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EFFECT OF COMPOSITE EDIBLE COATING ON THE STORAGE OF
FRIED CHICKEN PIECES
Najla H. Al-Garory* , Alaa G. AL-Hashimi
Department of food science, college of agriculture, university of Basrah, Basrah, Iraq
(Received ,Accepted 17 May 2020)
Key words: edible coat, starch, deep frying.
Corresponding author: Najla.saper@yahoo.com
ABSTRACT
Food packaging has a great importance to increase the shelf life and safety of food,
as well as packaging works as a buffer against the conditions that cause damage, such as
light, dust, oxygen, moisture and microbes, Native (NS)and modified (MS) potato starches
using stearic acid ,and different concentrations of whey protein (WP)0-50% were used as
edible coatings for the chicken pieces then kept at refrigerator (4±1°C) and deep freezing
conditions (-18°C) for periods of (2,5,7) days.The effect of coating was studied to
determine the moisture loss, oil uptake ,peroxide value and thiobarbituric acid in addition to
the sensory evaluation. The results showed that all the composite edible coats improved the
chemical characteristic and the best edible coat was MS50% +WP% which provided better
results in terms of reduction the moisture loss , oil uptake and the oxidation values and
improved the score of colour ,flavor ,texture and general appearance which reflect the
sensory evolution.
INTRODUCTION
Deep frying is a cooking method that is widely used in commercial food processing.
It is the method of strength flavor, texture and appearance of food products. However, one of
the main problems associated with fried foods was consuming a high percentage of oil, which
was badly related to the spread of diseases such as sudden rise in blood pressure and
cholesterol disturbances such as raising the level of cholesterol that is harmful to the blood
resulting in diseases and chronic problems in the heart with low immune capabilities of the
body ( 35). The consumer has become more aware of the effects of eating foods that are high
in fat and its effect on health (28). Therefore, the development of food products that have a
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low fat content by reducing oil absorption is the most important point in deep frying to
reduce the incidence of diseases such as obesity, high cholesterol levels, etc (46)
Moreover, oxidation of fats during frying generates various oxidative derivatives,
some of which are also associated with many diseases such as premature aging, membranes
damage, heart disease and cancer. Thus, fried foods have become a source of concern for
health (16).
The modern researches have prompted studies in order to reduce the oil content in
the fried food. An aqueous solution forms was commonly known method "edible coating
films" on the food to be fried (27) and thus applying the coating is a promising way to reduce
oil content (29).
Various packaging materials such as protein, dried breadcrumbs, starch,
carrageenan, and their combinations have been used to reduce moisture loss, to extend their
shelf life, as well as to reduce oil absorption during frying for meatballs, chicken, and
potatoes during deep frying with oil (1,35). The process of packing and packing food and
creating edible and biodegradable food packaging. An important process associated with food
safety and environmental conservation, proteins and carbohydrates are generally considered
good polymers for forming edible films and coating and biodegradation because of the
excellent mechanical properties as well as their ability to retain moisture, gas and odor, they
also act as a barrier against microorganisms and their ability to carry food additives and
improve the appearance of products, which makes them more attractive to the consumer
(20).The whey proteins are the by-product of the cheese industry that used as a functional
food ingredient as well as for their use to produce new edible and degradable polymeric
materials (36).
At the present time, polysaccharides are used in the preparation of edible films as
bio-materials which are inexpensive and abundant in nature as well as being renewable and
have the ability to form edible films or coating with good mechanical properties to preserve
the textures, flavor and extend the life of the food due to its hydrophobic nature, edible films
prepared from carbohydrates have good reservation properties of gases, flavor compounds
and fatty substances due to their ability to form a cross linking between polymeric chains
throw hydrogen bonds that make films have a good reservoir ability of gases while they are
weak barriers against water vapor because of their hydrophilic nature (11).
The polysaccharide edible coats are colorless, tasteless, odorless, and non-toxic, as
well as their ability to inhibit microbial growth because of the reduced water activity as the
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researcher showed that starch consists of amylose and amylopectin and presented in grains
such as corn, wheat, potatoes. Amylose is responsible for the ability of starch to form the
films, as the increase in its quantity increases the elasticity of the film and produces edible
film with good reservation properties of fat and oxygen and high solubility of water. Starch
films were used in packaging potatoes to prevent oxidation and discoloration after frying(9).
