Visible light-responsive TiO₂-based hybrid nanofiller reinforced multifunctional chitosan film for effective fruit...

In this study, we developed a multifunctional chitosan film with visible light-responsive photocatalytic properties by incorporating a novel nanofiller-a nanohybrid particle of poly(tannic acid) (PTA) and TiO₂ (TP-NPs). Firstly, the hybridization of TiO₂ with PTA not only improved its dispersion but also obtained TP-NPs with smaller band gaps (from 3.11 eV to 1.55 eV) and higher separation efficiency of photogenerated e^--h⁺ (about 1.5-fold enhancement), thereby producing more reactive oxygen species and enhancing the antibacterial efficacy (compared with TiO₂, the antibacterial effect of TP-NPs on Staphylococcus aureus and Escherichia coli was heightened by about 2 times under visible light for 1 h). Secondly, TP-NPs were hydrogen bonded with chitosan, strengthening its mechanical and barrier properties, while imparting exceptional antibacterial efficacy. Moreover, the multifunctional properties enabled the active film to effectively delay the quality deterioration of grapes and kiwifruit. Hence, this study presented a multifunctional active packaging film tailored for fruit preservation.