Yuanfeng Pan

BACKGROUND: Faced with the relentless depletion of fossil fuels and the global environmental crisis, the strategic utilization of abundant biomass resources has drawn significant attention, offering vast application prospects in the field of food packaging. This study pioneers an investigation into the effects of incorporating purple tea extract (PTE) in chitosan (CS) films on their fundamental physical properties and functionalization, leading to an active and intelligent CS/PTE composite film with pH‐responsive characteristics and improved physical properties. RESULTS: X‐ray diffraction and Fourier transform infrared analyses indicate that CS and PTE interact primarily through hydrogen bonding, demonstrating high compatibility. The impact of varying PTE concentrations on the water vapor permeability, transparency, mechanical properties, antioxidant activity, antimicrobial performance, and pH responsiveness of the CS film was systematically investigated. The experimental results show that PTE significantly enhances the films’ light and water vapor barrier properties. Specifically, films containing more than 6% PTE exhibit improved antioxidant, antimicrobial, and food preservation capabilities. The resulting composite film demonstrated excellent antioxidant and antibacterial performance with a DPPH radical scavenging rate of 83.2%, and inhibitory rates exceeding 90% against Escherichia coli and Staphylococcus aureus , as well as pH‐responsive color changes. CONCLUSION: Overall, the CS/PTE composite film represents a highly promising active and intelligent food packaging material. It not only expands the range of naturally available materials for smart packaging films but also holds significant potential for practical applications in the food industry. © 2026 Society of Chemical Industry.

The antioxidant composite film was prepared by blending the pericarp extract of the Chinese litchi variety “Nuomici” (NLPE) with chitosan (CS). The study examined the impact of various NLPE concentrations (0%, 2%, 5%, 10%, and 15% [w/v]) on the mechanical properties, water vapor barrier, UV–visible light barrier, and antioxidant properties of the CS film. The results indicated that the composite films displayed superior antioxidant and UV‐barrier properties, accompanied by lower water vapor permeability coefficients, water content, elongation at break, and tensile strength, compared to the pure CS film. Fourier‐transform infrared (FTIR) spectroscopy, SEM, and x‐ray diffraction were employed to analyze the hydrogen bonding between CS and NLPE, revealing their excellent compatibility. Furthermore, fruit preservation studies demonstrated that CS composite film containing 5% (w/v) NLPE retarded weight loss and shrinkage of green grapes more effectively than both the pure CS film and the control group without film packaging. Therefore, CS/NLPE film holds significant potential and value for practical applications in food packaging, while also offering a novel approach for the reuse of waste resources and sustainable packaging.

To solve the problems that poly(vinyl alcohol) (PVA) easily breeds bacteria and swells in a humid environment, PVA and ZnO nanopillar (ZnO NP) components were composed to generate PVA/ZnO NP composite films via a simple combination process of blending and heat treatment in this study. Here, ZnO NPs endowed composite films with good antibacterial properties, and the etherification and dehydration of hydroxyl groups between PVA molecular chains induced by heat treatment resulted in the composite films having excellent water-swelling resistance. Most importantly, PVA/ZnO NP composite films revealed excellent tensile strength in both humid (52.85 MPa) and dry (74.63 MPa) environments. In addition, PVA/ZnO NP composite films showed good antibacterial and antisepsis abilities as well as preservation functions in the packaging test of half-cut apples. The current work disclosed an easy strategy for producing a PVA-based antibacterial film for packaging materials that are water-resistant and highly strong, making them suitable for applications in humid environments.