Molecular characteristics and properties of gelatin from skin of seabass with different sizes

Gelatin was extracted from the skin of seabass (Lutes calcarifer) with different average sizes (2, 4 and 6 kg/fish), termed G2, G4 and G6, respectively and their characteristics and functional properties were determined. Yields of G2, G4 and G6 were 38.22, 40.50 and 43.48% (based on dry weight), respectively. G2 contained cc-chains as dominant component, whilst G4 and G6 comprised alpha-, beta- and gamma-chains with a larger content of high MW cross-links. All gelatins had the similar imino acid (hydroxyproline and proline) content. Net charge of G2, G4 and G6 became zero at pH of 6.73, 6.41 and 7.12, respectively. Amongst all gelatin samples, G6 exhibited the highest gel strength (321.5g) (p < 0.05), but had the lowest turbidity (p < 0.05). Gels of G6 sample had the lower L*-value but higher a*-, b*- and Delta E*-value, compared with others. Gelling and melting temperatures of all gelatins were 17.09-19.01 and 26.92-28.85 degrees C, respectively. Furthermore, all gelatins were able to set at room temperature, regardless of size of seabass used. G6 had the shorter setting time at room temperature than others. Therefore, size of seabass, in which skin was used for gelatin extraction, had the impact on yield, composition and properties of resulting gelatin. (C) 2014 Elsevier B.V. All rights reserved.