Safety Limits for Using Ostrich Olein in
Amany M Basuny1*,Amal R Tageldeen2,Marwa A El- Ghonamy2
1Department of Biochemistry, Beni-Suef University, Egypt
2Department of Oils & Fats, Food Technology Research Institute, Agricultural Research Center, Egypt
Submission:September 09, 2019Published: October 21, 2019
*Corresponding author:Amany M Basuny, Department of Biochemistry, Beni-Suef University, Egypt Agri Res
How to cite this article:Amany M Basuny, Amal R Tageldeen, Marwa A El- Ghonamy. Safety Limits for Using Ostrich Olein in Frying Process.Agri Res& Tech: Open Access J. 2019; 22(4): 556223. DOI: 10.19230/ARTOAJ.2019.22.556223
Ostrich (Struthio camelus) oil is used as a new source of animal oil. Physical and chemical characteristics for the ostrich oil, profile of fatty acid (%) and unsaponifiable matter (%) were analysis. Ostrich oil was fractionated to two phases (liquid and solid fractions) after fractionated some characteristics of two fractions was measured. Blending process of sunflower oil with liquid fraction (named ostrich olein) showed that oxidative stability, which was evaluated by the Rancimat method at 100°C, was obtained from ostrich oil by dry fractionation. The results indicated that blending process of sunflower oil with liquid fraction (ostrich olein) on effective method to prepare more stable vegetable oils. Ostrich olein was mixed separately with sunflower oil at (75:25, 50:50 and 25:75, v/v). The frying process was conducted at 180°C ± 5°Cfor 16hr/ 4hr per day. Some physical and chemical characteristics of non-fried and fried oil mixture were measured at various heating periods. The results demonstrate that mixing ostrich olein with sunflower oil increased the stability and hence improved the quality of sunflower oil during frying process.
Deep-fat frying is one of the best cooking processes to make palatable foods with golden color, exquisite flavor, and attractive surface through a total submersion of nourishment materials in frying oil. During frying processes, heat is moved from oil to sustenance food materials, and water in singed items dissipates at the same time with the items the oil . During commercial frying technique, frying oils are typically more than once utilized, thus changing quality of fried foods with development of non-volatiles and volatiles components, some of which are potentially harmful to human health. Thusly, it is critical to screen changes in quality of frying oils . Physical properties such as color index and viscosity, and chemical characteristics such as acid value, total polar compound, and p-anisidine value have been generally considered to assess the quality of frying oils . As total polar compound has been a reasonable factor to evaluate quality of frying oils, acceptable limits of total polar compound have been suggested to be 24-27% (w/w). In Korea, acid value has been used to monitor quality of oils with legal rejection limit of frying oil being 3.0 acid values. Volatile compounds, particularly aldehydes, shaped formed during frying technique of oils are a conclusive factor for flavor of fried products even at low concentrations. Along these lines, measurements of volatile compounds in frying oils would be significant to screen their quality .
