McRae Jacqui M, Ziora Zyta M, Kassara Stella, Cooper Matthew A, Smith Paul A
†The Australian Wine Research Institute, P.O. Box 197, Glen Osmond, South Australia 5064, Australia.
§Institute for Molecular Bioscience, University of Queensland, 306 Carmody Road, St. Lucia, Queensland 4072, Australia.
J Agric Food Chem. 2015 May 6;63(17):4345-52. doi: 10.1021/acs.jafc.5b00758. Epub 2015 Apr 22.
Changes in ethanol concentration influence red wine astringency, and yet the effect of ethanol on wine tannin-salivary protein interactions is not well understood. Isothermal titration calorimetry (ITC) was used to measure the binding strength between the model salivary protein, poly(L-proline) (PLP) and a range of wine tannins (tannin fractions from a 3- and a 7-year old Cabernet Sauvignon wine) across different ethanol concentrations (5, 10, 15, and 40% v/v). Tannin-PLP interactions were stronger at 5% ethanol than at 40% ethanol. The mechanism of interaction changed for most tannin samples across the wine-like ethanol range (10-15%) from a combination of hydrophobic and hydrogen binding at 10% ethanol to only hydrogen binding at 15% ethanol. These results indicate that ethanol concentration can influence the mechanisms of wine tannin-protein interactions and that the previously reported decrease in wine astringency with increasing alcohol may, in part, relate to a decrease tannin-protein interaction strength.
乙醇浓度的变化会影响红葡萄酒的涩味，然而乙醇对葡萄酒中单宁与唾液蛋白相互作用的影响尚未得到充分理解。采用等温滴定量热法（ITC）来测量模型唾液蛋白聚（L-脯氨酸）（PLP）与一系列葡萄酒单宁（来自3年和7年陈酿赤霞珠葡萄酒的单宁组分）在不同乙醇浓度（5%、10%、15%和40% v/v）下的结合强度。单宁与PLP的相互作用在5%乙醇时比在40%乙醇时更强。对于大多数单宁样品，在类似葡萄酒的乙醇浓度范围（10 - 15%）内，相互作用机制发生了变化，从10%乙醇时疏水结合和氢键结合的组合变为15%乙醇时仅氢键结合。这些结果表明，乙醇浓度会影响葡萄酒中单宁与蛋白质的相互作用机制，并且先前报道的随着酒精含量增加葡萄酒涩味降低的现象，可能部分与单宁 - 蛋白质相互作用强度的降低有关。
