarithmic model parameter was found to be higher than the other parameters.
y = 123.8e-0.36x
R² = 0.954y = -5.290x + 49.57
R² = 0.978
y = -29.9ln(x) + 69.53R² = 0.995
y = 0.479x2 - 11.08x + 64.99R² = 0.993
y = 431.4x-1.99
R² = 0.905
0
10
20
30
40
50
60
0 2 4 6 8 10
Tyro
sine
valu
e (m
g/10
0g)
Overall acceptability scores (9-Point hedonic scale)
107
Moreover, this analysis discovers that logarithmic model parameter was more
suitable than the other model parameters to address the changes of overall acceptability
of Chhana jalebi during storage period. Hence it was concluded that, tyrosine values of
the product was increased in terms of one log cycle while increasing of storage days.
Similarly positive results were obtained by Peter et al., (2012) [106] in their Research.
Figure 5.8 Chhana jalebi without and with preservative added sample
1. Chhana jalebi samples treated with 800 ppm of potassium sorbate (Preservative) on 14th day
2. Chhana jalebi Control samples (Without Preservative) on 2nd day
1
2
108
PART – III: SHELF LIFE ENHANCEMENT BY USING DIFFERENT
PACKAGING MATERIALS
5.4. EFFECT OF PACKAGING MATERIAL ON CHARACTERISTIC
CHANGES IN CHHANA JALEBI
This part of study deals with the results obtained during investigation on shelf-
life enhancement of Chhana jalebi with different packaging materials and techniques.
The first phase of packaging study was involved with selection of suitable packaging
materials under two major categories like low barrier and high barrier at both ambient
(28±2°C) and refrigeration (4±2°C) temperatures. The second phase of packaging study
was conducted to increase the shelf-life by using Modified Atmospheric Packaging
(MAP) and vacuum packaging in Low Density Poly-Ethylene (LDPE) and Metalized
polyester (MET) packaging material.
The packaging materials were selected based on their properties and suitable
storage conditions. Barrier properties of packaging materials influence the shelf-life of
product when it is packed. Hence, two types of packaging materials were selected under
both low barrier and high barrier categories.
i. Low barrier packaging materials: Polystyrene cups covered with aluminum foil
and Cardboard box lined with butter paper (generally using for packaging of
sweets).
ii. High barrier packaging material: Metalized polyester (MET) and Low density
polyethylene (LDPE) Pouches
These packaging materials were sterilized by exposing to UV light for 45 min
before packaging Chhana jalebi. About 20g Chhana jalebi was packed in each
packaging materials and stored at both ambient (28±2°C) and refrigerated temperatures
(4±2°C). At the interval of every alternate day the packets were cut opened and
evaluated for sensory acceptance.
5.4.1 Basic observation of packaging materials
Four selected packaging materials such as polystyrene cups covered with
aluminum foil, cardboard box lined with butter paper, LDPE and metalized polyester
pouches were selected based on sensory comments of panel members.
109 Table 5.31 Sensory comments on Chhana jalebi packaged in low barrier materials
stored at 28±2°C for various days
Low Barrier Packaging Materials
Sensory comments on different storage period at 28±2°C
Second day Fourth day Sixth day
Polystyrene cups
covered with
aluminum foil
Rich in juiciness,
flavor,
acceptable body
and texture
All sensory parameter
was same except flavor
Lack of freshness
and less juicy and
slightly dry
Cardboard box
lined with butter
paper
Juicy, acceptable
flavor, body and
texture
Less juicy , lack of
freshness and slightly
dry
Sticky and slightly
mold growth
observed
Table 5.32 Sensory comments on Chhana jalebi packaged in high barrier materials and stored at 28±2°C for various days
High barrier packaging materials
Sensory comments on different storage period at 28±2°C
Third day Sixth day Ninth day
LDPE Pouch
with heat sealed
Juicy, Acceptable
flavor, Body and
texture
Lake of freshness and
slightly dry
Mould growth
observed
Metalized
polyester with
heat sealed
Rich in Juiciness,
flavor, acceptable
Body and texture
Juicy, Acceptable
flavor, Body and
texture
Less fresh but
good body and
texture
From Table 5.31 and 5.32, it was observed that Chhana jalebi packaged in low
barrier packaging materials such as polystyrene cups and cardboard box were stayed
well for up to 4 days at 28±2°C, however the product packaged in LDPE and metalized
polyester were remain good more than 5 days.
110
The following analysis were carried out to identify suitable packaging material
i. Physico-chemical characteristics such as pH, water activity, peroxide value and
tyrosine value
ii. Microbiological analysis such as standard plate count and yeast and mold count
iii. Sensory characteristics such as color and appearance, flavor, body and texture
and overall acceptability
5.4.2 Physico-chemical characteristics of Chhana jalebi stored in different
packaging materials
All four packaging materials were considered for analyzing the changes in
various physico-chemical characteristics viz., pH, water activity (aW), peroxide value
and tyrosine value of Chhana jalebi during storage at ambient temperatures 28±2°C.
There were changes in the physico-chemical characteristics of jalebi during storage
period. The initial pH of jalebi was 5.43 which declined during storage (Figure 5.9).
i. Changes in pH
In cardboard box lined with butter paper packed samples, the pH rate was
decreased rapidly. The pH decreased from initial value of 5.43 to 5.14, 5.12, 5.10 and
5.18 for LDPE pouch, metalized polyester, polystyrene cups covered with aluminum
foil and cardboard box lined with butter paper respectively on 30th day of storage at
28±2°C shown in Figure 5.9. Relatively gradual decreasing trend was observed in all
the packaging materials. Kumar et al., (1997) [108] also reported the decrease of pH in
peda during the storage period of 180 days at 20°C. Similar results were also observed
by Londhe et al., (2012) [107] in their brown peda. This may be due to the growth of
yeast and molds and a few water activity tolerant bacteria.
111
Figure 5.9 Effect of packaging materials on pH of Chhana jalebi during storage at
28±2°C
ii. Changes in water activity
The changes in average value of water activity of Chhana jalebi packed in four
different packaged materials with preservative treated samples are illustrated in Figure
5.10. The curves in Figure 5.10 clearly reveal that with progress in storage period, the
water activity of Chhana jalebi decreased from 0.88 to 0.858, 0.851, 0.827 and 0.866 for
LDPE pouch, metalized polyester, polystyrene cups covered with aluminum foil and
cardboard box lined with butter paper respectively on 30th day of storage at 28±2°C.
Hence, it concluded that the growth of microorganism was possible. This could be
attributed to moisture loss through the packaging material or within the packaging
material. This also had a bearing on the body and texture attribute. From graph, it was
clearly understood that all the packaging material samples water activity score were
above 8.0. Similar observations were found in khoa jalebi and khoa samples [39,91].
4.9
5
5.1
5.2
5.3
5.4
5.5
0 10 20 30
pH v
alue
Storage days
LDPE pouches
Polystyrene cups covered with aluminum foil
Cardboard box lined with butter paper
Metalized polyester
112
Figure 5.10 Effect of packaging materials on water activity of Chhana jalebi during storage at 28±2°C
iii. Changes in peroxide value
The Chhana jalebi samples were analysed for peroxide value in terms of free
fatty acids (FFAs) expressed as ml/g of product with a view to monitor lipolytic changes
during storage [109]. Though the milk lipase, which hydrolysed milk fat and produce
lower chain fatty acid, gets inactivated during Chhana jalebi manufacture. Other lipase
is produced by the bacteria and yeast and mold during storage and thus causes increase
in free fatty acid. The excessive production of free fatty acid causes impact on rancid
flavor and defect in dairy based products. There was gradual increase in peroxide
content of Chhana jalebi sample irrespective to packaging materials.
Figure 5.11 Effect of packaging materials on peroxide value of Chhana jalebi during storage at 28±2°C
0.80.810.820.830.840.850.860.870.880.89
0 10 20 30
Wat
er a
ctiv
ity
Storage days
LDPE pouches
Polystyrene cups covered with aluminum foilCardboard box lined with butter paperMetalized polyester
00.5
11.5
22.5
3
0 10 20 30
Pero
xide
val
ue (
ml/g
)
Storage days
LDPE pouches
Polystyrene cups covered with aluminum foilCardboard box lined with butter paper
Metalized polyester
113
The rate of increase of peroxide value was maximum in LDPE pouch and metalized polyester samples. The peroxide value increases from initial value of 0.35 to 2.80 ml/g of product during 30 days of storage shown in Figure 5.11 at 28±2°C. The rate of increase of peroxide value in polyester cup and cardboard box lined with butter paper was less as compared to LDPE pouch and metalized polyester sample. Value of cardboard box lined with butter paper and metalized polyester samples varied from initial value of 0.35 to 1.90 ml/g of product whereas LDPE pouch and polystyrene cups covered with aluminum foil varied from 0.35 to 2.8 ml/g of product during 30 days storage at 28±2°C. Based on the sensory scores, acceptable peroxide values for final product were identified in the range up to 0.73 ml/g of product. Based on observation, it concluded that the LDPE pouch, metalized polyester, cardboard box and polystyrene cup packed samples shelf life were 20 days. During 20 days, all packed samples tyrosine value was 0.73ml /g of product. After 20 days, peroxide value of all the samples were considered as not acceptable limit based on acceptable level of sensory scores which is 6.5. Despite steady increase in FFAs in all samples during storage, none of the samples was found to have rancid flavor indicating that the level of free fatty acid production was not to that level which causes serious defect. Kumar et al., (1997) [108] also observed increasing trend in free fatty acid during storage of peda under different packaging technique however the rate of increase was different. Palit and Dharam Pal (2005) [109] also reported that the rate of increase in free fatty acid was high in control sample of burfi and lowest in vacuum packaged samples. Navajeevan and Rao (2005) [110] reported an increase trend in free fatty acid of retort processed kunda during storage at elevated temperature.
iv. Changes in tyrosine value
Tyrosine value showed a gradual increase during storage. The Chhana jalebi samples were analyzed for the value in terms of mg/100g of product with a view to monitor proteolysis during storage. This increase in tyrosine value may be attributed to the breakdown of proteins by the surviving micro flora or their enzymes [109]. The proteolytic enzymes break the protein down to simpler forms thereby increasing the amount of tyrosine in the product. It may also be attributed to heat stable proteolytic enzymes which survived the heat treatment. Microbial cells of lysis due to heat treated release enzymes from their cell walls, which may act on proteins [111].
114
Figure 5.12 Effect of packaging materials on peroxide value of Chhana jalebi during storage at 28±2°C
There was a gradual increase in tyrosine value in all type of treatment of Chhana
jalebi sample irrespective to packaging materials. The rate of increase of tyrosine value
was higher in LDPE pouch and metalized polyester samples. The tyrosine value
increases from initial value of 3.00 to 21.75 mg/100g of product during 30 days of
storage at 28±2°C (Figure 5.12). The rate of increase of tyrosine value in polyester cup
and cardboard box lined with butter paper was less as compared to LDPE pouch and
metalized polyester sample. Value of polyester cup and cardboard box lined with butter
paper samples varied from initial value of 3.00 to 35.40 mg/100g of product during 30
days of storage at 28±2°C (Figure 5.12). Based on the sensory scores, acceptable
tyrosine values for final product were identified in the range up to 13.30 mg/100g of
product. Based on observation, it concluded that the LDPE pouch, metalized polyester,
cardboard box and polystyrene cup packed samples had the shelf life of 20 days. The
tyrosine values of all packed samples were 13.30 mg/100g of product upto 20 days.
After 20 days, tyrosine value of all the samples were considered as not acceptable limit
based on acceptable level of sensory scores which is 6.5. Similar results were observed
by Goyal et al., (1989a) [112] in khoa samples.
05
10152025303540
0 10 20 30
Tyro
sine
Valu
es
(mg/
100g
)
Storage days
LDPE pouches
Polystyrene cups covered with aluminum foilCardboard box lined with butter paper
Metalized polyester
115 5.4.3 Microbiological characteristics of Chhana jalebi stored in different
packaging materials
Chhana jalebi stored in various packaging materials such as polystyrene cups
covered with aluminum foil, cardboard box lined with butter paper, LDPE and
metalized polyester were considered for analyzing the changes in microbial
characteristics viz., standard plate count (SPC) and yeast and mold count of Chhana
jalebi during storage at ambient temperatures 28±2°C.
i. Changes in standard plate count (SPC)
The observation relating to the standard plate count (in log10 values) of Chhana
jalebi samples packed and stored at 28±2°C is illustrated in Figure 5.13. The total
bacterial count was increased disrespected to the storage period.
The standard plate count of jalebi samples in LDPE pouch without gas flush,
metalized polyester without gas flush, polystyrene cups covered with aluminum foil and
cardboard box lined with butter paper was increased from 3.26 log10 cfu/g on 0th day to
5.28, 4.62, 5.90 and 6.51 respectively on 20th day of storage at 28±2°C. Based on
sensory scores, it concluded that above mentioned SPC values were considered as an
acceptable limit for Chhana jalebi. In the 30 day storage, the SPC count was found
higher in all the samples and spoiled due to contamination from packaging system and
environment. The microorganisms are favorable to grow at the room temperature and
increase their population. Majority of the yeasts and mold and bacteria got destroyed
due to heat treatment. The survivors and contaminants acted on sugars and produced
acids and reduced the pH over the period of storage. The microbial growth was higher
in cardboard box lined with butter paper as compared to metalized polyester without gas
flush treated sample. Earlier Researchers also reported an increasing trend in standard
plate counts of burfi during storage period [113-116].
