Development of packaging films based on UiO-66 MOF loaded melatonin with antioxidation functions for spinach preservation

Spinach tends to deteriorate after harvest due to physiological metabolic activities. As a natural, pollution-free, and environmentally friendly preservative, melatonin (MT) can effectively maintain the quality of fruits and vegetables after harvest and delay senescence. To enhance the preservation effect of MT, this study developed antioxidant films using MT-loaded UiO-66 metal-organic framework (MOF) nanoparticles. This approach effectively extends the shelf life of spinach while preserving its quality. The underlying mechanism involves leveraging the microporous structure and stability of UiO-66 MOF. Experimental results obtained from the packaging films demonstrated significant improvements in both mechanical strength and antioxidant properties when UiO-66 was loaded with MT at a concentration of 0.20 mg/mL and combined with sodium alginate. Freshness preservation experiments also indicated the effective preservation effect of these films on spinach. In conclusion, the results of this study suggest that MT-loaded UiO-66 MOF is a promising active packaging material for spinach preservation.