Prediksi Penurunan Kualitas Minyak Goreng Kelapa Sawit Menggunakan Fourier Transform Infrared (FTIR) Spektroskopi dengan Analisis Multivariat

Abstract

The using of fourier transform infra red (FTIR) spectroscopy to examine food samples such as frying oil has became popular in the last decade. In this study, FTIR profiles of palm oil which has been used for fish frying at the short term frying process were investigated, and their correlation to free fatty acid (FFA) and peroxide values (PV) using multivariate data analysis was then determined to confirm the oil quality. Two batches of commercial palm oil were repeatedly used to fry cat fishes for nine times at 180°C and within duration of 15 minutes for each frying. Oil samples were analyzed with respect to FFA and PV according to AOAC standard method. FTIR spectra were collected at wavenumber 400-4000 cm-1 and a setting at 32 scans and 1.9 cm-1 resolution. The correlation calculation was done using OLS (Ordinary Least Square) multivariate analysis. The main peaks observed in FTIR spectra showed the oil functional groups such as alkyl, ester, single and double bonds of carbon atoms. The absorbance values of the peaks in FTIR spectra and FFA values exhibited a significant correlation at R2 = 0.955 (Pvalue 0.042) obtained by the multivariate analysis, whilst the correlation with peroxide values showed a significance at R2 =0.955 (Pvalue 0.030). These results confirmed that FTIR spectroscopy can be used to analyze the quality of palm oil after food frying.