Effect of wheat gluten on gelation properties of soy protein isolate induced by transglutaminase crosslinking

To study the effect of transglutaminase ( TGase) on gel properties of soy protein isolate ( SPI) and wheat gluten ( WG) mixtures, the change of functional properties of mixed protein gels were measured, and compared with basic SPI gels.The effects of TGase enzyme concentration, temperature, and pH on colloidal characteristics had been investigated.The optimum parameters were determined as follows: protein concentration 11 g/100 mL, TGase enzyme concentration 30 U/g, temperature 40 ℃ and pH 7.0.Under these conditions, TGase had the highest improving effect on colloidal properties of mixed protein gels. Compared with TGase induced SPI gels, an increase in the β-sheet content and gel strength ( G') , and a reduction in free sulfhydryl content and resulted in denser and more homogeneous networks of the mixed protein gels.