Functional Bio-nanofibers for Active Packaging: Electro-Blown Gelatin/Xanthan Gum with Carbon Dots

This study reports the fabrication of multifunctional bio-nanofibers by incorporating molasses-derived carbon dots (MCDs), synthesized from sugar beet molasses, into a gelatin–xanthan gum (G-XG) matrix using the electro-blowing technique. The resulting G-XG-MCDs nanofibers were comprehensively characterized and demonstrated significantly enhanced antioxidant and antimicrobial activity. Antioxidant tests revealed a sharp increase in activity, with DPPH and ABTS scavenging rates reaching 56.9 ± 8.6% and 68.7 ± 6.3%, respectively (p < 0.05). Moreover, G-XG-MCDs exhibited antimicrobial zones of inhibition of 9.2 ± 0.7 mm against E. coli and 11.4 ± 1.9 mm against S. aureus. These effects are attributed to the abundant surface functional groups and nanoscale dimensions of MCDs, enhancing redox activity and membrane interactions. Compared to previous biopolymer systems, this study uniquely valorizes sugar industry by-products through a solvent-safe and scalable electro-blowing approach, advancing the development of green, active packaging materials. The integration of MCDs not only strengthens mechanical and thermal properties but also provides effective protection against oxidative degradation and microbial contamination, aligning with circular economy and food safety goals.