116
Figure 5.13 Effect of packaging materials on standard plate count (SPC) of Chhana jalebi during storage at 28±2°C
ii. Changes in yeast and mold
Yeast and mold growth tend to be major problem for most of the intermediate
food (e.g. khoa jalebi, peda, burfi, kalakand). Often it is the most single factor limiting
their shelf-life. With a view to improve the shelf-life of Chhana jalebi, the 800 ppm
level of preservative treated sample were packed in LDPE pouch without gas flush,
metalized polyester without gas flush, polystyrene cups covered with aluminum foil and
cardboard box lined with butter paper. The yeast and mold count was increased when
storage days increased. The result showed the increase in log10 counts during storage at
28±2°C (Figure 5.14). The initial count of yeast and mold was 0.41 for all the samples.
The yeast and mold count increases from initial value of 0.41 to 1.21, 0.88, 1.46 and
1.67 log10 cfu/g for LDPE pouch without gas flush, metalized polyester without gas
flush, polystyrene cups covered with aluminum foil and cardboard box lined with butter
paper respectively on 20th day of storage at 28±2°C shown in Figure 5.14.
02468
1012141618
0 10 20 30
Stan
dard
pla
te c
ount
(l og1
0cfu
/g)
Storage days
LDPE pouches
Polystyrene cups covered with aluminum foilCardboard box lined with butter paper
Metalized polyester
117
Figure 5.14 Effect of packaging materials on yeast and mold count of Chhana
jalebi during storage at 28±2°C
Based on results it concluded that above mentioned yeast and mold count were
considered as acceptable limits for Chhana jalebi upto 20 days. After that microbial
count of the samples were found higher in all the samples and spoiled due to
contamination from packaging system and environment. Similar results were obtained
by Garg (1987) [115] and Mishra (1988) [116] in burfi samples.
5.4.4 Sensory characteristics of Chhana jalebi stored in different packaging
materials
Sensory characteristics such as color and appearance, flavor and body and
texture were analyzed for the standardized Chhana jalebi with and without addition of
800 ppm potassium sorbate stored in different packaging materials such as polystyrene
cups covered with aluminum foil, cardboard box lined with butter paper, LDPE and
metalized polyester at both ambient (28±2°C) and refrigerated temperatures (4±2°C).
0
1
2
3
4
5
6
7
8
0 10 20 30
Yeas
t and
mol
d co
unt (
log 1
0cfu
/g)
Storage days
LDPE pouches
Polystyrene cups covered with aluminum foil
Cardboard box lined with butter paper
Metalized polyester
118 i. Changes in color and appearance
The color and appearance scores of the jalebi during storage was influenced by
four different packaging materials are presented in Table 5.33. It is clearly understood
from the Table 5.33 that, as storage days increased, the sensory score of color and
appearance was decreased irrespective to the packaging material used. The packet was
opened and visual appearance was recorded. It observed that the original light brown
colour was retained throughout the storage period, however colour and appearance
scores decreased mainly due to visible mold growth [91]. The scores at the end of 4th
day were 7.21, 7.23, 6.76 and 6.43, respectively for LDPE pouch, metalized polyester,
polystyrene cups covered with aluminum foil, cardboard box lined with butter paper
(Table 5.30). As the storage period increased, the product appeared dry probably
because of moisture evaporation through the packaging material itself in all packaging
materials except metallized polyester and LDPE pouches which are being good barrier
[117].
Table 5.33 Changes in color and appearance score* of Chhana jalebi control
samples packed in various packaging materials stored at ambient temperature
(28±2°C)
Packaging materialsControl samples stored at 28±2°C (days)
0 2 4 6 CD=0.43
LDPE pouch 8.91 8.21 7.21 4.33 7.17b
Metalized polyester 8.95 8.31 7.23 4.54 7.26b
Polystyrene cups 8.94 7.47 6.76 3.33 6.63a
Cardboard box lined with butter paper 8.93 7.45 6.43 3.54 6.59a
CD=0.43 8.93d 7.86c 6.90b 3.93a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
119
Table 5.34 Changes in color and appearance score* of 800 ppm of potassium
sorbate treated Chhana jalebi samples packed in various packaging materials
stored at ambient temperature (28±2°C)
Packaging materials
Preservative added samples stored at 28±2°C (days)
0 10 20 30 CD=0.77
LDPE pouch 8.91 7.41 6.50 3.13 6.48a
Metalized polyester 8.95 8.62 6.67 5.10 7.33ab
Polystyrene cups 8.94 8.12 6.53 3.63 6.80a
Cardboard box lined with butter paper 8.93 8.32 5.53 3.66 6.61a
CD=0.77 8.93d 8.11c 6.30b 3.88a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
It can also been observed from the Table 5.33, as low barrier and high barrier
packaging material had significant level of color and appearance scores irrespective to
storage period. The mean scores were 7.17, 7.26, 6.63 and 6.59 for LDPE pouch,
metalized polyester, polystyrene cups covered with aluminum foil, cardboard box lined
with butter paper respectively. These scores were statistically significant to low barrier
and high barrier packaging materials. These may be attributed to the effect of packaging
material on mold growth. The ANOVA indicates the significant effect of packaging
material and storage period and their interaction (P≤0.05).
The sensory scores decreased during storage as indicated in Table 5.34. The
initial colour and appearance score of preservative treated samples was 8.91, 8.95, 8.94
and 8.93 which declined to 6.50, 6.67, 6.53 and 5.53 at the end of 20 days for LDPE
pouch, metalized polyester, polystyrene cups covered with aluminum foil, cardboard
box lined with butter paper respectively. Thereafter, all the colour and appearance
scores decreased to below acceptable limits. In general, the jalebi became dry due to
evaporation of moisture either through the packaging material or within packaging
material. However, after 20 days the visible mold growth was observed and the product
appearance dry.
120
Table 5.35 Changes in color and appearance score* of 800 ppm of potassium
sorbate treated Chhana jalebi samples packed in various packaging materials
stored at refrigerated temperature (4±2°C)
Packaging materials
Preservative added samples stored at 4±2°C(days)
0 15 30 45 60 CD=0.33
LDPE pouch 8.91 8.71 8.42 8.16 7.90 8.42a
Metalized polyester 8.91 8.90 8.78 8.77 8.69 8.81b
Polystyrene cups 8.91 8.44 8.29 7.60 7.30 8.11a
Cardboard box lined with butter paper 8.91 8.66 8.38 8.20 7.72 8.37a
CD=0.37 8.91c 8.68bc 8.47ab 8.18a 7.90a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
Based on the observation, changes observed in the sensory score of color and
appearance of 800 ppm potassium sorbate treated samples were packed in all four types
of packaging materials and stored at 28°C and 4°C were presented in Table 5.33 and
5.34. At these storage temperatures, the effect of storage period, packaging material and
their interaction found to be significant as was observed at 28°C and 4°C. In that period
within which the color and appearance score remained 6.5 and above for LDPE pouch,
metalized polyester, polystyrene cups covered with aluminum foil packed products until
20 days; whereas cardboard box lined with butter paper samples were minimum of 10
days at 28°C and 60 days at 4°C for all materials. These may be attributed to the effect
of packaging material on mold growth [119]. The ANOVA indicates the significant
effect of packaging material and storage period and their interaction (P≤0.05).
ii. Changes in flavor
The flavor scores of jalebi during storage as influenced by four different
packaging materials are presented in Table 5.33. It is clearly understood from the Table
5.36 that as storage day increased, the sensory score of flavor was decreased
irrespective to the packaging material. The means score decreased from the initial value
of 8.94 to 3.66 at the end of 6 days of storage at room temperature. In case of
121 polystyrene cups covered with aluminum foil and cardboard box lined with butter paper
packed product score of 4th day was 6.74 and 6.41 respectively, which drastically
decreased to 3.62 and 3.46 on 6th day respectively. The LDPE pouch and metalized
polyester scores were 6.63 and 7.21 at the end of 4th day respectively. It is indicating
that the shelf life was 4 days, after this period due to mold growth the flavor turned to
unacceptable condition. This was determined by taking the minimum score of 6.5 as
acceptable limit.
Table 5.36 Changes in flavor score* of Chhana jalebi control samples packed in
stored at ambient temperature (28±2°C)
Packaging materialsControl samples stored at 28±2°C (days)
0 2 4 6 Avg. mean
LDPE pouch 8.91 8.32 6.63 4.32 7.05 NS
Metalized polyester 8.95 8.32 7.21 3.22 6.93NS
Polystyrene cups 8.95 7.43 6.74 3.62 6.69NS
Cardboard box lined with butter paper 8.95 7.41 6.41 3.46 6.56NS
CD=0.59 8.94d 7.87c 6.75b 3.66 a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05; NS-Non significant
Table 5.37 Changes in flavor score* of 800 ppm of potassium sorbate treated
Chhana jalebi samples packed in various packaging materials stored at ambient
temperature (28±2°C)
Packaging materialsPreservative samples stored at 28±2°C
(days)
0 10 20 30 CD=0.69
LDPE pouch 8.95 7.75 6.51 3.21 6.61a
Metalized polyester 8.94 8.65 6.69 4.25 7.13ab
Polystyrene cups 8.95 8.15 7.55 4.32 7.24b
Cardboard box lined with butter paper 8.95 8.36 7.56 5.25 7.53b
CD=0.69 8.95d 8.23c 7.08b 4.26a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
122
All packaging material had significant level of flavor scores irrespective to
storage period. The mean scores were 7.05, 6.93, 6.69 and 6.56 respectively for LDPE
pouch, metalized polyester, polystyrene cups covered with aluminum foil, cardboard
box lined with butter paper. These scores were not statistically significant to all the
packaging materials (Table 5.37).
The ANOVA indicates the significant effect of storage period and their
interaction (P≤0.05) whereas not significant to effect of packaging material. With regard
to the flavor characteristics, the jalebi possessed a pleasant sweet, nutty and flavor. This
was maintained up to 4 days as indicated by acceptable scores (6.41 to 7.21), then
thereafter the product developed off flavor, attributable to microbial growth [91].
Table 5.38 Changes in flavor score* of 800 ppm of potassium sorbate treated
Chhana jalebi samples packed in LDPE pouch, metalized polyester, polystyrene
cups and cardboard box lined with butter paper stored at refrigerated
temperature (4±2°C)
Packaging materialsPreservative samples stored at 4±2°C (days)
0 15 30 45 60 CD=0.46
LDPE pouch 8.91 8.24 7.93 7.54 7.16 7.96a
Metalized polyester 8.91 8.92 8.9 8.9 8.82 8.89b
Polystyrene cups 8.91 8.23 7.90 7.33 7.14 7.90a
Cardboard box lined with butter paper 8.91 8.39 7.90 7.43 7.20 7.97a
CD=0.52 8.91c 8.45bc 8.16ab 7.80a 7.58a
*Average three trials; Note: Values with different superscripts are differ significantly at
P≤0.05
The flavor was pleasant, however during storage period the flavor score was
declined. Based on the scores which remained above 6.5, it can be observed that the
flavor remained acceptable up to 20 days. Thereafter, off flavor developed which made
the jalebi unacceptable. Based on observation, the changes observed in the sensory
score of flavor for 800 ppm potassium sorbate treated samples were packed in all four
packaging materials and stored at 28°C and 4°C were presented in Table 5.37 and 5.38.
At this storage temperature, also the effect of storage period and effect of packaging
123 material and their interaction found to be significant as was observed at 28°C and 4°C.
In that period within which the flavor score remained 6.5 and above for all packaging
materials were reported upto 20 days at 28°C and 60 days storage period at 4°C.These
may be attributed to the effect of packaging material on mold growth. The ANOVA
indicates the significant effect of packaging material and storage period and their
interaction (P≤0.05).
iii. Changes in body and texture
The body and texture scores of the jalebi during storage as influenced by four
different packaging materials are presented in Table 5.39. It is clearly understood from
the Table 5.39 that as storage day increased the sensory score of body and texture was
decreased irrespective of the packaging material. The means score decreased from the
initial value of 8.90 to 3.80 at the end of 6 days of storage at room temperature. In case
of polystyrene cups covered with aluminum foil and cardboard box lined with butter
paper packed product score of 4th day was 6.58 and 6.43 which marginally decreased to
3.32and 3.45 on 6th day. During storage, the body and texture of jalebi became firm, but
turned slimy later because of mold growth [64]. LDPE pouch and metalized polyester
scores were 6.59 and 7.01 at the end of 4thday respectively. It is indicating that the
LDPE pouch packed samples shelf life was 4 days and metalized polyester packed
samples shelf life was 6 days [120,121]. This was determined by taking the minimum
score of 6.5 as acceptable limit.
