Abstract:This study aims to optimize the extraction process parameters of maca polysaccharides and preliminarily analyze their antioxidant activity. Maca polysaccharides were extracted by water extraction and ethanol precipitation method. The effects of extraction time， extraction temperature， solid-liquid ratio， and number of extractions on the extraction yield of maca polysaccharides were investigated by single-factor experiments.With the extraction yield of polysaccharides as the response value， a four-factor and three-level experiment was designed using Box-Behnken design， and response surface optimization experiments were conducted to determine the relationship between each influencing factor and the extraction yield of polysaccharides. By using ascorbic acid as the positive control， the antioxidant activity was evaluated by measuring the scavenging ability of maca polysaccharides against DPPH radicals， ABTS+ radicals， and hydroxyl radicals. The results showed that the optimal extraction conditions were as follows： extraction time of 120 min， extraction temperature of 70 ℃， solid-liquid ratio of 1∶30 （g/mL）， and three extractions. Under these conditions， the extraction yield of maca polysaccharides reached 30.38%. The antioxidant activity tests showed that maca polysaccharides possessed significant free radical scavenging ability and exhibited good antioxidant potential.