effect of the storage time and drying on chemical …

Revista Brasileira de Produtos Agroindustriais, Campina Grande, v.19, n.4, p.427-437, 2017 427 ISSN: 1517-8595

Revista Brasileira de Produtos Agroindustriais, Campina Grande, v.19, n.4, p.427-437, 2017

EFFECT OF THE STORAGE TIME AND DRYING ON CHEMICAL AND

PHYSICOCHEMICAL PROPERTIES OF CASHEW KERNEL OIL

Anna Sylvia Ramos de Rangel Moreira Cavalcanti1 Robert K. Kross2,

Maria Elita Martins Duarte3, Mario Eduardo R.M. Cavalcanti3

ABSTRACT

This article deals with oil extraction of the cashew kernels by using a hydraulic press. The

samples were submitted to thin-layer drying, by using hot air in the temperatures of 50 and 70 oC. The samples of the cashew kernel oil were stored in glass bottles of 70 mL with an internal

space above the liquid of 5 mL. During the storage, the luminosity effect was studied, by

placing some samples exposed to the light, while other samples were completely isolated and, in

this case, the bottles were covered with aluminum foil and stored in a closed box. The pre-

treatment of the cashew kernels by drying didn’t affect the physicochemical properties of the

oil. The other properties (color, appearance and aroma) were not affected by the operational

conditions of this experiment. According to the obtained results, the cashew kernel oil can be

included in the list of other commercial vegetable oils.

Keywords: vegetable oils; cashew kernel; thin-layer drying

EFEITO DO TEMPO DE ARMAZENAGEM E SECAGEM EM PROPRIEDADES

QUÍMICAS E FÍSICO-QUÍMICAS DO ÓLEO DE CASTANO DE CAJU

RESUMO

Este artigo trata da extração de óleo da castanha de caju utilizando uma prensa hidráulica. As

amostras foram submetidas a secagem em camada delgada, utilizando ar quente nas

temperaturas de 50 e 70 °C. As amostras do óleo da castanha de caju foram armazenadas em

garrafas de vidro de 70 mL com um espaço interno acima do líquido de 5 mL. Durante o

armazenamento, o efeito da luminosidade foi estudado, colocando-se algumas amostras

expostas à luz, enquanto outras amostras foram completamente isoladas e, neste caso, as

garrafas foram cobertas com papel alumínio e armazenadas em uma caixa fechada. O pré-

tratamento das castanhas de caju feita por secagem não afetou as propriedades físico-químicas

do óleo. As outras propriedades (cor, aparência e aroma) não foram afetadas pelas condições

operacionais deste experimento. De acordo com os resultados obtidos, o óleo da castanha de

caju pode ser incluído na lista de outros óleos vegetais comerciais.

Palavras-Chave: óleos vegetais, castanha de caju; secagem em camada delgada

Protocolo 70 2015 23 de 20/03/2014 1 Profa. Dra em Engenaharia de Materias de, FAVIP, Caruaru , PE, E-mail: [email protected] 2 Químico Industrial, Dr. em Engenaharia de Processos, Anaton de Kom University of Suriname, Suriname, Email:

[email protected] 3 Prof.(a) Titular, Unidade Academica de Engenharia Alimentos – UFCG, Email: [email protected];

[email protected]

mailto:[email protected]



428 Effect of the storage time and drying on chemical and physicochemical properties of cashew kernel oil Cavalcanti et al.


INTRODUCTION

The economic exploitation of the cashew

tree, a plant native to Brazil, is concentrated in

the states of Ceará, Piauí and Rio Grande do

Norte. These states account for 91% of the

national production, on 700,000 ha (IBGE

2012). The cashew agroindustry represents a

significant portion of the economy of the

Northeast of Brazil, generating annually about

217,062 tons of cashew nut.

Generally, the main products of cashew

processing are the cashew kernel, cashew nut

shell liquid and the juice from the cashew

apple. From the cashew nut several other non-

food products such as paint, isolating material

and insecticides can be produced.

