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Hepatocurative and Gluco-stabilizing Potentials
of Ethanol Extract of Stem bark of Flacourtia
indica in Aluminium Chloride induced Toxicity in
Albino Wistar rats
Amany M Basuny1, Shaker M Arafat2 and Aboel-Ainin AMH Mostafa1
1Depatmnet of Biochemisrty, Agriculture Beni-Suef University, Egypt
2Department of Oils & Fats Research, Food Technology Research Institute, Egypt
Submission: November 23, 2018; Published: January 18, 2019
*Corresponding author: Amany M Basuny, Biochemistry Department, Faculty of Agriculture Beni-Suef University, Oils & Fats Research Department, Food Technology Research Institute, Agricultural Research Center, Egypt
How to cite this article:Amany M B, Shaker M A, Aboel-A AMH M. Amany M Basuny1, Shaker M Arafat2 and Aboel-Ainin AMH Mostafa1. Curr Trends Biomedical Eng & Biosci. 2019; 18(1): 555976. DOI: 10.19080/CTBEB.2019.18.555976
The changes occurring in low acidity rice bran oil and its blend with palm olein during repeated frying cycles at 180˚C±5˚C for 4 hours a day up to five days of potato chips were determined. The parameters assessed were: acidity, color, smoke point, peroxide value, polar content, polymer content, oxidative stability by Rancimat method, tocopherol content, oryzanol content and fatty acid composition of rice bran oil, palm olein and binary oil mixtures were evaluated. Results indicated that, rice bran oil better stability than the palm olein in deep frying of potato chips. In general, this finding provides useful information to food processors and consumers who stable and healthy for frying process.
Frying is an ancient and well-established process in food preparation. This is evidenced by a great increase in fried food consumption in the recent years, of which more than 20 million tones of world annual oil production is extensively utilized for frying . The process is essentially a dehydration of food that involves rapid heat and mass transfer in food immersed in hot oil at temperatures greater than the boiling point of water . During frying, oils are degraded from thermal oxidation to form volatile and non-volatile decomposition products . The chemical changes in frying oil also result in changes in the quality of fried food. The fatty acids composition of the frying oil is an important factor affecting fried food flavor and its stability; therefore, it should be low level of polyunsaturated fatty acids such as linoleic or linolenic acids and high level of oleic acid with moderate amounts of saturated fatty acids [4,5].
As a result, the quality of frying oil is important because of absorbed oil of fried products during deep-fat frying process. Palm oil, particularly its liquid fraction palm olein, is extensively used in frying sectors. The oil is normally regarded as heavy duty oil because of its technoeconomic advantages over other vegetable oils; this can be explained from the basis of its stronger heat resistance and competitive trading price . Despite all this, the prospect of palm olein seems not convincing enough to some food processors and consumers not only because of perceptions on issues associated with saturated oils but also related to the preference of their local oils. Realizing the limitation of unsaturated oils in the perspective of stability, one of the routes
to penetrate the use of palm olein, particularly for industrial
frying, is through blending. Frying stability of palm olein blends is widely discussed [7-9].
Rice bran oil is one of the most nutritious and healthful edible oils due to the presence of abundance natural bioactive phytoceuticals such as γ-oryzanol, tocopherols, tocotrienols (tocols) and play important roles in preventing some diseases . Rice bran oil has about 30% linoleic acid, 44% oleic acid and about 23% saturated fatty acids. Unsaturated are susceptible to oxidation or thermal degradation during heating or frying , leading to various chemical changes such as oxidation, polymerization, pyrolysis and hydrolysis .
Rice bran oil is popular to be used as frying oil due to its high smoke point, low viscosity and high stability and unique frying characteristics which required less oil in frying compared to other oils . Rice bran oil plays important role as excellent salad and frying oil with high oxidative stability resulting from its high level of tocopherols and tocotrienols . The objective of this study was designed to investigate the effect of deep-fat frying on physico-chemical properties of rice bran oil extracted from heating process of rice at 100˚C for 6 minutes  and blends. Also, determine of γ-oryzanol and α-tocopherols in oil samples. And further provide an alternative heating oil source as major commercial vegetable oils in deep-fat frying process.
Low acidity rice bran oil was obtained from heating process of rice at 100˚C for 6min according to Arafat et al. . And palmolein for comparison in the frying was purchased from a local
Frying trials were carried out using a stainless-steel fryingpan.
The frying test was carried out at 180˚C±5˚C with the
frying time of 20hrs over 5 days. Potatoes were washed, peeled
and cut into slices (2mm thickness) previously soaked in NaCl
solution (10%w/v) was fried. The weight of chips fried for
each batch was about 200gm. The frying process was repeated
for five consecutive days for 4hrs every day. At the end of the
frying experiment each day, the oil was left to cool overnight. An
amount of 400ml frying oil was sampled in 500ml dark bottles,
flushed in nitrogen and stored at -18˚C for physic-chemical
analysis. All the samples collected were analyzed using the same
procedure used for initial oil analysis. All testing and analysis
were repeated three times to obtain an average reading.
