Dipartimento di Biotecnologie agrarie and Centro Interdipartimentale per la Ricerca in Viticoltura ed Enologia (C.I.R.V.E.) Università di Padova, via dell'Università 16, 35020 Legnaro (PD), Italy.
Anal Chim Acta. 2010 Feb 15;660(1-2):110-8. doi: 10.1016/j.aca.2009.10.038. Epub 2009 Oct 27.
During the storage, bottled white wines can manifest haziness due to the insolubilisation of the grape proteins that may 'survive' in the fermentation process. Although the exact mechanism of this occurrence is not fully understood, proteins and tannins are considered two of the key factors involved in wine hazing, since their aggregation leads to the formation of insoluble particles. To better understand this complex interaction, proteins and tannins from the same unfined Pinot grigio wine were separated. Wine proteins were then fractionated by hydrophobic interaction chromatography (HIC). A significant correlation between hydrophobicity of the wine protein fractions and the haze formed after reacting with wine tannins was found, with the most reactive fractions revealing (by SDS-PAGE and RP-HPLC analyses) the predominant presence of thaumatin-like proteins. Moreover, the effects of both protein heating and disulfide bonds reduction (with dithiotreithol) on haze formation in the presence of tannins were assessed. These treatments generally resulted in an improved reactivity with tannins, and this phenomenon was related to both the surface hydrophobicity and composition of the protein fractions. Therefore, haze formation in wines seems to be related to hydrophobic interactions occurring among proteins and tannins. These interactions should occur on hydrophobic tannin-binding sites, whose exposition on the proteins can depend on both protein heating and reduction.
在储存过程中，装瓶的白葡萄酒可能会因为在发酵过程中“存活”下来的葡萄蛋白质的不溶性而变得浑浊。虽然这种情况的确切机制尚未完全了解，但蛋白质和单宁被认为是导致葡萄酒浑浊的两个关键因素，因为它们的聚集导致了不溶性颗粒的形成。为了更好地理解这种复杂的相互作用，从同一种未经澄清的灰皮诺干白葡萄酒中分离出蛋白质和单宁。然后通过疏水相互作用色谱（HIC）对葡萄酒蛋白质进行分级。发现葡萄酒蛋白质分级的疏水性与与葡萄酒单宁反应后形成的浑浊度之间存在显著相关性，最具反应性的分级通过 SDS-PAGE 和 RP-HPLC 分析显示出 thaumatin 样蛋白的主要存在。此外，还评估了蛋白质加热和二硫键还原（使用二硫苏糖醇）对单宁存在下形成浑浊的影响。这些处理通常会导致与单宁的反应性提高，这种现象与蛋白质分级的表面疏水性和组成有关。因此，葡萄酒中的浑浊似乎与蛋白质和单宁之间发生的疏水相互作用有关。这些相互作用应该发生在疏水单宁结合位点上，这些位点的暴露取决于蛋白质的加热和还原。
