Synergistic improvement of antioxidant and antibacterial properties of carbon quantum complexes with zinc doping and chlorogenic acid for longan preservation

The deterioration of fruit could reduce the shelf life, decreased marketability and substantial economic value. Thus, a safe, simple, economical and environmentally friendly preservation technology for fruit is of great significance. Here, the postharvest preservation technology was investigated with zinc-doped carbon quantum dots and chlorogenic acid (Zn-CQDs/CGA) composite. Zn-CQDs/CGA composite were synthesized, which exhibits superior antioxidant and antibacterial activities. The binding mechanism of the Zn-CQDs/CGA composite was investigated, which revealed that the bindings of two components were mainly driven by hydrogen bonding and van der Waals forces to create a novel composite. The Zn-CQDs/CGA composite was applied to longan preservation and was found to significantly reduce the incidence of mildew spot, browning of fruit endocarp and pulp, as well as the degree of degradation of quality indexes. These results suggest that the Zn-CQDs/CGA composite has the potential for inhibiting browning and preserving the quality of longan during storage.