<i>Radix rubiae</i> Derived Carbon-Dot-Reinforced Chitosan/Locust Bean Gum Composite Film for the Preservation of Chicken Meat

Smart food packaging can extend the shelf life and maintain the quality of food by incorporating functional components. In this study, chitosan and guar gum were used as the matrix to prepare a multifunctional film that integrates meat freshness monitoring and preservation functions. Carbon dots derived from Radix rubiae (R-CDs) were selected as the antibacterial agent and freshness indicator, and a deep eutectic solvent (DES) was chosen to enhance the mechanical properties of the film. R-CDs showed favorable antibacterial activity against E. coli and S. aureus, with bacterial clearance rates of 46.2% and 76.85%, respectively. The introduction of R-CDs enhanced the mechanical properties of the CS-LBG-DES-CDs film, with the elongation at break increased by 49.073%, and endowed the film with excellent antibacterial performance; the corresponding bacterial clearance rates reached 86.06% and 93.7%, respectively. Moreover, the CS-LBG-DES-CDs film exhibited a good preservation effect on chicken samples, extending the shelf life by 1 day compared with commercial preservation films at 4 °C. The fluorescence intensity of the film increased with the degree of chicken spoilage, enabling simultaneous preservation and freshness monitoring of chicken under both room temperature and refrigerated conditions.