Abstract: For the production of peptide solution, Bacillus subtilis Shi HeziIII was grown on defatted soybean medium. Peptidesolutions processed with various fermentation time showed different processing properties. Hydrolysis degree (DH) increasedwith the increase of the fermentation time. Nitrogen solubility was related to time and pH: the longer the time was, the higher theNSI (Nitrogen solubility index) became. As for the effect of pH value, NSI at pH7 was the highest. Turbidity increased with adecrease in pH. Peptide solution at 36h showed the lowest turbidity from pH3.0 to pH7.0. Compared to 1% BSA, all solutionshad higher emulsifying activity index (EAI) and lower emulsifying stability index (ESI).

Key words: Bacillus subtilis, soybean peptide, DH, NSI, turbidity, EAI, ESI