Abstract: Taking red Chenopodium quinoa Willd. as the materials, the ultrasonic-assisted extraction method was applied to extract polyphenols from Chenopodium quinoa Willd.. The effects of particle size of material, the ratio of liquid to material, the extraction time and the extraction temperature on the extraction rate of polyphenols from Chenopodium quinoa Willd. were investigated by single-factor test. The response surface methodology was used to optimize ultrasonic-assisted water extraction of polyphenols from Chenopodium quinoa Willd. at room temperature and obtained the optimum conditions as follows： The particle size of 80 meshes, the ratio of liquid to material 100∶1（mL/g）, and the extraction time of 20 min. Under the optimum conditions, the extraction rate of polyphenols reached to 0.53%. The antioxidant analysis showed that the obtained polyphenols from Chenopodium quinoa Willd. extracts demonstrated strong DPPH scavenging capacity and total antioxidant capacity.

Key words: polyphenols from Chenopodium quinoa Willd., ultrasonic-assisted extraction, response surface methodology, antioxidation