Flavanols formulae

Aroma development during fermentation is accompanied by an increase in the volatile compounds typical of black tea. They are produced by Strecker degradation reactions of amino acids with oxidized flavanols (Formula 21.7) and by oxidation of unsaturated fatty acids and the caroti-noid neoxanthin. 

The chemical formulae for a variety of plant phenols are given in Fig. 16.2, including examples of simpler phenols, such as cinnamic acid derivative, and of tocopherols, flavonoids, flavonoid glycosides and anthocyanidins. The flavonoids include the following subclasses flavanones (taxifolin), flavones (luteolin), flavonols (quercetin) and flavanols (catechin/epicatechin). The... 

The enzymatic oxidation of flavanols via the corresponding o-quinones gives theaflavins (Formula 21.6, IX-XIt bright ted color, good solubility), bisflavanols (XIH-XV colorless), and epitheaflavic acids (XVI, XVII bright red color, excellent solubility). The theaflavins and epitheaflavic acids are important ben-zotropolone derivatives that impart color to black tea. 

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