Optimization of recombinant Zea mays transglutaminase production and its influence on the functional properties of yogurt.

The requirements for the production of optimized Zea mays transglutaminase (TGZo) using Pichia pastoris GS115 (pPIC9K-tgzo) were optimized in this study. Plackett-Burman design was used to screen variables that significantly influence TGZo production. Oleic acid, methanol, and loading volume were identified as the most significant parameters. Central composite design was employed to determine the optimal level of these three parameters for TGZo production. Results showed that 1078 mU/mL of TGZo activity and 7.6 mg/L of TGZo production were obtained under conditions of 0.07% oleic acid, 1.31% methanol, and 7.36% loading volume. To explore the functional characteristics of TGZo, it was used in yogurt. It was found that the addition of TGZo could produce yogurt with stronger acid gel and higher consistency, cohesiveness, index of viscosity, and apparent viscosity than the untreated product. Therefore, TGZo can be used as a substitute for microbial transglutaminase in the yogurt, even in the food industry.