title: The impact of aging wine in high and low oxygen conditions on the fractionation of Cu and Fe in Chardonnay wine.
abstract: Solid-phase extraction has previously been used to fractionate copper and iron into hydrophobic, cationic and residual forms. This study showed the change in fractionated copper and iron in Chardonnay wines with 1-year of bottle aging under variable oxygen and protein concentrations. Wines containing protein in low oxygen conditions induced a decrease (20-50%) in total copper and increased the proportion of the hydrophobic copper fraction, associated with copper(I) sulfide. In contrast, protein stabilised wines showed a lower proportion of the hydrophobic copper fraction after 1-year of aging. In oxidative storage conditions, the total iron decreased by 60% when at high concentration, and the concentration of the residual fraction of both copper and iron increased. The results show that oxidative storage increases the most oxidative catalytic form of the metal, whilst changes during reductive storage depend on the extent of protein stabilisation of the wine.
authors.affiliation: National Wine and Grape Industry Centre, Mambarra Drive, Wagga Wagga, NSW 2678, Australia; School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia. Electronic address: nkodoudakis@csu.edu.au.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Kontoudakis
authors.affiliation: National Wine and Grape Industry Centre, Mambarra Drive, Wagga Wagga, NSW 2678, Australia; College of Enology, Northwest A&F University, Yangling, Shaanxi 712100, China. Electronic address: guoanque@nwsuaf.edu.cn.
authors.forename: Anque
authors.initials: A
authors.lastname: Guo
authors.affiliation: National Wine and Grape Industry Centre, Mambarra Drive, Wagga Wagga, NSW 2678, Australia; School of Chemistry, The University of Melbourne, Vic. 3010, Australia. Electronic address: scollary@unimelb.edu.au.
authors.forename: Geoffrey R
authors.initials: GR
authors.lastname: Scollary
authors.affiliation: National Wine and Grape Industry Centre, Mambarra Drive, Wagga Wagga, NSW 2678, Australia; School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia. Electronic address: aclark@csu.edu.au.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Clark
mesh_terms: D005591:Chemical Fractionation; D003300:Copper / Q000737:chemistry*; D007501:Iron / Q000032:analysis / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods*; D014920:Wine / Q000032:analysis*
chemical_list: D003300:Copper; D007501:Iron; D010100:Oxygen
keywords: Aging; Bentonite; Copper; Fractionation; Iron; Oxidation; Protein; Wine