SORBITOL-PLASTICIZED VS GLYCEROL-PLASTICIZED WHEY-PROTEIN EDIBLE FILMS - INTEGRATED OXYGEN PERMEABILITY AND TENSILE PROPERTY EVALUATION

An integrated approach for evaluation of the oxygen permeability and tensile properties of plasticized whey protein-based edible films was developed. Relative humidity had an exponential effect on the oxygen permeability of whey protein films. The increase in oxygen permeability caused by increasing concentrations of glycerol was greater than that of sorbitol. Increasing concentrations of both glycerol and sorbitol resulted in significantly decreased tensile strength and increased elongation. Sorbitol was more effective than glycerol as a plasticizer in that films of equal tensile strength, elongation, and elastic modulus had lower oxygen permeabilities when plasticized using sorbitol. The oxygen permeability and tensile properties of whey protein-based films compared favorably with those of other protein and synthetic film materials.