Abstract: Defatted Soya-bean Cake that was highly denaturated was incubated in different pH. Its nitrogen solubility index increased as pH increased from 7 to 12. Nitrogen solubility Index. recovery of protein and amount of acid- solubility peptide were determinated by incubation under different As 1. 398 subtilisin concentration for different time at pH 7. 5, 40℃. It was found that low concentration of As 1. 398 subtilisin and long incubating time were much more efficient on hydrolysis of defated soya-bean cake. The optima of As 1. 398 subtilisin concentration and incubating time were 250 U/ml, 3 hours respectively. Further experiments showed that hydrolysis degree of As 1. 3.98 subtilisin to defated soya-bean cake was lower than that of 166 subtilisin and the rate of hydrolysis of As 1. 398 subtilisin was slower than that of 166 subtilisin.

Key words:  , Dcfated Soya-Bean Cake Hydrolysis Nitrogen Solubility Index Acid-Solubility Peptide As 1.398 Subtilisin 166 Subtilisin.；