Abstract:This paper aims to optimize the extraction conditions of water-soluble polysaccharides from peel of Rhizoma dioscoreae by single factor experiment and orthogonal experiment，followed by ultraviolet scanning and infrared spectroscopy.To be specific，the extraction rate with the help of pectinase，cellulase，and neutral protease was respectively determined，and the results showed that the highest extraction rate was achieved by cellulase.Thus，cellulase was used as auxiliary enzyme for the following optimization.According to the result of range analysis and variance analysis，the optimal conditions are as below:cellulase added at 5.0%，ultrasonic power of 350 W，enzymolysis-sonication duration of 60 min，and material-to-liquid ratio of 1∶50（g/mL）.Under these conditions，the extraction rate was 10.98%.The ultraviolet spectrum show：d no characteristic absorption peak at 260 nm-280 nm.Therefore，the extracted crude polysaccharide contained no nucleic acid or protein.According to the infrared spectrum(stretching vibration of functional groups)，the extracted substance had the basic characteristics of polysaccharide.