The effect of adding stearic and linoleic fatty acids on starch properties since it was
found that adding stearic acid had a greater effect on the adhesive properties of linoleic acid
and the addition of saturated fatty acids led to a significant decrease in starch retro gradation
as compared to natural starch (48).
Edible film made from proteins or polysaccharide are characterized by appropriate
mechanical and reservation properties but are permeable to moisture and their protective
properties toward water are weak while fat films (waxes or other fats and oils) have good
reservation properties towards water vapor but their mechanical resistance is weak and they
have high permeability to oxygen. The properties of these films can be improved by
combining these materials together to obtain films with good properties (5).
Therefore, the current study aims to study the efficiency of composite edible coats
(native starch and modified starch with stearic acid + whey protein) on the chemical and
sensory properties of chilled and frozen chicken pieces.
MATERIAL AND METHODS
Potato starch extraction: 500 g of potato( Solanum tuberosum ) was washed well, peeled
and cut into small slices. The distilled water was added, and the extraction process was done
using a centrifuge (Junior – England )at a speed of (4000) rpm for 15 minutes. after that , the
samples were filtered using Whatman no. 1(sigma Aldrich), the wet starch was dried at room
temperature for 5 hours then crushed into a white .soft, odorless fine powder (3).
Starch–fatty acids complexes preparation: Starch–fatty acids complexes were prepared
according to the method of (24). Potato starch suspension was prepared by adding starch to
the distilled water (10%, w/w) then heated in water bath (Cotter – Germany) with continuous
stirring at (63°C for 30 min), then stearic acid(that were purchased from Sigma-Aldrich (St.
Louis, MO). was completely dissolved in ethanol . The combination of starch –fatty acid was
heated at (63°C for 30 min). The complex was quickly cooled to room temperature. Excess
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fatty acids are eliminated by adding ethanol then centrifuged at 1500g for 20 min. The
complex was washed three times to be surely eliminated free fatty acids in the systems.
Whey proteins Preparation: whey proteins were prepared according to the method used by
(12).
Preparation of PS/WP coat: Potato starch (native and modified by stearic acid) and whey
protein (PS/WP) mixture were gained from the blending of the following ingredients:
solidphase: 60% (starch/whey protein) and liquid phase: 24% glycerol and 16% water. The
process of replacing the naive and modified starch with whey proteins was performed from
0% to 50% according to (7).
Sliced chicken packaging: The chicken breast was cut into small pieces (3x7x1cm) then
these pieces were divided into three groups by (8) pieces for each group randomly, and
immersed in the solution of the composite edible coat (natural and modified starch + whey
proteins) , and placed on a mesh tray of stainless steel for 5 to 10 minutes Until the excess
solution is removed and all the pieces were dried and then placed in packages. Coated and
uncoated samples were stored in the refrigerator (4 ± 1 °C) and in the deep freezer (-18 °C)
until analysis (40).
Frying process:The frying process was done according to the method used by (19), three
litters of sun oil was heated to (175-180 °C) and the pieces of non-coated and coated samples
chicken were dropped into the oil for 1.5 – 2 min and covered with a tight coater. The fried
pieces were put in polyethylene bags and stored in refrigerator at (4 ± 1 °C) and the another
in freeze at (-18 °C for 7 days). The frying process was carried out for each treatment with
triplicates.
Moisture and Fat content determination: Moisture and fat content were estimated based
on the method used by (6) and the test was performed with triplicates. Moisture content of
coated and non-coated samples stored by refrigerating was estimated by an oven-drying
method at (105 °C) until stability of weight was reached. Fat content was estimated by
Soxhlet method, which includes continuous evaporation and condensation of petroleum ether
solvent passing through 5 g of moisture-free chicken sample. The raw sample was collected,
dried and weighed.
The oil uptake (%) was calculated depending on the following equation:
􀀁􀀂􀀃 􀀅􀀆􀀇􀀈􀀉􀀊 % = 􀀍􀀎􀀏􀀍􀀐
􀀍􀀐 × 100
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of = oil content of fried chicken
or = the oil content of raw chicken.
