Abstract:Selenium polysaccharides extracting from selenium-enriched Auricularia auricula by the ultrasonic and microwave method was used as an index in this test. The effects of different ultrasonic time, microwave time, ultrasonic power, microwave power and ratio of liquor to material on extracting rate of selenium polysaccharides were investigated by single factor experiment, then ultrasonic time, microwave time, microwave power and ratio of liquor to material, the four factors which had significant effects on extraction rate of selenium polysaccharides were chosen to determine the optimum process parameters in response surface test. The results showed that under the conditions of 1∶58 (g/mL) of ratio of liquor to material, 26 min of ultrasonic time, 22 min of microwave time and 350 W of microwave power, the selenium polysaccharides extraction rate and the extraction time were the highest (11.79%) and shortest, which were 4.1% higher and 56.67% shorter than those by the water-extractable method. The results from the antioxidant tests in vitro with different selenium polysaccharides showed that absorbance values of reducing capacity, the IC50 values of scavenging against hydroxyl free radical and the IC50 values of scavenging against DPPH free radical of selenium polysaccharides by the ultrasonic and microwave method and the water-extractable method were 0.431 and 0.410, 3.81 and 4.91 mg/mL, and 4.59 and 5.70 mg/mL, respectively .The antioxidant activity of selenium polysaccharides extracted by ultrasonic and microwave method was better than that of selenium polysaccharides extracted by the water-extractable method.