In Brazil, the whole cashew nuts are

normally exported, while the pieces, the so-

called splits, are destined for the local market to

be used as raw material for ice-cream and other

products.

Although these pieces are of low commercial

value, they still preserve their nutritional and

organoleptic properties, presenting itself with a

great amount of valuable nutrients. So, this

rejected material from the cashew nut

processing industries could be used to improve

other valuable final products, considering their

nutrition facts. Due to the fact that these pieces

(splits) are practically off priced in the trade

market, it would be interesting to process them

into high value-added products, which is the

main objective of this work, trying to produce a

kind of salad dressing oil, comparable with the

olive oil.

The main objective of this article is to

extract the oil from cashew kernel in pieces,

aiming a new high value-added product. In

order to extract the cashew kernel oil, three

drying levels are considered: (1) kernels not

dried with a moisture content of 5% w.b.; (2)

kernels dried at a temperature of 50 oC and a

final moisture content of 3% w.b.; and (3)

kernels dried at a temperature of 70 oC and a

final moisture content of 1% w.b. In addition,

the chemical and the physicochemical

(physicochemical) properties of the produced

cashew kernel oil, considering each drying

level, are also determined.

MATERIAL AND METHODS

Raw Material A special variety of the cashew, a clone

called CCP 06 processed in an industry of

Barreiras, Ceará, Brazil, was used as raw

material. It was a mixture of non-dried kernels

classified as the type S (Splits), S1, S2 and S3,

packaged as recommended, which is the Bulk

Vacuum Packaging (50 Lbs.), in multilayer

laminate packaging material. The flowchart of

this case study can be presented as in Figure 1.

Figure 1. Flowchart of the cashew kernel oil production and its characterization.

Effect of the storage time and drying on chemical and physicochemical properties of cashew kernel oil Cavalcanti et al. 429


Selection

The first selection and classification of

the cashew kernels was realized at the cashew

nut processing industry, according to pre-

established procedures from the Food and

Agriculture Organization (FAO, 2005),

Carteira de Comércio Exterior do Banco do

Brasil S.A. – CACEX and also the Ministry of

Agriculture of Brazil. Classified cashew kernels

of the type S: S1, S2 and S3 were selected.

Although the samples were already selected and

classified, they were submitted once again to

this process aiming a uniform sampling before

drying.

Drying

Before the drying process, the initial

moisture contents of the cashew kernels were

determined, according to the official methods of

the Association of Official Agricultural

Chemists (AOAC, 2005), where samples are

dried at the temperature of 105 ± 2 oC during 72

hours. Afterwards, these samples were

submitted to a thin-layer drying process, where

they were placed on a stainless steel tray in a

stove with air circulation. For each temperature

in this study, 50 and 70 oC, the drying process

was realized until the pre-established moisture

content.

Oil Extraction The oil extraction of the cashew kernels

was according to the Cold Pressed Method, by

using a hydraulic press of 30 tons and batches

of 2 kg. In statistical terms, this experiment

consisted of 3 levels of drying treatments: (1)

oil from non-dried cashew kernels; (2) oil from

cashew kernels submitted to a drying process at

50 oC; and (3) oil from cashew kernels

submitted to a drying process at 70 oC.

Afterwards the oil was clarified by filtration

and centrifuging.

Storage The samples of the cashew kernel oil

were stored in glass bottles of 70 mL with an

internal space above the liquid of 5 mL. During

the storage, the effect of the luminosity was

studied, by placing some samples exposed to

the light, while other samples were completely

isolated and, in this case, the bottles were

covered with aluminum foil and stored in a

closed box (Figure 2).

The samples were stored for 120 days,

and every 30 days samples were analyzed for

their values (acidity, peroxide, saponification

value, unsaponifiable matter and the refractive

index), specific mass, appearance, color and

aroma.

Figure 2. Bottling and Storage of the cashew kernel oil.

