Fe/Cu MOF-Tartaric Acid Complexes for Banana Preservation

Conventional preservation methods such as low temperature and modified atmosphere packaging often target a single preservation requirement. However, these methods cannot address multiple problems such as bacterial growth, enzymatic browning, and loss of flavor during fruit preservation. Consequently, the development of efficient, environment-friendly, and multifunctional preservation technologies was imperative for maintaining fruit quality. In this study, an Fe/Cu metal–organic framework-tartaric acid complex (Fe/Cu MOF-TA) with excellent antibacterial and anti-browning properties was synthesized, which was expected to provide a new, green, and efficient preservation material for fruits. The successful preparation of the Fe/Cu MOF-TA was confirmed using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FT-IR). The antibacterial and anti-browning properties of the Fe/Cu MOF-TA were evaluated through antibacterial experiments and the inhibition rate of polyphenol oxidase. The results demonstrated that, among the five organic acids (citric acid, succinic acid, cinnamic acid, TA, and malic acid), TA exhibited the most significant inhibitory effect on polyphenol oxidase activity. Furthermore, when the concentration ranged from 0 to 1.0 g/L, the polyphenol oxidase activity and degree of browning of the bananas exhibited an inversely proportional relationship with increasing concentrations of TA. The SEM images indicated that the Fe/Cu MOF had a bicone structure with a rough surface and rounded edges. FT-IR analysis indicated the formation of a complex between TA and the Cu/Fe MOF through hydrogen bonding. In addition, the TA loading rate of the Fe/Cu MOF-TA was 21.77%. Furthermore, the minimum inhibitory concentration of the Fe/Cu MOF-TA against Escherichia coli and Staphylococcus aureus was 0.0625 mg/mL. The rate of inhibition of polyphenol oxidase by the Fe/Cu MOF-TA was 76.03%. The results demonstrated that Fe/Cu MOF-TA possesses remarkable antibacterial, antioxidant, and polyphenol oxidase inhibitory properties.