Potassium sorbate permeability in biodegradable alginate films: Effect of the antimicrobial agent concentration and crosslinking degree

Potassium sorbate permeability behavior in sodium alginate films crosslinked with different Ca2+ concentrations was examined using a diffusion cell. The films were previously characterized considering thickness, water solubility, mechanical properties, water vapor permeability coefficient and degree of swelling. Different potassium sorbate concentrations in an aqueous solution in contact with the films were used (from 150 to 1050 mg/L) resulting in permeability values in the order of 10−7 cm2/s. An increase in sorbate concentration increased the permeability values, reflecting modifications of the film polymeric structure. An increase of the degree of crosslinking decreased the permeability constant from 2.45 × 10−7 to 0.78 × 10−7 cm2/s when the concentration of the crosslinking solution used was raised from 2% to 7%.