CMC-based functional film incorporated with copper-doped TiO2 to prevent banana browning

Titanium dioxide (TiO2) and Cu-doped TiO2 (Cu-TiO2) were synthesized using a sol-gel method and used as nanofillers to prepare CMC-based functional packaging films. The Cu-TiO2 was spherical particles with a size range of 66.1 +/- 9.0 nm TiO2 and Cu-TiO2 nanoparticles had good compatibility with CMC and were evenly distributed in the CMC polymer matrix to form a composite film. The TiO2-added film did not show significant antibacterial activity, but the Cu-TiO2-added film exhibited high antibacterial activity against foodborne pathogenic bacteria (L. monocytogenes and E. coli) under visible light. When bananas were packaged with the CMC-based films, the CMC/Cu-TiO2 film effectively delayed the banana's browning. With strong antibacterial and ethylene scavenging capabilities under visible light, the CMC/Cu-TiO2 film has a high potential for active food packaging applications, especially in extending the shelf life of fruit.