Abstract: In order to explore the effect of transglutaminase (TGase) on the characteristics of soybean protein isolate (SPI), 7S and 11S protein gels, the parameters of these TGase-treated protein gels were determined by TA-XT plus SEM (scanning electron microscope) and fluorescence spectrophotometer. Results indicated that gel hardness of TGase-treated SPI gels was significantly increased compared with that of the control. The optimal conditions of TGase treatment for SPI were TGase addition amount of 40 U/g, treatment temperature of 40 ℃, treatment pH of 7.5 and treatment time of 2.5 h. After treatment with TGase, the surface hydrophobicity and water-holding capacity of soy protein isolate gels exhibited a decrease. Meanwhile, heating treatment also resulted in a significant increase in the hardness of TGase-treated protein gels, and TGase-treated SPI gels had the largest gel intensity, followed by 7S and 11S in turn.

Key words: transglutaminase, soy protein isolate, 7S, 11S, gel characteristics