Study On Soy Isoflavone Hydrolysis By β-glucosidase Enzymes From Rubber Seed

Soy isoflavones are a class of secondary metabolites formed in the process of soybean growth, mainly in the form of P-glucosidase, including 12 components such as genistin, genistein, daidzin and daidzein. The estrogen like strcture of soy isoflavones are characterized by the activities of of hormone secretion, anti-cancer, alleviating menopausal syndrome, improving osteoporosis and regulating blood lipid levels. Due to the bioactivity of isoflavone aglycone in soy isoflavones is considered more important than that of isoflavone glucosides, the hydrolysis of soybean isoflavone glucosides into isoflavone aglycone is receiving more and more attention. Therefore, the hydrolysis of soybean isoflavone glucosides receives widespread attention and study.The P-glucosidase in rubber seeds was extracted in this study and its thermal stability, pH stability, and storage stability were studied as well. On the basis of these studies, the hydrolysis effect of rubber seed β-glucosidase on soy isoflavones is studied too.1、A HPLC method was established for the determination of six kinds of soy isoflavones and researching the soybean β-glucosidase, the bitter almond β-glucosidase, rubber seed β-glucosidase and the hydrolysis effect of 1 mol/L sulfuric acid with soy isoflavones qualitatively and quantitatively.2、With the response surface method, the hydrolysis conditions of rubber seed P-glucosidase enzyme with soy isoflavones were researched. On the basis of single factor experiments, the experimental data by response surface analysis with the enzymatic hydrolysis time Were studied, the amount of enzyme and reaction pH value as independent variables and the glycosidase rate as response value. The results show that the optimum conditions of rubber seed β-glucosidase enzyme on soy isoflavones is: enzymatic solution pH 5.64,168.28 U β-glucosidase enzyme every 20 mg soy isoflavones, hydrolysis temperature 54.41℃. In the optimal process conditions, the average hydrolysis rate of genistin is 65.86%, and the average hydrolysis rate of daidzein is 95.14%.3、Effect on isoflavone hydrolysis of soybean P-glucosidase, bitter almond β-glucosidase, rubber seed β-glucosidase and 1 mol/L sulfuric acid wre compared. The results show that the hydrolysis effect of bitter almond β-glucosidase and rubber seed β-glucosidase on daidzein and genistin are close, and better than the other two hydrolysis methods. There is no obvious advantage on hydrolysis effect by soybean endogenous P-glucosidase. While the hydrolysis effect on glycitin by sulfuric acid is better than the other three enzymatic hydrolysis methods.4> Hydrolyzing soybean defatted powder using of rubber seed β-glucosidase, and then soaking extract by 80% ethanol solution, Under the condition of optimized by orthogonal designed, The total uality of daidzein and genistein extracted amount to 524.84 μ.g/g and 740.25 μg/g and the extraction yield was 98.58% and 103.66%.