Iodine number (Hanus), acid value, and peroxide value were
determined according to method of A.O.A.c Guideline . Smoke
point refers to the temperature to smoke and is recorded as out
lined by Nielson . A Lovibond Tintometer apparatus (The
Tintometer Ltd., Salisburg, England) was applied to measure
the color of non-fried and fried oil samples. The yellow glass
slide was fixed at 35 and the intensity of red glass was assigned
through matching with the oil samples . Polymer content
for oil samples was determined according to the methods Wu &
Nawar , respectively. Polar compounds in oil samples were
measured by column chromatography according to the method
described by Waltaking & Wessels .
The content of tocopherols was analyzed in high performance
liquid chromatography (HPLC) system (Gilson Inc., Middleton,
WT), equipped with a fluorescence detector and an outsampler
(Perkin Lmer, Waltham, MA), as described in AOCS Official Ce-
Oryzanol content was estimated given by Seetharamaiah
& Prabakar . Accurately weighed oil samples (About 10mg
each) in replicates were dissolved in hexane and made up
to 10ml. O.D. of the solution was recorded in a 1-centimeter
cell at 314nm in a Shimadzu UV-240 double beam recording
spectrophotometer (Solutions having OD more than 1.20 were
further diluted before recording). The oryzanol content in the oil
was calculated using the formula:
Oryzanol, g%= O.D of hexane solution/weight of oil
(g)/100ml x 100/ 358.9.
The oxidative stability was estimated by measuring the
oxidation induction time, on a Rancimat apparatus (Metrohm
CH series 679). Air (20L/h was bubbled through the oil (5.0g)
heated at 100 ˚C ± 2 ˚C, with the volatile compounds being
collected in water, and the increasing water conductivity
continually measured. The time taken to reach the conductivity
inflection was recorded Farhoosh .
Capillary gas chromatograph (HP 6890) was used for the
qualitative and quantitative determinations of fatty acids of
the oil samples and reported in relative area percentages. Fatty
acids were transesterfied into their corresponding fatty acid
methyl esters by shaking a solution of oil (0.1g) in heptane (2
ml) with solution methanolic potassium hydroxide (0.2 ml,
2N). The fatty acid methyl esters were identified using a gas
chromatograph equipped with DB-23 (5%-cyanopropyl–methyl
poly siloxane) capillary column (60mx 0.32mm X0.25μm film
thickness) and flame ionization detector. Nitrogen flow rate was
0.6ml/min, hydrogen and air-flow rates were 45 and 450ml/
min, respectively. The oven temperature was isothermally
heated 195˚C. The injector and the detector temperatures were
230˚C and 250˚C, respectively. Fatty acid methyl esters were
identified by comparing their retention times with known fatty
acid standard mixture. Peak areas were automatically computed
by an integrator. All GC measurements for each oil sample were
made in triplicate and the averages were reported.
All experiments and measurements were carried out in
triplicate, and the data were suggested to analysis of variance
(ANOVA). Analysis of variance and regression analyses were
performed according to the MStatC and Excel software.
Significant differences between means were determined by
Duncan’s multiple range tests. P values less than 0.05 were
considered statistically significant.
The initial qualities of rice bran oil and palm olein were
shown in Table 1. As overall, free fatty acids, peroxide value,
iodine value and smoke point of rice bran oil were tested higher
than palm olein. The free fatty acids of palm olein at 0.30% were
able to meet the standard trading specification of 0.1% free
fatty acids maximum. Meanwhile peroxide value of both oils
was considered lower than the specification for fresh oil. Iodine
value for rice bran oil was much higher due to the higher degree
of unsaturation. Smoke point for both oils was higher than 200˚C
making these oils were suitable for deep-fat frying purposes.
Fatty acids composition is one of the direct routes to predict
the stability of oils. Table 1 shows the fatty acids composition of parent oils that is palm olein, rice bran oil and binary blends.
Palm olein contains a balance proportion of saturated and
unsaturated fatty acids, and this imparts to the stability of oil.
Rice bran oil has palmitic acid (23.00%) as the major saturated
fatty acids. It is high in oleic acid (42.00%) and linoleic acid in
the largest component (28.40%) of or of polyunsaturated fatty
acids, followed by low level (1.10%) linolenic acid.
Smoke Point: Smoke point is the temperature of which the
oil starts to produce a continuous wisp of bluish smoke when
heating takes place. The presence of free fatty acids is generally
associated with the smoke point value. This is based on the fact
that the amount of smoke emanating from the oil is directly
proportional to the concentration of low-molecular-weight
constituents, for example, free fatty acids, monoacylglycerols,
diacylglycerols and volatile compounds . Changes in smoke
point of oil across 5 days of frying operation are illustrated
in Figure 1. Values of smoke point of fried rice bran oil were
gradually decrease compared with palm olein. It is worth nothing
that the smoke point of fried rice bran oil mixed with palm olein
at variance levels were generally higher than rice bran alone.
Color: In most cases, two types of colored glasses of
Lovibond Tintometer, i.e., yellow and red, were used to measure
the color of the oils. The yellow glasses were fixed at value of
35 and the variation in oil color was matched with red glasses.
