Efficient visible light-harvesting film with multi-channel sterilization behavior for ultra-persistent freshness of perishable products

In light of the microbial spoilage of perishable products such as fruits and vegetables, this work pioneered a visible light-harvesting film with multi-channel sterilization mode by the demand-oriented construction of functional fillers, aiming to efficiently utilize abundant sunlight to achieve long-term preservation of fruits and vegetables. In detail, cubic TiO2-anchored porous nitrogen-rich nanocarbons (TPNC) with excellent photothermal and photocatalytic activities was first prepared by two-step annealing of NH2-MIL-125(Ti) precursor in different atmospheres, which was incorporated as filler into chitosan (CS) matrix to obtain a series of TPNC-CS nanocomposite films. Benefiting from the synergy between the integrated photothermal and photocatalytic sterilization of TPNC and the inherent antibacterial properties of CS, the TPNC0.30-CS film exhibited outstanding antibacterial capacity with short processing times (10 min) and high antibacterial rates (≥99.4 %). The significantly prolonged shelf life of kumquats treated with TPNC0.30-CS film confirmed its satisfactory preservation ability. Although at the cost of a slight loss of transparency, upgraded performances in mechanical strength, barrier capability, and proven biosafety served as cornerstones for the practical application of TPNC-CS films. These desirable properties declared TPNC-CS films as a promising microbial control barrier for efficient preservation of fruits and vegetables.