Diffusivity of potassium sorbate in κ-carrageenan based antimicrobial film

The diffusion of potassium sorbate incorporated into κ-carrageenan based antimicrobial film was measured at 5 s intervals using a diffusion cell. The kinetics of potassium sorbate release followed Fick's law of diffusion, as shown by diffusional exponent characteristic n-value and high correlation coefficients between experimental and theoretical data. The effects of solution pH at the film surface (3.8, 5.2 and 7.0) and temperature (5, 25 and 40°C) on diffusion were investigated. Diffusion was found to be unaffected by adjacent solution pH in the range of values tested, but a decrease in temperature from 40 to 5°C resulted in a reduction of diffusion coefficients from 4.24×10^-13 to 1.29×10^-13 m²/s at pH 5.2.