Fabrication and characterization of a chitosan/cyclodextrin/TiO 2 -NPs composite for preservation of avocados.

In this study, a TiO 2 material with nanoparticle size of about 10-20 nm, surface area of 109 m 2 g -1 was synthesized using the microwave-assisted hydrothermal method. The chitosan/TiO 2 film combined with cyclodextrin (chitosan-cyclodextrin/TiO 2 , CS-CD/TiO 2 NPs) helps significantly improve the mechanical properties and enhance the antibacterial activity of the polymer film. Furthermore, the content of TiO 2 nanoparticles in CS-CD/TiO 2 NPs 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/TiO 2 NPs 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/TiO 2 NPs 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/TiO 2 NPs films extends the preservation time of avocados up to 7 days under conditions of 30 °C and 80% relative humidity.