Gel properties of collagens from skins of cod (Gadus morhua) and hake (Merluccius merluccius) and their modification by the coenhancers magnesium sulphate, glycerol and transglutaminase

The gel properties of two different kinds of fish gelatins prepared from co d (Gadus morhua) and hake (Merluccius merluccius) and modified by the coenh ancers glycerol, salt and microbial transglutaminase, were examined. Gel st rength was substantially increased by the addition of coenhancers although results varied, depending on the species. In gelatin from hake (M. merlucci us) skin, the highest values were obtained with 10 mg/g of transglutaminase , whereas magnesium sulphate was more effective at both concentrations (0.1 and 0.5 M) in gelatin from cod (G. morhua) skin. Although, in both gelatin s, the addition of any ingredient increased the viscosity modulus (G"), the elastic modulus (G') was only increased by the addition of glycerol 15% (w /v) and MgSO4 0.5 M in hake (M. merluccius) gelatins; in cod (G. morhua) it was increased by all ingredients. The gelling and melting points, very imp ortant properties in fish gelatin, showed a notable improvement, the behavi our being different, depending on the species. (C) 2001 Elsevier Science Lt d. All rights reserved.