Titanium dioxide nanoparticles in postharvest fruit preservation: diverse application modes, functional roles, and current challenges.

This review summarizes recent advances in the application of titanium dioxide nanoparticles (TiO2 NPs) for postharvest fruit preservation, with emphasis on their antimicrobial activity and photocatalytic degradation of ethylene. TiO2 NPs have been applied through direct treatment, edible coatings, and packaging films, effectively delaying ripening, reducing weight loss, maintaining firmness, and preserving bioactive compounds. Their preservation performance is influenced by ROS generation, crystalline form, particle size, dispersion state, and interactions with carrier matrices. Modification strategies, such as metal or non-metal doping and hybrid nanocomposites, enhance photocatalytic efficiency and broaden application conditions. Compared with conventional methods, TiO2-based systems exhibit multifunctional effects by combining ethylene scavenging, antimicrobial action, and quality maintenance. Nevertheless, challenges remain, including UV dependence, nanoparticle aggregation, and potential migration or toxicity. Distinct from previous reviews on TiO2 in packaging, coatings, or photocatalysis, this work specifically focuses on their role in postharvest fruit preservation.