Distribution of catechins, theaflavins, caffeine, and theobromine in 77 teas consumed in the United States.
Authors:
Friedman, M. Kim, S.Y. Lee, S.J. Han, G.P. Han, J.S. Lee, K.R. Kozukue, N. USDA, ARS
Source:
Journal of food science. 2005 Nov-Dec, v. 70, no. 9, p. C550-C559.
NALT Subjects:
tea food analysis food composition epicatechin theaflavins caffeine theobromine high performance liquid chromatography validity epigallocatechin catechin extraction water plant extracts United States
Issue Date:
Nov-2005
Abstract:
To help define the composition of commercial teas consumed in the United States, we have developed and validated an high-performance liquid chromatography (HPLC) method to analyze levels of catechins, theaflavins, and alkaloids in 77 commercial black, green, specialty (brown rice, white, oolong), and herbal teas extracted with hot water to simulate home use. The following 13 compounds were separated in a single analysis on an Inertsil ODS-3v column with acetonitrile/potassium dihydrogen phosphate as the mobile phase: (-)-epigallocatechin, (+)-catechin, (-)-epicatechin, (-)-epigallocatechin-3-gallate, (-)-gallocatechin-3-gallate, (-)-epicatechin-3-gallate, (-)-catechin-3-gallate, theaflavin, theaflavin-3-gallate, theaflavin-3'-gallate, theaflavin-3, 3'-digallate, caffeine, and theobromine. The data show that (1) extraction time from 3 min to 20 min did not significantly affect measured levels of tea compounds and (2) there was a wide variation in the composition of the tea compounds both within each tea category and among categories: black teas contained both theaflavins and catechins, green and white teas contained catechins and trace amounts of theaflavins, herbal teas contained very low amounts of all tea compounds. A statistical profile of the distribution of catechins, theaflavins, caffeine, and theobromine in the evaluated teas offers consumers a choice of teas containing high levels of health-promoting compounds.
