Determination of anisidine value of red fruit oil under elevated temperature using FTIR spectroscopy and multivariate calibration

This Study was conducted to evaluate anisidine value (AV) of red fruit oil (RFO) obtained from hexane fraction and chloroform Fraction of RFO in elevated temperature. RFO with and without butylated hydroxytoluene (BHT of 200 mg/Kg) and α-tocopherol (BHT of 200 mg/Kg) were subjected to elevated heating temperature (room temperature, treated at 100 ± 1°C, 150 ± 1°C, 180 ± 1°C, 200 ± 1°C, and 300 ± 1°C) for 90 minutes in the oven. A band shift was observed at wavenumbers of 1689 cm^-1 and 1716 cm^-1, assigned to the stretching vibrations of C=O and C-O from ester triglyceride, respectively. Besides, the absorbance change at wavenumber region of 1330 - 1454 cm^-1 was also observed, indicating the possible presence of aldehydic or ketonic groups with isolated cis double bonds in RFO. Based on the optimization processes, the best coefficient of determination (R^2) value for the relationship between actual value of AV as determined by AOCS method and FTIR predicted value on determination AV was in the range of 1685 - 1712 cm^-1. The R^2 value obtained was 0.9998 for RFO in hexane fraction, and 0.9989 for RFO in chloroform fraction. In this study, the effect of antioxidants on AV of RFO in hexane fraction and chloroform fraction was also investigated.