CELL 60 |
| In the process of black tea production, four major tea catechins are enzymatically oxidized to give the complex products. Theaflavins, the well known pigments produced by condensation between epicatechins and epigallocatechins, constitute only a few percent of total black tea polyphenols. The remaining black tea polyphenols are largely made up of numerous unknown minor compounds. The unknown polyphenols are mainly produced by oxidation of epigallocatechin and its gallate, which account for over 60% of tea catechins in tea leaves. The products include new pigments with benzotropolone or vicinal diketone structures and a catechin dimer having a pyrrolidinone unit derived from L-theanine. In this presentation, new cascade type oxidation mechanisms of tea catechins, in which unstable epigallocatechin quinone dimers play important roles, are summarized. In addition, inhibition activities of catechin oxidation products against amylase and lipase are compared. |
|
Poster Session
4:00 PM-6:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster
Division of Cellulose & Renewable Materials |