Characterization of the cashew kernel oil:

determination of the chemical and

physicochemical values

The following properties were

determined: acidity-, peroxide-, saponification

value and unsaponifiable matter, refractive

index as well as the specific mass, appearance,

color and aroma. Analyses were realized

according to the official methods of the AOAC

(2012), as shown in Table 1.

Table 1. Determination of the properties according to the official methods of the AOCS (2006).

Determination Method

Acidity AOCS Cd 3d-63

Peroxide AOCS Cd 8-53

Saponification AOCS Tl 1a-64

unsaponifiable matter AOCS Ca 6b-53

Refractive index (40°C) AOCS Cc 7-25



Statistical Analysis

Statistical analysis of the data was

performed using a completely randomized

design with 3 treatments of drying, 2 of

packaging and 5 storage times in a 3 x 2 x 5

factorial scheme with runs in duplicate, in this

way having: a) 3 drying levels: without drying;

with drying at 50 oC and with drying at 70 oC;

b) 2 packaging levels: with and without

exposure to light; c) 5 levels of storage: t = 0, t

= 30, t = 60, t = 90, and t = 120 days.

For the statistical analysis, the software

Assistat 7.5 beta (Silva and Azevedo, 2006)

was used.

RESULTS AND DISCUSSION

Determination of the physicochemical and

chemical properties

In Tables 2 and 3, the results of the

properties of the different cashew kernel oil

samples are presented.

Table 2. Characterization of the cashew kernel oil with 3 drying levels stored not exposed to light.

Level of

Drying 0 days 30 days 60 days 90 days 120 days

Acidity Value

no drying 0.90 ± 0.01 1.45 ± 0.04 1.63 ± 0.02 1.80 ± 0.04 1.91 ± 0.06

T = 50 oC 0.89 ± 0.06 1.38 ± 0.04 1.60 ± 0.06 1.81 ± 0.03 1.99 ± 0.03

T = 70 oC 0.92 ± 0.03 1.44 ± 0.03 1.65 ± 0.04 1.81 ± 0.04 2.01 ± 0.04

Peroxide Value (%)

no drying 0.92 ± 0.03 1.44 ± 0.03 1.65 ± 0.04 1.81 ± 0.04 2.01 ± 0.04

T = 50 oC 0.82 ± 0.01 0.88 ± 0.01 0.92 ± 0.01 1.49 ± 0.01 2.02 ± 0.01

T = 70 oC 0.89 ± 0.06 1.38 ± 0.04 1.60 ± 0.06 1.81 ± 0.03 1.99 ± 0.03

Saponification Value (%)

no drying 197.2 ± 0.6 195.2 ± 0.3 199.0 ± 0.7 198.9 ± 0.3 198.0 ± 0.7

T = 50 oC 196.9 ± 2.8 195.9 ± 2.1 198.4 ± 1.7 197.4 ± 1.7 197.8 ± 3.4

T = 70 oC 195.9 ± 0.6 196.7 ± 1.9 196.1 ± 2.2 196.9 ± 1.3 199.1 ± 0.8

Unsaponifiable matter (%)

no drying 0.17 ± 0.03 0.19 ± 0.00 0.19 ± 0.01 0.18 ± 0.02 0.16 ± 0.02

T = 50 oC 0.21 ± 0.03 0.22 ± 0.04 0.20 ± 0.01 0.20 ± 0.01 0.18 ± 0.01

T = 70 oC 0.21 ± 0.03 0.18 ± 0.01 0.20 ± 0.01 0.19 ± 0.00 0.22 ± 0.04

Refractive Index

no drying 1.4615 1.4615 1.4615 1.4615 1.4615

T = 50 oC 1.4615 1.4615 1.4615 1.4615 1.4615

T = 70 oC 1.4615 1.4615 1.4615 1.4615 1.4615

Specific Mass (g/mL)

no drying 0.9766±0.0004 0.9823 ± 0.0002 0.9990±0.0001 0.9956±0.0004 0.9900±0.0001

