Antioxidative activity of water extracts from the yam ( Dioscorea opposita Thunb.) tuber mucilage tororo

A water extract as a viscous solution was obtained from the yam Dioscorea opposita tuber mucilage tororo, and its functional properties were demonstrated. The protein content was about 280 μg/mL extract, and the main protein bands with an MW of ∼33 kDa without 2-mercaptoethanol (2-ME) and ∼31 kDa with 2-ME were detected by SDS-PAGE. The water extract possessed high antioxidative activity and scavenging activities against superoxide anion and hydroxyl radicals. However, it showed no inhibitory activity against angiotensin I-converting enzyme. The yam tuber contains relatively high contents of vitamins, different micro- and macroelements, enzymes, and dietary fibers. The yam D. opposita tuber will be increasingly regarded as a health-promoting food.