Study On Technique Of Extraction, Separation And Purification Of Polysaccharide In Tricholoma Mongolicum Imai

Tricholoma mongolicum Imai is a kind of valuable and nutritive edible fungus which is rich in polysaccharide and protein.Although it's good to human's health,the study on the bioactive substance of fruiting body was rarely reported.The Polysaccharide is one of the most substances in Tricholoma mongolicum Imai,and it is of important research value.In this dissertation,the extraction,separation and purification of polysaccharide in Tricholoma mongolicum Imai were systematic studied,and prepared the polysaccharide flour with high purity.This dissertation may provide a theoretical basis for the large scale industrial production and it also can lay a scientific basis for the exploitation of Tricholoma mongolicum Imai.The results are mainly as follow:1.The raw materials were defatted by Supercritical CO₂ extraction technology first,and the optimum conditions were determined through orthogonal test:extraction pressure was 30MPa,extraction temperature was 35℃,extraction time was 160min,CO₂ flow was 30L/h。The supercritical CO₂ extraction technology plays a good auxiliary role to the extraction of polysaccharide because it can remove fat,coloring material and abnormal flavour.2.The optimum conditions of extraction were determined through orthogonal test.The optimum conditions of hot water extracting were as follow:solid-liquid ratio was 1:40,extraction temperature was 90℃,extraction time was 3h,material grade size was 0.147mm.The optimum conditions of microwave extracting were as follow:microwave power was 300W,microwave processing time was 4min,solid-liquid ratio was 1:30,material grade size was 0.147mm.By comparing,the extraction rate was better than microwave extraction,but it waste time and energy.3.Studied on the volume of ethanol and the time of precipitating by ethanol.and the optimum conditions was determined as follow:precipitate with 3 times 95%ethanol for 6h.After precipitating and drying,we can get 21.34g crude polysaccharide per100g raw materials.4.The protein in polysaccharide was removed by Sevag method,trichloroacetic acid(TCA) method and anion exchange resin chromatography method,then the optimum conditions of each method was determined.The remove rate of protein by three method as follow:52.05%,41.29%and 56.25%,and the loss rate of polysaccharide by three method as follow:14.68%,24.67%and 14.91%.By comparing,the anion exchange resin chromatography method was the best mothod.5.Two gel column chromatography include Sephadex G-100 and Sephadex G-75 were used to separate and purify the polysaccharide after removing protein.Finally finding that there were two composition at least in polysaccharide,the ratio of high molecular composition was 16.77%,the ratio of low molecular composition which composed by three sections was 63.92%.The ratio of these three sections in the low composition was 28.35%,7.87%and 23.96%.Every composition can be gained in different conditions.