Abstract: Polygonum kingianum from Yunnan were used as raw materials, and composite probiotics wereapplied as fermentation strains. The ratio of material to liquid, inoculation amount, fermentation temperature , and fermentation time were selected as the influencing factors, with polysaccharide yield as the mainindicator. The fermentation process for polysaccharide production was optimized through single-factor experiments and response surface methodology. The antioxidant activity of the polysaccharides was evaluated bmeasuring their ability to scavenge DPPH and hydroxyl radicals. The results showed that the optimal fermentation conditions for polysaccharides were: material-to-liquid ratio of 1:50, inoculation amount of 4%fermentation temperature of 36 9C , and fermentation time of 25 hours. Under these conditions. the yield ofpolysaccharides was 23. 46%6 . The scavenging elfect of the polysaccharides on DPPH and hydroxyl free rad.icals was positively correlated with concentration, with ICs, values for DPPH and hydroxyl radical scavenging being 4. 29 mg/ml, and 2. 68 mg/mL., respectively. The findings indicate that fermentation significant.ly increased the polysaccharide content ( mass concentration) in the stems and leaves of Polygonatum king.ianum , and the fermentation products exhibited strong free radical scavenging activity.

Key words: polygonatum hingianum : polysaccharides : fermentation technology , optimization , antioxidant activit