Production of antimicrobial membranes loaded with potassium sorbate using a supercritical phase separation process

The production of antimicrobial packaging is one of the most interesting challenges in the food industry; its scope is to prolong the shelf life of a food maintaining its safety and freshness. The major limitation of traditional techniques used to produce antimicrobial packaging, is the difficulty in controlling the release of the active agent from the device to the food surface. In this work, a supercritical phase inversion process has been tested to produce potassium sorbate (PS) loaded cellulose acetate (CA) membranes, to be inserted in food packaging. The membranes have been obtained at different process conditions (pressures 150–250 bar, temperatures 35–55 °C) and at different polymer concentrations (10, 15 and 20% w/w). PS to CA weight ratio has been maintained constant at 5% w/w for all the formulations. The best process parameter combination to obtain the longest PS release time (about 325 min) was 250 bar and 35 °C.