Carboxymethylation modification process and antioxidant activity of polysaccharides from Pleurotus eryngii
Polysaccharides from Pleurotus eryngii (PEP) was carboxymethylated by alkaline chloroacetic acid to obtain carboxymethylated polysaccharides (CM-PEP).Carboxymethylation modification process and antioxidant activity of CM-PEF were studied.Substitution degree was selected as the index,and effects of sodium hydrate amount,chloroacetic acid amount,reaction time and reaction temperature on the substitution degree of CM-PEP were investigated through the single factor experiment.Carboxymethylation modification process was optimized by response surface analysis with Box-Behnken design.Antioxidant activity of CM-PEP was evaluated by scavenging ability of · OH,O2-· and DPPH free radicals.The optimal carboxymethylation modification process was:sodium hydrate amount 2.98 g,chloroacetic acid amount 2.51 g,reaction time 4h and reaction temperature 60 ℃.Under the optimal conditions,the degree of substitution was 0.891.Carboxymethylation modification changed the structure of PEP.Relative molecular weight of CM-PEF was smaller.CM-PEP mainly composed of arabinose,mannose,galactose and glucose.Content of arabinose and galactose of CM-PEF was higher.Compared with PEF,scavenging capacities of CM-PEP against hydroxyl free radicals and superoxide anion free radicals were improved,but the scavenging capacity against DPPH free radicals was weakened.
polysaccharides from Pleurotus eryngiicarboxymethylationmodificationresponse surface methodologyantioxidant activity
国家科技期刊平台
NSTL
万方数据
维普
