White-cheek shark skin gelatin (WSG) edible films were optimized with respect to its barrier, mechanical, and structural properties using response surface methodology (RSM), and with the introduction of gelatin concentrations (1-4% w/v based on film forming solution) and glycerol contents (15-35% w/w based on gelatin weight) as the independent variables. WSG films with moderate levels of glycerol had higher tensile strength (TS), elastic modulus (EM), and elongation at break (E@b) depending more significantly on gelatin content. Adding higher levels of glycerol, film roughness was observed to decrease exponentially but water vapor permeability (WVP) increased linearly. Structural analysis using FTIR showed more aggregated protein structures at higher gelatin content which could be strongly related to the notable increase of contact angle. According to the model, the optimum point for the WSG film formula were found to be 3.3% WSG, and 19.3% glycerol giving a predicted maximum E@b, TS, EM, roughness, and contact angle of 183%, 4.4MPa, 92MPa, 4.93nm, and 111°, respectively, with a predicted minimum WVP of 11.8 g.mm/day.m2.kPa.

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