Researchers at Kyushu University have developed a new biodegradable packaging material using carbon dots derived from pumpkin peel, aiming to combat food spoilage and lower reliance on petroleum-based plastics across the agricultural sector.
Innovative Material Composition and Physical Properties
The research team integrated carbon quantum dots—a fine black powder made of small carbon nanoparticles—into a non-toxic biopolymer film composed of gelatin and carboxymethyl cellulose (CMC/Gel). Pumpkin peel was selected as the raw material because it constitutes roughly 10% of the fruit’s total mass and contains high concentrations of natural antioxidant compounds.
Incorporating carbon dots into the CMC/Gel biopolymer improved its tensile strength by 147% and decreased its water vapour permeability. These structural improvements help maintain package integrity during transit and protect produce against moisture loss. Furthermore, the inclusion of carbon dots imparted enhanced antimicrobial and UV-blocking properties to the material, helping slow down oxidation and product decay.
“Our lab has long focused on extending the shelf life of agricultural produce while reducing reliance on petroleum-based plastics,” said Fumihiko Tanaka, Professor at Kyushu University’s Faculty of Agriculture.
Addressing Food Spoilage and Ambient Storage Logistics
Global agricultural supply chains face significant losses, with an estimated 40% to 50% of harvested fruits and vegetables lost before reaching consumers. The development of this functional biodegradable packaging aims to address these losses, particularly in regions where refrigeration systems are limited.
“Actually, this project began with the idea from a student of ours from Southeast Asia,” shared Fumihiko Tanaka. “Cold-chain logistics across much of Asia are still underdeveloped, so we hope our technology, which preserves food at ambient temperature, could help in places where that infrastructure is lacking.”
To evaluate performance, researchers tested the film on cherry tomatoes over a 25-day period, comparing them against unpackaged and plastic-wrapped controls. The tomatoes stored in the new material experienced lower weight loss, reduced softening, and significantly lower levels of microbial growth than the control samples, effectively mitigating food spoilage during storage.
Safety Profile and Environmental Performance
Safety evaluations were conducted to assess the suitability of the film for direct food contact applications.
First author M.A. Reshaka Kavindi, from Kyushu University’s Graduate School of Bioresource and Bioenvironmental Sciences said: “Cell viability tests confirmed the material is non-toxic below 2 mg/mL, and the coating itself uses only a fraction of that amount, at roughly 0.01 millimeters thick. Consumers can further reduce exposure simply by washing or peeling.”
The research highlights key environmental advantages over standard active packaging methods that rely on inorganic constituents.
“Conventional antimicrobial packaging typically relies on metal nanoparticles like zinc oxide or silver, which carry a larger environmental footprint than CQDs. Ours are derived from organic matter and show good biocompatibility at effective concentrations, something critical for any food contact material,” said Associate Professor Fumina Tanaka. “Beyond the environmental benefits, I’d also love for this material to bring a bit of fun to food packaging. Under UV light, the carbon dots fluoresce, and the color shifts with particle size. If we could eventually find a way to render text or illustrations with it, that would be pretty exciting too.”
Looking ahead, the researchers intend to further refine their biodegradable packaging material to meet formal safety regulations and industrial standards. Future research plans also include integrating natural antifungal agents into the biopolymer matrix to protect agricultural produce against mold growth and further extend shelf life.
