Antioxidant and in vitro digestion property of black rice (Oryza sativa L.): a comparison study between whole grain and rice bran
AbstractA comparison study between whole grain and rice bran to evaluate the antioxidant activity and starch digestion property of black rice was conducted. Total phenolics content (TPC) and total anthocyanins content (TAC) analysis found that TPC and TAC contribution of rice bran to the whole grain were over 73 and 91%, respectively. Cyanidin-3-glucoside with minor peonidin-3-glucoside were identified in all whole grain and rice bran samples by HPLC-ESI-MS. The rice bran exhibited much stronger antioxidant activities than the whole grain, acting as the major antioxidant contributor to the black rice due to the high levels of TPC and TAC. In vitro digestion analysis found that rice bran could significantly decrease the digestibility and predicted glycemic index (pGI) of rice flour by lowering the rapid digestion starch and increasing the resistant starch (RS). This study revealed that rice bran could be a potential edible resource of phenolic-enriched antioxidant and glycemic regulator in food industry.