Preparation and characterization of chitosan oligosaccharide derivatives containing cinnamyl moieties with enhanced antibacterial activities

The novel chitosan oligosaccharide derivatives modified with cinnamyl onto the NH₂ position were synthesized through a one-step reaction and their in vitro antibacterial activities were ascertained. The structural characterization and properties of derivatives were verified by UV–vis, FT-IR, ¹H, ¹³C NMR, TGA, XRD, and elemental analysis. The degrees of substitution (DS) of derivatives were from 0.255 to 0.366 with yields up to 82%. The in vitro antibacterial activities for the novel chitosan oligosaccharide derivatives against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were greatly improved compared to COS, sodium benzoate, and potassium sorbate. Moreover, their antibacterial activities were DS-dependent and more sensitive to S. aureus than E. coli. This study demonstrated that the new derivatives were expected to be a promising potential antimicrobial agent in the food industry.