Effects of transglutaminase-induced cross-linking on properties of fish gelatin–nanoclay composite film

A nanoclay composite film was produced using warm water fish gelatin as a base material and its physical, mechanical, and molecular weight change properties were observed after treatment with microbial transglutaminase. The viscosity of the MTGase-treated gelatin solution (2% w/w) increased from 86.25 ± 1.77 (0 min) to 243 ± 12.37 cp (80 min). SDS–PAGE results indicated that the molecular weight of fish gelatin solutions increased after treatment with microbial transglutaminase. Tensile strength decreased from 61.60 ± 1.77 (0 min) to 56.42 ± 2.40 MPa (30 min), while E% increased from 13.94 ± 5.09 (0 min) to 15.78 ± 5.97% (30 min) at 2% (w/w) MTGase concentration. The oxygen permeability and water vapour permeability did not change as a function of treatment time at 2% (w/w) MTGase concentration. The incorporation of nanoclay inhibited the increase of oxygen permeability. Film colour values (L, a, and b) did not change, but haze values increased from 5.24 ± 0.40 (0 min) to 6.44 ± 0.94 (50 min). XRD and TEM results suggested that the nanoclay was exfoliated in fish gelatin film.