The influence of enzymatic treatment time of microbial transglutaminase on the properties of edible film based on whey protein isolate

The effect of enzymatic treatment time of microbial transglutaminase (MTGase) on the characteristics of whey protein isolate (WPI) films was investigated. Results shown that the properties of MTGase-treated films were affected by increasing the enzymatic treatment time. Enzymatic treatment at lower incubation time, i.e. for 1 h, significantly resulted in higher values of tensile strength (TS) and lower values of elongation at break (EB) as compared to control film. In the MTGase-treated films, the TS values decreased gradually and EB values increased progressively with increasing incubation time from 1 to 3 h. Water vapor permeability (WVP)and total soluble matter(TSM) of control film in comparison with MTGase-treated films decreased from3.6 ×10 10 to 2.31 ×10 10 g m-1 s-1 pa-1 and from 37.07 to 19.97 percent, respectively. However, as the time of enzymatic treatment was increased the TSM and WVP were gradually increased.