Reduction of Bitterness and Astringency of Wine Tannins by Glycoproteins

虽然葡萄酒可溶性蛋白质来源于果汁、种子皮和酵母，但其中大部分来源于果汁（约占总蛋白质含量的90%）。所有的可溶性蛋白质都是糖蛋白。我们的实验和商业白色和红葡萄酒含有29.8至107.1 mg/L的可溶性蛋白质，和非常稳定的可溶性蛋白质（13.6至36.4 mg/L）检测后，严格的澄清和精炼的葡萄酒。通过硫酸铵沉淀和SephadexG-100柱层析从赛美蓉葡萄酒中分离得到糖蛋白。用50%乙醇水溶液提取赛美蓉种子中的总酚，通过硅藻土分配色谱分离得到4种酚组分（儿茶素、二聚酚、低聚单宁和聚合单宁）。糖蛋白、儿茶素和二聚酚在20 ℃下在葡萄酒样模型溶液（pH 3.0的10%乙醇水溶液）中储存48小时期间没有变化。然而，低聚和聚合单宁，以及总酚，引起了可观的浊度。添加的蛋白质可能的感官效果进行了研究，通过配对比较纯化合物（儿茶素和二聚体酚）与相同的化合物与蛋白质混合。据推测，蛋白质将通过降低儿茶素和二聚体酚与受体相互作用的可用性来降低儿茶素和二聚体酚的味道。当使用低浓度的酚类和蛋白质时，结果证实了这一假设。然而，在高浓度下观察到相反的趋势。据推测，高浓度的蛋白质通过添加它们自己的味道来增加总的味道强度。

Although wine soluble proteins originate in juice, seed skin and yeast, most of them originate in juice (approximately 90% of the total protein content). All the soluble proteins are glycoproteins. Our experimental and commercial white and red wines contained 29.8 to 107.1 mg/L soluble proteins, and very stable soluble proteins (13.6 to 36.4 mg/L) were detected in the wines after severe clarification and fining. Polysaccharides or polymeric tannins interacted with the proteins to form complexes or similar entities, thereby stabilizing the soluble proteins in the wines.Glycoproteins were isolated from Semillon wine by ammonium sulfate precipitation and Sephadex G-100 chromatography. Total phenols in Semillon seeds were subjected to extraction with 50% aqueous ethanol, and four seed phenol fractions (catechin, dimeric phenols, and oligomeric and polymeric tannins) were obtained by diatomaceous earth partition chromatography of the total phenols. The glycoproteins, catechin, and dimeric phenols appeared unchanged during storage in a wine-like model solution (aqueous 10% ethanol solution of pH 3.0) at 20oC for 48 hours. However, the oligomeric and polymeric tannins, as well as the total phenols, gave rise to appreciable turbidity. The possible sensory effects of the added proteins were investigated by paired comparisons of pure compounds (catechin and dimer phenols) with the same compounds mixed with proteins. It was hypothesized that proteins would decrease the taste of the catechin and the dimer phenols by decreasing their availability to interact with the receptors. The results corroborated the hypothesis when low concentrations of phenols and proteins were used. However, a reverse trend was observed at high concentrations. It was hypothesized that the high concentration of proteins increased the total taste intensity by adding their own taste.