Film forming ability of gelatins from splendid squid (Loligo formosana) skin bleached with hydrogen peroxide

Properties of gelatin films from splendid squid (Loligo formosana) skin bleached with hydrogen peroxide (H2O2) at various concentrations (0–8% w/v) were investigated. Tensile strength (TS) and water vapour permeability (WVP) of films decreased, but elongation at break (EAB) increased (p < 0.05) as the concentration of H2O2 increased. Among all films, that prepared from gelatin with 2% H2O2 bleaching showed the lowest ΔE∗-value (total colour difference), which was concomitant with the highest L∗-value (lightness). Generally, higher concentration of H2O2 resulted in increased b∗-value (yellowness) of resulting films. Electrophoretic study revealed that α-chains of gelatin in films became lowered with increasing H2O2 concentrations used for bleaching. Thermogravimetric analysis indicated that heat susceptibility and weight loss of different films varied with H2O2 concentrations. Rougher surface was obtained in gelatin films prepared from skin bleached with H2O2 concentrations above 4%. Thus, the concentrations of H2O2 used for bleaching of squid skin prior to gelatin extraction directly affected the properties of corresponding gelatin films.