Antioxidant capacity of soybean protein isolate hydrolyzed with protease produced by Aspergillus 3.084 in vitro

Abstract

Aspergillus, being known as a protease producing fungi, is used in Chinese and Korean traditional fermentation. In this paper, Aspergillus 3.084, one of the most common fungi in China fermentation industry, was employed to produce protease and hydrolyze soybean protein, and then the optimum extraction condition of protease was determined by the antioxidant activities of protease extraction solution. The protease was extracted from the culture medium, and performed in hydrolyzing soybean protein isolation. Extract condition of protease, hydrolysis ability of proteases of Aspergillus in hydrolyzing soybean protein isolation and the antioxidant ability of hydrolysate were investigated by detecting enzyme activity, degree of hydrolysis, scavenging activities of OH•, O2•and DPPH•. Maximum protease activity was obtained at 60 min, pH 7.5 and 32°C in extraction step. Optimum protease hydrolyzing time, E/S, temperature and pH for degree of hydrolysis and scavenging activities was 3 h, 6000, 37°C and 7.5, respectively.