During frying technique, hydrolysis, oxidation, and polymerization are formed of the oils. These chemical reactions of frying oils mostly depend on presence of fatty acid compositions and antioxidant contents. Its realized that the higher unsaturated fatty acids exist in the oils, the faster thermal oxidation occurs during frying. It has been recommended that fats and oils with high amounts of saturated fatty acids, example coconut oil and palm oil, be utilized in frying in substitution for traditionally frying oils with high amounts of unsaturated fatty acids . Ostrich bird (Struthio camelus) is an enormous flightless flying creature local to African Grassland and Desert. Wild ostrich has been recorded in the substance of Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) since 1973. Since it gives numerous things of extraordinary incentive to man, as a wellspring of ostrich meat, leather, feather, egg and fat, in excess of 50 nations have been advancing the ostrich ventures enthusiastically on the worldwide scale . Extracted oil from ostrich was used by ancient cultures like a cosmetic as well as in the remedy of burns and lesions. Cleopatra is thought to have used ostrich oil as part of her beauty regiment for maintaining her beauty and attractiveness in the desert climate. Most of the ostrich oil benefits are mainly caused by the ω-fatty acids contained in the oil [7,8]. Ostrich oil comes from the fat of the ostrich. This biggest flightless bird in the world, the Ostrich, has been a valuable source of food and other purposes for thousands of years for many native tribes . For centuries
ostrich oil has been used by Egyptian, Roman and African cultures
for the relief of dry skin, burns, lesions, eczema, sunburn and even
dry hair . Ostrich oil It’s a great source of Omega 3, 6 and 9
which contain vital fatty acids for the growth of new skin cells and
is naturally rich in vitamins well known for skin rejuvenating. Due
to the way that tamed ostriches are being fed with an all- natural
diet without any animal by-products, the natural oil is fantastic for
your skin. It infiltrates into the skin and provides a moisture layer
without clogging skin pores and leaves your skin without feeling
greasy. It can be combined with a variety of essential oils to sooth
aches and pains. At our Safari Ostrich Leather Shop, we stock a
brand-new range of modern cosmetics under the name of Struis
Lux. These exclusive products are all based on ostrich oils. The
Ostrich oil items extend from Hand creams, body creams, day and
night lotions and ostrich balsam [10-13]. The extracted oil from
ostrich contains 28% saturated fatty acids, mostly as palmitic
acid (20%) and stearic acid (8%). The polyunsaturated fatty acid
is about 20% linoleic acid and 2% linolenic acid and the oil is
high in oleic acid [11,12]. Ostrich oil was used as a new source
of dietary fat  and was also introduced in the production of
healthy biscuits . However, there is less study data elucidating
its fatty acid composition and physicochemical properties being
reported, which limits the utilization of this natural product. Such
characterization is indispensable for the in‐depth pharmacological
research and quality control of ostrich fat. Therefore, the present
study was focused on collecting the basic information of ostrich oil
in terms of fatty acid composition and physicochemical properties.
Separate into two distinct phases, a liquid phase and a solid phase
and study characteristics of two phases. Also, assess the ostrich
olein mixed with sunflower oil for deep-fat frying and to extent
the shelf- life of oils.
Ostrich was extracted from fat tissues by
dry rendering method reported by . The rendering process
was conducted at 90oC for 3 hrs. After cooling at 50oC, the fats
were filtered through a Whitman No.1 filter paper and kept in
brown bottles at 5oC until analysis.
index, melting point, smoke point, color, acid value, peroxide
value, iodine value, polar content, insoluble polymer content,
oxidized fatty acids, saponification number and unsaponifiable
matter content were determined according to . Fatty acid
composition of the samples was determined by analyzing. The
fatty acid methyl esters by gas liquid chromatography according
to , unsaponifiable matter composition of the samples
was determined by analyzed using gas liquid chromatography
according to  and oxidative stability by Rancimat method at
100oC ± 2oC were determined according to the method of .
Frying process: Ostrich olein, sunflower oil and their blends were
sued for frying potato chips as follows: A known amount (ca. 2kg)
of each system was placed separately in a stainless-steel pan fryer
(25cm diameter X 20cm height). The oils and their mixtures were
separately heated at 180°C ± 5°C, then a lot of potato chips (2mm
thickness) previously soaked in sodium chloride solution (10%,
w/v) were fried. After frying of potato chips and at end of each
day, sample oils were withdrawn and stored in brown bottles at
20°C until analysis.
A one-way ANOVA followed by Duncan’s
multiple range test (DMRT) were performed using SPSS 11.00
(SPSS Inc., Chicago, IL, USA) to analyze and compare the data.
Results were presented as mean ± SD and P- values ≤ 0.05 were
regarded as statistical significance.
The tabulated data in Table 1 showed that the moisture
and volatile matter contents% and some physical and chemical
properties of ostrich oil and its factions. From results in Table 1
the moisture and volatile matter content (%) within the ostrich oil
and 2 fractions (ostrich olein and stearin) was 0.01 %. Whereas,
the refractive index values at 40oC of ostrich oil and 2 fractions
(ostrich olein and stearin) were 1.4562±0.001, 1.4586±0.001
and 1.4472±0.001, respectively. Data in Table 1 showed that
the colour index of ostrich oil and 2 fractions (ostrich olein and
stearin) were underneath the limitation that rumored by the ,
that mentioned that the red were 00.00, 2.20 and 2.50 at yellow
35 for edible oils. Freezing point of ostrich oil was less than those different fats. This information is comparable and therefore the
proven fact that the ostrich oil is semi-solid at room temperature.
