Extraction and antioxidation of anthocyanin of black soybean seed coat

The technology for extracting anthocyanins of black soybean seed coat was optimized by quadric regression orthogonal rotary tests. The results showed that the optimum extraction parameters were as follows: temperature 60℃, time 1 h, ethanol concentration 60%, the ratio of black soybean seed coat mass to ethanol volume 1∶40. It also showed that the most significant (P<0.01) correlations existed between total antioxidant capacity and anthocyanins contents. Moreover, the scavenging free radical capacity of anthocyanins in black soybean seed coat to OH·, O^-₂· and DPPH· was 1.6 times, 2.2 times and 1.4 times as large as that of Vitamin C, respectively.