Effect of plasticizer type and concentration on the properties of edible film from water-soluble fish proteins in surimi wash-water

Edible film made from water-soluble fish proteins present in surimi wash-water were developed based on formulation conditions explored in a previous study. Type and concentration of plasticizer significantly (p < 0.05) affected the mechanical and barrier properties of the films. Sorbitol (SOR) plasticized films were the most brittle, with the highest tensile strength (TS, 3.14MPa) however its effect on water vapour permeability (WVP) was low (30.41g/mm/m(2)/d/kPa). In contrast, glycerol (GLY) and polyethylene glycol (PEG) plasticized films exhibited flexible structure despite a low TS (2.13MPa and 1.80MPa, respectively) resulting in higher WVP (125.8g/mm/m(2)/d/kPa and 89.52g/mm/m(2)/d/kPa). As plasticizer concentration increased, TS decreased concomitant with an increase in elongation as break (E) and higher WVP. SOR plasticized films, showed higher film solubility (FS) and protein solubility (PS) compared to GLY and PEG plasticized films. Increasing the plasticizer concentration, overall, resulted in both higher FS and PS. The colour of films was more affected by the nature of the plasticizer used than by its concentration.