Sulfide-binding to Cu(II) in wine: Impact on oxygen consumption rates

Nikolaos Kontoudakis; Andrew C Clark

doi:10.1016/j.foodchem.2020.126352

Sulfide-binding to Cu(II) in wine: Impact on oxygen consumption rates

Food Chem. 2020 Jun 30:316:126352. doi: 10.1016/j.foodchem.2020.126352. Epub 2020 Feb 3.

Authors

Nikolaos Kontoudakis¹, Andrew C Clark²

Affiliations

¹ National Wine and Grape Industry Centre, School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia. Electronic address: nickkont@yahoo.gr.
² National Wine and Grape Industry Centre, School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia. Electronic address: aclark@csu.edu.au.

PMID: 32062232
DOI: 10.1016/j.foodchem.2020.126352

Abstract

This study investigates the relationship between the two main forms of Cu in wine and their impact on the rate of oxygen consumption. The Cu forms were differentiated by medium exchange constant current stripping potentiometry, which classified the Cu as either bound to sulfide or not. Oxygen consumption rates were determined in red, white and model wines after saturation with oxygen. The results for white wines showed that the oxygen consumption was sensitive to the non-sulfide-bound Cu concentration when ascorbic acid was present, and the first order rates ranged from 0.02 to 0.11 h^-1. However, the same was not true for wines without added ascorbic acid that showed little influence of Cu form on oxygen decay rates. Cu forms were also found to significantly change in some wines during the oxygen decay experiment. Ascorbic acid is critical in enabling the form of Cu to significantly influence the oxygen reaction rate in wine.

Keywords: Ascorbic acid; Copper; Labile; Oxygen; Speciation; Stripping potentiometry; Sulfide.

MeSH terms

Copper / chemistry*
Molecular Structure
Oxygen / chemistry*
Potentiometry
Sulfides / chemistry*
Wine / analysis*

Substances

Sulfides
Copper
Oxygen