Determination of peroxide value (PV): The peroxide value of coated and non-coated
samples under cooling condition was estimated according to (6). 5g of each chicken samples
was homogenized with 30ml of glacial acetic acid and chloroform in a proportion of 3:2. on
magnetic stirrer, then 0.5 ml of saturated KI was added, the solution transferred to a dark
place for 15 min. Next, 30 -50 ml of distilled water and drops of starch indicator (1%) was
mixed with the solution until the purple color appear ,the mixture was titrated with standard
0.1 N sodium thiosulphate till the solution became colorless. All the samples were repeated
for three replicates.
The peroxide value was calculated according to the following equation:
Peroxide Value (meq/kg) = 􀀔􀀕 􀀖􀀎􀀗􀀘􀀙􀀚􀀛􀀜 􀀝􀀞􀀚􀀘􀀗􀀛􀀟􀀠􀀞􀀡􀀝􀀢 × 􀀣􀀤􀀤􀀤
􀀥 􀀖􀀎 􀀦􀀧􀀔􀀨􀀕􀀩
Thiobarbituric acid (TBA): The value of TBA was estimated on the basis of mg
malondialdehyde (MDA)/kg chicken according to (32).
Thermo gravimetric analysis (TGA):Thermo gravimetric analysis for whey protein –
modified starch based edible coats was performed to study the degradation characteristics of
the coats. The thermal stability of the sample was estimated using, Q50V20.13 Build 39 with
a heating rate of (10°C/min). Samples were heated from room temperature to (600°C). After
drying the samples were milled in powder according to (39).
Sensory evaluation: The sensory evaluation of chicken pieces coated with whey protein –
native starch or modified starch by stearic acid and un-coated after being fired in hot oil
for 10 minutes was conducted by panelists judgment from the Department of Food
Sciences – college of Agriculture, University of Basrah according to the sensory form
evaluation originated from proposals of edible coating applications(13).
Statistical analysis: Statistical analysis was done by using SPSS program, and a factorial
experiment using complete randomized design was applied. L.S.D. was used to compare
among means at 0.05 level. Triplicates were used in the experiments.
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RESULTS AND DISCUSSION
Moisture content
Three samples of chicken pieces were used, the first one was the control (uncoated),
the second was coated with compound edible coat consisting of native potato
starch incorporated with whey protein (NS+WP) with replacement ranged from 0% up to
50%, the third samples was coated with compound edible coat consisting of modified
potato starch with stearic acid (18 C) incorporated with whey protein (MS+WP) with
replacement range from 0% up to 50%, The coats were thin, homogeneous, transparent,
and attached to the surfaces of the chicken pieces, giving them shine and softness.
Table 1 shows the percentage of moisture of chicken pieces which were uncoated
and coated with (native starch and modified starch with stearic acid) incorporated
with whey protein in different percentage before frying, and storage in refrigerated at (1 ±
4 °C) and freezing at (- 18 °C) for a period of (2, 5, 7) days.
It was observed that the percentage of moisture for non-coated chicken samples
was low if it is compared to the coated samples. The percentage of moisture after two
days of uncoated chicken pieces storage in cooling and freezing conditions were 30.8,
49.2% and reduced to 25.4, 23.5% and 48.5, 45% on the fifth and seventh days,
respectively.
It was noted from the table that the percentage of moisture for chicken samples
coated with composite coat (whey - native and modified starch) with different rats of
replacement 0% -50 % has maintained the moisture and the highest moisture content was
for samples coated with the composite edible coat consisting of native and modified
starch with the rate of 50% and whey protein 50% which were (41.2, 40, 32)% and (45.6,
42.5, 40)%, for (2, 5, 5) days respectively when stored in cooling, the higher content of
moisture was due to the increasing of the interaction between the starch polymer and whey
polymer, therefore the binding of water decreased, as (2) reported, that the non-polar sits
and the covalent disulfide bond formed by the denaturation of whey protein which lead to
the reduction of moisture adsorption.
The amount of moisture was higher in frozen chicken pieces as compared to
those stored in cold, and the higher rate for the samples coated with MS50%+WP50%
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which was 72,3% when stored for two days. The statistical analysis for the all the treated
samples, storage period ( 2, 5, 7) days and the kind of storage (cooling and freezing)
showed a significant differences.
