Premium
The role of (−)‐epicatechin and polyphenol oxidase in the coupled oxidative breakdown of theaflavins
Author(s) -
Opie Shaun C.,
Clifford Michael N.,
Robertson Alastair
Publication year - 1993
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740630409
Subject(s) - theaflavin , chemistry , polyphenol oxidase , black tea , polyphenol , catechin , fermentation , oxidative phosphorylation , food science , chromatography , biochemistry , enzyme , antioxidant , peroxidase
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.