Optimization of gelatine gel preparation from New Zealand hoki (Macruronus novaezelandiae) skins and the effect of transglutaminase enzyme on the gel properties

Response Surface Methodology (RSM) was adopted to optimize the preparation of NZ hoki (Macruronus novaezelandiae) gelatine gels treated with Transglutaminase (TGase) and some of the rheological properties were characterized. The optimum concentration of the enzyme [X1] was 3.33 mg/g, incubation time, [X2] was 30 min, and incubation temperature, [X3] was 37 °C. The calculated gel strength achieved by RSM was in very good agreement with the experimental value. The addition of TGase to hoki gelatine at the optimum concentration of increased the gel strength from 197 ± 5 g to 278.2 ± 0.19 g and the melting point from 21.4 ± 0.8 °C to 25.9 ± 0.1 °C. The increase in the Gʹ values with the addition of TGase indicated the formation of firmer gels and the changes in Gʹ and G" values with increase in temperature showed increase in melting point.