ANALISIS LEMAK BABI DALAM MINYAK SAWIT (RBD PALM OIL) DENGAN SPEKTROSKOPI FOURIER TRANSFORM INFRARED (FTIR) DAN KEMOMETRIK

Abstract

Fourier Transform Infrared (FTIR) spectroscopy combined with chemometrics has been developed for simple analysis of lard in the mixtures with palm oil. In this research, measurements were made on pure palm oil and that adulterated with varying concentrations of lard (0.5–80% v/v in palm oil). Two multivariate calibrations, namely Partial Least Square (PLS) and Principal Component Regression (PCR) were optimized for constructing the calibration models, either for normal spectra or its first and second derivatives. The discriminant analysis (DA) was used for classification analysis between palm oil and that adulterated with lard. According to result of this research, PLS has an ability to construct the calibration model better than PCR model. PLS model at normal spectra with frequencies at fingerprint region (1500-800 cm ) revealed the best calibration models for predicting the concentration of adulterated lard samples, with highest coefficient of determination (R 2 ) of 0,995 and lowest Root Mean Square Error of Calibration (RMSEC) of 1,82. In addition, validation of this model has a good result of R 2 Leave One Out of Cross Validation (RMSEC) of 0,916 and R 2 prediction of 0,996. DA was able to classify pure palm oil and adulterated with lard on the basis of their FTIR spectra with accuracy 100% and no misclassified group of samples. In this model, DA was performed at frequency regions of 1500-800 cm -1 using 6 principal components. According to this result of test set validation, a level of 2% of LD can be detected in adulterated with PO. PLS and DA developed models was further used to predict the classes of unknown (commercial) oil in instant noodles samples. Using this model, all of local commercial instant noodles are in the class of pure palm oil without lard, but in the imported instant noodles samples are one sample is detected as a mixture with the lard with a concentration of 60,03 %