Nutrients and antioxidation of black rice pericarp and the preservation effects of processing techniques

The nutrients and antioxidation of black rice pericarp and the effects of processing techniques such as firing, microwave heating and extrusion techniques were studied. The results are as follows: the nutrients and antioxidation of the pericarp are significantly superior to those of milled rice of black rice. The total antioxidant capacity (TAC), total flavonoid and anthocyanin contents of the pericarp, which is only 12% in weight, account for over 98% of whole black rice grain, respectively. Black rice pericarp is rich in protein, fat, crude fiber, vitamins and mineral elements and is considered as the main carrier for nutrients and active substances of black rice, featuring complete and balanced amino acids and high percentages of essential amino acids and unsaturated fatty acids. The processing techniques such as firing, microwave heating and extrusion have different effects on the TAC, total flavonoid and anthocyanin contents of black rice pericarp, among them extrusion has the least effect, followed by microwave heating and firing. Extrusion is the best processing technique for preservation of black rice pericarp because it can achieve stabilizing effects on peroxide value(POV) and acid value(AV).