Liu_2026_Food.Chem_525_150316

The deacidification of rice bran oil remains a challenge owing to its high free fatty acid content. Enzymatic deacidification has emerged as a promising technology with lower refining loss. However, lipases used are triacylglycerol lipases that catalyze triacylglycerols and diacylglycerols, thereby altering the lipid profile. To address this issue, we proposed a targeted enzymatic deacidification strategy using covalently immobilized monoacylglycerol lipase (EstGtA2) from Geobacillus thermodenitrificans. EstGtA2 exhibited high selectivity for long-chain free fatty acids. Under optimized conditions, immobilization of EstGtA2 on ECR8285 resin showed the highest activity, improved thermal stability, and retained substrate selectivity for free fatty acids. Furthermore, a deacidification efficiency of 76.82% was achieved using immobilized EstGtA2, without altering triacylglycerol or diacylglycerol profiles of rice bran oil. Therefore, our findings provide insights into the substrate selectivity mechanism of EstGtA2 for fatty acids and establish a targeted enzymatic deacidification protocol to preserve the nutritional quality of rice bran oil.