Cellulose Nanofiber-Based Ethylene Scavenging Antimicrobial Films Incorporated with Various Types of Titanium Dioxide Nanoparticles to Extend the Shelf Life of Fruits

TiO2 nanotubes (TNTs) were synthesized hydrothermally and modified by Cu2O using a sol-gel method to provide photocatalytic activity in visible light. Cellulose nanofiber (CNF)-based films were prepared by adding TiO2, TNTs, and Cu2O-modified TNT (TNT-Cu2O). The TiO2-based nanoparticles (TiO2, TNTs, and TNT-Cu2O) were uniformly distributed in the base polymer to make compatible and flexible films. The incorporation of nanoparticles significantly enhanced the UV-shielding properties of the film while slightly decreasing the transparency. Incorporating nanofillers improved the film's mechanical and water resistance properties depending on the nanoparticle type. The TNT-Cu2O-added CNF film (CNF/TNT-Cu2O) showed the strongest antibacterial activity in visible light, followed by CNF/TNT and CNF/TiO2 films. The CNF-based films were used for tomato packaging to evaluate the ethylene scavenging property of the films. The CNF/TNT-Cu2O film scavenged ethylene gas produced in the headspace during storage, delaying the tomatoes' discoloration, softening, and weight loss. CNF/TNT-Cu2O films are expected to be excellent composite films for the active packaging application of fruits and vegetables.