Effect of Air Frying Pretreatment on Quality and Antioxidant Activities of Rapeseed Oil

ABSTRACT Air frying is an emerging pretreatment technology in the food processing industry. This study investigated the effects of air frying pretreatment on the microstructure of rapeseed, as well as on the fatty acid composition, functional components, and antioxidant activity of the resulting pressed oil. Compared with microwave and roasting, air frying pretreatment (190°C, 15 min) induced a greater degree of oil body coalescence within rapeseed cells, which correlated with enhanced oil release and extraction of functional components. Under these conditions, the pressed oil exhibited the highest nutritional value: total phytosterol content reached 7174.39 mg/kg and total phenolic content was 2474.30 mg/kg, both significantly higher than those from microwave pretreated, roasted, or untreated rapeseed. Although oxidation indices increased after pretreatment, all values remained within national safety limits. Moreover, rapeseed oil pressed from air fried rapeseed also demonstrated the strongest antioxidant capacity in DPPH, ABTS, •OH, and assays. Statistical analysis revealed a significant positive correlation between antioxidant activity and total phenolic content ( p ≤ 0.01). These results indicate that air frying is an effective pretreatment for enhancing the release of functional compounds and improving the antioxidant quality of rapeseed oil.