The results indicated that the definite quantity (as nothing oleic
acid) of ostrich oil was lower (0.10 %) than 2 fractions (0.27 and
0.30); respectively. The peroxide value of ostrich oil was 0.90
compared with 2 fractions that were, 1.70 and 1.85 meq. /kg
sample, respectively. The iodine value of ostrich oil (79.00 gI2)
is more than that of 2 fractions (53.00, and 56.00), respectively.
Saponification number and unsaponifiable matter of ostrich oil
(205.00 and 1.5%; respectively) were more those of 2 fractions
shown in Table 1. These results are agreement thereupon rumored
Fatty acid composition of ostrich oil, ostrich olein and
ostrich stearin were known by gas liquid chromatography and
the obtained results are tabulated in Table 2. It may be noticed
that monounsaturated fatty acid is found to be the dominant
unsaturated fatty acid in ostrich oil and ostrich olein, which
portrayed concerning (46.75±3.17%). Palmitic acid was found
additionally to be the dominant saturated fatty acid in ostrich oil
and ostrich stearin (28.50±1.24%). The results agree thereupon
reported by [21,22].
The changes in oxidative stability (Rancimat methodology at
100oC ± 2oC hrs) of ostrich oil, sunflower-seed oil (SO), stearin
fraction (OF) and blends (SO/OF) are conferred in Table 3. Ostrich
oil and stearin fraction were the foremost stable samples having
an induction period was 35.00±3.34 and 41.00±5.3hrs, whereas
sunflower-seed oil was the smallest amount stable sample with
induction period 9.00±1.50hrs. Results in Table 3 shows that
the oxidative stability of therefore supported induction amount
was considerably enlarged by mixing with ostrich oil and its
derivatives. The rise in oxidative stability was proportional to
the rise of proportion within the blends. This study showed that
combining therefore with completely different proportions of
obtained from ostrich oil by dry fraction crystallization provides
a good, simple, safe and accessible methodology to arrange
additional stable edible oils are often employed in manufacturing
French cooked potatoes.
Refractive index: Figure 1 show that the refractive index values
for the fresh ostrich olein, sunflower oil and their mixtures (75:25,
50:50 and 25:75 v/v). The values demonstrate that ostrich olein
refractive index value was higher than that of the refractive index of
sunflower oil and blended samples. There is a strong relationship
between the refractive index and iodine value, with higher iodine
values would have higher refractive index and this fact is in line
with data of the present work. The value of refractive index of fried
ostrich olein, sunflower oil and blended of them indicate a linear
relationship between their refractive indices and frying time. The
increase of the refractive index values over frying time for the oil
systems was in the order: Ostrich olein > ostrich olein + sunflower
oil blends (50:50 v/v) > sunflower oil + ostrich olein (75:25 v/v)
> sunflower oil + ostrich olein (75:25 v/v) > sunflower oil. This
sequence is in line index values for the conjugated compounds are
higher than that of their non-conjugated isomers. Its established
that during oil frying some of the non-conjugated double bonds are
converted to conjugated ones and this process cause an increase
in the refractive index value .
Smoke point (oC): Figure 2 shows the changes in smoke point
of fresh, fried oils and their blends at various periods compared
with those at zero time. The values of smoke point of fried ostrich
olein were gradually decrease compared with sunflower oil. It is
worth noting that the smoke points of fried ostrich oil mixed with
sunflower oil at various levels (75:25, 7:3 and 50:50, v/v) were
generally lower than ostrich olein alone.
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 a value of
35 and the variation in oil color was matched with red glasses.
