Optimization of Enzymolysis Process for Co-production of Polysaccharides and Polypeptides from Ostrea rivularis by Response Surface Methodology

The optimal enzymolysis conditions of simultaneous extraction of polysaccharides and polypeptides were explored from Ostrea rivularis by response surface methodology.Single factors experiments were used to find out the effects of hydrolysis time, enzymolysis proportion and solid-liquid ratio on the degree of hydrolysis, polypeptide content, glycosaminoglycan content and total-sugar content. Then three mathematical models were set up by response surface experiment. With three response values including polypeptide content, glycosaminoglycan content and total-sugar content, the three-factor and three-level response surface analysis was set up. The results showed that the optimal process for the preparation of polysaccharides from Oujiang oysters by enzymatic hydrolysis was 2.0 h, adding 3:1 alcalase and trypsin (total mass fraction of 0.8%), and the ratio of material to liquid was 1:3.6 g/mL. Under these conditions, repeated experiments were carried out to determine that the content of polypeptides was (251.70±5.73) mg·50 g^-1, the content of glycosaminoglycans was (8.17±0.29) mg·50 g^-1 and the content of total-sugar was (380.66±15.14) mg·50 g^-1.The yield of rough polysaccharides in whole organ of Ostrea rivularis was 21.29±0.77%, which contained 85.15%±1.00% total-sugar, 20.02%±0.38% glycosaminoglycans and 10.84%±0.12%polypeptides.Otherwise the yield of rough polypeptides was 31.41%±0.47%, which contained 84.03%±0.85% polypeptides, 0.11%±0.01% glycosaminoglycans and 5.68%±0.15% total-sugar.In one word, the co-production process for polysaccharides and polypeptides from Ostrea rivularis was feasible, basically the same as the predicted value.