indian journal of science method - discoveryjournals.org · viz., dhantu, khirkhire, honagone,...

Process optimization for drying of drumstick leaves Publication History Received: 03 February 2016 Accepted: 27 February 2016 Published: 1 March 2016 Citation Kannan K, Thahaaseen A. Process optimization for drying of drumstick leaves. Indian Journal of Science, 2016, 23(79), 275-288

Indian Journal of Science Method The International Journal for Science ISSN 2319 – 7730 EISSN 2319 – 7749 © 2016 Discovery Publication. All Rights Reserved

PROCESS OPTIMIZATION FOR DRYING OF DRUMSTICK LEAVES

K.KANNAN1*, A.THAHAASEEN2

[email protected]

ABSTRACT

There are many varieties of green leafy vegetables which are though rich in

micronutrients, but are usually discarded or are not used for human consumption. One such

leaf, a rich source of micronutrients but still under exploited is Moringa leaf (Moringa

oleifera). Dried Moringa leaves can be stored during off seasons however drying causes

degradation of colour characteristics which reduces its marketable value. In present

investigation, efforts were made to analyze the effect of different pre treatments and drying

methods such as sun, shade and hot air oven drying at different temperatures (50, 60, 70˚C) on

the nutritive value of the selected leaf for Moringa leaves drying. The results revealed that

Moringa leaves pre-treated with 0.1% sodium bicarbonate and dried in shade drying gave

better results in drying characteristics and nutritional analysis such as carbohydrates - 33.86g,

fibre - 8.18g , protein - 27.40g , vitamin-C – 13.21mg, chlorophyll content-3.1 mg

respectively. Similarly in oven drying at 50˚c Moringa leaves treated with Na2Co3 shows the

best result. The nutritional content in oven dried Moringa is iron – 15.2mg, carbohydrates –

28.6g, fibre - 6.5g , protein - 24.40g , vitamin-C – 10.81mg, chlorophyll content-2.4 mg

respectively. On the basis of obtained results it could be concluded that shade drying treated

with Na2Co3 is superior to that of sun and hot air oven drying in terms of nutritional content.

Key words: Moringa oleifera, dehydration, sun drying, shade drying, oven drying,

biochemical analysis

1*. Assistant Professor, Department Of Food Technology

2. M.Tech, Department Of Food Technology

Kongu Engineering College

Perundurai, Erode.

1. INTRODUCTION

Drumstick leaves (Moringa oleifera) is one of them, which is available at no cost and

is very rich in all the micronutrients. M. oleifera, commonly referred to simply as "Moringa",

is the most widely cultivated species of the genus Moringa, which is the only genus in the

family Moringaceae. It is an exceptionally nutritious vegetable tree with a variety of potential

uses. The tree itself is rather slender, with drooping branches that grow to approximately 10 m

in height. The "Moringa" tree is grown mainly in semi - arid, tropical, and subtropical areas,

while it grows best in dry sandy soil, it tolerates poor soil, including coastal areas. It is a fast -

growing, drought resistant tree that is native to the southern foothills of the Himalayas in north

western India. The immature green pods called “drumsticks” are probably the most valued and

widely used part of the tree. They are commonly consumed in India and are generally prepared

in a similar fashion to green beans and have a slight asparagus taste. The seeds are sometimes

removed from more mature pods and eaten like peas or roasted like nuts. The flowers are

edible when cooked, and are said to taste like mushrooms. The leaves are highly nutritious,

being a significant source of beta carotene, Vitamin C, protein, iron, and potassium. The

leaves are cooked and used like spinach. In addition to being used fresh as a substitute for

spinach, its leaves are commonly dried and crushed into a powder, and used in soups and

sauces. Murungakai, as it is locally known in Tamil Nadu and Kerala, is used in Siddha

medicine. Its leaves are full of medicinal properties (Pandhre GR, Satwase AN.,(2011).