For the coated samples , it was observed, that as the replacement of potato
starches by the whey protein increased the moisture content gradually, the lowest moisture
for the coating sample was for the sample coated with (NS100% +WP0%) which was
(27.5, 53.1)% when stored in cooling and freezing after seven days .
This result may ascribed to the fact that the amount of moisture evaporates
depends on the nutrient content of moisture and the relative moisture prevailing at storage,
and the susceptibility of coatings to the permeability of water vapor increases with the
increasing the relative moisture of the material to the atmosphere or vice versa, because of
its hydrophilic nature, as protein materials contain many polar groups such as hydroxylic
groups that are bound to water molecules at high relative humidity and thus cause its
spread in the polymer mold and reduce the membrane network cohesion, which leads to an
increase in its permeability to water vapor (37).
Chicken pieces coating with starch coat only had the lowest ratio of moisture,
this result was due to the high amount of water vapor permeability which was increased
because of the high rapprochement of glycerol for starch and its separation between these
molecules. The hydrophilic nature of glycerol leads to increase the interaction between
starch molecules and build hydrogen bond with the OH group of the two main components
of starch amylase and amylopectin (22), whey proteins have the ability bind to water
because they contain hydroxyl groups, so moisture can interfere inside the coat (47) the
reduction of moisture vapor is because of the polymer matrix which contains the
crystalline phase and the water evaporation exist in the amorphous phase of the polymer
through the empty space (38).
The high reservation of water for the coated samples used the modified starch (stearic
acid) might be due to controlling the evaporation of water and reducing dehydration. The
possibility of keeping the moisture of these samples followed the fact that swelling power
were reduced because of amylose – mono-glyceride complex formation and form insoluble
films on the starch granules surfaces Then delay the transfer of water into the starchy
granules (15).Thus, the results was in accordance with (14) and (٤) who indicated the
decreasing of the moisture loss when different kinds of coating are used.
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.
Table 1: moisture content % of chicken pieces un-coated and coated with ( native and
modified starch) incorporated with whey protein during storage at (4±1 ̊C and -18 ̊C)
Type of coating
Storage Time (days)
Cooling 4± 1 C Freezing -18 C
2 days 5 days 7 days 2 days 5 days 7 days
CONTROL 30.8 25.4 23.5 49.2 48.5 45
NS50%+WP50% 41.2 40 32 69.7 65.6 63.6
NS60%+WP40% 40.8 35.6 31.1 67.2 65.2 61.8
NS70%+WP30% 39 34 29.4 65.5 63.7 61
NS80%+WP20% 38.9 32.6 29 61.3 60.8 60
NS90%+WP10% 37.5 32 28 60 58.9 57
NS100%+WP0% 36.2 31.2 27.5 58.5 56 53.1
MS50%+WP50% 45.6 42.5 40 72,3 69.5 68.8
MS60%+WP40% 44 41.2 38 71.2 68.5 66.4
MS70%+WP30% 43 39.9 37.1 70.7 67.8 64.1
MS80%+WP20% 41.5 38 35.5 68.6 65.2 63.3
MS90%+WP10% 40 37.5 35.5 65.8 64.4 62.5
MS100%+WP0% 38.8 37 34 64.6 62.7 62
Oil uptake
Table 2 explains the changes in the oil uptake for the chicken pieces coated
and non-coated during cooling and freezing storage within seven days. As shown in
the table, the coating has an efficient effect on the oil uptake. The oil uptake of the
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standard pieces (non-coating) was significantly different from the pieces that were
coated with (native and modified starch – whey protein ). The oil uptake of chicken
pieces coated with the compound coat decreased gradually as the concentration of
whey protein increased and increased as the storage (cooling or freezing) time
increased ranging from 15.1 to 20.8%. The coated chicken pieces using modified
starch with stearic acid were less oil uptake than pieces coating with the native
potato starch and starches combined with different rates of replacement of whey
protein under the fixed conditions of storage and the rate of decreasing was higher
in frozen samples as compared to cooled one. It is worth noting that combining the
components of starch, whether natural or modified, with whey proteins decreased
fat absorption.There were significant differences (P ≤ 0.05) for all the factors
regarding the treatments, kind of storage as well as the storage time.
