• New integral and 100% organic fermentation activator
    From Vason's Research and Development department comes X-PRO® Verve
    X-PRO® Verve: from specific redox-balancing inactive yeasts to the development of the new organic nutrient for varietal protection, an indispensable contribution to fermentation well-being
    Published on: 05/14/2021

Oxidation mechanisms occurring in wines.

Oliveira, C. M.; Silva Ferreira, A. C.; Freitas, V. de; Silva, A. M. S. ; 2011 , Food Research International 44 (5) 1115–1126

The present review aims to show the state of the art on the oxidation mechanisms occurring in wines, as well as the methods to monitor, classify and diagnose wine oxidation. Wine oxidation can be divided in enzymatic oxidation and non-enzymatic oxidation. Enzymatic oxidation almost entirely occurs in grape must and is largely correlated with the content of hydroxycinnamates, such as caffeoyltartaric acid and para-coumaroyltartaric acid, and flavan-3-ols. Non-enzymatic oxidation, also called chemical oxidation of wine, prevails in fermented wine and begin by the oxidation of polyphenols containing a catechol or a galloyl group. These phenolic reactions, both enzymatic and non-enzymatic, result in by-products named quinones. However, in non-enzymatic oxidation, oxygen does not react directly with phenolic compounds. The limitation on the reactivity of triplet oxygen is overcome by the stepwise addition of a single electron, which can be provided by reduced transition metal ions, essentially iron(II) and copper(I). The sequential electron transfer leads to the formation of hydroperoxide radical (HOO*), hydrogen peroxide (H2O2), and hydroxyl radical (HO*). The later radical will oxidize almost any organic molecule found in wine and will react with the first species it encounters, depending on their concentration. Sulfur dioxide (SO2) and ascorbic acid, when added to wine, are able to reduce the quinones. Alternative options have been assessed for the prevention of oxidation during wine storage; nevertheless, these are not fully understood or commonly accepted. During aging, aldehydes are important intermediates in the chemical transformations occurring in wines, leading to color and flavor changes. In the same way, a range of off-flavors can be formed from wine oxidation. At low concentrations these flavors may add to the complexity of a wine, but as these increase they begin to detract from wine quality. In addition to the major chemical browning involving wine phenols, the main oxidation reactions occurring during grape juice heating or storage are caramelization and Maillard reaction, which are temperature dependent. Different methods have been proposed in the literature, addressing the complexity and multi-scale related with the oxidation process, to attempt the quantification of antioxidant activity in wines. These methods can be broadly divided in: (i) methods based on chemical reactions and (ii) methods based on the chemical-physical properties of antioxidants. (We recommend that you consult the full text of this article)
Published on 09/26/2012
Related sheets
© All Right Reserved
ISSN 1826-1590 VAT: IT01286830334
powered by Infonet Srl Piacenza
Privacy Policy
This website and its related third-party services make use of cookies necessary for the purposes described in the cookie policy. If you want to learn more about cookies or how to disable them (either totally or partially), please see the cookie policy. By closing this banner, scrolling through this page, clicking on a link or continuing navigation in any other way, you consent to the use of cookies.
More informationOK

- A +
ExecTime : 1,671875