Figure 3 illustrated that the initial red colors for ostrich olein,
sunflower oil were 1.70 and 2.10 respectively. As a general trend,
the intensity of the red color in all oil systems was increased as the
frying time increased. The darkness of oil color due to frying at
180°C ± 5°C was arranged according to the sunflower > sunflower
oil + ostrich olein blended (75:25, v/v) > sunflower oil + ostrich
olein (75:25, v/v) > sunflower oil + ostrich olein (50:50, v/v) >
ostrich olein. Accordingly blending ostrich olein with sunflower
oil produced lighter frying media.
Acid value is one of the indicators used to assess
oil quality. Figure 4 shows the changes of acid values for of fried
under study. The acid value of fried oils showed gradually increase
with frying time. Hence, the increase of the acid value was in the
order: sunflower oil > sunflower oil + ostrich olein mixture (75:25,
v/v) > sunflower oil + ostrich olein (75:25, v/v) > sunflower
oil + ostrich olein (50:50, v/v) > ostrich olein. These findings
demonstrate the improvement in sunflower oil quality during
frying at 180°C ± 5°C when mixed with ostrich olein.
This fat constant indicator the primary
oxidation products of the oils (hydroperoxides). Table 1 show
the peroxide value of ostrich olein and sunflower oil at the
beginning of the experiment and were 0.20 and 0.33 meq. O2 /
kg oil, respectively. The peroxide value of these oils was within
the recommended values for human consumption. The changes
in the peroxide values of fried ostrich olein, sunflower oil and
their blends are shown in Figure 5. The changes in peroxide value
of the fried oils were progressively and significantly increased during frying process. The values of peroxide values for the oils at
the end of frying indicate that the increase of peroxide value was
in the in the order: sunflower oil > sunflower oil + ostrich olein
mixture (75:25, v/v) > sunflower oil + ostrich olein (75:25, v/v) >
sunflower oil + ostrich olein (50:50, v/v) > ostrich olein. It’s well
known that the degree of oil oxidation is obviously dependent
upon oil unsaturation and this order is in line with this fact. In
other words, mixing ostrich olein with sunflower oil lowered the
peroxide value of sunflower oil during frying process and hence
increases the stability of sunflower oil during frying .
Changes in polar content of ostrich olein,
sunflower oil and blends of them (7:25, 75:5 and 50:50 v/v) are
show in Figure 6. At zero time, no detectable polar compounds
were found. Frying of ostrich olein, sunflower oil and their
blends at 180°C ± 5°C for 4hr/5 day caused increase in the
polar compounds content of all oil systems. The increases of
polar compounds contents of the oil systems were in the order:
sunflower oil > sunflower oil + ostrich olein mixture (75:25, v/v) >
sunflower oil + ostrich olein (75:25, v/v) > sunflower oil + ostrich
olein (50:50, v/v) > ostrich olein. In addition, blending ostrich
olein with sunflower oil induced lowering effect on the formation
of polar content .
At zero time, no detectable polymer
compounds were found for ostrich olein, sunflower oil and its
admixtures were nil Figure 7. The changes in polymer contents of
the fried oil systems showed increases with time. The increases of
polymer contents of the oil systems were in the order: sunflower
oil > sunflower oil + ostrich olein mixture (75:25, v/v) > sunflower
oil + ostrich olein (75:25, v/v) > sunflower oil + ostrich olein
(50:50, v/v) > ostrich olein. These results indicate that blending
ostrich olein with sunflower oil at different ratios possessed lower
effect on the formation of polymers during frying process. It is
well established that the degree of polymer formation is largely
depends on the oil unsaturation .
The results in Figure 8 showed the
formation of oxidized fatty acids in all oil systems. The changes in
oxidized fatty acids of the fried oil systems showed increases with
time. Accordingly, the increase of the oxidized fatty acids contents
were in the order: sunflower oil > sunflower oil + ostrich olein
mixture (75:25, v/v) > sunflower oil + ostrich olein (75:25, v/v) > sunflower oil + ostrich olein (50:50, v/v) > ostrich olein. These
results showed that blending ostrich olein with sunflower oil at
different ratios led to the decrease of oxidized fatty acids contents
during frying at 180°C ± 5°C.
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