Structural and functional properties of two phenolic acid-chitosan derivatives and their application in the preservation of Saimaiti apricot fruit

In this study, we incorporated gallic acid (GA) and salicylic acid (SA) onto chitosan (CS) using free radical grafting initiated by hydrogen peroxide/Vitamin C (H2O2/Vc) redox system. We characterized the structural properties of the GA (CS-GA) and SA (CS-SA) derivatives using UV–vis absorption, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and thermal stability analysis. We proved that these phenolic acids were successfully grafted onto the molecular skeleton of CS. We investigated the antioxidant and antibacterial properties of CS-GA and CS-SA and found that they had significantly higher antioxidant and antibacterial properties than native CS. Furthermore, the antioxidant ability increased with the increase in grafting ratios. Finally, in vivo tests showed that CS-GA could maintain the firmness and the content of soluble solids and titratable acids in Saimaiti apricots at cool storage. The storage period was prolonged by inhibiting the respiratory intensity of apricots. Our results suggest that CS-GA can be potentially used as an edible coating material to preserve apricots.