Migration kinetics of sorbic acid from polylactic acid and seaweed based films into food simulants

- New active biodegradable films based on polylactic acid and seaweeds were developed.
- Sorbic acid was incorporated into the films as antimicrobial agent.
- The diffusion of the sorbic acid into food simulants was studied.
- Diffusion and partition coefficients were calculated by using a mathematical model.

Active antimicrobial films based on biodegradable materials are now widely used for food packaging applications.In the present study, an extrusion process was used to prepare biodegradable films based on polylactic acid PLA and supplemented with sorbic acid and seaweeds (PLA + 0.5% sorbic acid; PLA + 0.5% sorbic acid + 8% seaweed).The kinetics of sorbic acid migration from the films into two food simulants (10% ethanol [v/v] and 95% ethanol [v/v]) were analysed at 5, 20 and 40 °C. The sorbic acid content in the food simulants was determined by reversed-phase high-performance liquid chromatography (detection wavelength, 260 nm). Separation was performed on a reversed-phase C18 column, at 30 °C. The diffusion coefficients were calculated using a mathematical model based on Fick's Second Law. The values obtained ranged between 4.11 × 10−9 and 1.00 × 10−13 cm2 s−1.The developed active films could be of great interest for food industry, since they could be useful for protecting packed food.