Highly efficient anchoring of γ-cyclodextrin-MOFs on chitosan/cellulose film by in situ growth to enhance encapsulation and controlled release of carvacrol

Natural biopolymers have widespread applications in active food packaging attribute to their low-cost, easy availability, environmental-friendly, and excellent processibility. Extensive attention has been paid to integrate or modify nanostructures on biopolymer substrates to endow packaging materials with satisfactory preservation effects. Herein, green γ-cyclodextrin-metal-organic frameworks (γ-CD-MOFs) were successfully integrated on chitosan-cellulose (CS-CEL) polysaccharide film through in situ growth method and encapsulated with carvacrol (CAR) for controlled release active packaging. The γ-CD-MOFs were anchored on CS-CEL film depending on the coordination of glucose units in CS-CEL and potassium ion, which significantly improved the surface area of CS-CEL film from 1.0294 m2/g to 43.3458 m2/g. Furthermore, the molecular docking and 1H NMR spectra indicated that γ-CD-MOF has better complexing and stabilizing ability for CAR molecules than γ-CD. Additionally, the inhibition rate of this composite film against Escherichia coli, Staphylococcus aureus and Botrytis cinerea reached more than 99%. The film performed a humidity-controlled release effect on CAR and the release conformed to non-Fick diffusion. The shelf life of strawberries was extended to 7 days after treated with this film during storage. By incorporating the merits of natural biopolymers and MOFs, this novel active packaging offers great potential as a substitute for traditional packaging materials.