Coordination Metal Complexes With Antibacterial and Antioxidant Functions for Food Packaging: From Single-Function Systems to Intelligent Materials.

During food storage and transportation, products are prone to microbial contamination and oxidative deterioration, which seriously affects their safety and shelf life. Therefore, it is necessary to develop adjustable intelligent active food packaging to address the above issues. Metal complexes exhibit advantages such as designable structures and diversified mechanisms of action, which can achieve efficient, long-lasting, and intelligently controllable antibacterial and antioxidant functions. In this review, we systematically summarize the research progress of coordination-type antibacterial/antioxidant metal complexes represented by silver, copper, zinc, and iron and focus on analyzing the effects of different coordination structures, ligand types, and carrier forms on their biological activity and stability. Among these metal complexes, silver complexes exhibit strong antibacterial activity; copper complexes offer a favorable balance between activity and cost; zinc complexes demonstrate outstanding biocompatibility; and iron complexes show excellent antioxidant activity. At the same time, the antibacterial/antioxidant mechanisms of metal complexes are elaborately described, and the relationship between their physical-chemical structure and properties is deeply discussed. Furthermore, the applications of metal coordination-type active materials in the preservation and packaging of fruits and vegetables, meat products, and other foods are discussed. Nevertheless, despite the considerable application potential of these materials, several critical challenges persist in their practical implementation, such as the potential toxicity of metal ions, migration behavior, scalability of production, and associated costs. Finally, in response to these challenges, future research directions for metal coordination-type materials in the field of food preservation and packaging are proposed.