Diffusivity of potassium sorbate in κ-carrageenan based antimicrobial film

The diffusion of potassium sorbate incorporated into K-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 degreesC) 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 degreesC resulted in a reduction of diffusion coefficients from 4.24 x 10(-13) to 1.29 x 10(-13) m(2)/s at pH 5.2. (C) 2004 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.