Fabrication and characterization of a chitosan/cyclodextrin/TiO₂-NPs composite for preservation of avocados

In this study, a TiO₂ material with nanoparticle size of about 10-20 nm, surface area of 109 m² g^-1 was synthesized using the microwave-assisted hydrothermal method. The chitosan/TiO₂ film combined with cyclodextrin (chitosan-cyclodextrin/TiO₂, CS-CD/TiO₂NPs) helps significantly improve the mechanical properties and enhance the antibacterial activity of the polymer film. Furthermore, the content of TiO₂ nanoparticles in CS-CD/TiO₂NPs also affects the tensile strength, antibacterial activity, ripening rate, ethylene production rate, and water vapor permeability during food preservation of the CS-CD film that has been studied. The CS-CD/TiO₂NPs film is effective against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aereus) reaching over 99.5% after 15 min of contact. The preservation ability of avocados coated with CS-CD/TiO₂NPs was evaluated through some physiological parameters of the avocados, such as sensory evaluation, weight loss, and hardness. The results show that the use of CS-CD/TiO₂NPs films extends the preservation time of avocados up to 7 days under conditions of 30 °C and 80% relative humidity.