Drumstick leaves are commonly consumed in India and are generally prepared in a

similar fashion to green beans and have a slight asparagus taste. The seeds are sometimes

removed from more mature pods and eaten like peas or roasted like nuts. The flowers are

edible when cooked, and are said to taste like mushrooms. The leaves are highly nutritious,

being a significant source of beta - carotene, Vitamin C, protein, iron, and potassium. It is

commonly said that Moringa leaves contain more Vitamin A than carrots, more calcium than

milk, more iron than spinach, more Vitamin C than oranges, and more potassium than

bananas,” and that the protein quality of Moringa leaves rivals that of milk and eggs. The

leaves are cooked and used like spinach. In addition to being used fresh as a substitute for

spinach, its leaves are commonly dried and crushed into a powder, and used in soups and

sauces. Its leaves are full of medicinal properties.

Incorporation of dried leaves in food products can have good sensory

acceptance. Lalitha and Sathya (2003) incorporated curry leaves, and coriander leaves powder

in commonly used instant mixes such as dhal powder, bajji mix and vadai mix and reported

that all products were equally acceptable. Singh and Awasthi (2003) investigate the effect of

powder made from kachnar, colocasia and curry leaves incorporated food products and found

that it is significantly acceptable. The food products prepared using powders of amaranth,

curry leaves, gogu and mint were rated as highly acceptable for all the sensory attributes and

were scored from good to excellent on five point scale Lakshmi and Vimala (2000). The effect

of blanching prior to dehydration in cross air flow drier was studied in seven leafy vegetables

viz., dhantu, khirkhire, honagone, chakota, palak, kachiand fenugreek showed the highest

retention of chlorophyll (Premavalli et al., 2001). Blanching of amaranth in hot water (95 ±

3°C) for one minute followed by cooling in running tap water and dipping in 0.5 per cent

solution of potassium meta bisulphite for one minute prior to drying in cabinet drier showed

higher retention of chlorophyll, ß-carotene and lowered non-enzymatic browning (Negi and

Roy, 2001)

Drying is almost certainly the oldest method that humans have practiced to preserve

food for future use. Drying foods in sunlight reduced the weight and volume of the foods so

that they could be more easily stored and transported by our ancestors. Drying occurs by

effecting vaporization of the liquid by supplying heat to the wet feedstock. As noted earlier,

heat may be supplied by convection (direct dryers), by conduction (contact or indirect dryers),

radiation or volumetrically by placing the wet material in a microwave or radio frequency

electromagnetic field (Arun S. Mujumdar and Sakamon Devahastin 2001). Over 85 percent of

industrial dryers are of the convective type with hot air or direct combustion gases as the

drying medium. Over 99 percent of the applications involve removal of water.

The major challenge that is being faced in the moringa leaves production is its lower shelf life.

Thus the objective of our project is

To pre-treat the sample with sodium chloride and sodium bicarbonate.

To dehydrate the leaves with various drying methods (sun, shade, hot air oven) and

temperature (50˚C, 60˚C, 70˚C).

To estimate Proximate analysis of the dehydrated drumstick leaves

To determine the drying characteristics and obtain a solution by comparative study.

2. MATERIALS AND METHODS:

The drumstick leaves, one of green leafy vegetable was obtained from local vegetable

market. These leaves were easily available across every corner even in remote areas .The

leaves were also grown in many house hold especially in villages.

Selection of drumstick leaves

↓

Cutting

↓

Washing

↓

Pretreatment (NaCl & Na2Co3)

↓

Drying using sun, shade and Hot air oven (50°, 60° and 70°C)

↓

Grinding

↓

Optimization

Fig.1 Methodology

Independent variables are type of drying (sun, shade, hot air oven drying) and

temperature of hot air oven (50˚C, 60˚C, 70˚C). Dependent variables are moisture content, ash,

crude fibre, carbohydrate, protein, chlorophyll, and vitamin-C.

The drumstick leaves were pretreated to retain the colour. The drumstick leaves

were, washed and then pretreatment was done with sodium chloride (2% NaCl) and sodium

bicarbonate (0.1% Na2Co3). Then the water is drained and drying is done. The leaves are

spread on a large tray and different types of drying are carried out (sun, shade, hot air oven

drying).

DRYING

The techniques used for dehydration were (i) Sun drying; (ii) Shade drying and (iii) Hot air

oven drying

Sun drying:

The leaves were placed on large tray. The tray were placed in a direct sunlight on a

roof away from dust to assure even drying. During drying the temperature of the leaves were

noted. The temperature is about 26˚c.