Table 5.39 Changes in body and texture score* of Chhana jalebi control samples packed in various packaging materials stored at ambient temperature (28±2°C)
Packaging materialsControl samples stored at 28 ±
2°C (days) Avg. mean
0 2 4 6
LDPE pouch 8.90 8.22 6.59 5.21 7.19NS
Metalized polyester 8.80 8.10 7.01 3.21 6.78NS
Polystyrene cups 8.93 7.50 6.58 3.32 6.58NS
Cardboard box lined with butter paper 8.95 7.46 6.43 3.45 6.57 NS
cd=0.83 8.90d 7.82c 6.61b 3.80a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05; NS-Non significant
124
All packaging material had significant level of body and texture scores
irrespective to storage period. The mean scores were 7.19, 6.78, 6.58 and 6.57
respectively for samples packed in LDPE pouch, Metalized Polyester, Polystyrene cups
covered with aluminum foil, cardboard box lined with butter paper (Table 5.39). These
scores were not statistically significant to all the packaging materials. The ANOVA
indicates the significant effect of storage period and their interaction (P≤0.05) whereas
not significant to effect of packaging material.
Table 5.40 Changes in body and texture* score of 800 ppm of potassium sorbate treated Chhana jalebi samples packed in various packaging materials stored at
ambient temperature (28±2°C)
Packaging materialsPreservative added samples stored at
28±2°C (days)
0 10 20 30 CD=0.73
LDPE pouch 8.90 7.45 6.21 3.15 6.43 a
Metalized polyester 8.80 8.10 6.62 4.21 6.93ab
Polystyrene cups 8.93 8.17 7.51 5.44 7.51b
Cardboard box lined with butter paper 8.95 8.35 7.54 5.34 7.55b
CD=0.73 8.90d 8.02c 6.97b 4.54 a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
Table 5.41 Changes in body and texture score of 800 ppm of potassium sorbate treated Chhana jalebi samples packed in various packaging materials stored at
refrigerated temperature (4±2°C)
Packaging materialsPreservative added samples stored at 4±2°C (days)
0 15 30 45 60 CD=0.29
LDPE pouch 8.90 8.66 8.48 8.32 7.87 8.45ab
Metalized polyester 8.90 8.74 8.70 8.68 8.65 8.73b
Polystyrene cups 8.90 8.20 8.10 7.77 7.32 8.06a
Cardboard box lined with butter paper 8.90 8.40 8.39 8.12 7.75 8.31a
CD=0.33 8.90c 8.50b 8.42b 8.22ab 7.90a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
125
The body and texture score declined from an initial score of 8.8 - 8.95 to 6.21 -
7.54 at the end of 20 days. These decreased scores were due to loss of moisture and
dryness and no mold growth was observed till this period. Based on observation, the
changes observed in the sensory score of body and texture for 800 ppm potassium
sorbate treated samples were packed in all four packaging materials and stored at 28°C
and 4°C are represented in Table 5.40 and 5.41. At this storage temperature and also
the effect of storage period and effect of packaging material and their interaction found
to be significant as was observed at 28°C and 4°C. The body and texture score was
remained 6.5 and above, for all packaging materials upto 20 days at 28°C and 60 days at
4°C [120,121]. These may be attributed to the effect of packaging material on mold
growth. The ANOVA indicates the significant effect of packaging material and storage
period and their interaction (P≤0.05).
iv. Changes in overall acceptability
Up to 4 days of storage, the body and texture score of Chhana jalebi in all
packaging material was remained unchanged and thereafter a decreasing trend with
further advancement of storage period was noticed from the Table 5.42. The overall
acceptability scores of jalebi during storage as influenced by four different packaging
materials are presented in Table 5.42, it clearly understood from observation that as
storage day increased, the sensory score of body and texture was decreased irrespective
to the packaging material. The means score decreased from the initial value of 8.95 to
4.47 at the end of 6 days of storage at room temperature. In case of polystyrene cups
covered with aluminum foil and cardboard box lined with butter paper packed product
score of 4th day was 6.75 and 6.45 which drastically decreased to 3.33 and 3.50 on 6th
day respectively. The scores at the end of 4th day were 7.00, 7.21, 6.75 and 6.45,
respectively for LDPE pouch, metalized polyester, polystyrene cups covered with
aluminum foil, cardboard box lined with butter paper. These scores remained within the
acceptable range up to 4 days of storage. Thus, it can be understood that the jalebi
packaged in LDPE pouch or metalized polyester or polystyrene cups covered with
aluminum foil or cardboard box lined with butter paper remained well up to 4 days,
which is slightly more than the shelf life of the Chhana jalebi left without any
packaging. The spoilage of the product may be attributed mainly due to the growth of
yeasts and molds. There was no change in shelf life of the product packaged in the four
packaging materials, though LDPE pouch and metalized polyester showed higher scores
126 at the end of 4 days. Statistical means of the packaging materials did not show statistical
difference for flavour and body and texture scores, whereas storage period had
significant influence on the change in sensory attributes (P<0.05). LDPE pouch and
metalized polyester scores were 7.00 and 7.21 at the end of 4th day respectively. It is
indicating that the LDPE pouch packed samples shelf life was 4 days and metalized
polyester packed samples shelf life was 6 days. This was determined by taking the
minimum score of 6.5 as acceptable limit. Similarly results were reported by Kumar et
al., (1983) [120] in khoa and Kumar et al., (2008a) [121] in paneer samples.
Table 5.42 Changes in overall acceptability score* of Chhana jalebi control
samples packed in various packaging materials stored at ambient temperature
(28±2°C)
Packaging materialsControl samples stored at 28±2°C (days)
0 2 4 6 CD=0.73
LDPE pouch 8.93 8.31 7.00 5.32 7.39b
Metalized polyester 8.96 8.45 7.21 6.75 7.84ab
Polystyrene cups 8.95 7.50 6.75 3.33 6.63a
Cardboard box lined with butter paper 8.96 7.45 6.45 3.50 6.59a
CD=0.73 8.95d 7.93c 6.85b 4.47a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
The mean scores were 7.39, 7.59, 6.63 and 6.59 respectively for samples packed
in LDPE pouch, metalized polyester, polystyrene cups covered with aluminum foil,
cardboard box lined with butter paper. These scores were statistically significant to all
the packaging materials. The ANOVA indicates the significant effect of packaging
material and storage period and their interaction (P≤0.05). The decreasing score with
advancement of storage period may be mainly attributed to the decline in aroma and
flavor.
127 Table 5.43 Changes in overall acceptability score* of 800 ppm of potassium sorbate
treated Chhana jalebi samples packed in various packaging materials stored at
ambient temperature (28±2°C)
Packaging materials
Preservative added samples stored at 28±2°C (days)
0 10 20 30 CD=0.67
LDPE pouch 8.97 7.50 6.50 3.20 6.54a
Metalized polyester 8.95 8.65 6.69 5.30 7.40ab
Polystyrene cups 8.95 8.15 6.50 4.65 7.06a
Cardboard box lined with butter paper 8.95 8.40 6.50 4.60 7.11a
CD=0.67 8.96d 8.18c 6.55b 4.44a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
Overall, the scores remained acceptable up to a storage period of 20 days
(overall acceptance score 6.5 - 6.69). After 20 days the overall acceptance scores fell to
unacceptable limits because of off flavours caused by proteolysis and oxidation.
Rajorhia et al., (1984) [122] reported that by using 0.3% potassium sorbate in khoa
could be preserved up to 23 days at 30oC. Potassium sorbate has been used in a number
of products and is a useful preservative in food industry [21].
Based on observation, the changes observed in the sensory score of overall
acceptability for 800 ppm potassium sorbate treated samples were packed in all four
packaging materials and stored at 28°C and 4°C are represented in Table 5.43 and 5.44.
At this storage temperature, also the effect of storage period and effect of packaging
material and their interaction found to be significant as was observed at 28°C and 4°C.
The overall acceptability score was persisted 6.5 and above for all packaging materials,
were obtained upto 20 days at 28°C and 60 days at 4°C. The decreasing score with
advancement of storage period could be mainly attributed to the decline in aroma and
flavor score of Chhana jalebi. These may be attributed to the effect of packaging
material on mold growth. The ANOVA indicates the significant effect of packaging
material and storage period and their interaction (P≤0.05).
128 Table 5.44 Changes in overall acceptability score* of 800 ppm of potassium sorbate
treated Chhana jalebi samples packed in various packaging materials stored at
refrigerated temperature (4±2°C)
Packaging materials
Preservative added samples stored at 4±2°C(days)
0 15 30 45 60 CD=0.34
LDPE pouch 8.93 8.67 8.45 8.22 8.00 8.45b
Metalized polyester 8.93 8.93 8.88 8.86 8.86 8.89c
Polystyrene cups 8.93 8.18 8.00 7.60 7.40 8.02a
Cardboard box lined with butter paper 8.93 8.33 8.40 8.02 7.75 8.29ab
CD=0.38 8.93c 8.53b 8.43b 8.18ab 8.00a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
Based on observation, package material had effect on shelf life of Chhana jalebi.
It was concluded that Chhana jalebi samples packed in all four types of packaging
material without addition of preservative had shown 2 days shelf life at ambient
temperatures (28±2°C) whereas 800 ppm potassium sorbate treated samples had given
20 days. Similarly preservative treated samples stored under refrigeration temperature
(4±2°C) had shown shelf life of 60 days. All four packaging materials along with
Chhana jalebi samples are shown in Figure 5.15.
129
Figure 5.15 Different packaging materials used for shelf life enhancement of
Chhana jalebi
1. Cardboard box lined with butter paper packed samples
2. Polystyrene cups covered with aluminum foil
3. Low density polyethylene (LDPE) packed samples
4. Metalized polyester (MET) packed samples
3 4
21
130 PART – IV: SHELF LIFE ENHANCEMENT OF CHHANA JALEBI BY USING
DIFFERENT PACKAGING TECHNIQUES
5.5 SHELF LIFE ENHANCEMENT OF CHHANA JALEBI BY USING
MODIFIED ATMOSPHERE PACKAGING
Modified Atmosphere Packaging (MAP) technique is based on changing the gas
combination of packaging of the products. MAP has been used to preserve the freshness
of many food products and can improve the food safety under certain conditions
reported by Hotchkiss (1989) [123], Farber et al., (1991) [124]. Compared to traditional
product packaging methods, MAP offers many key benefits the most important one is
extending the shelf life [124]. The MAP has proved to be capable of extending the shelf
life of many foods by altering the relative proportions of the surrounding atmospheric
gases. The MAP can bring about changes in the respiration rate, microbial growth, and
oxidation reactions, hence effective against shelf life of food products [125]. The CO2,
O2 and N2 are normally used in MAP. These gases are tasteless and have peculiar
characteristics such as CO2 inhibits the microbial growth as well as insect infestation in
packaged stored products and N2 is an inert, tasteless gas mostly used as a filler gas.
[126 - 128]. Generally O2 concentration must be below the atmospheric levels (i.e. < 21
% v/v) [124, 129]. The most important gas from a microbiological stand point is CO2,
which effectively inhibits the growth of spoilage bacteria and molds [123].
Two packaging materials such as Low Density Poly-Ethylene (LDPE) and
Metalized polyester (MET) were selected for studying the effect of modified
atmospheric condition. Vacuum packaging technique was also done parallel along with
MAP for both packaging materials. Results were obtained and discussed separately for
both LDPE and MET.
5.6 SHELF LIFE ENHANCEMENT CHHANA JALEBI BY USING
MODIFIED ATMOSPHERE PACKAGING IN LDPE
In this study LDPE pouches were exposed in UV light around 45 min. The 2 to 3
pieces of Chhana jalebi was kept inside the sterile LDPE pouches. Carbon-di-oxide
(CO2) and nitrogen (N2) gases were flushed in three different combinations such as
100% CO2, 100% N2 and combination of 50% CO2 and 50% N2. Gas flushed and sealed
pouches were stored at 28±2°C and 65% RH. Study was conducted based on three
131 characteristics such as physico-chemical (pH, water activity, peroxide value and
tyrosine value), microbiological (standard plate count and yeast and mold count),
textural characteristics (hardness, adhesiveness, springiness, cohesiveness and
chewiness) and sensory characteristics (color and appearance, flavor, body and texture
and overall acceptability). Vacuum packaging was also done in LDPE pouches. Since
the product was compaction and resulting in loss of body and texture though given good
shelf life to the product. Results and discussions of the MAP in LDPE are presented
below.
5.6.1 Physico-chemical characteristics of Chhana jalebi stored in LDPE with
MAP and vacuum technique
Four physico-chemical parameters such as pH, water activity, peroxide value
and tyrosine values were analyzed for Chhana jalebi stored in LDPE with MAP and
Vacuum packaging techniques.
i. Changes in pH
The pH of fresh Chhana jalebi was 5.43 in control as well as in preservative
sample. Data on the pH of Chhana jalebi sample packed in LDPE pouch filled with
100% N2, 100% CO2 and 50% N2 with 50% CO2 and vacuum with preservative treated
samples stored at 28±2°C are given in Figure 5.16.
Figure 5.16 Effect of gas flushed LDPE packaging on pH values of Chhana jalebi
during storage at 28±2°C
4.64.74.84.9
55.15.25.35.45.5
0 10 20 30 40 50
pH v
alue
Storage days
LDPE (Control)
LDPE (100% N2)
LDPE (100% CO2)
LDPE (50% N2+50% CO2)LDPE (Vacuum)
132
In LDPE with gas combination packed samples were reduced the pH rapidly
from initial value of 5.43 to 5.04, 5.05, 5.01 and 5.06 for LDPE pouch filled with 100%
N2, 100% CO2 and 50% N2 with 50% CO2 and vacuum respectively for the period of 40
days at 28±2°C (Figure 5.16). Decreasing trend was observed in all samples during
storage at 28±2°C. Kumar et al., (1997) [108] also reported that pH of peda product
was decreased during storage period of 180 days at 20°C. This was attributed to the
growth of yeast and mold as in present study. Related results were also observed by
other Researchers [32, 64, 91].
ii. Changes in water activity
Water activity has relationship with moisture content since loss of moisture is
common phenomena during storage; Figure 5.17 shows the trend of Chhana jalebi.
