A konjac glucomannan composite film embedding proanthocyanidin-grafted chitosan and carvacrol@ZIF-8 nanoparticles for synergistic antioxidant/antibacterial packaging

Few bio-based active packaging films simultaneously achieve sustained antioxidant and antibacterial functions, making a dual sustained-release system highly desirable. To extend postharvest fruit shelf life, this study developed an active packaging film based on konjac glucomannan (KGM). A dual-release antioxidant and antibacterial system was constructed by introducing proanthocyanidin-grafted chitosan (PACS) and carvacrol-loaded ZIF-8 nanoparticles (CV@ZIF-8). The resulting KPCZ-3 film exhibited a tensile strength of 34.36 MPa, a water vapor permeability of 2.72 g·mm·m^-2·day^-1·kPa, and an oxygen permeability of 1.27 × 10^-3 g·s^-1·m^-2. In strawberry preservation tests at 25 °C, the film synergistically delayed quality deterioration and maintained optimal sensory and nutritional quality for over 4 days. In addition, the film showed good biodegradability and biocompatibility. These results indicate that KGM/PACS/CV@ZIF-8 films, as novel degradable active packaging, have promising application prospects.