A new polymer was produced from the interaction between whey protein
and the starches which was completely different from the two polymers, this
interaction was developed the favorite functional properties and characteristic of
these polymers and made them more cohesive (44), the cohesive character of the
combined film was formed via many bonds like Vander Waals forces, hydrogen
bonding, Covalent bond and disulfide bond, these bonds were formed because of
charges of amino acid of the protein which has the feature of polarity and nonpolarity
and the hydrophilic groups which have the ability to react with the starch is
– OH- NH2 – COOH – and SH and all these factors made the film more strong (31).
The result behind the reduction of oil uptake for coated and non-coated
samples depends on the relationship between fat and moisture content which were
related to the replacement of water with oil, that depends on the moisture
evaporation during frying processing, so the samples coated by potato starch–whey
protein prevent water evaporation during frying which avoided the absorption of oil,
samples coated with modified starch using stearic acid had the lower fat uptake
because of the formation of amylose-stearic acid complexes, the formation of
complexes increases by increasing the molecular weight of fatty acids and by
increasing the length of the hydrocarbon chain for them and thus creating more
stable complexes and more cohesive film (43; 18), These results are consistent with
the results presented by (42, 21).
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Table 2: Oil uptake % of fried chicken pieces un-coated and coated with (native
and modified starch) incorporated with whey protein during storage at (4±1ºC and -18 ºC).
Type of coating
Storage Time (days)
Cooling 4± 1 C Freezing -18 C
2 days 5 days 7 days 2 days 5 days 7 days
CONTROL 29.50 30.4 31.5 28.1 28.6 29
NS50%+WP50% 16 16.4 16.8 15.3 15.9 16.2
NS60%+WP40% 17.6 17.9 18.2 16.9 17.3 17.8
NS70%+WP30% 18 18.5 18.9 17.3 17.8 18.3
NS80%+WP20% 18.3 18.9 19 18 18.5 18.6
NS90%+WP10% 18.6 19.3 19.8 18.2 18.8 19.3
NS100%+WP0% 20 20.4 20.8 19 19.5 20
MS50%+WP50% 15.1 15.6 15.9 14 14.5 15.6
MS60%+WP40% 15,7 16 16.8 14.9 15.5 15.9
MS70%+WP30% 16.2 16.9 17.1 15.8 16 16.5
MS80%+WP20% 16.6 17 17.5 16.2 16.7 17.3
MS90%+WP10% 16.8 17.5 17.8 16.6 16.8 17.6
MS100%+WP0% 17 17.6 18 16.9 17 17.9
Lipid oxidation
One of the most important feature of the edible coat is its possibility to delay the
oxidation and spoilage processes for the food and increase its shelf life. Peroxide value
(PV) and thiobarbituric acid (TBA) values are good indicators for detecting damage and
degradation of oils and fats in un-coated and coated samples of chicken piece table (3, 4).
As shown in the tables there were significant differences between the un coated and coated
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samples and PV and TBA of un-coated (control) chicken samples were significantly
higher than that of coated chicken (native and modified starch + whey protein), as well as
the results showed that PV and TBA of all treatments has increased constantly during
storage.
The highest values of peroxide and thiobarbituric acid for the control samples
after seven days storage in cooling 3.023Meq 02/kg, 0.954MDA/kg. As the concentration
of whey protein increased in the complex polymer of the edible coat, PV and TBA
decreased the lowest amount was for the sample coated with the modified starch 50%
incorporated with whey protein 50% which was 0.216Meq 02/kg and, 0.111 MDA/kg
respectively when storage at freezing (-18 ºC) two days.
The statistical analysis indicated that there is a significant differences (P ≤ 0.05)
for the period and the kind of storage (cooling and freezing) and there is a significant
differences between the coating samples except the samples consisting of 70% starches +
30% whey protein and 70% starches + 30% whey protein and 80% starches + 20% whey
protein there were no significant (P ≥0.05) between them.
Gas barrier characteristics of edible films for O2 and CO2 affected on the
breathing or oxidant reactions. polymer types, gas type and temperature are the most
important factors affected barrier characteristics (41). Films barrier properties are largely
dependent on polymer components and increasing the ratio of whey proteins reduces gas
transmission (10).