Water activity of Chhana jalebi was decreased from 0.88 to 0.766, 0.725, 0.743 and
0.791 for LDPE pouch filled with 100% N2, 100% CO2 and 50% N2 with 50% CO2 and
vacuum respectively during 40 days of storage at 28±2°C.
Figure 5.17 Effect of gas flushed LDPE packaging on water activity (aW) of
Chhana jalebi during storage at 28±2°C
Several previous studies have been reported an increase in the shelf life of
traditional dairy foods by using hurdle technology, water activity changes, increasing of
sugar content etc. [91, 108, 130-132]. However, not much Scientific literature is
00.10.20.30.40.50.60.70.80.9
1
0 10 20 30 40 50
Wat
er a
ctiv
ity
Storage days
LDPE (Control)
LDPE (100% N2)
LDPE (100% CO2)
LDPE (50% N2+50% CO2)LDPE (Vacuum)
133 available on the use of MAP for extending the shelf life of traditional dairy foods except
as reported by Biradar et al., (1985) [130] for peda, Rai et al.,(2008) [133] and
Thippeswamy et al., (2011) [134] for paneer and Londhe et al., (2012) [107] for brown
peda.
iii. Changes in peroxide value
Peroxide shows lipolytic changes during storage in Chhana jalebi samples in
terms of ml /g of product. Lipase enzyme present in milk is responsible for rancidity
gets inactivated during Chhana jalebi manufacturing, but it is produced by the bacteria
and yeast and mold during storage and thus causes increase in free fatty acid. The
excessive production of free fatty acid is responsible for rancidity in dairy products.
There was gradual increase in peroxide value in all Chhana jalebi samples irrespective
to gas combination levels. The rate of increase of peroxide value was higher in LDPE
with gas filled combination of 50% N2 and 50% CO2 sample. The initial value of 0.35
was increased to 0.68, 0.68, 0.65 and 0.73 ml/g of product for LDPE pouch filled with
100% N2, 100% CO2, 50% N2 with 50% CO2 and vacuum respectively during 50 days of
storage at 28±2°C (Figure 5.18).
Figure 5.18 Effect of gas flushed LDPE packaging on peroxide values of Chhana
jalebi during storage at 28±2°C
0
0.5
1
1.5
2
2.5
3
0 10 20 30 40 50 60
Pero
xide
val
ue
(ml/g
)
Storage days
LDPE (Control)
LDPE (100% N2)
LDPE (100% CO2)
LDPE (50% N2+50% CO2)LDPE (Vacuum)
134
The rate of increase of peroxide value was minimum in LDPE pouch filled with
100% N2 samples as compared to LDPE with gas combination of 50% N2 with 50%
CO2. During 20 days, all packed samples peroxide value was 0.73ml /g of product
stored at 28±2°C. After 50 days, all samples peroxide value were considered as not
acceptable limit based on acceptable level of sensory scores which is 6.5. None of the
samples was found to have rancid flavor indicating that the level of free fatty acid
production was not to that level that causes serious defect, despite steady increase in
peroxide value in all samples during storage. Kumar et al., (1997) also observed
increasing trend in peroxide value during storage [108]. Jha et al., [59] and Kumar et al.,
(2010) [135] also reported that peroxide value in khoa increased significantly with the
progression of storage period. Oxygen is the causative factor for the occurrence of lipid
oxidation in foods and in this case, elimination of oxygen from the package reduced the
deteriorative changes. Similar findings have been reported by Hong et al., (1995) where
lipid oxidation in cheeses was significantly reduced by the removal of oxygen from the
package environment [136].
iv. Changes in tyrosine value
The deteriorating agents of the food quality are oxygen contained in the air and
microorganisms such as bacteria and mold. Oxygen promotes several types of
deteriorative reactions in foods including oxidation of fat, browning reactions and
pigment oxidation. Most of the common spoilage bacteria and fungi require oxygen for
growth. Therefore, to increase the shelf life of foods, the package atmosphere should
contain a low concentration of residual oxygen [137]. The increase in tyrosine value
may be attributed to the breakdown of proteins by the surviving micro flora and their
enzymes. The proteolytic enzymes break the proteins down to simpler forms there by
increasing the amount of tyrosine in the product. It may also be attributed to heat stable
proteolytic enzymes which survived the heat treatment [111]. Tyrosine value showed a
gradual increase during storage which depicted in figure 5.19. The Chhana jalebi
samples were analysed for tyrosine value in terms of mg/100g of product with a view to
monitor proteolysis during storage. The rate of increase of tyrosine value was higher in
LDPE with gas filled combination of 50% N2 with 50% CO2 sample.
135
Figure 5.19 Effect of gas flushed LDPE packaging on tyrosine values of Chhana
jalebi during storage at 28±2°C
The initial value of 3.00 increased to 12.5, 12.5, 11.4 and 13.3 and 34.2 mg /
100g of product for LDPE pouch filled with 100% N2, 100% CO2, 50% N2 +50% CO2
and vacuum respectively during 50 days of storage at 28±2°C (Figure 5.19). In 50 days
storage at 28±20C, tyrosine value of all packed samples was 13.3 mg/100g of product.
After 50 days, all samples tyrosine value were considered as not acceptable limit based
on acceptable level of sensory scores which is 6.5. [108, 131]
5.6.2 Microbiological analysis of Chhana jalebi stored in LDPE with MAP and
vacuum technique
There were two microbial analyses such as standard plate count and yeast and
mold count were determined during storage and results are presented below.
i. Changes in standard plate count (SPC)
The increasing trend in standard plate count (in log10 values) of Chhana jalebi
samples packed and stored at 28±2°C are illustrated in Figure 5.20. The total microbial
count was found to increased when storage period increase. Earlier Researchers also
reported increasing of microbial counts in burfi during their storage studies [113, 115,
116], whereas Kumar et al., (1997) [108] did not observed increase in the microbial
0
5
10
15
20
25
30
35
40
0 10 20 30 40 50 60
Tyro
sine
valu
e (m
g/10
0g)
Storage days
LDPE (Control)
LDPE(100% N2)
LDPE(100% CO2)
LDPE(50% N2+50% CO2)LDPE (Vacuum)
136 growth during storage of the product packed under MAP with oxygen scavengers in his
study on the enhancement of shelf life of peda. Palit and Pal (2005) [109] observed that
the rate of increase of total viable counts in control sample of burfi was higher than that
of vacuum packaged burfi . The initial count of 3.26 was increased to 5.90, 590, 5.55
and 6.51 log10 cfu/g for LDPE pouch filled with 100% N2, 100% CO2, 50% N2 with 50%
CO2 and vacuum respectively during 50 days of storage at 28±2°C (Figure 5.20). Based
on sensory scores, it concluded that above mentioned SPC values were considered as
acceptable limits for Chhana jalebi. During 60th day storage, the SPC count was found
higher in all the samples and spoiled.
Figure 5.20 Effect of gas flushed LDPE packaging on standard plate count (SPC)
of Chhana jalebi during storage at 28±2°C
ii. Changes in yeast and mold
For most of the inter-mediate Indian dairy foods such as peda, burfi and
kalakand etc. are affected by mold growth tends to be a major problem and often most
important single factor limiting their shelf life [107]. Yeast and mold are the most
important factor to limiting the shelf-life of low water activity food. The results shows
the increase in log10 counts during storage at 28±2°C and Figure 5.21 shows the trend in
this respect. Londhe et al., (2012) [107] reported that increase of yeast and mold count
when the progress of storage period for the brown peda. The initial count of 0.41 was
increased to 1.46, 1.46, 1.28 and 1.67 log10 cfu/g for LDPE pouch filled with 100% N2,
100% CO2 and 50% N2 with 50% CO2 and vacuum respectively during 50 days of
0
2
4
6
8
10
12
0 10 20 30 40 50
Stan
dard
pla
te c
ount
(log 1
0cf
u/g)
Storage days
LDPE (Control)
LDPE(100% N2)
LDPE(100% CO2)
LDPE(50% N2+50% CO2)LDPE(Vacuum)
137 storage at 28±2°C (Figure 5.21). The yeast and mold count of samples increased during
storage period due to contamination from packaging system and environment on 60th
day. The yeast and mold count was found to be increased irrespective to the storage
time.
Figure 5.21 Effect of gas flushed LDPE packaging on yeast and mold of Chhana
jalebi during storage at 28±2°C
5.6.3. Textural characteristics of Chhana jalebi stored in LDPE with MAP
technique
A textural characteristic is one of the significant analyses for food products in
order to know consumption comfort ability of the food. The changes in textural quality
of Chhana jalebi in terms of texture profile analysis (TPA) during storage with
packaged under different packaging conditions are given in Table 5.45. The TPA
comprises a two-bite test that gives textural properties of food products in terms of
hardness, adhesiveness, cohesiveness, springiness and gumminess [138]. These textural
characteristics were analyzed for Chhana jalebi during 0th day, 50th day for LDPE
packed samples. Based on sensory scores and other analysis, it was found that shelf life
of Chhana jalebi treated with 800 ppm stored in LDPE packaging materials was 50
days. Hence textural analysis was carried out for the same. The force necessary to attain
a given deformation, called as hardness, is commonly evaluated parameter while
determining the texture of milk products. It is the height of the peak force on the first
compression cycle (first bite) [107].
0
0.5
1
1.5
2
2.5
3
0 10 20 30 40 50
Yeas
t and
mol
d co
unt
(log 1
0cf
u/g)
Storage days
LDPE (Control)
LDPE (100% N2)
LDPE (100% CO2)
LDPE (50% N2+50% CO2)LDPE (Vacuum)
138 Table 5.45 Textural characteristics* of Chhana jalebi stored in gas flushed LDPE
packing material during 50th day at ambient temperature (28±2°C)
Textural characteristics 0th Day
50thDay analysis for LDPE packing material
100 % N2 100 % CO2 50% N2 + 50% CO2
Hardness (N) 1.41 1.83 2.23 1.98
Adhesiveness (Ns) -5.65 -4.38 -5.07 -4.65
Springiness (mm) 0.817 0.876 0.945 0.923
Cohesiveness 0.53 0.57 0.614 0.595
Chewiness (Nm) 0.57 1.24 1.68 1.59
*Average three trials
Hardness of the product was increased from 1.41N on 0th day to 1.83N, 2.23N and 1.98N for 100% N2, 100% CO2 and 50% N2 + 50% CO2 gas filled packaging on 50th day respectively. Hardness of the product was increased due to moisture loss,relative permeability of the gases through film and sugar crystallization etc. In another study, a gradual increase in hardness of all brown peda samples irrespective of the packaging techniques was used [107]. Moisture loss occurred due to absorption of moisture by the both the nitrogen and oxygen gases in the packaging materials. Gupta et al., (1990) [139] observed that hardness of khoa (a heat desiccated milk product) was highly correlated with total solids and increasing total solids resulted in higher hardness. Similar findings were reported by Bhatele (1983) [99] and Sachdeva (1982) [140] in burfi samples. They observed that when burfi was packaged in parchment paper, its hardness continuously increased with the progress of storage period due to high amount of moisture loss.
Adhesiveness is the negative force of the first bite representing the work necessary to pull the compressing plunger away from the sample [107]. Adhesiveness also increased from initial value of -5.65Ns on 0th day to -4.38 Ns, -5.07 Ns and -4.65 Ns for 100% N2, 100% CO2 and 50% N2 + 50% CO2 gas filled packaged samples on 50th day respectively (Table 5.45) due to the moisture loss from the product.
The distance that food recovered its height during the time elapsed between end of first bite and start of second bite was defined as springiness [138]. Springiness of the product increased from initial value of 0.817mm on 0th day to 0.876mm, 0.945mm and
139 0.923 mm for 100% N2, 100% CO2 and 50% N2 + 50% CO2 gas filled packaged samples on 50th day respectively. It is believe that, springiness was increased due to increasing the activity of gluten content. In another study on brown peda, all samples showed increasing trend in springiness values irrespective of packaging technique during storage. However the rate of increase differed in each packaging technique [107]. Earlier Researchers [138, 141] reported that springiness was the only textural attribute which had no correlation with any of the compositional parameters of khoa. Palit (1998) [142] reported an increase in springiness value of burfi during storage irrespective to type of packaging.
Cohesiveness is molecular attraction by which the particles of a body are bounded throughout the mass. Cohesiveness may be defined sensorily as the degree to which a substance is compressed between the teeth before it breaks. Instrumentally, it is measured by calculating the ratio of the area of second bite to that of first bite A2/A1) [138]. Cohesiveness of the product increased from initial value of 0.53 on 0th day to 0.57, 0.614 and 0.595 for 100% N2, 100% CO2 and 50% N2 + 50% CO2 gas filled packaged samples on 50th day respectively. Since loss of moisture content from the product, strength of internal bond was increased. Reason for moisture loss was already discussed.
