Abstract: In this study, the effects of pectinase, cellulase, papain and neutral protease on the extraction of soluble soybean polysaccharide from bean curd were investigated by single factor method, and then the optimal amount of enzyme was investigated after the combination of two enzymes and three enzymes. The results showed that 1.5% pectinase and 4.5% cellulase had the best effect on soybean polysaccharide extraction, and 0.5% papain and 3.0% neutral protease had the best effect on protein removal. The ratio of pectinase and papain was 1.5∶0.5, and the ratio of pectinase and neutral protease was 1.5∶3.0. The mixture of cellulase and papain was 4.5∶0.5, and that of cellulase and neutral protease was 4.5∶3.0. The results showed that the effect of pectinase and papain was better at the dosage of 3.5%, and that of pectinase and neutral protease was 1.0%. The cellulase was mixed with the above composite enzyme at the ratio of 4.5∶3.5 and 4.5∶1.0, respectively. The results showed that complex enzyme of cellulase, pectinase and neutral protease was the best, the dosage was 5.0%, the polysaccharide yield was 24.21%, and the protein residue was 2.29%. The optimal amount of complex enzyme will provide a theoretical basis for the subsequent extraction of soybean meal polysaccharide by complex enzyme.

Key words: soybean meal polysaccharide, compound enzyme extraction, optimal dosage, process research