Chitosan-based multifunctional films reinforced with cerium oxide nanoparticles for food packaging applications

The current study discusses the use of nanoceria as a multifunctional filler in food packaging biopolymer films for the first time. Nanoceria was synthesized using co-precipitation method. Chitosan-based food packaging films incorporated with 1 wt% and 2 wt% nanoceria were prepared and characterized. The FTIR absorption spectra confirms the presence of hydrogen bonding between nanoceria and chitosan structure. The nanocomposite films displayed strong UV-A and UV-B blocking properties besides being mechanically strong, thermally stable and possessing high moisture barrier properties. Further, due to the switching of oxidation states by cerium between Ce3+ and Ce4+, nanoceria shows high photocatalytic activity. This results in strong antimicrobial activity against E. coli and L. monocytogenes, especially under visible light. Further, the nanocomposite films displayed ∼1.25 times and ∼2.3 times higher ABTS and DPPH free radical scavenging potential, respectively, compared to pristine chitosan films, which indicate their high antioxidant potential. Moreover, the films depicted good biocompatibility towards L929 cells indicating their safety for food contact applications. With all these properties, the nanoceria-added chitosan films display strong potential for use in active food packaging, especially for high fat food products such as nuts and meats.