LAQV-REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
LAQV-REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
Food Res Int. 2021 May;143:110261. doi: 10.1016/j.foodres.2021.110261. Epub 2021 Mar 5.
Phenolic compounds are partially removed during fining, which may influence the organoleptic properties of beverages. