Technology for extraction of polysaccharide by usingmicrowave technology from Porphyra yezoensis

Based on the comparison between microwave extraction and hot water extraction, by the experiments of microwave extraction and the analysis of orthogonal test, the effects of microwave power, extraction duration and solvent/solid ratio on the extraction ratio of porphyra polysaccharides were investigated. The result showed that the extraction ratio of polysaccharide by using microwave extraction was better than that by using hot water extraction. The result of microwave and freeze extraction is the best, the extraction ratio is up to 7.45%, and the extraction ratio of hot water extraction is 2.05%. The primary factor which affects microwave extraction was the extraction duration, microwave power was the second factor and solvent/solid ratio was the third factor. The optimal conditions for the extraction of porphyra polysaccharides were as follows: 200 W microwave power for 8 min extraction duration in combination with 40∶1(volume/weight) solvent and solid weight ratio. In addition, the result suggested that the quality of the porphyra polysaccharide treated by the vacuum-freeze drying was obviously better than those by reduced pressure and normal pressure heat-air drying.