Shade drying:

In shade drying, the leaves were spread on large tray but instead of keeping them on

the roofs the leaves were kept in the room only. The room selected for shadow drying was

well ventilated. Natural current of air was used for shadow drying the leaves.

Hot air oven drying:

The leaves were spread on the trays and kept in hot air oven ( Hasthas Hot air oven).

The leaves were dried in the hot air oven by forced air technique. The temperature was

maintained at 50°C, 60°C, 70°C and the leaves were dried. The dried leaf samples were then

analyzed for (i) Proximate composition (Protein, fiber, carbohydrate). (ii) Vitamin (vitamin

C). (iii) Minerals (Iron).

NUTRITIONAL ANALYSIS

Nutritional analysis was done as described in the table given below

Parameters Determination methods Reference

Moisture content Oven method Sadhasivam and Manikam, 2008

Ash Muffle furnance Sadhasivam and Manikam, 2008

Crude fibre Alkali treatment method Sadhasivam and Manikam, 2008

Carbohydrate Anthrone Sadhasivam and Manikam, 2008

Protein Kjeldahl Sadhasivam and Manikam, 2008

Iron Spectrophotometer Sadhasivam and Manikam, 2008

Chlorophyll Spectrophotometer Sadhasivam and Manikam, 2008

Vitamin - C Iodine titration method B.K.Sakhale et al

3. RESULTS AND DISCUSSIONS:

Drying Characteristics

The time required for drying in different drying condition is shown in Fig.4.2. There

was wide variation in drying time. The hot air oven drying method took least time of 140

minutes for drying due to higher temperature and the moisture content dried Moringa leaves

was about 10.3%. In shade and sun drying methods required maximum time of about 240 and

200 minutes to reach the final moisture content of 12 – 14%. The rate of moisture removal in

hot air oven drying was much faster than the sun and shade drying. The final moisture content

of dried leaves was in the range of 8-15%. The moisture content of Moringa leaves in hot air

oven drying at 70˚c was comparatively low because of higher temperature. In shade drying the

moisture content is higher because of lower temperature.

The change in moisture content with respect to time for controlled, Nacl and Na2Co3

treated Moringa leaves are shown in the figure 4.2, 4.3, 4.4.In fenugreek samples for fresh

leaves the moisture content was in the range 77.8% (Pallavi Joshi and Dipika Mehta, 2010)

Protein Content

The protein content in the controlled, Nacl and Na2Co3 treated dried leaves was in

the range of 20.42 - 26.78 g per 100 g. Maximum protein content of 27.4 g was in the shade -

dried moringa leaves treated with Na2Co3 and the minimum was in the oven dried at 70˚C

treated with Nacl. At lower temperature the protein content at 50˚C is 23.75 g when compared

to sun and oven drying at 60 and 70˚c which is about 16 – 18 g respectively. The difference in

the protein content of the dried moringa leaves was shown in fig 4.5.

Fibre Content

The fibre content in the dried moringa leaves was in the range of 5.3 to 8.8g with

the highest level in shade dried moringa leaves 8.1g followed by sun dried 7.92g and the

minimum values of fibre were found in oven dried moringa leaves at 70˚C which is about

5.12g/100g of moringa leaves as shown in fig 4.7. Shade drying treated with Na2Co3 contains

higher fibre content when compared with oven dried moringa leaves. At higher temperature

the fibre content is low, as fibre is heat sensitive.

Carbohydrate Content

Carbohydrate content of moringa leaves was found to be in the 34.76g/100g.

Sample which was shade dried and treated with Na2Co3 contains higher carbohydrate content

of 34.45g than the oven dried sample at 70˚C which is about 24.34g respectively. Oven drying

at 50˚C contains carbohydrate content of about 25 - 27g.

Iron

Fresh drumstick leaves have an iron content of 0.085 mg/ 100 g of iron. Maximum

amount of iron content was in the shade dried moringa leaves 16.21 mg/ 100 g leaf powder

followed by sun dried moringa leaves 15.12 mg/ 100 g leaf powder and it was the lowest in

oven dried moringa leaves at 70˚C is 9.42 mg/ 100 g leaf powder.The difference in the iron

content of the dried moringa leaves was significant as shown fig 4.5

Chlorophyll Content

The maximum retention of chlorophyll was in shade dried moringa leaves is

2.7mg and followed by oven dried moringa leaves at 50˚C is 2.2 mg. Shade drying though

took longer time than sun and oven drying. Shade drying treated with Na2Co3 has the

maximum color retention than shade drying with Nacl. The difference between the dried

moringa leaves of drumstick leaves was significant.

