This study aims to acetylate
Rehmannia glutinosa polysaccharides by acetic
anhydride method, optimize process
parameters and evaluate their
antioxidant activity. With the degree of substitution(D_s) as a criterion, the effects of
reaction time, acetic
anhydride-to-
polysaccharides ratio and
temperature were investigated. Process
parameters were optimized by single-factor experiment and response surface
methodology. The infrared
spectroscopy(IR) and
scanning electron microscopy(SEM) proved the successful
acetylation and were employed to preliminarily analyze the structural characteristics of acetylated derivatives. The results showed that the D_s was 0.327 under the optimal technological conditions, including m(acetic
anhydride)m(R. glutinosa
polysaccharides)=2.70,
reaction time 3.0 h and
temperature 48 ℃. Further, the
antioxidant properties of acetylated derivatives were investigated
in vitro and
acetylation was found effective to improve the
antioxidant activity of R. glutinosa
polysaccharides. This study provides a reference for the further development and application of R. glutinosa
polysaccharides.