Development of γ-CD-MOF/Chitosan platform with sustained release capacity for food preservation

γ-Cyclodextrin (γ-CD) is one of the most widely used materials for encapsulating hydrophobic functional molecules due to its distinctive structural features, especially an internal hydrophobic cavity surrounded by external hydrophilic surface. However, its limited loading capacity, adsorption efficiency, and poor stability hinder its broader applications. To address this issue, γ-cyclodextrin-based metal-organic frameworks (γ-CD-MOFs) was formed by anchoring potassium ions with γ-CD through hydrothermal self-assembly. After loading different hydrophobic small molecule active substances, a multifunctional composite coating was prepared by embedding them into the chitosan (CS) matrix. The release kinetic model analysis confirmed that the release behavior of Cinnamaldehyde (Cia), 2-methoxycinamaldehyde (2-MCA), and Curcumin (Cur) from γ-CD-MOFs conformed to the Ritger-Peppas equation. Compared with CS, CS/γ-CD-MOF@Cia has a strong inhibitory effect on E. coli O157: H7 and S. aureus. Sprayed on green grapes, the shelf life is extended to 21 days. CS/γ-CD-MOF@2-MCA can significantly reduce the spoilage of milk caused by photooxidation. Furthermore, compared with CS, the oxidation and browning of banana peels were effectively delayed by CS/γ-CD-MOF@Cur, and complete blackening is not observed even after 11 days of storage. By combining the advantages of chitosan and γ-CD-MOF, the active molecules with different functions were encapsulated on the platform of γ-CD-MOF to achieve antibacterial, light-blocking, and antioxidant effects on food. The novel functional coating materials presented in this work offer a promising approach to effectively prolonging the shelf life of fresh foods products.