Effect of rice parboiling on the functional properties of an enzymatic extract from rice bran

• Enzymatic hydrolysis of rice bran yields extracts rich in bioactive compounds.
• Main bioactives in enzymatic extracts are γ-oryzanol, tocopherols and tocotrienols.
• Parboiling of rice increases lipophilic antioxidant content in bran enzymatic extract.
• Parboiling method decreases hydrophilic antioxidant content in bran enzymatic extract.
• Parboiling method decreases total antioxidant capacity in bran enzymatic extract.

We have studied the influence of the parboiling process on enzymatic extract obtained from rice bran. Two rice bran enzymatic extracts have been obtained; one from non-parboiled (RBEE), the other from parboiled rice (RBEEp), and their chemical composition and antioxidant capacities have been compared. These extracts differ in their main chemical composition; RBEEp has less carbohydrates and more fat content than RBEE. No differences in protein content were found.With regard to bioactive compounds, both extracts are rich in phytosterols, tocopherols, tocotrienols and γ-oryzanol, being γ-oryzanol similar in both extracts. However RBEEp is richer in total tocols and phytosterols and RBEE has the highest content in hydrophilic phenols. Functional properties such as total antioxidant activity revealed that RBEE has higher capacity to scavenger peroxyl radicals than RBEEp. Accordingly, specific antioxidant studies showed that RBEE has greater protective capacity against lipid and protein oxidation than RBEEp. Therefore, we can conclude that RBEE has better bioactive properties than RBEEp.In conclusion, these findings suggest that the parboiling pretreatment of rice modifies the bioactive composition of derived products such as rice bran enzymatic extract, that have been shown to exert bioactive properties with application in the nutraceutical and cosmetic fields.