<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Nikolantonaki, M.a</style></author><author><style face="normal" font="default" size="100%">Magiatis, P.b</style></author><author><style face="normal" font="default" size="100%">Waterhouse, A.L.a</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Measuring protection of aromatic wine thiols from oxidation by competitive reactions vs wine preservatives with ortho-quinones</style></title><secondary-title><style face="normal" font="default" size="100%">Food Chemistry</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Addition reactions</style></keyword><keyword><style  face="normal" font="default" size="100%">Antioxidant effect</style></keyword><keyword><style  face="normal" font="default" size="100%">Antioxidants</style></keyword><keyword><style  face="normal" font="default" size="100%">article</style></keyword><keyword><style  face="normal" font="default" size="100%">Ascorbic acid</style></keyword><keyword><style  face="normal" font="default" size="100%">carbon nuclear magnetic resonance</style></keyword><keyword><style  face="normal" font="default" size="100%">Chemical compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Competitive reactions</style></keyword><keyword><style  face="normal" font="default" size="100%">controlled study</style></keyword><keyword><style  face="normal" font="default" size="100%">electrophilicity</style></keyword><keyword><style  face="normal" font="default" size="100%">electrospray mass spectrometry</style></keyword><keyword><style  face="normal" font="default" size="100%">food preservative</style></keyword><keyword><style  face="normal" font="default" size="100%">glutathione</style></keyword><keyword><style  face="normal" font="default" size="100%">Glutathiones</style></keyword><keyword><style  face="normal" font="default" size="100%">heteronuclear multiple bond correlation</style></keyword><keyword><style  face="normal" font="default" size="100%">limit of quantitation</style></keyword><keyword><style  face="normal" font="default" size="100%">Nuclear magnetic resonance spectroscopy</style></keyword><keyword><style  face="normal" font="default" size="100%">Nucleophiles</style></keyword><keyword><style  face="normal" font="default" size="100%">Nucleophilic additions</style></keyword><keyword><style  face="normal" font="default" size="100%">nucleophilicity</style></keyword><keyword><style  face="normal" font="default" size="100%">oxidation</style></keyword><keyword><style  face="normal" font="default" size="100%">oxidation reduction reaction</style></keyword><keyword><style  face="normal" font="default" size="100%">Peptides</style></keyword><keyword><style  face="normal" font="default" size="100%">phloroglucinol</style></keyword><keyword><style  face="normal" font="default" size="100%">Protective action</style></keyword><keyword><style  face="normal" font="default" size="100%">proton nuclear magnetic resonance</style></keyword><keyword><style  face="normal" font="default" size="100%">quinone derivative</style></keyword><keyword><style  face="normal" font="default" size="100%">Quinones</style></keyword><keyword><style  face="normal" font="default" size="100%">Reaction intermediates</style></keyword><keyword><style  face="normal" font="default" size="100%">Reactivity (nuclear)</style></keyword><keyword><style  face="normal" font="default" size="100%">Redox reactions</style></keyword><keyword><style  face="normal" font="default" size="100%">reversed phase liquid chromatography</style></keyword><keyword><style  face="normal" font="default" size="100%">Secondary product</style></keyword><keyword><style  face="normal" font="default" size="100%">Sulfur determination</style></keyword><keyword><style  face="normal" font="default" size="100%">Sulfur dioxide</style></keyword><keyword><style  face="normal" font="default" size="100%">synthesis</style></keyword><keyword><style  face="normal" font="default" size="100%">tannin</style></keyword><keyword><style  face="normal" font="default" size="100%">thiol derivative</style></keyword><keyword><style  face="normal" font="default" size="100%">Two-electron reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Wine</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2014</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.scopus.com/inward/record.url?eid=2-s2.0-84900821255&amp;partnerID=40&amp;md5=4f172cd0a910a2f4b9d644b9763d15b0</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">Elsevier Ltd</style></publisher><volume><style face="normal" font="default" size="100%">163</style></volume><pages><style face="normal" font="default" size="100%">61-67</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Quinones are central intermediates in wine oxidation that can degrade the quality of wine by reactions with varietal thiols, such as 3-sulfanylhexanol, decreasing desirable aroma. Protection by wine preservatives (sulphur dioxide, glutathione, ascorbic acid and model tannin, phloroglucinol) was assessed by competitive sacrificial reactions with 4-methyl-1,2-benzoquinone, quantifying products and ratios by HPLC-UV-MS. Regioselectivity was assessed by product isolation and identification by NMR spectroscopy. Nucleophilic addition reactions compete with two electron reduction of quinones by sulphur dioxide or ascorbic acid, and both routes serve as effective quenching pathways, but minor secondary products from coupled redox reactions between the products and reactants are also observed. The wine preservatives were all highly reactive and thus all very protective against 3-sulfanylhexanol loss to the quinone, but showed only additive antioxidant effects. Confirmation of these reaction rates and pathways in wine is needed to assess the actual protective action of each tested preservative. © 2014 Elsevier Ltd. All rights reserved.</style></abstract><notes><style face="normal" font="default" size="100%">cited By (since 1996)0</style></notes></record></records></xml>