Determining frying oil deterioration using chemical and physical methods
This research was performed to assess the oil deterioration during deep fat frying. It was also conducted to compare and correlate oil quality parameters namely, total polar compound (TPC), free fatty acids (FFA), peroxide value (PV), P-Anisidine value (p-AV), specific extinction (E1%lcm233, 269n...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2009
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/8516/1/FSTM_2009_12_UPMIR.pdf |
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| Summary: | This research was performed to assess the oil deterioration during deep fat frying. It
was also conducted to compare and correlate oil quality parameters namely, total
polar compound (TPC), free fatty acids (FFA), peroxide value (PV), P-Anisidine
value (p-AV), specific extinction (E1%lcm233, 269nm), iodine value (IV), flavor,
color, viscosity, with changes in the heating profile of melting point, and investigate
changes in the properties of oils with different kinds of food during deep-fat frying
of chicken, banana and sweet potato. The frying oil consisted of five types of
commercial oils, namely, canola, corn, soybean, sunflower and palm olein. These
oils were used to fry, banana, sweet potato and chicken at 185 ± 5°C for 6 hr per day
for sixe days until the total time of 30 hours with an interval time of 20 min. One and
half kilograms of each oil sample to be tasted and 100g of each fried product was
used for the frying. The frying time was set for 7 minute for banana and sweet potato
and 1 5 minute for chicken. Each day, fresh oil was added to replenish the oil used.
Oils used were withdrawn on the following day and before starti ng the next frying cycle and was kept in the freezer at -20˚C. The oils were analyzed for PV, N, p-AV,
FFA, E1%lcm233, 269nm, TPC, color, viscosity, flavor (by zNose) and thermal
behavior (melting point by DSC).
In this study, DSC was used to monitor the deterioration of frying oils during deep
fat frying based on qualitative investigation of the thermal behavior (melting point). The
investigation began with the successful comparison of the DSC thermal curves of
five different vegetable oils. The heating thermogram for the oils showed varying
degree of changes especially in the last melting peak position during the course of
frying. The heating thermogram showed that there is one major peak and two small
shoulders peaks and used the offset of last melting peak; ("the last order peak of the
DSC heating thermogram was used to represent the changes in melting point"). Flavor
analysis is typically performed by a qualitative analysis of zNose chromatogram. A
novel approach using a surface acoustic wave (SAW) sensing based electronic nose for
favor analysis was used in this study for detecting the losing of volatile compound in
vegetables oils. A statistical correlation was carried out on the DSC heating
thermogram with standard chemical and physical methods. Significant linear
relationship was found between melting point, TPC, N, E1%1cm233 , 269nm and
viscosity. The DSC heating thermogram showed excellent correlation (P<0.05) with
the standard chemical analysis.The finding of this study reveals that palm olein showed significantly (P<0.05)
lower in all measured parameters than the other oils used. The extent of oil
deterioration was best reflected in the changes in percent TPC, N, E1%cm at 233nm |
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