Two other parameters viz., gumminess and chewiness were derived by calculation from the measured parameters. Gumminess was defined as the product of hardness and cohesiveness while chewiness was defined as the product of gumminess and springiness [138]. Gumminess and chewiness are mutually exclusive characteristics since gumminess applicable for semisolid food and chewiness is applicable for solid food. Since Chhana jalebi is considered as solid food, chewiness was analyzed. Chewiness of the product also increased from initial value of 0.57 Nm on 0th day to 1.24 Nm, 1.68 Nm and 1.59 Nm for 100% N2, 100% CO2 and 50% N2 + 50% CO2 packaged material samples respectively on 50th day (Table 5.45). Since loss of moisture content from the product, there may be little increased energy required for converting Chhana jalebi solid food in to semisolid state in order to swallow the product. Reason for moisture loss was already discussed. This increasing trend in chewiness in all Channa jalebi samples during storage could be attributed to increase in gumminess and springiness values. These findings are correlated with Palit et al., (1998) [142] findings and reported that the gumminess and chewiness of burfi increase with the progress of storage period irrespective to type of package used. Bourne (2002) [138] also observed that soft burfi was significantly less gummy than hard burfi.
140 5.6.4 Sensory characteristics of Chhana jalebi stored in LDPE with MAP and
vacuum packaging techniques
Four sensory characteristics such as color and appearance, flavor, body and
texture and overall acceptability analyses were carried out at both ambient (28±2°C) and
refrigerated temperatures (4±2°C) with and without 800 ppm of potassium sorbate
preservative treated Chhana jalebi stored in LDPE with MAP and vacuum packaging.
The results are presented as below.
i. Changes in color and appearance
Under the treatment of gas flushing, the initial color and appearance scores of
Chhana jalebi during storage was influenced by all combination of gas flushing in
LDPE pouches which are presented in Table 5.46. Based on the observation concluded
that as storage days increased or progressed, the sensory score of color and appearance
was decreased irrespective of the gas flushing levels and same results were reported by
other researchers [107, 121]. The mean score decreased from the initial value of 8.92 to
5.35 at the end of 45 days of storage at room temperature, which was due to extensive
mold growth inside the package. LDPE pouch filled with 100% N2, 100% CO2, 50% N2
+ 50% CO2 and vacuum packed products scores were 7.32, 7.23, 7.01, and 7.13 at the
end of 30 days respectively. The sensory scores showed a decreasing trend during
storage in all samples of Chhana jalebi irrespective of packaging techniques. Despite
decreasing trend the samples were found to score well over the minimum acceptable
limit during the storage period of entire storage study but there was fungal growth on
the samples on 45thday. It can be also observed from the Table 5.46 that, LDPE pouch
with gas filled and vacuum packed samples had significant level of color and
appearance scores irrespective of storage period. The mean scores were 7.43, 7.56, 7.43
and 7.51 for samples packed in LDPE pouch filled with 100% N2, 100% CO2, 50% N2 +
50% CO2 and vacuum packed products respectively. These scores were statistically
significant to all combination of gas flushing. Same impact was observed in danedar
khoa [132]. The Table 5.46 indicates the significant effect of gas flushing in LDPE
packing material, storage period and their interaction (P≤0.05). The mean scores of
color and appearance for LDPE pouch filled with 100% CO2 packed sample was 7.56
which is higher score than other gas combinations (Table 5.46). It attributed that CO2 is
having a property of retaining freshness of the product.
141
Table 5.46 Changes in the color and appearance score* of Chhana jalebi control samples packed in gas flushed LDPE packaging materials stored at ambient
temperature (28±2°C)
LDPE with different MAP Conditions
Control samples stored at 28±2°C (days)
0 15 30 45 CD=0.37
LDPE (100% N2) 8.91 8.25 7.32 5.22 7.43a
LDPE (100% CO2) 8.94 8.54 7.23 5.54 7.56ab
LDPE (50% N2 + 50% CO2) 8.92 8.45 7.1 5.23 7.43a
LDPE (vacuum) 8.93 8.54 7.13 5.44 7.51a
CD=0.33 8.92d 8.44c 7.20b 5.35a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
Similarly, studies on color and appearance were carried out for Chhana jalebi
treated with 800 ppm of potassium sorbate as preservative. The changes in the sensory
score of color and appearance of the samples which packed in all combinations of gas
filled and vacuum packed LDPE pouches, stored at 28°C are presented in Table 5.47. At
this storage temperature, the effect of storage period and effect of gas flushing in LDPE
pouches and their interaction found to be significant (Table 5.47).
Table 5.47 Changes in the color and appearance score* of 800 ppm of potassium sorbate treated Chhana jalebi samples packed in gas flushed LDPE packaging
materials stored at ambient temperature (28±2°C)
LDPE with different MAP Conditions
Preservative added samples stored at 28±2°C (days)
0 20 40 60 CD=0.54
LDPE (100% N2) 8.95 8.64 6.82 3.21 6.91a
LDPE (100% CO2) 8.95 8.72 7.83 3.21 7.18b
LDPE (50% N2 + 50% CO2) 8.95 8.44 7.21 3.12 6.93a
LDPE (vacuum) 8.93 8.82 7.83 3.11 7.17ab
CD=0.49 8.94d 8.65c 7.42b 3.16a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
142
In that period, the color and appearance score was remained 6.5 and above for
all gas filled and vacuum packed samples until 50 days. These may be attributed to the
effect of packaging material on mold growth. The ANOVA indicates the significant
effect of gas flushing in LDPE packaging material, storage period and their interaction
(P≤0.05).
ii. Changes in flavor
Gas flushing plays key role to retain the aroma and flavor score of Chhana jalebi
at 28±2°C with 65% relative humidity. The flavor scores of Chhana jalebi during
storage was influenced by all combination of gas flushing in LDPE pouches which are
presented in Table 5.48. The mean score decreased from the initial value of 8.93 to 5.00
at the end of 45 days of storage at room temperature due to extensive mold growth. The
mean flavor score of LDPE pouch filled with 100% N2, 100% CO2, 50% N2 + 50% CO2
and vacuum packed products scores were 7.32, 7.20, 7.46, and 7.41 respectively. All
the LDPE packed samples with gas flushing shown retained original flavor
characteristics and no microbial growth for 30 days. There was no deterioration of
flavor until 40th day, however thereafter there was slight mold growth observed,
therefore flavor was unacceptable. It indicated that the packed samples shelf life was 30
days. The findings of the present study are in accordance with the report of Biradar et
al., (1985) [130].
Table 5.48 Changes in the flavor score* of Chhana jalebi control samples packed
in gas flushed LDPE packaging materials stored at ambient temperature (28±2°C)
LDPE with different MAP Conditions
Control samples stored at 28±2°C(days)
0 15 30 45 Avg. mean
LDPE (100% N2) 8.92 8.01 7.02 5.31 7.32
LDPE (100% CO2) 8.95 8.22 7.09 4.55 7.20
LDPE (50% N2 + 50% CO2) 8.94 8.42 7.03 5.45 7.46
LDPE (vacuum) 8.94 8.23 7.12 5.35 7.41
CD=0.38 8.93d 8.24c 6.98b 5.00a
*Average three trials; Note: Values with different superscripts are differ significantly at
P≤0.05
143
The changes in the sensory score of flavor of preservative treated samples which
packed in all combinations of gas filled and vacuum packed LDPE pouches, stored at
28°C are represented in Table 5.49. Based on observation, at this storage temperature,
the effect of storage period and effect of gas flushing in LDPE pouches and their
interaction found to be significant. The ANOVA indicates the significant effect of gas
flushing in LDPE packaging material, storage period and their interaction (P≤0.05). It
attributed that CO2 is having a property of retaining freshness of the product. Sharma et
al., (2001) [132], also reported the decrease in mean flavour scores of the control and
MAP packaged malai peda samples in flexible packaging material at room temperature
[132]. The reduction in flavour score for control (without MAP) was much rapid than
for MAP samples. Similar observation was reported by Kumar et al., (1997) [108].
The decrease in flavour scores may be attributed to slight loss of freshness,
which is inherent with any food product. The findings of the present study are in
accordance with the report of Biradar et al., (1985) [130].
Table 5.49 Changes in the flavor score* of 800 ppm of potassium sorbate treated Chhana jalebi samples packed in gas flushed LDPE packaging materials stored at
ambient temperature (28±2°C)
LDPE with different MAP Conditions
Preservative added samples stored at 28±2°C (days)
0 20 40 60 CD=0.52
LDPE (100% N2) 8.94 8.63 6.53 3 6.78 a
LDPE (100% CO2) 8.96 8.73 7.55 3.11 7.09 a
LDPE (50% N2 + 50% CO2) 8.96 8.52 7.32 3.2 7.00 a
LDPE (vacuum) 8.94 8.84 7.86 3.15 7.20 ab
CD=0.46 8.95c 8.68c 7.31b 3.11 a
*Average three trials; Note: Values with different superscripts are differ significantly at
P≤0.05
Despite decreasing trend the samples were found to score well over the
minimum acceptable limit during the entire storage study. None of the judges reported
the presence of any objectionable off flavour such as oxidized, rancid, acidic etc. during
the entire period of storage.
144 iii. Changes in body and texture
The body and texture score of Chhana-jalebi in LDPE as well as gas flushing
was almost same within 30 days (Table 5.50). Up to 30 days of storage, the mean value
of body and texture scores decreased from 8.89 to 4.21 at 28±2°C. The ANOVA report
indicates that significant effect of gas flushing in LDPE packaging material and storage
period and their interaction (P≤0.05). Due to slight evaporation of moisture Chhana
jalebi surface became slightly hard. The findings of the present study are in accordance
with the report of Biradar et al., (1985) [130] and Londhe et al., (2012) [107]. Another
study also reported the decrease in mean body and texture scores of the control and
MAP packaged malai peda samples in flexible packaging material at room temperature.
The reduction in body and texture score for control (without MAP) was much rapid than
for MAP samples [132]. Similar observation was reported by Kumar et al., (1997)
[108].
The decrease in body and texture scores may be attributed to slight loss of
freshness that is common in food product. The findings of the present study are
correlated with previous Biradar et al., (1985) [130] and Sharma et al., (2001) [132]
also reported the decrease in mean body and texture scores of the control and MAP
packaged malai peda samples in flexible packaging material at room temperature.
Table 5.50 Changes in the body and texture score* of Chhana jalebi control samples packed in gas flushed LDPE packaging materials stored at ambient
temperature (28±2°C)
LDPE with different MAP Conditions
Control samples stored at 28±2°C(days) Avg.
mean0 15 30 45
LDPE (100% N2) 8.92 8.02 7.04 4.01 7.00
LDPE (100% CO2) 8.91 8.00 7.03 4.27 7.05
LDPE (50% N2 + 50% CO2) 8.93 8.4 6.92 4.30 7.14
LDPE (vacuum) 8.80 8.21 7.01 4.27 7.07
CD=0.43 8.89d 8.15c 7.00b 4.21 a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
145
Table 5.51 Changes in the body and texture scores* of 800 ppm of potassium sorbate treated Chhana jalebi samples packed in gas flushed LDPE packaging
materials stored at ambient temperature (28±2°C)
LDPE with different MAP Conditions
Preservative added samples stored at 28±2°C(days)
0 20 40 60 CD=0.61
LDPE (100% N2) 8.95 8.59 6.56 3.33 6.86a
LDPE (100% CO2) 8.96 8.76 7.58 3.23 7.13ab
LDPE (50% N2 + 50% CO2) 8.93 8.46 7.1 3.1 6.90a
LDPE (vacuum) 8.8 8.2 7.83 3.11 6.99a
CD=0.54 8.92d 8.50c 7.26b 3.19a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
In case of preservative treated samples which packed in all combinations of gas
filled and vacuum packed LDPE pouches samples body and texture score remained 6.5
and above for all gas filled and vacuum packed samples for 40 days (Table 5.51). The
ANOVA indicates the significant effect of gas flushing in LDPE packaging material,
storage period and their interaction (P≤0.05).
iv. Changes in overall acceptability
During storage the scores of all the samples decreased at the same rate up to 30
days. The rate of decrease in LDPE gas flushed sample was not significant as storage
days increased the sensory score of overall acceptability was decreased irrespective of
the gas flushing levels. The average overall acceptability score was decreased from the
initial value of 8.93 to 5.32 at the end of 45 days of storage period at room temperature.
Similar observations were reported in brown peda [107].
The LDPE packed samples with gas flushing shown retained their characteristics
and no visible microbial growth for 30 days. The ANOVA Table 5.52 indicates the
significant effect of gas flushing in LDPE packing material and their interaction,
whereas not significant on storage period. The decreasing score with advancement of
storage period may be attributed mainly to the decline in aroma and flavor and product
became dry.
