Abstract:
Total PAM extracted by ethanol precipitation and three hierarchical PAMs extracted by chromatography purified were carboxymethylation modified by chloroacetic acid method. With chloroacetic acid concentration, reaction time and reaction temperature as the independent variables and carboxymethyl substitution degree (DS) of modified product as the response value,the modification conditions were optimized by response surface analysis.The antioxidative activity of modified product was tested by H
2O
2/Fe
2+system and pyrogallol oxidation. The results showed that the optimal modification conditions were 1.3 mol/L of chloroacetic acid, the reaction temperature was 63 ℃ and reaction time was 3.2 hours.Under these conditions,the obtained DS was 0.882. Carboxymethylated modification can enhance the antioxidative activity of PAM