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.

This research aims to evaluate the profile of lard using the chemometric method to discriminate lard from other types of fat after the heating-process and determination of biomarkers in lard. In this research, two types of samples were conducted. First, a total of 270 lard were collected from belly fats (BL), back fats (BK), and shoulder fats (SF) from northern, southern, and central regions of Peninsular Malaysia, which were measured using FTIR. PCA utilised the chemometrics evaluation on lard profiles using PCA and extended Hotelling T2. The scores vectors were found inside Hotelling T2 eclipses at first 3 PCs (99.5% confidence interval) and successfully validated by PCA projection. This indicates that the FTIR profile for lard is undifferentiated for all regions and body parts. Second, for discrimination purposes, a total of 60 fats, lard, chicken, beef, mutton, and plant have undergone twelve heating-process protocols (at 120 °C, 180 °C, 240 °C for 0.5. 1, 2 &3 hrs). In addition, each species without any heating was included in this study. After the heating-process, fat samples were analysed using FTIR, 1H-NMR, 13C-NMR, GC-FID, and LC-MS/MS. The classification was performed using multivariate classification (LDA, MDA, QDA & SVMDA) and multivariate regression (OSC-PLSR, PCR & PLSR) on FTIR and 1H-NMR. Multivariate classification found MDA, QDA, and SVMDA on 1H-NMR provided the best results for classifying lard from other fats. In the multivariate regression, the result of OSC-PLSR on FTIR (R2, adj. R2, RMSEC, RMSEV & MSEP; 0.985, 0.984, 0.049, 0.051 & 0.056) was found to outperform than the OSC-PLSR on 1H-NMR. Finally, profiling lard by 13C-NMR, GC-FID, and LC-MS/MS combined with the PCA were conducted to determine the biomarker of lard. The 13C-NMR-PCA data found that the lard differed against the chicken fats at C-2 of the TAG isomer, denoted by δ 34.21 and δ 62.10 resonances. Meanwhile, the GC-FID-PCA data found that animal fats and plant fats can differ after fatty acids )FAs( degradation of the cis into trans isomers. The lard heated at 180 °C (at 0.5, 1 & 2 hrs.) was found to differ significantly from others by LC-MS/MS-PCA, contributed by saturated fatty acids (SFA) of the diacylglycerol (DAG) and phosphatidic acids (PA) lipid classes. The application of chemometrics was found to discriminate lard against other fats after the heating-process successfully, and FAs were tentatively identified as biomarkers.