The possible reason behind the reduction of oil oxidation was the cooking
process and exposure of oxygen which are the factors that influence the oxidation of oil in
foods (34), therefore edible films prevent the penetration of oxygen into the food material.
Our results were in agreement with the results of (26, 17, 25).
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Table 3: peroxide value Meq 02/kg of fried chicken pieces un-coated and coated with
(native and modified starch) incorporated with whey protein during storage at (4±1 ºC and
-18 ºC).
Type of coating
Storage Time (days)
Cooling 4± 1 C Freezing -18 C
2 days 5 days 7 days 2 days 5 days 7 days
CONTROL 2.941 3.12 3.023 2.531 2.860 2.905
NS50%+WP50% 0.772 0.856 0.984 0.701 0.823 0.911
NS60%+WP40% 0.812 0.901 0.993 0.800 0.854 0.890
NS70%+WP30% 0.865 0.932 1.022 0.823 0.911 0.998
NS80%+WP20% 0.891 0.987 1.132 0.858 0.950 1.112
NS90%+WP10% 1.112 1.136 1.1887 0.982 0.987 1.238
NS100%+WP0% 1.128 1.154 1.140 1.021 1.119 1.146
MS50%+WP50% 0.636 0.767 0.896 0.216 0.342 0.543
MS60%+WP40% 0.763 0.790 0.961 0.381 0.436 0.658
MS70%+WP30% 0.871 0.892 0.989 0.409 0.552 0.698
MS80%+WP20% 0.888 0.982 0.998 0.552 0.768 0.736
MS90%+WP10% 0.979 0.975 1.132 0.698 0.887 0.985
MS100%+WP0% 1.054 1.068 1.087 0.824 0.934 1.509
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Table 4: TBA value MDA/kg of fried chicken pieces un-coated and coated with (native
and modified starch) incorporated with whey protein during storage at (4±1 ºC and -18
ºC).
Type of coating
Storage Time (days)
Cooling 4± 1 C Freezing -18 C
2 days 5 days 7 days 2 days 5 days 7 days
CONTROL 0.336 0.787 0.954 0.298 0.569 0.686
NS50%+WP50% 0.176 0.382 0.476 0.137 0.259 0.379
NS60%+WP40% 0.197 0.402 0.499 0.166 0.282 0.398
NS70%+WP30% 0.213 0.453 0.518 0.178 0.290 0.433
NS80%+WP20% 0.259 0.470 0.523 0.186 0.397 0.474
NS90%+WP10% 0.272 0.486 0.553 0.189 0.400 0.483
NS100%+WP0% 0.289 0.497 0.590 0.212 0.443 0.493
MS50%+WP50% 0.122 0.272 0.366 0.111 0.222 0.279
MS60%+WP40% 0.135 0.285 0.382 0.123- 0.154 0.286
MS70%+WP30% 0.178 0.291 0.398 0.135 0.188 0.323
MS80%+WP20% 0.192 0.300 0.412 0.152 0.256 0.365
MS90%+WP10% 0.201 0.321 0.433 0.175 0.277 0.379
MS100%+WP0% 0.233 0.352 0.458 0.212 0.443 0.394
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Thermogravimetric analysis (TGA
The technology of gravimetric decomposition is
for determining the stability of polymers in general and polymeric films
particular towards manufacturing temperatures.
curve of the composite coat consisting of modified starch with stearic acid 50% and whey
protein 50%. A weight loss of 3
loss of free water in the polymer,
bound water, and this result
water were lost at temperature below
In the second stage, the degradation of the whey protein in addition of the plasticizer
in the polymer matrix was occur
46% of its weight and the degradation involves the release of gases from the dissociation of
the film, such as CO2, NH3, and CO. At the same time
bonds C- N, C(O)-NH, C(O)
indicated that the compound film had the ability to withstand high temperatures without
degradation till (270 °C) which is higher than the boiling point of oil
slightly. The present study was in agreement with
thermal stability of composite edible films consisting of carbohydrate as well as different
concentration of whey protein, revealed that the thermal degradation of these films
than (170 °C).
