Abstract:This manuscript with soybean protein isolate as the substrate to study the optimum enzyme hydrolysis parameters of the combination of the neutral protease and aminopeptidase.with free amino acids,peptide distribution,the hydrolysis degree as indexes and aminopeptidase ProteAXG as the control,the optimum conditions were determined and listed as follows:temperature 50℃,substrate concentration of 6%,neutral protease addition ratio E/S=5000U/g,aminopeptidase addition ratio E/S=9.75×105 U/g,pH 8.5 and 4h.Under the optimum conditions,the results of the hydrolyzate is that: the content of free amino acid in the hydrolyzate is 13.6 mg/mL,which is 1.95 times than that of ProteAXG hydrolysis,the molecular weight of the polypeptide is less than 1100D,which consist of by 16% of 600D and 75% of dipeptide and tripeptide.The hydrolysis degree achieved at 50.8%.Under the optimum conditions,the degree of hydrolysis is up to 62%.From the above results,we concluded that aminopeptidase from Bacillus subtilis either alone or in combination with the neutral protease,can hydrolyze the soybean isolated protein in-depth.
