A promising edible cyclodextrin-based metal-organic framework: From preparation, characterizations to applications in active ingredient loading in food.

With the increasing attention on food safety and health promotion, the development of natural, non-toxic and biodegradable encapsulation materials is upcoming in food system. Cyclodextrin-based metal-organic frameworks (CD-MOFs) are promising edible MOFs currently reported, consisting of cyclodextrins and alkali metal ions with different crystal configurations and cavity sizes. CD-MOFs not only maintain advantages of common MOFs such as highly porous structure, diversified functional sites, unique host-guest interactions, but also bring the desirable features of CDs such as nontoxicity, biocompatibility, and environmental friendliness. CD-MOFs possessed good properties of internal and external hydrophilicity, adsorption and separation, and biocompatibility. The loading of active ingredients into CD-MOFs can enhance their stability, targeted delivery and controlled release. These features make CD-MOFs great potential in applications in biomedicine, chemical products, environment protection, as well as food industry. Here, the most advanced progress in the study on the structure, synthesis and physicochemical properties of CD-MOFs was introduced. Then, the current status of the application of CD-MOFs in active ingredients loading, protection, targeted delivery and slow release in food matrix were comprehensively summarized, especially the relevant reports in the past five years. The potential opportunities and prospects for the development of novel complexes with CD-MOFs are envisioned.