Vitamin C

Vitamin C content of the dried leaves was less than the fresh moringa leaves. The

maximum amount of vitamin C was in shade - dried moringa leaves 12.80 mg as in this

technique the leaves were not exposed to direct heat and air. As vitamin –C is heat sensitive 60

and 70˚C vitamin C content is 6-8mg which is relatively low. Maximum amount of Vitamin-C

is retained in shade drying treated with Na2Co3 which contains 12.80 mg/100 g of moringa

leaves followed by oven dried at 50˚c is 11.8 mg/100 g of moringa leaves.

Fig.2 Drying characteristics for untreated moringa leaves

Fig.3 Drying characteristics for pretreated Na2Co3 moringa leaves

Fig.4 Drying characteristics for pretreated NaCl moringa leaves

Fig.5 Effect of drying method on temperature on protein content of moringa leaves

Fig.6 Effect of drying methods and temperature on CHO content of moringa leaves

Fig.7 Effect of drying methods and temperature on fibre content of moringa leaves

Fig.8 Effect of drying methods and temperature on iron content of moringa leaves

Fig.9 Effect of drying methods and temperature on chlorophyll content of moringa leaves

Fig.10 Effect of drying methods and temperature on vitamin-c content of moringa leaves

4. SUMMARY AND CONCLUSION:

Drying of drumstick leaves resulted in concentration of nutrients. The shade drying of

leaves had high nutritional properties during the process which increased the consumer

acceptance of the product than the outer drying methods. Pretreatment the sample with 2%

Nacl and 0.1% Na2Co3 helped in better retainment. The dried sample at 70°C took less time to

dry until the desired moisture content of about 8.9%. From the studies conducted it can be

concluded that: The best method for drying of drumstick leaves was shade drying treated with

Na2Co3 as it showed the higher values of nutritional content in iron - 16.3mg, CHO - 33.86g,

fibre - 8.18g , protein - 27.40g , Vitamin-C – 13.21mg, chlorophyll content-3.1 mg

respectively. Another reason for this conclusion is its lower nutritional loss in shade drying

treated with Na2Co3 and colour retention is high. The moringa leaves at 70ᵒC shows the higher

nutritional loss because of higher temperature. Next to shade drying, moringa leaves treated

with Na2Co3 in hot air oven at 50˚C shows best nutritional value. So, drying of drumstick

leaves promotes wider application by in corporating in food products. For further studies, the

parameters like drying temperature, different pretreatment and by varying moringa leaves

thickness, etc., can be analysed for the best results.

REFERENCE

1. Aletor O and Abiodun A.R. (2007). Nutrient and antinutrient components of some

tropical leafy vegetables. Food Chem.,53:375-379.

2. Arun S. Mujumdar and Sakamon Devahastin “Fundamental principles of drying”

Exergex, Brossard, Canada (2000)

3. Bamji, Mahtab.S, 2008 ”Maternal nutritional status and practices and perinatal,

neonatal morality in rural Andhra Pradesh ,India”, Indian journal of medical research

127.1:44

4. Bajaj, M., Aggarwal, P., Minhas, K.S. and Sidhu, J. S., 1993, Effect of blanching

treatments on the quality characteristics of dehydrated fenugreek leaves. J. Food Sci.

Tech., 30(3): 196-198.

5. Chacko, M. and Khyrunissa B., 2007, Eating behavior and nutrient intake among

adolescent girls from middle income families. The Indian J. Nutr. Diet.,44(7): 367-373.

6. Chandrashekhar, U., Kowsalya, S. and Eapen, D., 2000, Retention of beta carotene

from selected greens and absorption of beta carotene from pumpkin leaves in adults.The

Indian J. Nutr. Diet.,37: 233-239.