T = 50 oC 0.9701±0.0001 0.9802±0.0005 0.9561±0.0001 0.9652±0.0005 0.9861±0.0005

T = 70 oC 0.9800±0.0008 0.9789±0.0006 0.9799±0.0006 0.9800±0.0001 0.9834±0.0003

Appearance

no drying Liquid Clear Liquid Clear Liquid Clear Liquid Clear Liquid Clear

T = 50 oC Liquid Clear Liquid Clear Liquid Clear Liquid Clear Liquid Clear

T = 70 oC Liquid Clear Liquid Clear Liquid Clear Liquid Clear Liquid Clear

Color

no drying yellow yellow yellow yellow yellow

T = 50 oC yellow yellow yellow yellow yellow

T = 70 oC yelllow yelllow yelllow yelllow yelllow

Aroma

no drying Typical Typical Typical Typical Typical

T = 50 oC Typical Typical Typical Typical Typical




Table 3. Characterization of the cashew kernel oil with 3 drying levels stored and exposed to light.

Level of

Drying 0 days 30 days 60 days 90 days 120 days

Acidity Value

no drying 0.90 ± 0.03 1.91±0.04 2.21±0.04 2.44±0.03 2.66±0.04

T = 50 oC 0.89±0.03 1.88±0.01 2.20±0.07 2.42±0.03 2.70±0.05

T = 70 oC 0.92±0.03 1.92±0.03 2.22±0.01 2.43±0.02 2.71±0.04

Peroxide Value (%)

no drying 0.82 ± 0.02 1.53±0.02 1.80±0.03 2.51±0.05 3.98±0.08

T = 50 oC 0.80±0.03 1.51±0.03 1.81±0.03 2.58±0.08 4.02±0.06

T = 70 oC 0.81±0.04 1.50±0.03 1.82±0.03 2.54±0.03 4.06±0.04

Saponification Value (%)

no drying 197.2 ± 1.6 188.3±0.9 199.2±0.8 199.1±5.0 197.3±1.6

T = 50 oC 196.9±1.3 190.9±2.2 193.9±1.3 198.7±1.2 197.9±1.3

T = 70 oC 195.9±2.2 191.1±2.8 198.0±0.7 198.1±1.5 199.1±2.9

Unsaponifiable matter (%)

no drying 0.19 ± 0.01 0.19 ± 0.00 0.18 ± 0.01 0.21± 0.01 0.21 ± 0.02

T = 50 oC 0.19 ± 0.01 0.20 ± 0.01 0.20 ± 0.01 0.18 ± 0.02 0.22 ± 0.04

T = 70 oC 0.17±0.03 0.20 ± 0.01 0.20 ± 0.01 0.22 ± 0.04 0.19 ± 0.01

Refractive Index

no drying 1.4615 1.4615 1.4615 1.4615 1.4615

T = 50 oC 1.4615 1.4615 1.4615 1.4615 1.4615

T = 70 oC 1.4615 1.4615 1.4615 1.4615 1.4615

Specific Mass (g/mL)

no drying 0.9766±0.00

04

0.9856±0.0023 0.9888±0.000

6

0.9979±0.0006 0.9872±0.00

05

T = 50 oC 0.9701±0.00

05

0.9901±0.0069 0.9900±0.000

3

0.9888±0.0008 0.9679±0.00

01

T = 70 oC 0.9800±0.00

04

0.9896±0.0004 0.9891±0.001

1

0.9923±0.0009 0.9833±0.00

23

Appearance

no drying Liquid

Clear

Liquid Clear Liquid Clear Liquid Clear Liquid

Clear

T = 50 oC Liquid

Clear


Clear

T = 70 oC Liquid

Clear


Clear

Color

no drying yellow yellow yellow yellow yellow

T = 50 oC yellow yellow yellow yellow yellow

T = 70 oC yelllow yelllow yelllow yelllow yelllow

Aroma

no drying Typical Typical Typical Typical Typical



Results of the saponification value,

refractive index and specific mass are also in

agreement with the ones mentioned in the

literature, respectively given by 137 mg

KOH/g, 1.458 and 0.962 g/mL for Akinhanmi

and Akintokun (2008); and 168.3 mg KOH/g;

1.654 and 0.964 g/mL for Aremu et al. (2007).

