Effects of small laccase from Streptomyces coelicolor on the solution and gel properties of whey protein isolate

Abstract

Laccase from Streptomyces coelicolor (SLAC) can catalyze protein cross-linking without any phenolic acid assistance, and its effects on the solution and gel properties of whey protein isolate (WPI) were investigated in this study. WPI solution (5% w/v) was catalyzed by SLAC at 60 °C for 10 min at different enzymatic activities (0–20U). Results showed that, cross-linked by SLAC, the foaming capacity and emulsifying activity properties of WPI solution were improved. SLAC treated solutions had more negative charge in zeta potential, indicating more stable in protein solutions. SLAC-modified increased the apparent visicosities of WPI solutions. Rheological results showed that SLAC-treated WPI gels had higher dynamic storage modulus (G′) and took longer gelation time, compared to control (0U). SLAC treatment improved the strength of WPI gels and increased their water holding capacity (WHC). The results indicate that suitable SLAC catalysis could be used to modify whey protein isolate to improve its solution and gel properties.