Study On Polysaccharides Extraction Technology, Bioactivity And High Polysaccharides Germplasm Screening Of Oolong Tea

This study compared and analysed polysaccharides from oolong tea, green tea, black tea and white tea. The extraction technology, biological function of oolong tea were studied systematically, based on which germplams containing high polysaccharide were screened. The results were as follows:1．Optimizing extracion technology of oolong tea polysaccharides. The experiments showed that using hot water ( 80℃) and acetone to extract and precipitate polysaccharides has good results. Through analysing extraction technology by orthogonal test, we obtained the optimal extracton conditions: solid/liquid 1:1, temperature 100℃, time 3h, and three times of actone in volume for polysaccharides precipitation.2．Preliminary Purification of oolong tea polysaccharides. Using Tieguanyin polysaccharides as material, we studied the basic physical and chemical properties, separation and purification of polysaccharides. The results showed that tea polysaccharides mainly were constituted by uronic acid, protein and neutral sugar. After purification,it suggest that polysaccharides were a kind of compounds of polysaccharides and proteins, which had complex ingredients.3．Comparing tea polysaccharides of different preparation treatments. This study used fresh Dangui leaves as materials to undergo different preparation treatments to prepare oolong tea, green tea, black tea and white tea respectively. After hot water extraction,the components were determined and analysed. The results indicated that white tea and green tea had higher polysaccharides availibility and capability of clearing OH free radicals.4．Hypoglycemic effect of oolong tea polysaccharides. Feed polysaccharides for six days to hyperglycemic ICR mouse induced by tetraoxypyrimidine. Fast the mouse for 18 hours and then observe the effects on blood glucose and liver SOD,T-AOC,GSH-PX and MDA. The results indicted that after intaking tea polysaccharides for 6d continuously, the hyperglycemic mice had 21．7% lowered blood sugar level than the control group. and the activity of SOD was enhanced. 5．Screening oolong tea germplasms for high polysaccharides. The experiment selected 52 tea cultivars suitable for oolong tea preparation. The results indicated that there were varitaion among different tea cultivars in polysaccharides content. The cultivar with highest polysaccharides was A01, which polysaccharides content is 4．31%, and it was 1．7, 2 and.2．5 times as high as that of the average level of the 52 cultivar, Tieguanyin and Huangjingui, respectively.