Photocatalytic chitosan/hydroxypropyl methylcellulose-based multifunctional film incorporated with chlorophyll-TiO2@carbon sphere dual heterojunction and L-arginine for banana preservation

Over-ripening and spoilage of fruits, driven by excessive ethylene (C 2 H 4 ) production and microbial proliferation, present critical challenges in fruit postharvest preservation. Herein, a multifunctional photocatalytic film, CTC-Arg@CS/HPMC, is developed by incorporating chlorophyll-TiO 2 @carbon sphere (CTC) photocatalyst and L-arginine (Arg) NO donor into chitosan/hydroxypropyl methylcellulose (CS/HPMC) matrix for banana preservation. The distinctive dual heterojunction structure of CTC enhances photocatalytic activity under visible light, promoting reactive oxygen species (ROS) generation that triggers NO release from Arg. Under combined action of ROS and NO, CTC-Arg@CS/HPMC can not only inactivate bacteria with high antibacterial efficiency against Escherichia coli (93 ± 3 %) and Staphylococcus aureus (99 ± 2 %) within 60 min but also delay fruit ripening through C 2 H 4 degradation and inhibition of biosynthesis. In practical application scenario, CTC-Arg@CS/HPMC can effectively extend banana shelf-life by over 100 % at 25 °C, highlighting its potential as an active packaging material for extending the postharvest life of climacteric fruits.