Influence of starch content on the physicochemical and antimicrobial properties of starch/PBAT/ε-polylysine hydrochloride blown films

Starch/PBAT/ε-polylysine hydrochloride (ε-PL) antimicrobial blown films were prepared, in which the proportion of starch was 0 to 50%. ε-PL interacted with starch through hydrogen bonds, and hindered the crystallization of PBAT. Some clumps appeared on the ε-PL-containing films' surface and then disappeared with increasing starch content. ε-PL-loaded films with higher starch content exhibited reduced lightness and significant yellowing. The largest reduction of strength (42%), elongation (18%), and moisture barrier (68%) occurred as ε-PL was added into low-content starch/PBAT films. With an equal ε-PL content, the films with ≥ 20% starch content showed inhibitory zone against both Staphylococcus aureus and Escherichia coli, which was enlarged by further increasing starch content. Results suggested that the physicochemical properties and ε-PL release could be controlled by adjusting the starch content in starch/PBAT/ε-PL composites.