According to the analysis of variance

(ANOVA) of the chemical and

physicochemical properties (Table 4), it can

be noticed that only the acidity and peroxide

values presented significant differences,

considering the effects along the storage period.

Furthermore it can be concluded that there are

no significant differences for the 3 variables:

drying, packaging and storage time.

Acidity value

For the statistical analyses considering

the interaction between the variables drying and

storage time, it can be observed that there was



no influence of the drying process on the

acidity value and that it is increasing along the

storage time. More results are shown in Table 5

and the corresponding Figure 3.

Table 5. Results of the interaction, considering the variables drying and storage time for the acidity

value.

Drying treatment Storage time

(Days)

0 30 60 90 120

Without drying 0.8875 aE 1.6800 aD 1.9000 aC 2.0950 aB 2.2500 bA

Drying at 50 °C 0.8575 aE 1.6200 aD 1.8550 aC 2.1350 aB 2.3375 aA

Drying at 70 °C 0.9000 aE 1.6600 aD 1.9175 aC 2.0975 aB 2.3850 aA MSD for the columns = 0.0441 (lowercase)

MSD for the rows = 0.0627 (uppercase)

Values with the same lowercase means that there was no significant change caused by the factor luminosity; Values with

the same uppercase means that there is no significant difference between these values, because of the storage time.

aE aE aE

aD aD aD

aC aC aC

aB aB aB

bA aA aA Without drying T=50 °C T=70 °C

0 30 60 90 120

Storage time (days)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

Aci

dit

y v

alu

e (%

)

Figure 3. Histogram graphic for the acidity values, considering the interaction between the variables

drying and storage time.

According to these results it can be

noticed that only by the end of the storage, the

acidity value of the cashew kernel oil samples

that were not submitted to any drying process

presented statistical differences corresponding

by lower values; furthermore it is observed that

the acidity value is increasing along the storage

time.

For the statistical analyses considering

the interaction between the variables

packaging and storage, taking into account the

effect of the light, it was clear that the acidity

value increased along the storage time.

Another important fact is that the samples

exposed to the light always presented higher

acidity values than samples not exposed to the

light. These results are shown in Table 6 and

its corresponding histogram in Figure 4.

The increase of the acidity value was

also confirmed by Vacca et al. (2006) and

Guitierrez et al. (2001) who studied the

stability of olive oil during a storage time of

180 days, with and without exposure to the

light. In this study, the increase was caused by

hydrolyses reactions of free fatty acids (FFA).

The same phenomenon was observed by

Mendez and Falque (2005), when they were

studying the effect of the storage time and the

type of packaging on the quality of extra virgin

oil; they attributed this behavior to the

hydrolytic processes of the triglycerides.



Table 6. Results of the interaction, considering the variables packaging and storage time for the acidity

value.

Packaging

Storage time

(Days)

0 30 60 90 120

Exposed to the

light

0.8800 aE 1.3983 bD 1.6000 bC 1.7933 bB 1.9717 bA

Not exposed to

the light

0.8833 aE 1.9083 aD 2.1817 aC 2.4250 aB 2.6767 aA

MSD for the columns = 0.0441 (lowercase)




0 30 60 90 120

Storage time (days)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

aE aE

bD

aC

bB

aB

bA

aA

bC

aD

With exposure to the light Without exposure to the light

Aci

dit

y v

alue

(%)

(%)

Figure 4. Histogram graphic for the acidity values, considering the interaction between the variables

packaging and storage time.

