role of (-)-epicatechin and polyphenol oxidase in the coupled oxidative breakdown of theaflavins

An enzymic in-vitro model tea fermentation system has been used in combination with gradient elution reversed-phase HPLC to study the oxidative breakdown of black tea theaflavins in the presence and absence of (-)-epicatechin. It was found that theaflavin, theaflavin-3-monogallate, theaflavin-3'...

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Veröffentlicht in:Journal of the science of food and agriculture 1993, Vol.63 (4), p.435-438
Hauptverfasser: Opie, S.C, Clifford, M.N, Robertson, A
Format: Artikel
Sprache:eng
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Zusammenfassung:An enzymic in-vitro model tea fermentation system has been used in combination with gradient elution reversed-phase HPLC to study the oxidative breakdown of black tea theaflavins in the presence and absence of (-)-epicatechin. It was found that theaflavin, theaflavin-3-monogallate, theaflavin-3'-monogallate and theaflavin-3,3'-digallate were not substrates for tea polyphenol oxidase (EC 1.14.18.1) whereas (-)-epicatechin alone, or mixtures of (-)-epicatechin and a theaflavin were rapidly converted to a complex mixture of thearubigin-like substances. While the chromatographic profiles varied with the identity of the theaflavin precursor each resembled the equivalent profile obtained with a whole black tea liquor. It is concluded that theaflavins are degraded by a coupled oxidation with (-)-epicatechin-quinone. It is suggested that thearubigins may form via these pathways during black tea manufacture.
ISSN:0022-5142
1097-0010
DOI:10.1002/jsfa.2740630409