Figure 2 illustrate that the initial red colors for palm olein were
1.90 and 1.80, respectively. As a general trend, the intensity of
the red color in all oil systems was increased as the frying time
increased. Accordingly blending palm olein with rice bran oil
produced lighter frying media.
Acidity: Acidity is basically development when oils
composition in hydrolytically altered as a result of reaction with
moisture release from food, and partly due to decomposition of
oils at frying temperatures . Fresh rice bran oil, palm olein
and the oil blends were of good quality. Acidity increased after
the deep-fat frying cycles but no significant differences (P <
0.05) was observed in the acidity of rice bran oil and blended oil samples between consecutive frying cycles, 1 day to 3 day
(Figure 3). Rice bran oil and oil blended samples obtained after
4 day frying cycles had significantly different acidity. Hence, the
increase of the acidity was in the order palm olein > palm olein
+ rice bran oil (30:70) > palm olein + rice bran oil (50:50) > rice
bran oil + palm olein (70:30) > rice bran oil.
Peroxide Value: Primary oxidation reactions cause an
increase in the concentration of peroxides to a maximum value
beyond which its concentration decreases due to thermal
decomposition therefore into carbonyl compounds and
aldehydes . The results given in Figure 4 shows that the
peroxide value of rice bran oil and blended during frying at
180˚C±5˚C, which gradually increased from to Meq.O2/kg oil.
The values of peroxide value for the oils samples at the end of
frying period indicate that the increase of peroxide value was in
the order: palm olein > palm olein + rice bran oil (30:70)> palm
olein + rice bran oil (50:50) > rice bran oil + palm olein (70:30)
> rice bran oil. Slow rate of increase in acidity and peroxide
value may be attributed due to the protective effect of oryzanol
present in rice bran oil.
Polar Compounds: Polar compounds are considered as
the most objective method to examine the deteriorative effect
in frying oils . The polar compounds fractions that is,
polymerized and oxidized triacylglycerol and diacylglycerol and
free fatty acids are being development during the oxidation and
polymerization stages . Changes in polar content of rice
bran oil and blended oil are shown in Figure 5. At zero-time,
non-detectable polar compounds were found. Frying of rice
bran oil at 180 ˚C±5 ˚C for 4hr/5 days caused increased in polar
compounds content of all oil systems. The increases of polar
compound content of oil systems were in palm olein > palm
olein + rice bran oil (70:30) > palm olein + rice bran oil (50:50)
> rice bran oil. In addition, blending rice bran oil with palm olein
induced lowering effect on the formation of total polar content.
Polymer Compounds: Polymer compounds which are a
fraction of polar compounds are developed through tertiary
oxidation and thermal modification in oil structure when exposed
to high temperature, the latter is more prominent based on the
fact that steam release from the product provides some form of
protection to the frying oil by minimizing content with oxygen
. The formation of polymer compounds is responsible for
the change in oil viscosity, tendency to foam during frying and
imparts bitterness to the fried product . The development
of polymer compounds across throughout the course of frying is
shown in Figure 6. At the end of frying the percentage of polymer
compounds in palm olein was the greatest, followed by palm
olein + rice bran oil (70:30), rice bran oil +palm olein (70:30)
and rice bran oil.
Oxidative Stability: Oxidative stability is an expression to
describe the extent of oil stability by examines the time needed
for oil to resist oxidation at elevated temperatures . From
Figure 7, the oxidative stability of fresh palm olein, rice bran oils
and their blends were the highest, Results shown in Figure 7
demonstrate a gradual decrease and significant in the oxidative
stability of oil samples during the first stage of frying time
Oryzanol Content: Rice bran oil is known for the oryzanol
content present in it and the derived potential benefits. However,
it is absent in the palm olein therefore the resultant blended oils
from the rice bran oil and palm olein contained lesser oryzanol
content. The oryzanol content decreased with the frying time
in both the oils, when used as frying media for potato chips.
However, the decrease during the frying operation was more
prominent in rice bran oil as compared to the blended oils. The
oryzanol content reduction was more in rice bran oil, when
used to fry the potato chips. Significant changes in the oryzanol
content of rice bran oil and blended oil were observed after
3rd frying day (Figure 8) Shin et al.  found that oryzanol
(Gamma) acts as an antioxidant in the oil but is lost during the
Tocopherol: Tocopherol commonly known as vitamin E are
natural antioxidants that inherently present in oils. These vital
constituents principally protect the oils by acting as radical
scavenger to decelerate the propagation phases of oxidative
degradation . The change in tocopherol with the increase
in frying times is also presented in Figure 9. All oil samples
experienced a gradual drop of tocopherol content during the
This study examined the physico-chemical changes in oil
samples when rice bran oil was blended with palm olein in the
form of binary mixtures. This is to improve oil stability before use
under continuous frying conditions. Oil samples deterioration
was relatively slow across frying times and in most cases, the
oxidative stability of the oil blends was equivalent to that of
rice bran oil. Indeed, this finding provides useful information to
food processors and consumers who are looking for stable and
healthy oil for frying process.