Measure of thermo-oxidation of vegetable oils microwave-heated in model systems

A study was conducted to evaluate the extent of thermo-oxidative degradation in different types of oils (sunflower, soybean, peanut, and virgin of olive) microwave heated in model systems. The acidity determination, peroxide value, specific UV spectrophotometric constants, and p-anisidine value - useful for a basic evaluation - were carried out. Polar compounds and the single classes of substances constituting them were also determined to better estimate the extent of oxidative and hydrolytic degradation of the oils under study. The obtained results showed a high oxidative degradation degree of the oils that, however, seemed to be correlated to the poly-enoic fatty add content and to the presence of pro-oxidant substances. The hydrolytic degradation, otherwise, resulted moderate.