Development of active food packaging using carboxymethyl cellulose/gelatin composites reinforced with carbon quantum dots derived from pumpkin peel waste

Carbon quantum dots (CQDs) were synthesized from pumpkin peel waste by a hydrothermal method and embedded in carboxymethyl cellulose (CMC) and gelatin (Gel) to develop a biodegradable and functional food packaging for preserving fruits. The CQDs were uniformly dispersed in the CMC/Gel solution, forming an unbroken, compact film with strong bonds within the polymer chains. The tensile strength of CQDs incorporated films increased by 78-147% compared to the control sample. Interestingly, the 3% CQDs concentrated on film exhibited 72.5 ± 1.3% and 94.3 ± 2.1% UV-A and UV-B blocking capabilities, respectively, while the water vapor permeability decreased by 12.32%. Also, the water contact angle of the films was expanded by 12.87-26.14% with the addition of CQDs. The CMC/Gel/PP_CQDs 3% film exhibited the potent antioxidant efficacy (88.58%) against the DPPH. CQDs incorporated formulations did show a strong resistance effect against the microbial pathogens and non-toxic at concentrations below 2 mg/mL in the human colorectal adenocarcinoma cells (Caco-2) lines. Cherry tomatoes packaged with CMC/Gel/PP_CQDs 3% composite film exhibited the best quality preservation among all the formulations.