Peroxide value

The results of the analysis of variance

(ANOVA) of the peroxide values are presented

in Table 7.

According to Table 7 there was a

significant difference for the variables

packaging and storage. On the other hand, there

was no influence of the drying process on these

values.

Table 7. Analysis of variance of the peroxide values of the cashew kernel oil stored for 120 days.

Source. D.F. M.S.

Drying (D) 2 0.00052 ns

Packaging (P) 1 1.35788 **

Storage time (S) 4 9.13638 **

D x P 2 0.00330 ns

D x S 8 0.00373 *

P x S 4 1.50896 **

D x P x S 8 0.00085 ns

Residual 30 0.00137 **= significant at a level of 1% of probability (p < 0.01); * = significant at a level of 5% of probability (0.01 < p < 0.05); ns =

not significant (p > 0.05); D.F = Degrees of Freedom; M.S.= Mean Squares



For the statistical analysis, considering

the interaction between the variables drying and

storage, it was observed that the peroxide

values are increasing along the storage time and

that this value wasn’t affected when cashew

kernels were submitted to the drying process,

except at the end of the storage time for the oil

samples from cashew kernels which were not

submitted to any heat treatment. The results for

these analyses are shown in Table 8 and its

corresponding histogram in Figure 5.

Table 8. Results of the interaction, considering the variables drying and storage time for the peroxide

value.

Drying treatment Storage time

(Days)

0 30 60 90 120

Without Drying 0.8300 aE 1.1950 aD 1.3475 aC 1.9775 aB 2.9650 bA

Drying at 50 °C 0.7800 aE 1.1600 aD 1.3325 aC 1.9900 aB 3.0450 aA

Drying at 70 °C 0.7825 aE 1.1725 aD 1.3450 aC 1.9950 aB 3.0600 aA MSD for the columns = 0.0644 (lowercase)


Values with the same lowercase means that there was no significant change caused by the factor luminosity; Values with the

same uppercase means that there is no significant difference between these values, because of the storage time.

0 30 60 90 120

Storage time (days)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Per

ox

ide

val

ue

Without Drying Drying at 50 o C Drying at 70 o C

aE aE aE

aD aD aD aC aC aC

aB aB aB

bA aA aA

Figure 5. Histogram graphic for the peroxide values, considering the interaction between the variables

drying and storage time.

For the statistical analysis, considering

the interaction of packaging and storage it was

observed that the peroxide value increased

along the storage time. This increment was

always higher for samples exposed to the light.

The results of the interaction, considering the

variables Packaging and Storage time for the

peroxide value is shown in Table 9

.

Table 9. Results of the interaction, considering the variables Packaging and Storage time for the

peroxide value.

Packaging Storage time (Days)

0 30 60 90 120

Not exposed to

the light

0.7950 aD 0.8567 bCD 0.8933 bC 1.4683 bB 2.0433 bA

Exposed to the

light

0.8000 aE 1.4950 aD 1.7900 aC 2.5067 aB 4.0033 aA

MSD for the columns = 0.0437 (lowercase)






The corresponding histogram of these results is plotted in Figure 6.

Per

ox

ide

val

ue

val

ue

0 30 60 90 120 0.0

0.5

1.0

1,5

2.0

2.5

3.0

3.5

4.0

4.5 With exposure to the light

Without exposure to the light

aD

aD

aE bCD bC

aC bB

aB

bA

aA

Storage time (days)

Figure 6. Histogram graphic for the peroxide values, considering the interaction between the variables

packaging and storage time.

The increase of the peroxide values was

also confirmed by Caro et al. (2006) and

Vacca et al. (2006) when studying the storage

and exposure influence on extra virgin olive oil

components. This rise probably occurred due

to auto-oxidation reactions of the lipids and

fatty acids. In the propagation stage all these

reactions are stopped when all the free radicals

are deactivated. Exposure to light accelerates

the kinetics of this process. Even more,

Guitierrez and Fernandez (2002) and Mendez

and Falque (2005) also added the effects of the

permeability of the packaging as an important

factor, when they studied the storage

parameters of some vegetable oils, confirming

in this way the increase of the peroxide values.

