Study On The Tea Polysaccharide Extraction And Purification Of Yunnan Black Tea

Yunnan Black tea was known well and welcomed around the world for its special quality and sweet taste. Tea polysaccharide(TPS) is a kind of acidic polysaccharose or acidoglycoprotein which is combined with protein, it has many bioactivities, such as hpyerglycemic, inoxidizability, anticancer, boost immunity and so on. This article try screening the best extraction and purification process of black tea polysaccharides by comparing polysaccharide content of different black tea and researching extraction, deproteinization and decolorization of polysaccharide. The results are as follows:1. Determining the polysaccharide content of three kind of Yunnan Gongfu black tea, sun-dried Gongfu black tea made from big tree leaves, Gongfu black tea made from big treeleaves and Gongfu black tea made from strip-cropping tea trees leaves by phenol-sulfuric acid colorimetry method, and the total antioxidant capacity(T-AOC) of three types black tea by kit. The results of sorting the polysaccharide content is: Sun-dried Gongfu black tea made from big tree leaves> Gongfu black tea made from big treeleaves > Gongfu black tea made from strip-cropping tea trees leaves. The highest T-AOC is sun-dried Gongfu black tea made from big tree leaves, and the lowest is Gongfu black tea made from strip-cropping tea trees leaves. Therefore we choose the Sun-dried Gongfu black tea made from big tree leaves as material for further experiment.2. Tea polysaccharides are extracted from ancient sun-dried black tea by hot water extraction method, then optimizing its extraction temperature, time and liquid to solid ratio by orthogonal experimental design and using the data processing software SASS to perform statistics analysis on the result, to get the best extraction process. The best extraction process is as follows: the extraction temperature is 100?, time is 70 minutes and solid ratio is 1:20. In this condition, the polysaccharide yield is 3.1%, T-AOC is 38.13 unit/m L of polysaccharide, and crude polysaccharide extraction efficiency is 7.59%.3. We know that trichloroacetic acids method have the highest removal rate of protein and its polysaccharide retention rate is high by comparing the trichloroacetic acids(TCA) method, Sevag method and hydrochloric acid method. Compared with hydrochloric acid method, trichloroacetic acid method can take off more protein, but its polysaccharide retention is lower than hydrochloric acid method. Sevag is the worst method to take off protein and its removal rate is only to 10.08%. TCA method's removal rate of protein is 88.59% and polysaccharide retention rate is 77.04%.4. Making use of static adsorption method to compare five kinds of resin decolorization effect, we learn that D-900 macro-porous weak base anion exchange resin have the highest decolorization rate. By orthogonal experiment, we screen out the optimum technological condition to discolor of D-900 macro-porous weak base anion exchange resin: the resin is 1.5 gram, p H value is 4.5 and temperature is 75?. Certification experiment was done under these conditions, the results showed as follows: decolorization rate of polysaccharide solutions is 78.573%, polysaccharide retention rate is 78.023% and removal rate of protein is 94.112%.