Abstract:

Ultra-high pressure technology was applied to the extraction of effective components from tea for the purpose of improving their dissolution and keeping natural quality of tea at the same time. The effects of ultra-high pressure treatment on extraction rate of tea polyphenols and DPPH radical scavenging activity of 50% ethanol extract of tea were studied. A maximum extraction rate of tea polyphenols of 19.43% was obtained under the optimized conditions: extraction pressure, 500 MPa; pressure holding time, 10 min; and extraction solvent, 50% ethanol solution. High pressure and long treatment time both were effective for the dissolution of tea polyphenols. Moreover, the DPPH radical scavenging activity went up significantly, with the prolongation of pressure holding time at the initial stage, and then it tended to stable when the holding time was over 5 min. In the experimental range, the DPPH radical scavenging activity tended to increase progressively, with the increase of treatment pressure.

Key words: ultra-high pressure, tea, antioxidant activity, extraction