Abstract:The aim of this study is to synthesize pyridine chitosan(Py-chitosan) by introducing the pyridine group onto the chitosan backbone and test its antioxidant activity. The resulting polymer was characterized by FT-IR, UV-vis and NMR. The degree of substitution (DS), solubility, toxicity and in-vitro antioxidant activity of Py-chitosan were further investigated. Results showed that pyridine was introduced onto chitosan with substitution degree of 0.66 and better water-soluble properties and it was non-toxic. Scavenging power for ·OH, DPPH and reducing power of Py-chitosan had been improved compared with water soluble chitosan (WSC). In the β-carotene bleaching assay, Py-chitosan showed strong inhibition power towards linoleic acid. Also, IC50 of Py-chitosan was 0.9 mg·mL-1 and at 1.8 mg·mL-1, the inhibition rate was up to 60.7%, while that of WSC was 27.5%. The study will provide theoretical basis and reference for application of chitosan in the field of food additives and free-radical scavengers.