Abstract: In this study,the synthetic conditions of Lonicera japonica polysaccharides carboxymethylation derivatives were investigated.The influences of reaction time,concentration of chloroacetic acid and reaction temperature on the degree of substitution (DS) of the synthesized derivatives were optimized by response surface methodology (RSM).The optimal conditions were reaction time of 2.6 h,concentration of chloroacetic acid of 3.2 mol/L and reaction temperature of 60 ℃.The degree of substitution was 0.793.Compared with L.japonica polysaccharides,the antioxidant ability of the synthesized carboxymethylation derivatives was improved.

Key words: Lonicera japonica polysaccharides, acetylation, response surface methodology, antioxidant ability