Optimization of Extraction Process of Polysaccharide from Sophora japonica by Compound Enzyme Method and Its Antioxidant Activity

Objective: Sophora japonica polysaccharides were extracted by compound enzyme method, and the extraction process was optimized. The antioxidant activity in vitro was evaluated. Methods: The effects of addition amount of compound enzyme, pH, proportion of compound enzyme and enzymatic hydrolysis time on the extraction yield were investigated by single factor experiment. On the basic of single factor experiment, response surface method was used to determine the optimal extraction parameters of Sophora japonica polysaccharide. Compared with V_C, the antioxidant activity of Sophora japonica polysaccharides was investigated by measuring the scavenging rate of DPPH· and ABTS⁺· and the total reducing power. Results: The optimal extraction parameters of Sophora japonica polysaccharides were as follows: The addition amount of compound enzyme was 23.8 mg/g, pH4.8, and the ratio of pectinase to cellulase was 0.912:1. Under this process, the yield of Sophora japonica polysaccharides was 10.71%, and the extracted polysaccharide showed good scavenging ability for DPPH· and ABTS⁺·. When the concentration of the polysaccharide solution was 2.8 mg/mL, the scavenging rate of DPPH· and ABTS⁺· reached 94.19% and 99.79% of V_C at the same concentration, respectively, and the total reducing power reached 75.99% of V_C. Conclution: Sophora japonica polysaccharide could be effectively extracted by compound enzymatic method and its antioxidant activity could be improved, which provided a theoretical reference for the development of functional food of Sophora japonica polysaccharide .