Sustainable Active Food Packaging: Biodegradable Nanofibrous Mats Incorporated Spent Pumpkin Carbon Dots for Enhanced Shelf Life

Carbon dots (CDs), the subject of the Nobel Prize in chemistry in 2023, are promising materials for active food packaging with properties, such as antioxidant and antimicrobial activity, non-toxicity, and ultraviolet protection. Therefore, composite films containing CDs have been investigated for food packaging applications in recent years. However, as far as we know, limited studies have been carried out in which carbon dots are added to nanofibrous mats, which show superior properties such as high surface area-to-volume ratio compared to film structures. In this study, CDs were produced via hydrothermal carbonization from the waste material, the spent pumpkin. Aimed to develop and evaluate composite nanofibrous mats incorporating carbon dots (CDs) for active food packaging, specifically utilizing spent pumpkin-derived carbon dots (SPCDs) to enhance the functional properties of the packaging materials. The composite nanofibrous mats, fabricated from a blend of polyvinyl alcohol and carboxymethyl cellulose incorporating SPCDs, demonstrated low toxicity on chondrocyte and lung cell types, indicating their safety for food packaging applications. The inclusion of SPCDs enhanced the antioxidant activity provided inhibitory effects against E. coli and S. aureus , and improved the mechanical strength of the mats. Real food trials with walnut oils revealed that the mats effectively reduced lipid oxidation, thereby extending the product's shelf life. Additionally, the mats were fully biodegradable, decomposing completely in soil within 42 days. These results suggest that the novel composite nanofibrous mats have great potential for sustainable and active food packaging, offering a practical and comprehensive solution for the industry. Graphical abstract