7. Dharwad, Pushpa Bharati,2008 “Dehydration of amaranthus Leaves and its quality

evaluation.” Karnataka Journal Of Agricultural Sciences 26.2

8. Deepa, K. S., 2002, Nutritional and health profile during menarche and seasonal

variations in iron status. M. H.Sc. Thesis, Uni. Agri. Sci., Dharwad.

9. Gupta, D. K., Baburao, N. and Jayaraman, K. S., 1999, Improvement in rehydration

and shelf life stability of hot air dried and sun dried cabbage by pre-drying treatment.

Indian Food Packer, 53(6): 51-60.

10. Kaveri, G. V., Gupta, S., Lakshmi, J. A. and Prakash, J. 2004. Physiochemical

characteristics and sensory attributes of wheat-based “Papads” incorporated with green

leafy vegetables. Journal of Food Quality 27: 459 - 470.

11. Kasturiba, B., 1999, Promotion of vitamin A status through horticulture intervention.

Ph.D. Thesis, Uni. Agri. Sci., Dharwad.

12. Kowsalya, S., and Vidhya, M. R., 2004, Nutritive value of selected dehydrated green

leafy vegetables. The Indian J. Nutr. Diet.,41: 279-286.

13. Lakshmi, B. and Vimala, V., 2000, Nutritive value of dehydrated green leafy vegetable

powders. J. Food Sci. Tech., 37(5): 465-471.

14. Lalitha.R., and Sathya.K., 2003 Enrichment of instant food mix with beta carotene

through green leafy vegetables: acceptability characteristics. Proceedings of international

food conference;SS 02:75

15. Mosha, T. C., Pace, R. D., Adeyeye, S., Mtebe, K. And Laswai, H. S. 1995. Proximate

composition and mineral content of selected Tanzanian vegetables and the effect of

traditional processing on the retention of ascorbic acid, riboflavin and thiamine. Plant

Foods for Human Nutrition 48(3): 235 - 245.

16. Negi P. S. and Roy S. K. 2000. Effect of blanching and drying methods on β-carotene,

ascorbic acid and chlorophyll retention of leafy vegetables. Lebensmittel Wissenchaft und

Technologie 33(4): 295-298.

17. Negi, P. S. and Roy, S. K., 2001, Effect of drying conditions on quality of green leaves

during long term storage. Food Res. International, 34: 283–287.

18. PallaviJoshi and Dipika Mehta, 2010. Effect of dehydration on the nutritive value of

drumstick leaves

19. Pandhre GR, Satwase AN, Hashmi SI (2011) Effect of different pretreatments and

drying methods on color characteristics fenugreek leaves. Int J Cur Sci Res 1: 115- 119.

20. Prameela, Y., Chittemma Rao, K. and Sarojini, G., 1995, A comparative study on the

nutritional status of rural adolescent girls and boys (11-18 years) in Andhra Pradesh. The

Indian J. Nutr. Diet.,32: 175-179.

21. Premavalli, K. S., Jamudar, T. K. and Madhura, 2001, Processing effect on color and

vitamins of green leafy vegetables. J. Food Sci. Tech., 38(1): 79-81.

22. Saroj-Dahia., 2002, Nutritional status assessment of pregnant women from Hisar city

of Haryana. Nutrition and Health, 16(3): 239-247.

23. S. Sadasivam, A. Manickam (2008) , Biochemical methods :1-19. Published by New

Age International (P) Ltd., Publishers.

24. Singh, U., Sagar V. R., Behera, T. K., Suresh Kumar P., 2006, Effect of drying

conditions on the quality of dehydrated selected leafy vegetables. J. Food Sci. Tech.,

43(6): 579-582.

25. Singh, H., Bawa, A. S. and Ahmed, J., 1997, Dehydration characteristics of some

green leafy vegetables. Indian Food Packer, 51(2): 5-13.

26. Singh, P., and Awasthi, P., 2003, Sensory and nutritional quality evaluation of green

leafy vegetable (GLV) powder incorporated food products. Proceedings of International

Food Conference, SS-07: 77.

27. Unde, P.A., Padian, S.M. and Chaudhari, R. S., 2000, Osmotic dehydration of leafy

vegetables. Beverage and Food World, 26(1): 26-27.

indian journal of science method - discoveryjournals.org · viz., dhantu, khirkhire, honagone,...

Documents