Abstract: The extraction process of Polyporus umbellatus polysaccharide (PUPS) was optimized by orthogonal test via multiplex-enzyme hydrolysis with ultrasonicassisted treatment.The in vitro antioxidant activity of polysaccharides extracted through enzymatic-ultrasonic process were evaluated preliminarily.The results showed that the proportion of enzymes,temperature,pH value and time affected the extraction of PUPS through enzymatic hydrolysis.The order of impact of various factors on PUPS extraction was temperature> pH value> enzyme dosage> extraction time.The highest yield of 4.31% was obtained in the 1:1 ratio of cellulase:pectinase (by mass as Polyporus 1%) at 50 ℃ and pH 6.5 for 60 min.The yield of polysaccharide increased to 5.48% with additional 30 min of ultrasonic treatment after enzymatic extraction.The in vitro antioxidant activity of the extracted PUPS was proved to be similar to that of Vc.Therefore,the enzymatic-ultrasonic extraction of PUPS had the advantage of simple process,mild reaction condition and environmental protection.The extracted polysaccharides had antioxidant activity.

Key words: Polyporus umbellatus polysaccharide, cellulose, pectinase, ultrasonic extraction