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Chemistry of Secondary Polyphenols Produced during Processing of Tea and Selected Foods.


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Title: Chemistry of Secondary Polyphenols Produced during Processing of Tea and Selected Foods.
Authors: Tanaka, Takashi / Matsuo, Yosuke / Kouno, Isao
Issue Date: Jan-2010
Citation: International journal of molecular sciences, 11(1), pp.14-40; 2010
Abstract: This review will discuss recent progress in the chemistry of secondary polyphenols produced during food processing. The production mechanism of the secondary polyphenols in black tea, whisky, cinnamon, and persimmon fruits will be introduced. In the process of black tea production, tea leaf catechins are enzymatically oxidized to yield a complex mixture of oxidation products, including theaflavins and thearubigins. Despite the importance of the beverage, most of the chemical constituents have not yet been confirmed due to the complexity of the mixture. However, the reaction mechanisms at the initial stages of catechin oxidation are explained by simple quinone-phenol coupling reactions. In vitro model experiments indicated the presence of interesting regio- and stereoselective reactions. Recent results on the reaction mechanisms will be introduced. During the aging of whisky in oak wood barrels, ellagitannins originating from oak wood are oxidized and react with ethanol to give characteristic secondary ellagitannins. The major part of the cinnamon procyanidins is polymerized by copolymerization with cinnamaldehyde. In addition, anthocyanidin structural units are generated in the polymer molecules by oxidation which accounts for the reddish coloration of the cinnamon extract. This reaction is related to the insolubilization of proanthocyanidins in persimmon fruits by condensation with acetaldehyde. In addition to oxidation, the reaction of polyphenols with aldehydes may be important in food processing.
Keywords: Black tea / Catechin / Ellagitannin / Oxidation / Polyphenol / Proanthocyanidin
URI: http://hdl.handle.net/10069/23018
ISSN: 14220067
DOI: 10.3390/ijms11010014
PubMed ID: 20161999
Rights: © 2010 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).
Type: Journal Article
Text Version: publisher
Appears in Collections:Articles in academic journal

Citable URI : http://hdl.handle.net/10069/23018

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