Some of the most significant changes in the Fourier transform infrared spectra of edible oils under oxidative conditions

The oxidation of a broad collection of commercial edible oils, including extra virgin olive, olive, sesame, sunflower, corn, unknown seed, soybean, safflower, rapeseed, peanut and walnut oils, was monitored by Fourier transform infrared spectroscopy. Samples were kept in a convection oven with air circulating at 70 °C. Duplicate spectra were collected each day of the experiment by applying a film of pure oil between two KBr disks. The frequency and absorbance of each infrared band were automatically registered by a macro program. Ratios between absorbances of different bands of the spectra were calculated. Changes in frequency values of different bands and in ratios between absorbances of some bands allow different stages of the oxidation process to be distinguished as well as determining their oxidative stability in a simple and fast way, showing the usefulness of this technique in monitoring oil oxidation processes.