Eco-friendly mixed-metal MOF embedded in PVA-based packaging films for ethylene adsorption and enhancing fresh produce shelf-life

Abstract

This study aims to investigate the integration of MOF materials into packaging films to improve their functional properties, prolong the shelf life of fresh produce, and minimize economic losses caused by post-harvest spoilage. Ethylene plays a significant role in accelerating the aging and spoilage of fruits and vegetables, creating a demand for advanced food packaging systems capable of scavenging ethylene without external activation. This study introduces an eco-friendly ethylene scavenger based on mixed-metal MOF-74, synthesized via a green method that replaces toxic solvents with sustainable alternatives. The optimized G-CuZnMOF-74, with a 2:1 Cu/Zn ratio, exhibited an exceptional ethylene adsorption capacity of 5.26 mmol/g at 25 °C and 110 kPa. Theoretical calculations confirmed enhanced ethylene binding, with an adsorption energy of ∆E_C₂H₄ = − 0.42 eV surpassing single-metal MOF-74. To integrate this high-performance material into a functional packaging solution, G-CuZnMOF-74 was embedded in a PVA-based packaging film (PVA-PEG/G-CuZnMOF-74). This film significantly reduced ethylene-induced ripening in green bananas, maintaining over 60 % of their initial firmness and minimizing weight loss and browning over 20 days at 25 °C. Additionally, the inclusion of G-CuZnMOF-74 enhanced the film's tensile strength from 27.82 MPa to 40.66 MPa and improved its water vapor barrier properties by 23 % (p < 0.05), contributing to its durability and protective performance.

Group Members

William A. Goddard III

Charles and Mary Ferkel Professor