Review of Oxidative Processes in Wine and Value of Reduction Potentials in Enology / (Record no. 3160)

000 -LEADER
fixed length control field 02772nma a2200217 4500
008 - FIXED-LENGTH DATA ELEMENTS--GENERAL INFORMATION
fixed length control field 2012 eng
022 ## - INTERNATIONAL STANDARD SERIAL NUMBER
ISSN 0002-9254
040 ## - CATALOGING SOURCE
Transcribing agency Sonoma County Wine Library
041 ## -
-- eng
100 0# - MAIN ENTRY--PERSONAL NAME
Personal name John C. Danilewicz.
245 10 - TITLE STATEMENT
Title Review of Oxidative Processes in Wine and Value of Reduction Potentials in Enology /
Statement of responsibility, etc by John C. Danilewicz.
260 ## - PUBLICATION, DISTRIBUTION, ETC. (IMPRINT)
Name of publisher, distributor, etc American Society for Enology and Viticulture,
Date of publication, distribution, etc 2012.
300 ## - PHYSICAL DESCRIPTION
Type Journal article
490 0# - JOURNAL TITLE
Title of the journal American Journal of Enology and Viticulture
520 ## - ABSTRACT
Abstract The reduction potential of wines has been thought to indicate their level of oxidation or reduction, but how that relates to wine composition has remained vague. Reduction potentials are generated by redox couples, which are at equilibrium and both adsorbed on the measuring electrode, the magnitude of the potential for any couple being determined by the relative proportion of the oxidized and reduced component. However, redox couples associated with polyphenols, which are most likely to determine reduction potentials, are not at equilibrium in wine due to the instability of quinones. Reduction potentials are highly dependent on oxygen concentration and it is proposed that they are generated by the oxidation of ethanol coupled to the reduction of protons or of oxygen. While the so-called reduction potential is therefore of little value for wine, cyclic voltammetry has proved very useful in determining the reduction potential of wine constituents and estimating the concentration of the most readily reduced polyphenols. The reduction potentials of proposed redox couples involved in the reduction of oxygen and oxidation of polyphenols, ethanol, and sulfite are useful in determining the thermodynamic feasibility of possible interactions. The reaction of polyphenols with oxygen is mediated by iron, which redox cycles between them assisted by copper. Catechol-quinone and oxygen-hydrogen peroxide couples have similar reduction potentials. Consequently, the oxidation of catechols such as (+)-catechin cannot proceed to completion and is accelerated by substances that react with quinones, such as sulfite, which reduces them back to polyphenols. Sulfite, therefore, has multiple antioxidant activities. It accelerates oxygen consumption, prevents loss of polyphenols by regenerating them, and intercepts hydrogen peroxide, thus preventing ethanol oxidation.
710 2# - ADDED ENTRY-CORPORATE NAME
CORPORATE NAME 144 Sandwich Road, Ash, Canterbury, Kent CT3 AF, United Kingdom.
773 0# - SOURCE JOURNAL
Journal title American Journal of Enology and Viticulture.
Related parts (Vol.) 63. (No.) 1. 2012. (Pages.) 1-10.
Page numbers 1-10
Volume number 63
856 42 - ELECTRONIC LOCATION & ACCESS
URI http://ajevonline.org/content/63/1/1.abstract
991 ## - OAI IDENTIFIER
OAI set code AJEV
OAI set name American Journal of Enology and Viticulture
100 0# - MAIN ENTRY--PERSONAL NAME
-- 11154
710 2# - ADDED ENTRY-CORPORATE NAME
-- 11155
856 42 - ELECTRONIC LOCATION & ACCESS
-- Link to original article.

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