Antimicrobial-releasing films and coatings for food packaging based on carvacrol and ethylene copolymers

Efficiency in antimicrobial packages based on the release of active agents depends on their retention into the packaging materials and on the extent and rate of their release to the package headspace. In this work, the effects of polymer chemical composition and matrix morphology on the release of carvacrol were explored. Films and coatings containing carvacrol, and manufactured from four polyolefin latexes of a range of polarities (ethylene–octene (LLDPE) ION > EMA) were obtained, exhibiting morphologies generally correlated with the melting temperatures and active behaviours of the polymers. LLDPE and EVA, the most heterogeneous polymers, were generally more permeable, less resistant, more deformable, less transparent and more wettable than EMA and ION, of coalesced structure. For carvacrol, LLDPE and EVA yielded higher values of the diffusion coefficient, in agreement with their permeability results, whereas EMA and ION showed higher solubilities, according to their greater affinity for the active molecule, as derived from their ionic nature. The evolution of the release of carvacrol from the studied films was experimentally measured and theoretically predicted through determination of its solubility and diffusivity parameters. Excellent agreement between both experimental and predicted data was finally observed. © 2015 Society of Chemical Industry Controlled release of antimicrobial agent from polymeric films manufactured from suitable ethylene copolymer latexes was investigated with application in the active packaging of food, and full characterization of the materials was carried out.