Abstract:

Big yam was used as the raw material to explore the optimal enzymatic extraction processing for dietary fiber through orthogonal experiments. Results indicated that the optimal extraction processing conditions of dietary fiber from big yam were 0.6% compound enzyme composed of α-amylase and glucoamylase at a ratio of 6:1, hydrolysis temperature of 80 ℃ and hydrolysis time of 80 min. The carbohydrate and protein in big yam could be completely cleared out if big yam was treated with 0.6% compound enzyme at 60 ℃ for 60 min. The scavenging effects of dietary fiber from big yam with various concentrations (5－35 mg/mL) on DPPH, superoxide anion and hydroxyl free radicals were also investigated in vitro. Results exhibited that the dietary fiber from big yam had strong scavenging capability on 3 kinds of free radicals. The scavenging rates of dietary fiber from big yam on DPPH, superoxide anion and hydroxyl free radicals were 24.30%, 51.08% and 46.07%, respectively. In addition, the dietary fiber at the concentration of 15 mg/mL exhibited the strongest scavenging activity with the scavenging rates of 27.52%, 60.0% and 48.43%, respectively.

Key words: big yam, dietary fiber, free radical, scavenging