Department of Agronomy Food Natural Resources Animals and Environment, Centro Interdipartimentale per la Ricerca in Viticoltura ed Enologia (CIRVE), University of Padua, via dell'Università 16, 35020 Legnaro (PD), Italy.
J Agric Food Chem. 2012 Oct 24;60(42):10666-73. doi: 10.1021/jf302916n. Epub 2012 Oct 11.
Residual proteins in finished wines can aggregate to form haze. To obtain insights into the mechanism of protein haze formation, a reconstitution approach was used to study the heat-induced aggregation behavior of purified wine proteins. A chitinase, four thaumatin-like protein (TLP) isoforms, phenolics, and polysaccharides were isolated from a Chardonnay wine. The same wine was stripped of these compounds and used as a base to reconstitute each of the proteins alone or in combination with the isolated phenolics and/or polysaccharides. After a heating and cooling cycle (70 °C for 1 h and 25 °C for 15 h), the size and concentration of the aggregates formed were measured by scanning ion occlusion sensing (SIOS), a technique to detect and quantify nanoparticles. The chitinase was the protein most prone to aggregate and the one that formed the largest particles; phenolics and polysaccharides did not have a significant impact on its aggregation behavior. TLP isoforms varied in susceptibility to haze formation and in interactions with polysaccharides and phenolics. The work establishes SIOS as a useful method for studying wine haze.
残留在成品酒中的蛋白质会聚集形成浑浊。为了深入了解蛋白质浑浊形成的机制，采用重组方法研究了纯化葡萄酒蛋白质的热诱导聚集行为。从霞多丽葡萄酒中分离出一种几丁质酶和四种类硫素蛋白（TLP）同工型、酚类物质和多糖。用同样的葡萄酒去除这些化合物，然后分别用其重组每种蛋白质，或者与分离出的酚类物质和/或多糖一起重组。经过加热和冷却循环（70°C 加热 1 小时，25°C 冷却 15 小时）后，采用扫描离子封闭感应（SIOS）技术测量形成的聚集体的大小和浓度，该技术可用于检测和定量纳米颗粒。几丁质酶是最容易聚集且形成最大颗粒的蛋白质；酚类物质和多糖对其聚集行为没有显著影响。TLP 同工型在形成浑浊的易感性和与多糖及酚类物质的相互作用方面存在差异。该研究确立了 SIOS 是一种研究葡萄酒浑浊的有用方法。