Figure (1) TGA for the edible
166
TGA)
one of the most important techniques
Figure (1) shows the thermal decomposition
3-4% occurs at a temperature between (54
the initial weight loss was 9-8% at (82.86 °C
agreed with ( 45 ) who indicated that the absorbed or bound
(130 ºC).
occurred at a temperature (269.26 °C). The film loses about 45
, it includes the degradation of the
O)-NH2, C(O)-OH and NH2 as mentioned by
the study of (8) whose
coat 50% modified starch +50% whey protein
and coats in
) 54-59 °C) due to the
C) due to the
. 45-
(23) and this
(180°C) or more
investigated the
higher
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Sensory evaluation
The two coated treatment (NS 50% +wp50%) and (MS 50% + wp50%) were
amelioration the mean values of the sensory evaluation for the characteristics of color,
flavor, texture, juiciness, and general acceptance of chicken breast comparing to the control.
As shown in fig 2, the coated samples showed a clear effect on the color characteristic of
coefficients (A and B) with values up to (7.82, 8.99), while the control sample reached (7).
A and B samples were distinguished by an attractive, shiny, brownish appearance due
to the presence of starch, whey, and Millard reactions. Consumers pay great attention to the
color of fried food products and it is one of the most important criteria used before eating the
product (33).
The flavor score which includes test and crispy for the coated samples (A, B) were
(8.23, 9.8) respectively which had a significantly higher score (P ≤ 0.05) than (C) 7.3.
The results of the statistical analysis of juiciness, texture and general appearance
indicated that the score of the coated samples (A and B) were significantly (P ≤ 0.05) higher
than non – coated one (control), B sample had the high score for these characteristics which
were (9.3, 9, 9.8).
Edible coats have demonstrated their efficiency in improving the sensory
characteristics of samples by increasing their tenderness due to their low moisture loss and
reduced fat absorption. As the reason for the low moisture loss of food coated with edible
coats of a hydrophilic nature prevents the water permeability from food during the frying
process (35). Also, coated with different concentrations of proteins reduces the oil content in
the fried final product due to the formation of covalent bonds inside the coats during heating
(13). The results were consistent with (30) who indicated that the use of methylcellulose for
coating the chicken improved the sensory properties.
Bas.J.Vet.Res.Vol.19, No.2, 2020.
Figure (2): Effect of coating of fried chicken on the sensory
composite edible coat (NS50% +WP50%)
+WP50%)C: non coated (control)
تأثیر الطلاء المرکب للأکل على تخزین قطع الدجاج المقلیة
نجلاء حسین الجاروری آلاء غازی الھاشمی
البصره، العراق.
لتغلیف الغذاء أھمیة کبیرة على زیادة عمر صلاحیة وسلامة الاغذیة فضلاً عن أن التغلیف یعمل کعازل ضد
تم استخدام نشأ البطاطا الطبیعی والمحور
کطلاء قابل للاکل، اذ تم تغلف قطع الدجاج وحفظھا فی
٧ أیام) .تمت دراسة تأثیر ، ٥، مدد ( ٢
الطلاء لتحدید مقدار فقدان الرطوبة وامتصاص الزیت وقیمة البیروکسید وحامض الثایوباربیوترک وکذلک التقییم الحسی،
MS إذ أظھرت النتائج إن جمیع الأغشیة المرکبة الصالحة للأکل حسنت من الخواص وأفضلھا کان للغشاء المرکب
( % 50
فقدان الرطوبة وامتصاص الزیت وقیم الأکسدة
وزیادة درجات
0
2
4
6
8
10
Color
168
evaluation
B: Coated with composite edible coat (MS50%
control).
قسم علوم الاغذیة ,کلیة الزراعة ,جامعة البصرة, البصره
الخلاصة
کالضوء والغبار والاوکسجین والرطوبة والمیکروبات. ٥٠ % - بحامض الستیریک مع نسب مختلفة من بروتینات الشرش
٠
) وعند 􀀀 ) والتجمید العمیق بحرارة (- ١٨ م 􀀀 ١ م ± ٤)
الثایوباربیو
التی توفر نتائج أفضل من حیث خفض اللون والنکھة والملمس والمظھر العام الذی یعکس التقییم الحسی.
Flavor Juiciness Texture General
acceptance
A : Coated with
الظروف المسببة للتلف ک
ظروف التبرید بحرارة (
والتی (+ WP50%
الحسی
A
B
C
169
Bas.J.Vet.Res.Vol.19, No.2, 2020.
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