Diffusivity of potassium sorbate in antimicrobial films of whey protein isolate

The effect of concentration of potassium sorbate, solution p H and temperature on diffusion of potassium sorbate of whey protein composite films were investigated by the measured value and calculated value with Fickian diffusion model.The kinetics of potassium sorbate release followed non- Fickian diffusion ( p H 3.8) and Fick's first law of diffusion as shown by diffusional exponent of power function model. Diffusion coefficient was found to be increased with increased concentration of potassium sorbate and temperature in the range of values tested, but decreased with p H due to swelling behavior in low p H condition.When p H was 3.8 and at 35℃, diffusion coefficient of antibacterial films was up to 5.722 × 10- 12m2/ s. According to activation energy ( Ea) of the Arrhenius activation energy model, when p H was 3.8, the diffusivity to temperature changes was more sensitive.