Biosynthesis of ZnONPs and TTOL for enhancing preservation of CTS films

• Chitosan-ZnO nanoparticles-tea tree oil liposomes composite films were prepared. • ZnO nanoparticles and tea tree oil liposomes addition enhanced the mechanical of chitosan films. • The composite films showed good antibacterial activities. • The composite films have great potential for fruit preservation. In this investigation, a novel chitosan composite film was prepared through the casting method, featuring the integration of tea tree oil liposomes (TTOL) and ZnO nanoparticles (ZnONPs). The SEM and FTIR results indicated that TTOL and ZnONPs were successfully composited with chitosan film. Compared to pure chitosan films, the composite film exhibited a 272% increase in tensile strength (42.26±1.50 MPa) and a 13.26% enhancement in elongation at break (82.28±0.73%), alongside improved the thermal stability. Furthermore, the composite film demonstrated remarkable antibacterial activity, achieving 90.67% inhibition against Staphylococcus aureus and 91.33% against Escherichia coli . During 14-day storage at 4 °C, fresh strawberries wrapped in the composite film showed a 25.5% slower reduce in hardness (from 10.7 to 7.97 N) compared to the polyethylene (PE) group, while maintaining 71.22% of initial acid titration value and 61.22% of soluble solid content. These results highlight the composite film's potential as an antibacterial food packaging material, effectively extending the shelf life of perishable produce.