Usefulness of the frequency data of the Fourier transform infrared spectrato evaluate the degree of oxidation of edible oils

The oxidation process of 13 edible oil samples with different proportions o f oleic, linoleic, and linolenic acyl groups has been studied using Fourier transform infrared spectroscopy. The oxidation experiments were carried ou t by heating the samples in a convection oven at 70 degrees C. Duplicate sp ectra were recorded from a film of pure oil between two disks of KBr for ea ch sample every day during the course of the oxidation, and frequency data of each band of the spectrum were collected automatically. Changes in the v alues of the frequency of most of the bands of the spectra were observed. T he shiftings of the frequency value of specific bands allowed one to distin guish between the different stages of the oxidation process and to establis h the oxidation degree of each oil sample. This methodology could be useful to evaluate the oxidative stability of edible oils in a simple, fast, and accurate way.