Abstract: In this study, carbon dots (CDs) were synthesized and characterized from cuttlefish ink by the hydrothermal method. With polyvinyl alcohol (PVA)/carboxymethyl cellulose (CMC) as the film-forming matrix, PVA/CMC/CDs composite films were prepared by adding different concentrations (1%, 2% and 3%) of CDs. The resulting films were denoted as PVA/CMC/1CDs, PVA/CMC/2CDs, and PVA/CMC/3CDs, respectively. The effect of CD addition on the physicochemical properties and functional characteristics of the composite films was studied. The composite films were applied to package pork mince to explore their effects on the quality and shelf life of pork mince during 10 days of refrigeration at 4 ℃. The results showed that under the excitation wavelength of 360 nm, CDs exhibited bright blue fluorescence at 450 nm. CDs had excellent antioxidant and antibacterial activities, scavenging 70.3% of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and 62.9% of 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cations at 100 μg/mL. CDs inhibited Escherichia coli and Staphylococcus aureus by 94.35% and 87.00% at 2 mg/mL, respectively. Compared with the PVA/CMC film (with no CDs added), the water vapor permeability of the PVA/CMC/CDs films was significantly reduced, and the antioxidant and antibacterial activities were significantly enhanced. The tensile strength and elongation at break of PVA/CMC/1CDs were increased significantly. Compared with the control group and PVA/CMC, the growth rate of total viable count (TVC) and total volatile basic nitrogen (TVB-N) value of minced pork packaged with PVA/CMC/CDs was significantly reduced. Among them, minced pork packaged with PVA/CMC/3CDs showed the slowest increase in TVC and TVB-N value, with its shelf life extended by 4 days. PVA/CMC/CDs demonstrate promising application potential in active food packaging, which can be used to prolong the shelf life of packaged meat products while maintaining their quality.

Key words: carbon dots; cuttlefish ink; preservation; antibacterial activity; antioxidant activity; active packaging