Nisin (NIS) Z was incorporated (0.05 %, 0.1 %, 0.2 %) into edible films based on chitosan lactate (CHL) and 75/25 blends of polysaccharides (corn starch (CS), wheat starch (WS), oxidized potato starch (OPS), pullulan (PUL)) with CHL. The increase in the NIS/polymer ratio promoted the diffusion-driven release. Compared with the fully dissolvable CHL and PUL/CHL carriers, the starch/CHL films had limited solubility (≈27-37 %) and, consequently, ensured slower/incomplete release of NIS. The assayable NIS half-release times, determined in water, ranged from <1 min to ∼13 h. Probably due to the similar pH (≈4.5), there were generally no large differences between the antibacterial activities of the formulations. The NIS-supplemented systems limited the growth of some pathogens (B. cereus, L. monocytogenes, S. aureus), phytopathogens (P. carotovorum), and bacterial starter cultures. The NIS improved the UV-blocking ability of the films, but the 0.2 % NIS addition weakened (by ≈17-32 %) the tensile strength of most of the films.
Keywords: Antimicrobial activity; Chitosan lactate; Controlled release; Nisin; Pullulan; Starch.
Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.