| Polysaccharide is rich in Lentinusedodes. The polysaccharides with biological activity are widely used in medicine industries. A systematical study on its main resources, extraction and purification from Lentinusedodes was undertaken to boost its yield and quality. Moreover, this provides references in theory for industrial production.The experiments data and results are reported as follows:1. The extraction of polysaccharides from Lentinusedodes.The optimal extraction conditions with the alkali and enzyme methods are investigated, and the further improved conditions by ultrasonic treatment were also discussed. The results indicated that the yield of polysaccharides increased obviously by alkali and enzyme methods, and the extraction rate was greatly enhanced by the treatment of ultrasonic. The optimal conditions for alkali method are at 65℃, alkali consentration of 1.0mol/L and powder-water ratio of 35:1, but for enzyme method, the optimal conditions are at 55℃, pH6.5 and enzyme concentration (to polysaccharide liquor) of 2.5%. Compared the two methods, the latter has lower proteinization concentration and is more suitable to industrial production. 2. The purification of raw polysaccharides.In order to further enhance the purity of polysaccharides and reduce the preparation cost, a simple processdure including both the pretreatment with active carbon and the ultra filtration by ceramic membrane was studied in detail. The optimal conditions demonstrated from the experimental data were as follows: 1% active carbon was used for pretreatment with the sample containing 45% polysaccharides; then the ceramic membrane was employed for ultra filtration and the conditions were at 40℃, 0.20MPa and flow velocity of 4.5 m/s on the surface of membrane. Treated by these simple united processdure, the decolored rate could reach 98.2%, the deproteinization rate were 81.0%, the sample purity increased from 45% to 89.7% and the recovery rate was 77.6%.
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