Visible light-responsive chitosan/sodium alginate/QDs@ZIF-8 nanocomposite films with antibacterial and ethylene scavenging performance for kiwifruit preservation

The deterioration of postharvest fruits and vegetables caused by ethylene and microorganisms leads to global resource waste. Therefore, the development of multifunctional packaging materials that scavenge ethylene and inhibit microorganisms is essential to extend the shelf life of fruits and vegetables and minimize waste. Herein, the excellent photocatalytic performance of QDs@ZIF-8 nanoparticles (NPs) was incorporated into chitosan (CS) and sodium alginate (SA) matrix by layer-by-layer (LBL) assembly method to obtain CS/SA/QDs@ZIF-8 nanocomposite films. These as-prepared films exhibited excellent antibacterial (antibacterial ratio >99%) and ethylene scavenging properties (scavenging ratio >40%) due to the synergistic effect between visible light-induced reactive oxygen species (ROS) and the higher specific surface area of ZIF-8. The extended shelf life of kiwifruit further confirmed the enhanced preservation performance of CS/SA/QDs@ZIF-8 nanocomposite films. In addition, with the addition of QDs@ZIF-8 NPs, the color, and transparency of the films decreased, but the mechanical strength, thermal stability, hydrophobicity, and barrier properties were improved. In summary, the successful construction of ethylene scavenging and antibacterial films provides new ideas for the innovation of environmentally adaptive and functionalization of films.