146
Table 5.52 Changes in the overall acceptability score* of Chhana jalebi control
samples packed in gas flushed LDPE packaging materials stored at ambient
temperature (28±2°C)
LDPE with different MAP Conditions
Control samples stored at 28±2°C (days)
0 15 30 45 Avg. mean
LDPE (100% N2) 8.91 8.21 7.01 5.58 7.43
LDPE (100% CO2) 8.91 8.52 7.23 5.74 7.60
LDPE (50% N2 + 50% CO2) 8.95 8.52 7.1 5.48 7.51
LDPE (vacuum) 8.95 8.61 7.2 4.5 7.32
CD=0.38 8.93d 8.46c 7.13b 5.32a
*Average three trials; Note: Values with different superscripts are differ significantly at
P≤0.05
Similarly, studies on overall acceptability were carried out for Chhana jalebi
treated with 800 ppm of potassium sorbate as preservative. The changes in the sensory
score of overall acceptability of the samples which packed in all combinations of gas
filled and vacuum packed LDPE pouches, stored at 28°C are given in Table 5.53. At
this storage temperature and preservative level, the effect of storage period and effect of
gas flushing in LDPE pouches and their interaction found to be significant (Table 5.53).
The overall acceptability score was remained 6.5 and above for all gas filled and
vacuum packed samples until 40 days. The decreasing score with advancement of
storage period may be mainly attributed to the decline in aroma and flavor. The
ANOVA indicates the significant effect of gas flushing in LDPE packaging material,
storage period and their interaction (P≤0.05).
Despite decreasing trend the samples were found to score well over the
minimum acceptable limit during the storage period of 40 days of LDPE with various
gas flushing levels and vacuum packaging methods. Same results were observed other
indigenous dairy products such as brown peda, burfi, khoa etc., [107, 113, 114 and 120].
147
Table 5.53 Changes in the overall acceptability score* of 800 ppm of potassium
sorbate treated Chhana jalebi samples packed in gas flushed LDPE packaging
materials stored at ambient temperature (28±2°C)
LDPE with different MAP Conditions
Preservative added samples stored at 28±2°C (days)
0 20 40 60 CD=0.57
LDPE (100% N2) 8.96 8.65 7.62 3.41 7.16 a
LDPE (100% CO2) 8.96 8.76 7.83 3.32 7.22b
LDPE (50% N2 + 50% CO2) 8.96 8.60 7.23 3.2 7.00 a
LDPE (vacuum) 8.96 8.85 7.85 3.3 7.24 a
CD=0.51 8.96c 8.71c 7.63b 3.30a
*Average three trials; Note: Values with different superscripts are differ significantly at
P≤0.05
Based on observation, modified atmospheric and vacuum packaging packed
Chhana jalebi samples had effect on their shelf life. It was concluded that Chhana jalebi
samples packed in 100% N2, 100% CO2, 50% N2 with 50% CO2 and vacuum packaging
in LDPE without addition of preservative had shown 30 days shelf life at ambient
temperatures (28±2°C) whereas 800 ppm potassium sorbate treated samples had given
40 days. All four packaging materials along with Chhana jalebi samples are shown in
Figure 5.28-1.
5.7 SHELF LIFE ENHANCEMENT OF CHHANA JALEBI BY USING
MODIFIED ATMOSPHERE AND VACUUM PACKAGING
TECHNIQUE IN METALIZED POLYESTER
Metalized polyester (MET) pouches were selected for study the effect of
modified atmosphere and vacuum packaging instead of LDPE material and same study
was repeated as like above LDPE study. MET pouches were exposed in UV light
around 45 min. The five pieces of Chhana jalebi was kept inside the sterile MET
pouches. Carbondioxide (CO2) and nitrogen (N2) gases were flushed in three different
combinations such as 100% CO2, 100% N2 and combination of 50% CO2 and 50% N2.
Gas flushed and sealed pouches were stored at 28±2°C and 65% relative humidity.
148 Study was conducted based on three characteristics such as physico-chemical (pH,
water activity, peroxide value and tyrosine value), microbiological (standard plate count
and yeast and mould count), textural characteristics (hardness, adhesiveness,
springiness, cohesiveness and chewiness) and sensory characteristics (color and
appearance, flavor, body and texture and overall acceptability). Vacuum packaging was
also done in MET pouches. Similar observations were also found in MET pouches.
Results and discussions of the MAP and vacuum packaging effects in MET are
presented below.
5.7.1 Physico-chemical characteristics of Chhana jalebi stored in MET with MAP
and vacuum packaging techniques
Four physico-chemical parameters such as pH, water activity, peroxide value
and tyrosine value were analyzed for Chhana jalebi which stored in MET with MAP and
vacuum packaging techniques. The results are presented below.
i. Changes in pH Value
Chhana jalebi is slightly acidic in nature as indicated by its pH value of 5.43.
This showed further decreasing trend during storage even in modified atmospheres
(Figure 5.22). In all the metalized polyester with gas flushed and vacuum treated
samples shows decreasing trend in pH. The pH decreased from initial value of 5.43 to
4.84, 4.86, 4.81 and 4.87 for metalized polyester pouch filled with 100% N2, 100% CO2,
50% N2 with 50% CO2 and vacuum respectively on 60th days of storage at 28±2°C. All
the treated samples had shown the pH value between 4.81 and 4.87, thus indicating that
nitrogen, carbon dioxide and vacuum hindered the growth of bacteria and mold. Bharat
and Pagote (2012) [102] also observed decreasing trend of pH during storage period of
khoa jalebi. The changes in pH cannot be directly correlated with change in acidity; still
it was found that with the increase in acidity, the pH exited on decreasing. Kumar et al.,
(1997) [108] also reported a decrease in pH of peda during storage for 180 days at 20°C.
149
Figure 5.22 Effect of gas flushed metalized polyester packaging materials on pH
values of Chhana jalebi during storage at 28±2°C
ii. Changes in water activity
During storage of Chhana jalebi there was slight evaporation of moisture content
therefore a declining trend was observed in water activity. From the graph 5.23, it was
observed that the initial value of water activity of Chhana jalebi decreased from 0.88 to
0.685, 0.634, 0.657 and 0.721 for metalized polyester pouch filled with 100% N2, 100%
CO2, 50% N2 with 50% CO2 and vacuum respectively on 60th days of storage at 28±2°C.
Hence, it concluded that the samples packed in metalized polyester with 100% CO2 was
shown less water activity and more prone to microbial spoilage as compared to other
gas flushed samples. Earlier, several scientists have been also reported considerable
loss of moisture in peda during storage which made the product dry and hard and thus
sensorily unacceptable. Bhatele et al., (1983) [114] reported that the rate of moisture
evaporation from burfi samples was different from samples packaged in different
packaging materials. A decreasing trend in water activity was observed in brown peda
[117]. Lowest moisture loss was noticed in peda samples packaged in MAP as
compared to control reported by Sharma et al., (2003) [143].
4.54.64.74.84.9
55.15.25.35.45.5
0 10 20 30 40 50 60
pH v
alue
Storage days
Metalized polyester
Metalized polyester (100% N2)Metalized polyester (100% CO2)Metalized polyester (50% N2+50% CO2)Metalized polyester (Vacuum)
150
Figure 5.23 Effect of gas flushed metalized polyester packaging materials on pH
values of Chhana jalebi during storage at 28±2°C
iii. Changes in peroxide content
The free fatty acid production during storage in products produces rancidity
which is unacceptable. Lipase enzyme produced by yeast and mold is responsible for
that because it acts on lipid and released free fatty acid. Therefore a gradual increased in
peroxide value during storage was observed. The Figure 5.24 shown rate of increase of
peroxide value was higher in vacuum as compared to gas filled and packed samples.
Peroxide value increased from initial value of 0.35 to 1.77, 1.29. 0.98 and 2.05 for
metalized polyester with gas filled in the combination of 100% N2, 100% CO2, 50% N2
with 50% CO2 and vacuum respectively during 65 days of storage at 28±2°C (Figure
5.24). During 60 days, all packed samples peroxide value were 0.73 ml /g of product
stored at 28±2°C and 65% relative humidity. After 65 days, all samples peroxide value
were considered as not acceptable limit based on acceptable level of sensory scores
which is 6.5. Navajeevan and Rao (2005) [110] reported the increase trend in free fatty
acid of retort processed kunda during storage at elevated temperature.
00.10.20.30.40.50.60.70.80.9
1
0 10 20 30 40 50 60
Wat
er a
ctiv
ity
Storage days
Metalized polyester (Control)Metalized polyester (100% N2)Metalized polyester (100% CO2)Metalized polyester (50% N2+50% CO2)Metalized polyester (Vacuum)
151
Figure 5.24 Effect of gas flushed metalized polyester packaging on peroxide values
of Chhana jalebi during storage at 28±2°C
Jha et al., (1977) [59] and Kumar et al., (2010) [135] also reported that FFA in
khoa increased significantly with the progression of storage period. The reason for the
delayed lipolysis of the Channa jalebi during storage under MAP could be attributed to
the absence of oxygen in the package during storage. Oxygen is the causative factor for
the occurrence of lipid oxidation in foods and in this case, elimination of oxygen from
the package reduced the deteriorative changes. Similar findings have been reported by
Hong et al., (1995) [136] where lipid oxidation in cheeses was significantly reduced by
the removal of oxygen from the package environment.
iv. Changes in tyrosine value
Proteolysis during storage of processed food products is a natural phenomenon
due to surviving of microorganisms and their enzymes. Owing to proteolysis, protein
gets broken into simpler form increasing the amount of tyrosine in the product which
shown in Figure 5.25. It may also be attributed to heat stable proteolytic enzymes which
survived the heat treatment. The Chhana jalebi samples were analysed for tyrosine value
in terms of mg/100g of product.
0
0.5
1
1.5
2
2.5
0 10 20 30 40 50 60 65
Pero
xide
val
ue (
ml/g
)
Storage days
Metalized polyester (Control)
Metalized polyester(100% N2)
Metalized polyester(100% CO2)
Metalized polyester(50% N2+50% CO2)
152
Figure 5.25 Effect of gas flushed metalized polyester packaging materials on
tyrosine values of Chhana jalebi during storage at 28±2°C
The rate of increase of tyrosine value was higher in vacuum treated and
packaged in metalized polyester. The tyrosine value increased from initial value of 3.00
to 20.1, 16.3, 14.5 and 24.3 mg/100 g for samples packed in metalized polyester with
gas combination of 100% N2, 100% CO2, 50% N2 with 50% CO2 and vacuum
respectively for 65 days of storage at 28±2°C (Figure 5.25). It concluded that samples
packed in metalized polyester with gas combination of 50% N2 with 50% CO2 showed
less tyrosine value compared to the 100% N2, 100% CO2 and vacuum treated samples.
Since tyrosine value of 13.3 mg/100g was considered as maximum acceptable limit
based on sensory values and all the samples were within the limit or acceptable range.
Hence, it concluded that metalized polyester packaging material is suitable for
packaging the Chhana jalebi with modified atmosphere techniques. A tyrosine value
decreasing trend was reported in brown peda [107]. Goyal and Srinivasan (1989a) [112]
Kumar and Srinivasan (1983) [120] and Sharma et al., (2001) [132] reported in khoa.
Similarly, Palit and Pal (2005) [109] and Sachdeva and Rajorhia (1982) [140] in burfi
whereas, Kumar et al., (2008a) [121] in paneer and Sharma et al., (2003) [143] in peda
and Navajeevan et al., (2005) [110] in retort processed kunda during storage at 37°C.
0
5
10
15
20
25
30
0 10 20 30 40 50 60 65
Tyro
sine
valu
e (m
g/10
0g)
Storage days
Metalized polyester (Control)
Metalized polyester(100% N2)
Metalized polyester(100% CO2)
Metalized polyester(50% N2+50% CO2)
153 5.7.2 Microbiological characteristics of Chhana jalebi stored in MET with MAP
and vacuum packaging techniques
There were two microbial analyses such as standard plate count and yeast and
mold count carried out during storage and results are presented below.
i. Changes in standard plate count (SPC)
The following Figure 5.26 shows the trend in standard plate count (log10 values)
in Chhana jalebi stored at 28±2°C. The total microbial count was found to be increased
irrespective to storage period.
Figure 5.26 Effect of gas flushed metalized polyester packaging materials on
standard plate count (SPC) of Chhana jalebi during storage at 28±2°C
The initial count of SPC value was 3.26 increased to 16.52, 11.47, 8.59 and
21.33 log10 cfu/g for metalized polyester pouch filled with 100% N2, 100% CO2, 50% N2
with 50% CO2 and vacuum respectively during 65 days of storage at 28±2°C and shown
in Figure 5.26. It was found out that 4.92, 5.28, 4.76 and 6.26 log10 cfu/g for metalized
polyester pouch filled with 100% N2, 100% CO2, 50% N2 with 50% CO2 and vacuum
respectively on 60th days of storage. During 65th day, the SPC count was found higher in
all the samples and spoiled. The control sample supported the growth of microbial flora
as the gaseous atmosphere was same as air containing oxygen. The samples containing
nitrogen showed delayed microbial growth, because nitrogen is an inert gas which does
not support microbial growth. Previous Researchers also reported that increasing
0
5
10
15
20
25
0 10 20 30 40 50 60 65
Stan
dard
pla
te c
ount
(log
10cf
u/g)
Storage days
Metalized polyester (Control)Metalized polyester (100% N2)Metalized polyester (100% CO2)Metalized polyester (50% N2+50% CO2)Metalized polyester (Vacuum)
154 bacterial counts of burfi during their storage studies [113, 115, 116], however Kumar et
al., (1997) [108] did not observe increase in the microbial growth during storage in the
product packed under MAP with oxygen scavengers in study on the enhancement of
shelf life of peda. Palit and Pal (2005) [109] observed that the rate of increase of total
viable counts in control sample of burfi was higher than that of vacuum packaged burfi.
ii. Yeast and mold
In the presence of oxygen, many of oxidation reactions and proceed mold
proliferation occurred. Gas flushing in the present study was able to reduce the oxygen
concentration. [144, 145]. Figure 5.27 shows the increase in log10 counts of mold and
yeast during storage at 28±2°C. Yeast and mold growth tend to be major problem for
high moisture food items. All the sample of Chhana jalebi showed the presence of yeast
and mold count which increased with the progress of storage period.
