Abstract: Soybean cake,soybean power and soybean peel were hydrolyzed by Protease M "Amano" G to prepare soybean polypeptides,respectively. For the three raw materials the effects of dispersion consentration,dispersion time,dispersion temperature,hydrolysis temperature,hydrolysis time,hydrolysis pH value,enzyme amount on the hydrolysis degrees of raw materials,bitters and flavors of the soybean polypeptides were discussed. The result showed that the soybean polypeptides have special flavor and no bitter on higher hydrolysis degree. Finally,the distrbution of molecular weight and the IR spectra of the soybean polypeptides were determined.

Key words: soybean, soybean polypeptide, enzymolysis, preparation