Study On The Extraction, Isolation And Puriifcation Of Proteins And Polysaccharides From Tea Residue

With the continuous development of field deep processing of tea, large tea drinks,tea polyphenols processing factory have begun to establish, which generated a lot of tearesidue. Studies showed that we used only the water-soluble ingredients in the process oftea, tea residue still have1%-2%of tea polyphenols,0.1%-03%of the caffeine,17%-19%of crude protein and crude fiber16%-18%.The content lysine and methioninewere1.5%-2%and0.5%-0.7%respectively in tea residue. So tea residue has highpotential utilization valueThis paper studied on the extraction of effective components from tea residue,Systematic study the cellulose hydrolysis conditions, alkaline protease enzymolysisconditions, tea protein purification and component analysis, purification of teapolysaccharide, the main results are as follows：Analyzed main components of the tea residue：moisture content of3.57%, ashcontent of5.83%, protein content of21.05%, crude fiber content is23.20%.Usingcellulose enzyme processing tea residue, through the single factor experiment andresponse surface experiments to determine the best conditions of cellulase enzymolysis.Results showed that the optimum condition of cellulose enzymolysis is as follows:extraction temperature41℃, dosage of cellulose enzyme2%, extraction pH6.4,extraction time64min. The soluble sugar extraction rate was2.18％under theseconditions. Through the single factor experiment and response surface experiments todetermine the best conditions of alkaline protease enzymolysis. Results showed that theoptimum condition of alkaline protease enzymolysis is as follows: extraction temperature60℃, dosage of alkaline protease2%, extraction pH8.7, extraction time90min. Theprotein extraction rate was20.93％under these conditions. According to the best ofcellulase and alkaline protease enzymolysis condition, final the protein extraction rate ofdouble enzyme was32.18%.Determine the protein isoelectric point by adjusting the pH of protein solution, theresult showing that when the solution ph value is2, protein precipitation effect is best.Studied on the effect of the active carbon decoloring effect, the determination results ofsingle factor experiment and orthogonal experiment showing that the optimum conditionof decolorization is as follows: dosage of activated carbon3.5%, decolorizationtemperature45℃, decolorization time60min.In these conditions, the decolorization rateof protein solution was88.80%, the protein retention rate was77.76%。The analysis results of tea protein by automatic amino acid analyzer showing that teaprotein amino acid composition is rich,7kinds of essential amino acids were found,including aspartic acid, glutamic acid, leucine, the proportion reached9.69%、10.75%and8.43%respectively, and Lysine, phenylalanine, threonine, isoleucine, valine, etc alsohave very high levels.Orthogonal experiment is used to determine the optimum precipitation conditions ofpolysaccharides, result showing that the optimum condition is as follows: the proportionof polysaccharide concentrate and ethanol1:3.5, Settling time5h, the centrifugal time15min.The weight of the polysaccharide precipitation was20.93％under theseconditions. After the processing of tea polysaccharide solution by anion exchange resin D315,result showing that the decolorization rate of tea polysaccharide solution was65.37%, the tea polysaccharide retention rate was77.76%. Adjusting the solution pH oftea polysaccharide to3.0with trichloroacetic acid, the final protein removal rate was51.86%after stewing2h and centrifugal30min, and polysaccharide retention rate of57.89%. Tea polysaccharide purified yield was43.4%, polysaccharides of the color islight yellow after purification. Polysaccharides can be soluble in water, dilute acid ordilute alkali, but the solubility of polysaccharides is not good. Polysaccharide wasinsoluble in a high concentration of ethanol, ethyl ether, acetone, etc. The anthraceneketone-sulfuric acid reaction of Polysaccharide was positive, and potassium iodidereactions were negative.