Sustainable agar-based film with zinc oxide/carbon quantum dot (ZnO/CQD) nanocomposite for photocatalytic antimicrobial and antioxidant packaging of chicken breast

The rising need for sustainable food packaging has spurred the creation of biopolymer-based films with improved functionality. However, many conventional biopolymer films exhibit poor mechanical strength and oxidative stability, limiting their practical use in real food packaging. In this research, functional biopolymer-based films were developed by incorporating ZnO and zinc oxide/carbon quantum dot (ZnO/CQD) nanocomposites into agar at 4 wt% and 8 wt%, respectively, using a green synthesis method involving chestnut shell. The Agar +8 %-ZnO/CQD (8 %) film (8ZCA8) enhanced the dispersion within the agar matrix, attributed to the presence of CQDs, facilitating a more homogeneous film structure and bolstering mechanical strength and barrier properties. In photocatalytic antimicrobial activity against Escherichia coli, Salmonella Typhimurium, and Listeria monocytogenes, the 8ZCA8 film achieved more than a 3-log CFU/g reduction on inoculated film surfaces and approximately a 2-log reduction on contaminated chicken breast under blue light irradiation. It also showed 13–20 % higher DPPH and ABTS radical scavenging activity than the ZnO-only film (ZA8). Moreover, the 8ZCA8 film exhibited lower cytotoxicity than the ZA8 film. When applied to the storage of chicken breast at 4 °C, the 8ZCA8 film demonstrated the highest photocatalytic antimicrobial activity and antioxidant performance, significantly outperforming the pristine agar film. These results highlight its potential as an effective active packaging material with antioxidant and antimicrobial functionalities, while also being environmentally friendly and sustainable.