Properties of fish myofibrillar protein film: effect of glycerol-sorbitol combinations.

The effects of glycerol-sorbitol combinations (G/S) at different ratios (0: 2, 0.5: 1.5, 1: 1, 1.5: 0.5, and 2: 0, w/w) on the properties of fish myofibrillar protein (FMP) films were evaluated and then compared to those of synthetic wrap film (polyvinyl chloride; PVC). The thickness of FMP films plasticized with G/S at various ratios was in the range of 0.012 to 0.013 mm and transparency values were 3.81-3.86. Significant increases in elongation at break (65.81-116.53%), oxygen permeability (12.83-36.11 cm 3 /m 2 /day), and water vapour permeability (0.27-1.43 × 10 -10  g/m/s/Pa) were observed when the proportion of glycerol increased ( P  < 0.05). No significant difference was observed in a * and b * values, compared to the PVC film. However, tensile strength values (12.56-3.52 MPa) decreased when the proportion of glycerol increased ( P  < 0.05). A change in the amount of sorbitol influenced the thermal properties of FMP films. According to their properties, up to 50% of glycerol could be substituted for sorbitol in order to enhance the strength, barrier, and thermal properties of the FMP films.