Solvent extraction method: leaching tea powder-filtration concentration-precipitation impurity removal-filtration concentration-dealkalization extraction-desolventization-drying-tea polyphenols.

Ion precipitation method: leaching tea powder-salting out-precipitation-acid dissolution-extraction-washing-evaporation concentration-tea polyphenols.

Laboratory instrument

Electric stirrer, centrifuge, pH test paper, vacuum drying oven, filter bottle, rotary evaporator, vacuum pump, balance, ultraviolet spectrophotometer, volumetric flask, beaker, measuring cylinder, etc.

Experimental reagent

Green tea, sodium chloride, sodium bicarbonate, citric acid, aluminum sulfate, hydrochloric acid, sodium bisulfite, ethyl acetate, vitamin C (ascorbic acid), disodium hydrogen phosphate, potassium dihydrogen phosphate, ferrous sulfate, potassium sodium tartrate, sulfuric acid, ethanol, etc.