Analysis Of Lard In Cooking Oil Using Gas Chromatography-Flames Ionisation Detector (GC-FID) Combined With Chemometric Technique
In view of the religious restrictions and risks associated with consumption of lard, there is a growing need for lard detection methods in cooking oil that sold at low price in soft plastic packaging. In fact, it is very challenging to distinguish lard adulteration in used cooking oil due to the...
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| Format: | Thesis |
| Language: | en_US |
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| Summary: | In view of the religious restrictions and risks associated with consumption of lard,
there is a growing need for lard detection methods in cooking oil that sold at low price
in soft plastic packaging. In fact, it is very challenging to distinguish lard adulteration
in used cooking oil due to the degradation and similarity of chemical composition.
Therefore, this study is aimed to determine the potential of analytical techniques using
GC (Gas Chromatography) combined with chemometrics technique for the detection
of lard contamination in cooking oils that used by night market and food operators.
Preliminary study was to determine the change of FAs (Fatty Acids) profile at
different levels of lard in fi-ying palm oil at temperatures and times through PCA
(Principal Component Analysis). In the second stage, compositional FAs of spiked
lard in cooking oil were compared with blanks of palm oils and corn oils by a series of
experiments involving the percentages of spiked lard in cooking oil (0 %, 1 %, 10 %
and 20 %); temperatures of heating (120 O C, 180 C and 240 O C) and periods of
frying (0.5, 1,2 and 3 hrs). The multivariate data was analysed using chemometrics by
unsupervised techniques as PCA. A matrix size of 84 x 16 data set &om samples and
FAs composition were subjected to PCA by observing Scores and Loadings plot. This
chemometric technique was applied as calibration set to predict the test samples fkom
the samples collection. PCA results showed that 4 groups were visualized fkom Scores
plots which consist of 2 groups of control and spiked lard into palm olein samples (A
& B, C, D, E), 2 groups control and spiked lard into corn oils (X & Y). The samples
were unable to observe clearly because of each point is close each other. These can be
identified manually by referring values of PC1 and PC1 in Scores tables. Loadings
plot showed 3 clusters of FAs contribute to PCA model. FAs C18:2n6c and C18:3n3
were major contributed FAs in spiked lard for corn oil; and C18:ln9t, C18:2n6t and
C16:O were prominent FAs in spiked lard for palm olein. The final study is the
determination of lard residues which was carried out on collected samples from night
market at Jalan Tunku Abdul Rahman (TAR) and Jalan Wangsa Maju, Kuala Lumpur.
The results show that no lard was found in the collected samples. |
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