Modification of the properties of gelatin from skins of Baltic cod (Gadus morhua) with transglutaminase

The aim of the investigations was to optimize the procedure of gelatin extraction from the skins of Baltic cod (Gadus morhua) and to modify the properties of fish gelatin, using transglutaminase, to form gels at room temperature. A temperature of 45 °C and 30 min of extraction was established as optimal conditions for preparing gelatin from cod skins. Fish gelatin in 5% solutions formed gels at room temperature in the presence of transglutaminase (0.15–0.7 mg of enzyme protein/ml), depending on the reaction time. Transglutaminase was also active in crosslinking of fish gelatin at 4–5 °C. The deformation of gels obtained from 5% gelatin solutions after a 24-h incubation with transglutaminase, at concentration 0.25 mg/ml, measured at 6–8 °C, was the same as or slightly lower than in control samples (without enzyme). Fish gelatin gels, enzymatically crosslinked, did not melt after 30 min of heating in a boiling water bath.