Film composition effects on diffusion of potassium sorbate through whey protein films

The effect of film composition on potassium sorbate diffusion in whey protein films was studied using mixture response surface methodology. The model developed for potassium sorbate diffusivity was statistically significant (P less than or equal to 0.01) with no significant lack of fit. The diffusivities of potassium sorbate in the films at 25degreesC varied between 5.4 and 9.8 x 10(-11) m(2)/s. Amounts of protein, sorbitol, beeswax, and potassium sorbate in the films significantly affected potassium sorbate diffusion coefficients. Increasing the relative amounts of protein and beeswax in the films decreased potassium sorbate diffusivity, while increasing the relative amounts of sorbitol and initial potassium sorbate in the films increased the diffusion of potassium sorbate. Strong interactions were observed between protein and beeswax, and potassium sorbate and beeswax.