Carrageenan/Alginate-Based Functional Films Incorporated with Allium sativum Carbon Dots for UV-Barrier Food Packaging

Hydrothermally prepared garlic (Allium sativum) cloves-derived carbon dots (CDs) were used to fabricate carrageenan/sodium alginate (Car/Alg)-based functional films for UV-barrier food packaging. The effects of different concentrations of CDs on the films' structural, functional, physical, and mechanical properties were analyzed. The CDs acted as a reinforcing agent to improve the films' mechanical stability and surface hydrophobicity. The structural characterization indicated good compatibility between CDs and the Car/Alg polymer matrix. The functional films showed a significant bacteriostatic effect against foodborne pathogenic bacteria E. coli and L. monocytogenes. Besides, they exhibited excellent UV-blocking properties (similar to 85.1% in the UV-A and 99.0% in the UV-B). In addition, CD-incorporated Car/Alg films showed high antioxidant activity as determined by ABTS (98.6 +/- 0.3%) and DPPH (34.2 +/- 0.3%) free radical scavenging methods. When used for UV protection packaging of raw meat, the functional film could preserve the meat color even when directly exposed to UV light for 30 h. The results indicate the potential of CD-containing Car/Alg-based films for active food packaging applications, especially as UV-blocking films for preserving the visual quality of meat products.