Abstract:Nowadays, due to changes in consumer life style and health awareness, brown rice is receiving increased interest as a source of healthy attributes. Compared with white rice, brown rice is rich in several health beneficial nutrients such as vitamins, dietary fiber, minerals, antioxidants and essential amino acids. It is necessary to study the influence of processing on nutrients of brown rice, because these nutrients are easily lost during processing. High pressure processing (HPP) is a new non-thermal preservation technology that enhances food safety and retains the food original nutrients. Up to date, the research on the effect of HPP on nutritional property of brown rice is limited. Phenolic, flavonoid content and antioxidant activity of brown rice after HPP (100~400MPa) by single step (5min and 10min of holding time) or two step process (two cycles, 5min of holding time each) were investigated. The antioxidant activity was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS+·) scavenging assays. Results showed that phenolic, flavonoid contents and antioxidant activity of brown rice were increased with the increase of pressure. Moreover, under the same pressure level, the phenolic, flavonoid contents and antioxidant activity of brown rice under two step HPP were higher than those from single step HPP. Percentage retention of phenolic and flavonoid content in brown rice treated by two step process at 300MPa was 97%. These findings suggested that the HPP was an effective non-thermal processing to retain antioxidants in brown rice.
