Comparative effects of infrared and radio-frequency stabilization on rice bran oil quality: Yields, bioactive compounds, and storage stability

• IR-VC improved oil yield by enhancing heat transfer and reducing oxidation • RF stabilization suppressed rancidity, extending shelf-life up to 39-fold • IR-VC preserved γ-oryzanol, tocotrienols, and tocopherols during storage • Comparative insights guide industrial selection of energy-efficient methods This study systematically evaluated the mechanistic effects of four stabilization technologies—infrared (IR), vacuum-assisted infrared (IR-VC), hot air-assisted IR (IR-HA), and radio-frequency (RF)—on rice bran oil yield, lipid stability, and bioactive compound retention. All treatments were designed to deliver comparable thermal energy inputs, enabling quantitative comparisons. Among the methods, IR-VC achieved the highest extraction yield (8.87 g/100 g dry basis), while RF treatment provided the strongest suppression of hydrolytic and oxidative deterioration, resulting in the lowest acid value (14.86 mg KOH/g) and peroxide value (6.16 meq O 2 /kg) after 8 weeks of storage. Shelf-life projections based on free fatty acid accumulation at 30°C indicated substantial extensions: RF (39.2 days), IR-VC (27.4 days), IR (16.8 days), and IR-HA (13.4 days), compared with only 1.7 days in non-stabilized controls. IR-VC preserved the highest levels of bioactive compounds during 8-week storage, including γ-tocotrienol (1,033 mg/kg), α-tocopherol (360 mg/kg), and γ-oryzanol (6,920 mg/kg). These results demonstrate that IR-VC offers a balanced strategy for maximizing oil recovery and bioactive retention, while RF is most effective for extending storage stability. The mechanistic insights provided here can guide engineering design and optimization of rice bran stabilization processes for commercial RBO production.