Increasing Soybean Isoflavone Aglycones In Soymilk By Three ?-glucosidase

Soybean isoflavones has many important physiological activity,and these prominent biological functions play a role in the form of free aglycons mainly(The total of aglycons was only 2%-3%of soybean isoflavones)leading to a waste of soybean isoflavone resources.So it is necessary to improve the content of isoflavone aglycons in soybean.This study was used to determine the content of isoflavones in different soybean varieties,and the effects of different soybean milk production methods on soybean isoflavones,and explored a method to examine the optimum hydrolysis of soybean isoflavone glycosides in soybean milk by four kinds of?-glucosidase.The main results are as follows:(1)Soybean isoflavones are affected by the species of different soybean.The total content of soybean isoflavones glycoside was the highest,accounting for 86.9?95.1%of the total isoflavones.The descending order of soybean isoflavones content for varieties of fresh soybean milk was as follows:the northeast black beans,small yellow beans,Zhong huang 13,Zhong huang 57,Zhong huang 25,Zhong huang 17,and Zhong huang 37.The soybean isoflavones glycosides in northeast soybean contains the highest proportion of total flavonoids,about 13.1%.(2)Study on the effects of rubber seed ?-glucose glycosidase on isoflavones in soybean milk,from the response surface optimization test,the best combination of hydrolysis reaction is the enzyme addition of 4.34 U/5 mL and time of 2.50 h,temperature of 44.98 ?.According to the optimum hydrolysis process,the concentration of daidzein and glycitein,genistein was 37.633± 1.71?6.212±0.53?54.337± 2.11?g/mL.(3)Study on the effects of Aspergillus Niger ?-glucose glycosidase on isoflavones in soybean milk,from the response surface optimization test,the best combination of hydrolysis reaction is the enzyme addition of 0.028 U/5 mL and time of 1.64 h,temperature of 53.82 ?.According to the optimum hydrolysis process,the concentration of daidzein and glycitein,genistein was 39.434±1.410?4.626±0.462?45.851±2.098?g/mL.(4)Study on the effects of almond ?-glucose glycosidase on isoflavones in soybean milk,from the response surface optimization test,the best combination of hydrolysis reaction is the enzyme addition of 1.4 U/5 mL and time of 40 min,temperature of 46.0 ?.According to the optimum hydrolysis process,the concentration of daidzein and glycitein,genistein was 36.954± 1.67,5.119±0.275,38.643±2.03 ?gg/mL.(5)Studying the hydrolysis of soybean isoflavones glycosides with ?-glucose glycosidase from rubber seed,Aspergillus Niger,almond.In the respects of addition,the dosage of aspergillus Niger ?-glycosidase is minimum in soybean isoflavone hydrolysis,and more less than rubber seed and almond.The almond can complete the hydrolysis of soybean isoflavone glycoside in a shorter time.In the best conditions,the total of aglycons:rubber seed>aspergillus Niger>almond.