Kinetics of stepwise peroxidation of rapeseed oil, flaxseed oil, high oleic peanut oil and high oleic sunflower oil under heating conditions

Abstract

This study investigates the oxidative stability of rapeseed, flaxseed, high oleic peanut, and high oleic sunflower oils during short-term thermal oxidation. By monitoring peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) levels before and after purification and at 100 °C and 180 °C, the oxidative behavior and antioxidant capacity of each oil under high temperature conditions were evaluated. Additionally, the depletion patterns of tocopherols and sterols during thermal oxidation were analyzed. To elucidate oxidation mechanisms, the kinetics of lipid hydroperoxide (LOOH) concentration changes in the oils were examined. Results indicate that high oleic peanut oil exhibits superior oxidative stability, maintaining lower PV and TBARS levels throughout the heating cycle. Tocopherol and sterol depletion correlated positively with oxidation time and temperature, and the heat loss varied among different oils. Kinetic modeling revealed that oils with a more diverse fatty acid composition tend to undergo stepwise oxidation. High oleic peanut oil, flaxseed oil and high oleic sunflower oil displayed a single-step reaction, whereas rapeseed oil progressed through a two-step reaction before reaching a typical termination phase.