Effect of Protein and Sorbitol Concentrations on the Properties of Fish Gelatin Films

Abstract

Edible films were prepared with bone gelatins extracted from red snapper and grouper at different concentrations of protein (1, 2, 3, 4 and 5%) and sorbitol (10, 20, 30, 40 and 50% of protein). Gelatin films made with 5% protein had maximum tensile strength (TS), elongation at break (EAB) and Young’s modulus (YM) in the range of 63.2 to 73.1 MPa, 67.0 to 76.1% and 724 to 809 MPa, respectively. Gelatin films prepared with increasing concentration of sorbitol had reduced the TS and YM of the films, but increased the EAB from 21.7 to 63.7% in grouper and 27.3 to 67.3% in red snapper. Grouper gelatin films had greater TS, YM and thickness compared to red snapper gelatin films. Opacity of the films increased with protein and sorbitol concentrations even in the UV region, which would make them excellent light barriers. Grouper gelatin films had high strength, while red snapper films had high elongation.