Figure 5.27 Effect of gas flushed metalized polyester packaging materials on yeast
and mold of Chhana jalebi during storage at 28±2°C
The rate of increase of yeast and mold was higher in vacuum treated samples.
The initial value of 0.41 increased to 7.23, 4.12, 2.43 and 12.41 and 1.67 log10 cfu/g for
metalized pouch filled with 100% N2, 100% CO2 and 50% N2 with 50% CO2 and
vacuum respectively during 65 days of storage at 28±2°C and shown in Figure 5.27.
0
2
4
6
8
10
12
14
0 10 20 30 40 50 60 65
Yeas
t and
mol
d co
unt
(log
10cf
u/g)
Storage days
Metalized polyester (Control)Metalized polyester (100% N2)Metalized polyester (100% CO2)Metalized polyester (50% N2+50% CO2)Metalized polyester (Vacuum)
155
It was found that the yeast and mold counts of Chhana jalebi were 1.05, 1.21,
0.95 and 1.54 log10 cfu/g respectively for metalized polyester pouch filled with 100%
N2, 100% CO2, 50% N2 with 50% CO2 and vacuum respectively on 60th days of storage.
During 65th day, the yeast and mold count was found higher in all the samples and
found spoiled. Due to effect of gas flushing, the growth was slow in gas flushed and
packed in metalized polyester samples compared to vacuum treated samples. The
microorganisms are able to grow at the room temperature and increase their
populations. The yeast and mold count of samples increased during storage due to
contamination from packaging system and environment on 65th day. The yeast and mold
count was found to increase with increase in storage time. Londhe et al., (2012) [107]
reported that increase of yeast and mold count when the progress of storage period for
brown peda.
5.7.3 Textural characteristics of Chhana jalebi stored in MET with MAP and
vacuum packaging techniques
Based on physic chemical and sensory analysis, it was found that shelf life of
800 ppm potassium sorbate added and packed in metalized polystyrene Chhana jalebi
samples was 60 days. Hence textural analysis was carried out for the same. Hardness of
the product was increased from 1.41N on 0th day to 2.24N, 2.45N and 2.16N for 100%
N2, 100% CO2 and 50% N2 + 50% CO2 gas filled packaging material samples
respectively on 50th day. Hardness of the product was increased due to moisture loss.
Moisture loss occurred due to absorption of moisture by the both the nitrogen and
oxygen gases in the packaging materials. This is in accordance with the earlier findings
of Gupta et al., (1990) [146], Patel et al., (1990) [147] and Suresh et al., (1994) [148]
and reported that the increased hardness of khoa correlated with the increase in the total
solids and the moisture content of peda had a direct relationship with the hardness.
156
Table 5.54 Textural characteristics* of Chhana jalebi stored in gas flushed
metalized polyester packing material during 60th day at ambient temperature
(28±2°C)
Textural characteristics
60th Day analysis for metalized polyester pouches
100 % N2 100 % CO2 50% N2 + 50% CO2
Hardness (N) 2.24 2.45 2.16
Adhesiveness (Ns) -4.27 -4.78 -4.56
Springiness (mm) 0.867 0.924 0.912
Cohesiveness 0.583 0.633 0.624
Chewiness (Nm) 1.28 1.43 1.53
*Average three trials
Adhesiveness also increased from initial value of -5.65 Ns on 0th day to -4.27
Ns, -4.78 Ns and -4.65 Ns for 100% N2, 100% CO2 and 50% N2 + 50% CO2 gas filled
packaging material samples respectively on 50th day.. The decline in the adhesion could
be due to the decrease in free moisture during storage. The adhesiveness of the lal peda
samples were found to be higher than that brown peda reported by Londhe et al., (2012)
[107]. The higher adhesiveness values could be attributed to the higher moisture content
in the lal peda. Springiness refers to a food ability to return to its original form after
compression. The Chhana jalebi samples in all trials showed an increasing trend in
springiness. Springiness of the product increased from initial value of 0.817 mm on 0th
day to 0.867 mm, 0.924 mm and 0.912 mm for 100% N2, 100% CO2 and 50% N2 + 50%
CO2 gas filled packaging material samples respectively on 50th day. It indicates that,
springiness was increased due to increase of activity of gluten content. Current findings
were in accordance with Palit (1998) [142]. Cohesiveness is the ratio of area under the
second bite curve before reversal compression to that under the first bite curve. It is the
measure of the extent to which the Chhana jalebi structure was disrupted during the first
compression.
Cohesiveness of the product increased from initial value of 0.53 on 0th day to
0.583, 0.633 and 0.624 for 100% N2, 100% CO2 and 50% N2 + 50% CO2 gas filled
packaging material samples respectively on 50th day (Table 5.54). However, the
157 cohesiveness of the MAP packed product remained fairly constant throughout the
storage. Londhe et al., (2012) [107] have been reported that cohesiveness of MAP
packed brown peda remained constant upto 20-30 days. Current findings are in
accordance with their observation. Loss in moisture content may be responsible for the
decrement in the cohesiveness with the progression of storage. Similar findings have
been reported by Gupta et al., (1990) [146] where cohesiveness of khoa tended to
decline with increasing the total solids.
Chewiness refers to the energy required to masticate food into a state ready for
swallowing and is a product of gumminess and springiness. Chewiness of the product
also increased from initial value of 0.57 Nm on 0th day to 1.28 Nm, 1.43 Nm and 1.53
Nm for 100% N2, 100% CO2 and 50% N2 + 50% CO2 gas filled packaging material
samples respectively on 50th day (Table 5.54). This increasing trend in chewiness in all
Channa jalebi samples during storage could be attributed to increase in gumminess and
springiness values. These findings are in agreement with the findings of Palit (1998)
[142] who observed that the gumminess and chewiness of burfi increase with the
progress of storage period irrespective to type of packaging. Patil et al., (2002) [138]
observed that soft burfi was significantly less gummy than hard burfi.
Based on textural characteristics ultimately it was revealed that, fresh sample of
final standardized Chhana jalebi was very suitable for consumption. Even after 50 days
or 60 days of storage, there was very small variation in all textural characteristics.
Hence it concluded that, final standardized Chhana jalebi was more suitable and
comfortable for human consumption.
5.7.4 Sensory characteristics of Chhana jalebi stored in MET with MAP and
vacuum packaging techniques
There were four sensory characteristics such as color and appearance, flavor,
body and texture and overall acceptability analyses carried out and results are presented
as below.
i. Changes in color and appearance
The color and appearance scores of jalebi during storage as influenced by four
different gas flushing are presented in Table 5.55. The sensory scores showed a
decreasing trend during storage in all samples of Chhana jalebi irrespective of
158 packaging techniques. The mean score decreased from the initial value of 8.93 to 4.13
at the end of 60 days of storage at room temperature. All the gas flushed packed
samples scores in range between 7.22 and 7.55 at end of 40th day whereas color and
appearance score of the product was 6.50 until 50th day. After this, due to mold growth
and little dryness of the product, the color and appearance score turned in unacceptable.
This was determined by taking the minimum score of 6.5 as acceptable limit. The mean
scores were 8.93, 8.27, 7.36 and 4.13 respectively for samples packed in metalized
polyester filled with 100% N2, 100% CO2, 50% N2 and 50% CO2 and vacuum. Same
results were observed by other Researchers [107, 121].
Table 5.55 Changes in the color and appearance score* of Chhana jalebi control
samples packed in gas flushed metalized polyester packaging materials stored at
ambient temperature (28±2°C)
Packaging material
Control samples stored at 28±2°C (days)
0 20 40 60 Avg. mean
Metalized polyester (100% N2) 8.94 8.25 7.45 4.22 7.22
Metalized polyester (100% CO2) 8.95 8.31 7.23 4.54 7.26
Metalized polyester (50% N2 + 50% CO2)
8.91 8.25 7.55 4.44 7.29
Metalized polyester (vacuum) 8.91 8.25 7.22 3.32 6.93
CD=0.44 8.93d 8.27c 7.36b 4.13a
*Average three trials; Note: Values with different superscripts are differ significantly at
P≤0.05
Statistical analysis results also showed highly significant effect of all packaging
techniques and storage period on all the sensory attributes of Chhana jalebi during
storage (P<0.05). The colour and appearance of the product was retained well up to 40
days of storage.
159
Table 5.56 Changes in the color and appearance score of 800 ppm potassium
sorbate treated Chhana jalebi samples packed in gas flushed metalized polyester
packaging materials stored at ambient temperature (28±2°C)
Packaging material
Preservative added samples stored at 28±2°C(days)
0 30 60 65 Avg. mean
Metalized polyester (100% N2) 8.94 8.31 7.52 5.91 7.67
Metalized polyester (100% CO2) 8.94 8.86 6.62 5.45 7.46
Metalized polyester (50% N2 +50%CO2)
8.93 8.42 7.63 7.13 8.02
Metalized polyester (vacuum) 8.93 8.62 6.67 5.1 7.33
CD=0.81 8.93c 8.55c 7.11b 5.89a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
The acceptability scores became lower because of dry appearance which could
be attributed to moisture evaporation from the product within the package. Also, the
product’s initial moist appearance disappeared during storage imparting slightly cloudy
appearance because of surface moisture evaporation and hydration of proteins. It is
known that protein hydration continues with storage time [149]. These scores were
statistically significant to all the gas filled and packed in metalized polyester packaging
material irrespective of storage period. It can be also observed from the Table 5.56 that
different gas flushing level had not significant. The ANOVA indicates the significant
effect of gas flushing and storage period and their interaction (P≤0.05). Same impacts
were observed in danedar khoa [132].
The changes observed in the sensory score of color and appearance for 800 ppm
potassium sorbate treated samples were packed in all four gas filled metalized polyester
packaging materials and stored at 28°C are represented in Table 5.56. At this storage
temperature and also the effect of storage period found to be significant and effect of
gas flushing and their interaction found to be not significant (P≤0.05). In that period
within which the color and appearance score remained 6.5 and above for all packaging
materials were 60 days. After 60th days, color and appearance turned unacceptable.
160 These may be attributed to the effect of packaging material on mold growth. Despite
decreasing trend the samples were found to score well over the minimum acceptable
limit during the entire storage study.
ii. Changes in flavor
Like color and appearance, the rate of aroma and flavor deterioration was not
rapid in the sample of Chhana jalebi packed in metalized polyester with different gas
flushed. There was no significant (P>0.05) difference between all the combination of
gas filled and packed in metalized polyester packaging material whereas statistically
significant difference were observed on storage period. The mean scores of flavor were
8.94, 8.22, 7.28 and 4.38 for respectively for samples packed in metalized polyester
filled with 100% N2, 100% CO2, 50% N2 and 50% CO2 and vacuum. It indicated that the
all gas flushing packed samples shelf life was 40 days (Table 5.57).
Similarly, preservative treated samples which packed in all combinations of gas
filled and vacuum packed metalized polyester packed samples flavor score remained 6.5
and above for 60 days whereas the flavor score was turned unacceptable after 60 days.
The decrease in flavour scores may be attributed to slight loss of freshness, which is
inherent with any food product.
Table 5.57 Changes in the flavor score* of Chhana jalebi control samples packed
in gas flushed metalized polyester packaging materials stored at ambient
temperature (28±2°C)
Packaging materialControl samples stored at 28±2°C (days)
0 20 40 60 Avg. mean
Metalized polyester (100% N2) 8.91 8.21 7.20 4.70 7.26
Metalized polyester (100% CO2) 8.96 8.34 7.46 4.8 7.39
Metalized polyester (50% N2 + 50% CO2) 8.92 8.00 7.24 4.02 7.05
Metalized polyester (vacuum) 8.95 8.32 7.21 4.00 7.12
CD=0.20 8.94d 8.22c 7.28b 4.38a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
161
Table 5.58 Changes in the flavor score* of 800 ppm potassium sorbate treated
Chhana jalebi samples packed in gas flushed metalized polyester packaging
materials stored at ambient temperature (28±2°C)
Packaging material
Preservative added samples stored at 28±2°C (days)
Avg. mean
0 30 60 65
Metalized Polyester (100% N2) 8.95 8.42 7.69 5.45 7.63
Metalized Polyester (100% CO2) 8.97 8.87 7.75 4.58 7.54
Metalized Polyester (50% N2 + 50% CO2) 8.95 8.41 7.90 5.86 7.78
Metalized Polyester (vacuum) 8.94 8.65 7.39 4.25 7.31
CD=1.48 8.95c 8.59c 7.68b 5.04a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
The findings of the present study are in accordance with the report of Biradar et
al., (1983) [130] and Sharma et al., (2001) [132] also reported the decrease in mean
flavour and body and texture scores of the control and MAP packaged malai peda
samples in flexible packaging material at room temperature. The reduction in flavour
and body and texture score for control (without MAP) was much rapid than MAP
samples. Similar observation was reported by Kumar (1997) [108]. The ANOVA
indicates the not significant effect of gas flushing in metalized polyester packaging
material, but significant effect on storage period and their interaction (P≤0.05) (Table
5.58).
iii. Changes in body and texture
Up to 45 days of storage the body and texture score of Chhana jalebi in all gas
filled metalized polyester packed samples remained unchanged and thereafter a
decreasing trend with further advancement of storage period was noticed in Table 5.59.
