DETERMINATION OF FREE FATTY-ACIDS IN PALM OIL BY NEAR-INFRARED REFLECTANCE SPECTROSCOPY

A near-infrared (NIR) spectroscopy calibration was developed for the d etermination of free fatty acids (FFA) in crude palm oil and its fract ions based on the NIR reflectance approach. A range of FFA concentrati ons was prepared by hydrolyzing oil with 0.15% (w/w) lipase in an incu bator at 60 degrees C (200 rpm). Sample preparation was performed in D utch cup, and the spectra were measured in duplicate for each sample. The optimized calibration models were constructed with multiple linear regression analysis based on C=O overtone regions from 1850-2050 nm. The best wavelength combinations were 1882, 2010, and 2040 nm. Multipl e correlation coefficients squared (R-2) were: 0.994 for crude palm oi l, 0.961 for refined-bleached-deodorized (RBD) palm olein, and 0.971 f or RED palm oil. Calibrations were validated with an independent set o f 8-10 samples. R-2 of validation were 0.997, 0.943, and 0.945 respect ively. The developed method was rapid, with a total analysis time of 5 min, and environmentally friendly, and its accuracy was generally goo d for raw-material quality control.