The Extraction of Polyphenols from Tea Leaves Based on Mechanochemical Methodology and Aqueous Two-Phase System

Abstract

In order to extract tea polyphenols (TPs) by water under room temperature, the mechanochemical methodology was used for leaching process, and then TPs was purified from leaching solution by ethanol and ammonium sulfate aqueous two-phase system. The optimum parameters of mechanochemical methodology leaching TPs were determined by response surface methodology (RSM), which optimum parameters were: Na2CO3content 25~27wt%, solid material particle size D9540~45μm, liquid/solid mass ratio55~60, leaching time 16~18min. The TPs leaching rate was 16.46%. When ammonium sulfate mass composition0.2, ethanol mass composition0.35 as the composite of the extraction system, TPs maximum extraction rate was 93.4%. The maximum yield of TPs was 15.25% on the average, with average purity was 96.54% ultimately. Under such technology, water is only solvent used in TPs leaching at room temperature, and aqueous two-phase system extraction system under mild conditions, avoid the use of toxic solvent, is a green technology for extracting TPs.