Evolution of oxidation markers and rancid off-flavors in Tenebrio molitor mealworm oil during thermal oxidation

Abstract

This study aimed to elucidate the thermal oxidation process of mealworm oil, thereby providing insights into the potential development of oxidation or rancidity during thermal treatment. The oxidative status of Tenebrio molitor (mealworm) oil was assessed via oxidative indices, which tended to increase with accelerated thermal oxidation. Acid and peroxide values exhibited a rapid increase within the initial 30 min across all heating temperatures, whereas the p-anisidine value showed a gradual increase in the early stages of heating, followed by a sharp rise after 4 h of heating at 180 °C. Furthermore, differences among oils heated for 8 h were visualized using a partial least-squares discriminant analysis (PLS-DA) models, based on volatile oxidation compounds that changed during the heating oxidation process. Low-molecular-weight aldehydes, the thermal oxidation products of oleic, linoleic, and α-linolenic acids, played a key role in this distribution, and the patterns became more pronounced at higher heating temperatures.