ARS | Publication request: MAJOR FLAVONOIDS IN DRY TEA

Submitted to: Journal of Food Composition and Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 14, 2005
Publication Date: December 10, 2005
Citation: Peterson, J., Dwyer, J., Bhagwat, S.A., Haytowitz, D.B., Holden, J.M., Eldridge, A., Beecher, G.R., Aladesanmi, J. 2005. Major flavonoids in dry tea. Journal of Food Composition and Analysis. 18:487-501.

Interpretive Summary: As part of the development of a special interest database on the flavonoid content of selected foods, data was collected on the flavonoid content of dry tea. Teas are a major source of flavan-3-ols in the diet. The flavan-3-ol subclasses are ranked by degree of polymerization. The catechins are monomers (catechin, epicatechin, epicatechin gallate, epigallocatechin, and epigallocatechin gallate), the theaflavins are dimers (theaflavin, theaflavin 3-gallate, theaflavin 3'-gallate, theaflavin 3,3'digallate), and the derived tannins. These compounds are theorized to be responsible for the positive health effects of tea. As levels of fermentation increased from green to oolong to black tea, the major flavan-3-ol profiles changed. Total catechins were 13.6 g/100 g in dry weight green tea and 4.2 g/100 g dry weight in black tea. The database will help in investigating relationship between intake of flavan-3-ols and disease risk.

Technical Abstract: Estimates of the flavonoid content of four types of tea were assembled from the relevant data in the analytical literature on food composition and were reviewed using standardized protocols developed by the US Department of Agriculture for evaluating data quality. They were then aggregated, and assembled as part of a special interest database for the major flavonoids in foods. As levels of fermentation increased from green to oolong to black tea, the major flavan-3-ol profiles changed. Total catechins were 13.6 g/100 g dry weight in green tea and 4.2 g/100 g dry weight in black tea. A discussion of methods used to calculate the flavonoid content in tea is presented. The database will help in investigating relationship between intake of flavan-3-ols and disease risk.