Hydrophobic chitosan-based films for sustained release of essential oils: Synergy via dual crosslinking and supramolecular assembly.

The hydrophilicity of polysaccharide-based films and the volatility of essential oils limited their application in food packaging as active materials. A hydrophobic chitosan-based essential oils sustained release film was prepared through dual crosslinking and supramolecular assembly strategy. Composite essential oil (cinnamon and oregano essential oil) was encapsulated by A-type gelatin and gum arabic (GA) and then incorporated into the chitosan-based film-forming solution, supplemented by hydroxypropyl-β-cyclodextrin (HPβCD) and carboxymethylcellulose (CMC) to fabricate the composite films (CS-EO-HPβCD-CMC). CS-EO-HPβCD-CMC exhibited surface roughness and internal dense film structure, constructed by physical and Maillard reaction crosslinking. The hydrophobicity of essential oils and the Maillard reaction crosslinking between GA and chitosan provide hydrophobicity to the chitosan-based film. The physical crosslinking between CMC and other firm-forming matrices and the supramolecular assembly of HPβCD synergistically increased the sustained release capability. The retention rate of CS-EO-HPβCD-CMC was 61.12 ± 1.37 %. Furthermore, CS-EO-HPβCD-CMC exhibited oil-resistant properties, high-barrier capabilities, antimicrobial and antioxidant activities, and degradability. In summary, CS-EO-HPβCD-CMC could be used as an active packaging material to replace food packaging plastics.