Lard (LD) has been commonly used as an adulterant in fats and oils. The similar physical characteristic of virgin coconut oil (VCO) to LD makes LD a desirable adulterant in VCO. Differential scanning calorimetry (DSC) provides unique thermal profiling for each oil and can be used to detect LD adulteration in VCO. In the heating thermogram of the mixture, there was one major endothermic peak (peak A) with a smaller shoulder peak embedded in the major peak that gradually smoothed out to the major peak as the LD% increased. In the cooling thermogram, there were one minor peak (peak B) and two major exothermic peaks, peak C which increased as LD% increased and peak D which decreased in size as the LD% increased. From Stepwise Multiple Linear regression (SMLR) analysis, two independent variables were found to be able to predict LD% adulteration in VCO with R 2 (adjusted) of 95.82. The SMLR equation of LD% adulteration in VCO is 293.1 -11.36 (T e A) -2.17 (T r D); where T e A is the endset of peak A and T r D is the range of thermal transition for peak D. These parameters can serve as a good measurement index in detecting LD adulteration in VCO.
Fourier transform infrared (FTIR) spectra at mid infrared regions (4,000-650 cm -1 ) of lard and 16 edible fats and oils were compared and differentiated. The chemometrics of principal component analysis and cluster analysis (CA) was used for such differentiation using FTIR spectra intensities of evaluated fats and oils. With PCA, an ''eigenvalue'' of about 90% was achieved using four principal components (PCs) of variables (FTIR spectra absorbances at the selected frequency regions). PC1 accounted for 44.1% of the variation, while PC2 described 30.2% of the variation. The main frequency regions that influence the separation of lard from other evaluated fats and oils based on PC1 are 2,852.8 followed by 2,922 and 1,464.7 cm -1 . Furthermore, CA can classify lard into its group based on Euclidean distance.
Lard (LD) and virgin coconut oil (VCO) share some similarities such as having transparent to yellowish color and are solid at room temperature; hence, as a consequent, LD may be a potential oil adulterant in VCO. This study highlights the application of fast gas chromatography with surface acoustic wave detector (GC-SAW system) and Fourier transform infrared (FTIR) spectroscopy combined with chemometrics to analyze the presence of LD in VCO. Binary admixtures of LD in VCO in various percentage concentrations ranging from 1% to 50% (v/v) were assayed using the fast GC-SAW system and FTIR spectroscopy. Using the fast GC-SAW system, ten different chromatogram peaks were identified as the adulterant peaks. One peak in the fast GC-SAW system chromatogram was found to have the best relationship, with a coefficient of determination (R 2 ) value of 0.9344. Furthermore, FTIR spectroscopy coupled with partial least square (PLS) and discriminant analysis (DA) can be successfully developed for quantification and classification of LD in VCO. The results showed that PLS able to predict the LD contents in VCO with equation of y ¼ 0:999 Â þ0:006, for the correlation between actual value of LD (x) and FTIR predicted value (y) with R 2 of 0.9990 at frequency regions of 3,020-3,000 cm −1 and 1,120-1,000 cm −1 . DA can classify VCO and that adulterated with LD using the FTIR spectra at the same frequency regions used in quantification.
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