Oxidative changes in some vegetable oils during heating at frying temperature

Abstract

The oxidative changes in refined sunflower, grape seed, soybean, corn and olive oils caused by frying temperature were studied. The oxidative degradation of the oils was evaluated by monitoring their respective peroxide value (PV), oxidation stability (IP), content of conjugated dienes as absorbance at 232 nm (A232nm), content of conjugated trienes as absorbance at 270 nm (A270nm), changes in fatty acid composition (C18:2/C16:0), and content of total polar components (TPC). Results showed that olive oil has better stability against thermal oxidation when compared to polyunsaturated oils. On the other hand, corn and soybean oils (among unsaturated oils) are most resistant to oxidation at frying temperature. The best correlation was observed between the rate of decrease in C18:2/C16:0 ratio and the content of total polar components.