Abstract: Polysaccharides from Hyriopsis cumingii was extracted using methods of microwave-assisted hot water lixiviation,ethanol precipitation and Sevag’s deproteinization. On the basis of single-factor tests,parameters combination for the microwave-assisted extraction and Sevag’s deproteinization of H.cumingii polysaccharides was optimized using orthogonal experiment.Results showed that optimal conditions for the microwave-assisted extraction of H. cumingii polysaccharides were:ratio of water to raw material of 15 mL/g,extraction temperature of 50 ℃,microwave time of 150 s and microwave power of 1080 W.The extraction yield of polysaccharides from H. cumingii was 4.06% under the optimal extraction conditions.The optimal conditions for the Sevag’s deproteinization of H. cumingii polysaccharides were:volume ratio of nbutyl alcohol to chloroform of 0.2,volume percentage of mixture (n-butyl alcohol-chloroform) to polysaccharides solution of 20%,deproteinization duration of 10 min and times of deproteinization of 8.Under this optimal condition,protein removal percentage and polysaccharide remaining percentage of polysaccharides from H. cumingii was 52.24% and 65.13% respectively.

Key words: Hyriopsis cumingii, polysaccharides, microwave, extraction, deproteinization