Carbon Dots-Enhanced Soy Protein Isolate/Polyvinyl Alcohol Composite Film for Active Preservation of Oxidation-Sensitive Foods

Carbon dots perform a variety of functions when they are incorporated into active films synthesized from soy protein isolate/polyvinyl alcohol. The study examined the impact of varying concentrations of carbon dots on the structural, bioactive, and physicochemical properties of composite films. The addition of carbon dots improved the UV-blocking rate (up to 99.64%) with a higher water-barrier property of the films. The films with carbon dot-enhanced antioxidant activities (ABTS was 99.71%, and DPPH was 51.44%) exhibited strong antibacterial activities against <i>Escherichia coli</i> and <i>Staphylococcus aureus</i>. In a hydrophilic environment, the high release rate of carbon dots was found to enhance the biological activity of films. The application of 0.8% composite film resulted in significant shelf-life extension for fresh jujubes, meatballs, and soybean oil. These results demonstrated the feasibility of composite films as an active packaging material.