Non-Thermal Stabilization Strategies for Rice Bran: Mechanistic Insights, Technological Advances, and Implications for Industrial Applications

Abstract

Rice bran, a major byproduct of rice processing, is rich in unsaturated fatty acids, high-quality proteins, and bioactive compounds such as γ-oryzanol and ferulic acid. However, its poor storage stability and susceptibility to hydrolytic and oxidative rancidity critically limit industrial exploitation. Recent advances in non-thermal stabilization technologies—valued for their energy efficiency, scalability, and nutrient preservation—offer promising solutions. This review systematically elucidates the enzymatic and microbial mechanisms driving bran rancidity, emphasizing lipase and lipoxygenase activity, and critically evaluates the efficacy of emerging non-thermal strategies. Key findings highlight the superiority of non-thermal methods: cold plasma reduces lipase activity by 70% within 5 min via reactive oxygen species-induced structural disruption; ultra-high pressure preserves 95% of γ-oryzanol by selectively breaking hydrogen bonds in enzymes; high-energy electron beam irradiation suppresses rancidity markers by 45–78%; and enzymatic stabilization with immobilized papain achieves 78% lipase inactivation while retaining <5% nutrient loss. Compared to thermal approaches, non-thermal technologies enhance bioactive retention, while extending shelf-life by 2–3 weeks. By addressing challenges such as microbial synergy, parameter optimization, and industrial scalability, this review provides actionable insights for deploying green, energy-efficient strategies to valorize rice bran into functional foods and nutraceuticals, aligning with global demands for sustainable ingredient innovation.