Antioxidant coatings from elastomeric vinyl acetate-vinyl laurate copolymers with reduced bacterial adhesion

A vinyl laurate-based elastomeric copolymer, developed as chewing gum base, was used to produce functional coatings with the antioxidant curcumin. Both the polymer and curcumin were dissolved in MIBK, methyl isobutyl ketone. Coatings were applied on glass but also on natural alginate and gelatin film surfaces by dip-coating. Microscopy analysis indicated that coatings had very homogenous surface and curcumin was effectively encapsulated within the polymeric matrix. In addition, curcumin-laden coatings (10 wt%) remained transparent with excellent UV filtering properties. The flexibility of alginate and gelatin films was maintained after coating, whereas their hydrophobicity and water vapor barrier properties improved. Furthermore, coating biocompatibility and low bacterial adhesion properties were confirmed by cell proliferation and bacterial surface contamination experiments, respectively. The radical scavenging activity of the coating was assessed with both DPPH and ABTS assay, revealing effective antioxidant properties. In addition, in weak acetic acid solutions, curcumin could be released in a sustained manner from the coatings. This coating can be used as a suitable option for improving the antioxidant and bacterial resistance properties of natural polymer films including food packaging or other relevant applications.