Preparation and bioactivities of chitosan nicotinamide derivatives and their application in the preservation of cherry tomatoes

Three pyridine-3-formyl chitosan derivatives were successfully prepared, and the preservation performance of the derivatives was examined. According to the results, the derivatives exhibited better antifungal and antioxidant properties than that of chitosan. At a supply concentration of 0.5 mg/mL, 2-ANACS could scavenge DPPH radicals at a rate of (92.82 ± 0.38)%. Additionally, all three derivatives exhibited less cytotoxicity and higher biocompatibility. In the freshness preservation studies of cherry tomatoes, the three derivatives considerably decreased the weight loss rate and postponed the drop in V C and titratable acid content. After 32 days of 2.0 g/L VPPCS treatment, the weight loss of cherry tomatoes was (4.0 ± 0.52) % among them. Still, the weight loss of cherry tomato in the chitosan treatment and blank control was (5.5 ± 1.33) % and (5.94 ± 1.02) %, respectively, which was considerably decreased by VPPCS therapy. These findings demonstrated that adding niacin improved chitosan's antifungal and antioxidant properties, extended the shelf life of cherry tomatoes, and increased the potential uses of chitosan and its derivatives in fruit preservation.