Cross-linking of soybean proteins by transglutaminase in the presence of gelatin to improve their rheological properties

Abstract Soybean protein isolates (SPI) was cross-linked by transglutaminase in the presence of gelatin in this work to prepare a cross-linked composite soybean protein-gelatin, a modified SPI. The concentration of total proteins was fixed at 5% (w/v), and the ratio of SPI to gelatin was fixed at 4:1 (w/w). The cross-linking of the proteins was carried out as fellows: enzyme addition level at 20U/g proteins, reaction time of 2 h and temperature of 40°C. Compared to the original SPI and transglutaminase-induced cross-linked SPI, the dispersion of the modified SPI exhibited improved apparent viscosity and viscoelastic behaviors, indicating that cross-linking of SPI by transglutaminase in the presence of gelatin could improve the rheological properties of soybean proteins.