The mean value of body and texture scores decreased drastically from 8.89 to 4.28 up to
60 days of storage at 28±2°C. There was no significant (P>0.05) difference between gas
flushing in metalized polyester packaging material but significant difference on storage
period and their interaction.
162
Table 5.59 Changes in the body and texture score* of Chhana jalebi control
samples packed in gas flushed metalized polyester packaging materials stored at
ambient temperature (28±2°C)
Packaging material
Control samples stored at 28±2°C (days)
Avg. mean
0 20 40 60
Metalized polyester (100% N2) 8.91 8.10 7.33 4.00 7.09
Metalized polyester (100% CO2) 8.93 8.12 7.43 4.20 7.17
Metalized polyester (50% N2and 50% CO2) 8.93 8.10 7.64 4.92 7.40
Metalized polyester (vacuum) 8.80 8.10 6.64 4.00 6.89
CD=0.36 8.89d 8.11c 7.26 b 4.28a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
The changes in sensory score of body and texture of the preservative treated
samples which packed in all combinations of gas filled and vacuum filled metalized
polyester packing material, stored at 28°C are presented in Table 5.60. The mean score
of body and texture samples were 8.91 to 4.97 at the end of 65 days stored at 28°C. In
that period, within which the body and texture score remained 6.5 and above for all gas
filled and vacuum packed samples until 60 days of storage at 28±2°C. The product’s
initial moist appearance disappeared during storage imparting slightly cloudy
appearance due to surface moisture evaporation and hydration of proteins. It is known
that protein hydration continues with storage time [149]. This affected the body and
texture scores and became firm during storage attributable not only to loss of moisture,
however also to continued conformational changes of proteins [110]. The findings of
the present study are in accordance with the report of Londhe et al., (2012) [107] and
Biradar et al., (1985) [130]. Another study also reported the decrease in mean body and
texture scores of the control and MAP packaged malai peda samples in flexible
packaging material at room temperature. The reduction in body and texture score for
control (without MAP) was much rapid than MAP samples [132]. Similar observation
was reported by Kumar et al., (2008a) [121]. The ANOVA indicates that there was no
significant (P>0.05) difference between gas flushing in metalized polyester packaging
material but significant difference on storage period and their interaction.
163 Table 5.60 Changes in the body and texture score* of 800 ppm potassium sorbate
treated Chhana jalebi samples packed in gas flushed metalized polyester
packaging materials stored at ambient temperature (28±2°C)
Packaging material
Preservative added samples stored at 28±2°C (days)
Avg.
mean0 30 60 65
Metalized polyester (100% N2) 8.92 8.32 7.52 5.59 7.59
Metalized polyester (100% CO2) 8.97 8.84 6.61 4.55 7.24
Metalized polyester (50% N2 + 50% CO2) 8.93 8.40 7.93 5.51 7.69
Metalized polyester (vacuum) 8.80 8.10 6.62 4.21 6.93
CD=1.16 8.91c 8.42c 7.17b 4.97a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
iv. Changes in overall acceptability
The average overall acceptability scores for all gas filled and vacuum filled and
packed samples control and preservative treated sample are given in Table 5.61. A
decreasing trend with further advancement of storage period was noticed in Table 5.61.
The mean score of overall acceptability samples were 8.95 to 7.22 at the end of 40 days.
Later on, the mean scores of overall acceptability decreased drastically from 7.22 to
4.08 on 60 days of storage at 28±2°C. From Table 5.61, it indicates that the shelf life of
all gas flushed and packed in metalized polyester samples had 40 days. The effect of the
gas flushing and the interval of storage on overall acceptability of Chhana jalebi were
found significant (P>0.05).
The overall changes are reflected in changes in overall acceptance scores. These
gradually decreased and remained acceptable up to 40 days of storage at 28oC. The
scores were 7.21, 7.18, 7.34 and 7.14 respectively for 100% N2, 100% CO2, 50% N2 and
50% CO2 and vacuum packaging at the end of 40 days. After 40 days, the scores knock
down to unacceptable limit because of visible mold growth, dry appearance and rancid
flavor which could be attributed to chemical reactions.
164
Table 5.61 Changes in the overall acceptability score* of Chhana jalebi control
samples packed in gas flushed metalized polyester packaging materials stored at
ambient temperature (28±2°C)
Packaging material
Control samples stored at 28±2°C(days)
Avg. mean0 20 40 60
Metalized polyester (100% N2) 8.96 8.45 7.21 4.09 7.18
Metalized polyester (100% CO2) 8.95 8.23 7.18 4.03 7.17
Metalized polyester (50% N2 + 50% CO2)
8.95 8.56 7.34 4.18 7.26
Metalized polyester (vacuum) 8.95 8.22 7.14 4.02 7.08
CD=0.56 8.95d 8.37c 7.22b 4.08a
*Average three trials; Note: Values with different superscripts are differ significantly at
P≤0.05
Thus, the shelf life of the product could be ascertained as 40 days irrespective of
the type of gas used. The effect of the gas flushing and the interval of storage on overall
acceptability of Chhana jalebi were found significant (P<0.05). Despite decreasing trend
the samples were found to score well over the minimum acceptable limit (65% score of
the total score) during the 40 days of storage study in metalized polyester with various
gas flushing levels and vacuum packaging methods.
The changes in sensory score of overall acceptability of the preservative treated
samples which packed in all combinations of gas filled and vacuum filled metalized
polyester packing material, stored at 28°C are presented in Table 5.62. The mean score
of overall acceptability scores were 8.95 to 5.31 at the end of 65 days stored at 28°C. In
that period, within which the overall acceptabilty score remained 6.5 and above for all
gas filled and vacuum packed samples until 60 days of storage at 28±2°C. Same results
were observed other indigenous dairy products such as brown peda, burfi, khoa etc.,
[107, 113, 114, 120]. The MAP was found to enhance the sugar containing products.
Kumar et al., (1997) reported that peda packed under 80% N2 and 20% CO2 stayed well
up to 15 days at 37oC and 30 days at 20oC [108]. Malai peda shelf life was enhanced to
31 days at 11oC when packed under vacuum-nitrogen [143].
165
Table 5.62 Changes in the overall acceptability scores* of 800 ppm potassium
sorbate treated Chhana jalebi samples packed in gas flushed metalized polyester
packaging materials stored at ambient temperature (28±2°C)
Packaging material
Preservative added samples stored at 28±2°C Average
mean0 30 60 65
Metalized polyester (100% N2) 8.93 8.43 7.20 5.18 7.44
Metalized polyester (100% CO2) 8.95 8.88 7.06 5.63 7.63
Metalized polyester (50% N2 + 50% CO2)
8.95 8.50 7.34 6.04 7.71
Metalized polyester (vacuum) 8.95 8.65 6.69 4.40 7.17
CD=1.31 8.95c 8.62c 7.07b 5.31a
*Average three trials; Note: Values with different superscripts are differ significantly at P≤0.05
Based on the study, it was concluded that Chhana jalebi samples packed in
100% N2, 100% CO2, 50% N2 with 50% CO2 and vacuum packaging in MET without
addition of preservative had shown 40 days shelf life at ambient temperatures (28±2°C)
whereas 800 ppm potassium sorbate treated samples had given 65 days. All four
packaging materials along with Chhana jalebi samples are shown in Figure 5.28-2.
5.8. EFFECT OF VACUUM PACKAGING ON SHELF LIFE OF CHHANA
JALEBI PACKED IN LOW AND HIGH BARRIER MATERIAL
Chhana jalebi samples were packed in low density polyethylene and metalized
polyester with different vacuum levels viz. 608 mm of Hg (80%), 646 mm of Hg (85%),
684 mm of Hg (90%), 723 mm of Hg (95%) and 750 mm of Hg (100%). Settings of
heating time were 1.5 and 2 sec for metalized polyester and LDPE respectively and
cooling time for both samples were 9 sec. Chhana jalebi samples were observed that
compressed appearance, ruptured the coils, oozed out the sugar syrup at all the level of
treatment after opened whereas, very slow microbial growth, less increase of acidity and
peroxide values were observed for the same samples (Figure 5.28-3). Same results were
observed for other dairy products such as brown peda [107], lal peda [150] etc., in
microbial growth, acidity and peroxide value. Several earlier Researchers also reported
166 the similar trends for different dairy products during their storage studies. Goyal and
Srinivasan (1989a) [112], Kumar and Srinivasan (1983) [120] and Sharma et al., (2001)
[132] reported in khoa. Similarly, Palit and Pal (2014) [105], Sachdeva and rajorhia
(1982) [140] in burfi, whereas Kumar et al., (1997) [108], and Sharma et al., (2001)
[132], in peda and Navajeevan and Rao (2005) [110] in retort processed kunda.
Interesting fact is that, all these Researchers have found vacuum packaging was one of
the best suited packaging techniques for their products since those products nature was
dried and solid, whereas, nature of jalebi was different from other mentioned dairy
products since it was fried in oil and soaked in sugar syrup. Hence, it was experiential
that, vacuum packaging was not suitable for commercialization due to loss of desirable
appearance, body and texture and oozing out of sugar syrup though product retaining
good internal characteristics such as slow microbial growth, less increase of acidity and
peroxide value.
167
Figure 5.28 Different packaging techniques for Chhana jalebi storage
1. Modified atmospheric packaging in low density polyethylene 2. Modified atmospheric packaging in metalized polyester 3. Vacuum packaging technique
1
2
3
168 5.9 CONSOLIDATED SHELF LIFE OF CHANNA JALEBI IN VARIOUS
PACKAGING MATERIALS AND TECHNIQUES
Based on the study, it was reported that 800 ppm of potassium sorbate
preservative treated and packed in metalized polyester packaging material with all the
gas flushed samples was acceptable for storage at both ambient and refrigerated
temperatures. Table 5.63 represented shelf life of all packaging materials with different
conditions.
Table 5.63 Shelf life of all packaging materials for control and 800 ppm potassium sorbate treated Chhana jalebi stored at both ambient (28 ±2°C) and refrigerated
temperatures (4 ±2°C)
Packaging materials
Ambient temperature(28 ±2°C)
Refrigerated temperature (4±2°C)
Control(days)
800 ppm Potassium sorbate(days)
Control(days)
800 ppm Potassium sorbate(days)
LDPE pouch 4 20 15 60
Metalized polyester 4 20 15 60
Polystyrene cups 4 20 15 60
Cardboard box lined with butter paper 4 20 15 60
LDPE (100% N2) 30 40 - -
LDPE (100% CO2) 30 40 - -
LDPE (50% N2 + 50% CO2) 30 40 - -
LDPE (vacuum) 30 40 - -
Metalized polyester (100% N2) 40 60 - -
Metalized polyester (100% CO2) 40 60 - -
Metalized polyester (50% N2 + 50% CO2) 40 60 - -
Metalized polyester (vacuum) 40 60 - -
Based on the chemical and microbial analyses, metalized polyester with 50% N2
and 50% CO2 was found as more suitable for packing Chhana jalebi samples to store at
ambient temperature.
169 5.10 COST ANALYSIS OF STANDARDIZED CHHANA JALEBI
Cost of Chhana jalebi was calculated based on the cost of all the ingredients used
for making and the processing cost which is 30% of ingredient cost. Along with that
packaging material cost was also included. After preparing Chhana jalebi it was packed
in polystyrene cups, cardboard box, metalized polyester pouch and LDPE pouches. In
polystyrene cups/cardboard box/metalized polyester/LDPE pouches 3-4 pieces of
Chhana jalebi of 20g weight was considered for packaging (Table 5.64).
Table 5.64 Cost analysis for standardized product packed in gas flushed metalized
polyester packaging material
Ingredients Quantity Cost per unit (Rs.)
Total cost (Rs.)
Milk (3% fat) for 3 kg Chhana yield 18 liters 26.00 468.00Maida 3 kg 40.00 120.00
Corn flour 0.5 kg 90.00 45.00Sugar 15 kg 35.00 525.00
Water 20 liters 0.30 6.00Refined oil 4 liters 88.00 176.00*
Cardamom 0.009 kg 750.00 6.75Preservative 0.1384 kg 1728 239.16
Citric acid 0.02 kg 360 7.20Total raw material cost 1593.11
Processing (30% of ingredient cost) 477.93
Packaging cost in cardboard box / polystyrene cup / LDPE pouch / metalized polyester for 1000 pieces (1000 × 0.60) 600.00
Total cost of production for 1000 pieces including packaging cost 2671.04
*same oil can be used for frying, partial oil price (50%) was considered
Cost of production per piece of Chhana jalebi (2671.04/1000) = Rs. 2. 67 (approx.)
Weight per piece of Chhana jalebi = 5 g
Total number of Chhana jalebi in 1 kg (1000 / 5) = 200 Nos.
Cost of production of Chhana jalebi per kg (200 x 2.67) = Rs. 534 /-