Stabilization of rice bran and its effect on bioactive compounds content, antioxidant activity and storage stability during infrared radiation heating

Rice bran (RB), a by-product of rice milling industry has limited uses despite its nutritional value. Thus, the aim of the current study was to improve the process of RB stabilization and it was conducted in three stages a) optimization of the infrared radiation (IR) conditions in order to inactivate lipase activity b) investigation of the effect of IR treatments on γ-oryzanol, vitamin E, total phenolic contents and antioxidant activity of stabilized RB as well as on color and fatty acid composition c) stability tests of free fatty acid (FFA) content and lipophilic compounds. Results indicated that IR heating at 140 °C for 15 min is an effective method for RB stabilization without any loss of γ-oryzanol and fatty acid composition, but with a significant decrease in vitamin E content. Contrary, phenolic content and antioxidant activity of bound extracts of stabilized RB increased as the IR power increased, whereas an insignificant increase was observed on free extracts. Storage stability tests showed that γ-oryzanol of stabilized RB was relatively less stable after 6-months storage than vitamin E. In conclusion, the selection of optimum IR conditions is important to guarantee the quality RB in terms of health beneficial components and undesirable components.