Optimizing oxidative stability of Camellia oleifera seed oil: Multimodal analysis of antioxidant efficacy, tocopherol loss, benzo[a]pyrene suppression, and kinetic mechanisms

Camellia oleifera seed oil (COSO) is highly susceptible to thermo-oxidative degradation due to its high content of unsaturated fatty acids, leading to nutrient loss and carcinogenic benzo[ a ]pyrene (BaP) formation. In this study, we employed a multimodal approach (Fourier transform infrared spectroscopy, FTIR; electron paramagnetic resonance, EPR; oxidation kinetics, α-tocopherol and BaP monitoring) to systematically compare four antioxidants (PG, TBHQ, BHT, VE) at industrially relevant concentrations. Results showed that TBHQ (0.2 g/kg) and PG (0.1 g/kg) optimally preserved α-tocopherols (6.70/4.58 mg/kg) and minimized BaP (1.40/1.46 μg/kg) during 15-day oxidation. FTIR revealed preferential stabilization of C H, cis-C=C, and C O bonds, while EPR confirmed superoxide radical (•O₂ − ) quenching via HAT/SET mechanisms. Kinetic analysis indicated higher activation energies for TBHQ (126.60 kJ/mol) and PG (92.63 kJ/mol), confirming enhanced stability. Mechanistically, TBHQ and PG function via phenolic hydroxyl H-transfer and quinonoid transformation. PG is a low-toxicity alternative to TBHQ for COSO stabilization.