Oxygen accelerates the production as well as

the decomposition of hydro peroxides into

volatile compounds of low molecular weight,

responsible for the unpleasant aroma and taste.

At the other side, the light also catalysis

the photo-oxidation, reason why samples

exposed to the light presented higher

increments than the other ones not exposed.

Saponification value and unsaponifiable

matter

According to the analysis of variance of

the Saponification value and Unsaponifiable

matter, considering the different drying levels

as well as the 3 effects (variables: drying,

packaging and storage) there was no

significant difference at the interactions of

these variables. These results were also

observed by Morello et al. (2004), when

studying the modifications of olive oil during

its storage with and without exposure to the

light for a period of 12 months. The results of

these interactions are presented in the Tables

10 and 11.

Table 10. Analysis of variance of the saponification values of the cashew kernel oil stored for 120 days.

Source D.F. M.S.

Drying (D) 2 3.25617 ns

Packaging (P) 1 9.92267 ns


D x P 2 11.34117 ns

D x S 8 5.74242 ns

P x S 4 9.56392 ns

D x P x S 8 5.62242 ns

Residual 30 3.63133 **= significant at a level of 1% of probability (p < 0.01); ns = not significant (p > 0.05); D.F = Degrees of Freedom; M.S.=

Mean Squares.



Table 11. Analysis of variance of the unsaponifiable matter of the cashew kernel oil stored for 120

days.

Source D.F. M.S.

Drying (D) 2 0.00100 ns

Packaging (P) 1 0.00008 ns

Storage time (S) 4 0.00007 ns

D x P 2 0.00092 ns

D x S 8 0.00022 ns

P x S 4 0.00056 ns

D x P x S 8 0.00074 ns

Residual 30 0.00039 ns = not significant (p > 0.05); D.F = Degrees of Freedom; M.S.= Mean Squares

Specific mass

According to the analysis of variance of the specific mass (Table 12) there was a significant

difference for all the effects (variables), nevertheless it was impossible to establish any tendency or

correlation between these values and the effects.

Table 12. Analysis of variance of the specific mass of the cashew kernel oil stored for 120 days.

Source D.F. M.S.

Drying (D) 2 0.00056 **

Packaging (P) 1 0.00035 **


D x P 2 0.00020 **

D x S 8 0.00012 **

P x S 4 0.00022 **

D x P x S 8 0.00013 **

Residual 30 0.00000 ** **= significant at a level of 1% of probability (p < 0.01); D.F = Degrees of Freedom; M.S.= Mean Squares

As can be observed in Figure 7, the

values are spread between 0.9678 and 0.9991

g/mL, which could possibly be caused by

experimental or random errors.

0 30 60 90 120

0.90

0.91

0.92

0.93

0.94

0.95

0.96

0.97

0.98

0.99

1.00

With exposure to the light

Without drying

T=50 °C T=70 °C

Without exposure to the light

Without drying

T=50 °C

T=70 °C

Spec

ific

mas

s (g

.mL

-1)

Time (days)

Figure 7. Dispersion graph of the specific mass values of the cashew kernel oil along the storage time.



CONCLUSIONS

The pre-treatment of the cashew kernels

by drying at a temperature of 50 and 70 oC

didn’t affect the physicochemical properties of

the oil;

The peroxide and acidity values

increased along the storage time of 120 days;

Exposure to light resulted in a

significant increase of the peroxide and acidity

values;

The other properties (color, appearance

and aroma) were not affected by the operational

conditions of this experiment;

Considering the International Food

Safety Regulations, the cashew kernel oil can

be included in the list of other commercial

vegetable oils, because of its nutritional aspects

and stability.

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Revista Brasileira de Produtos Agroindustriais, Campina Grande, v.19, n.4, p.438, 2017

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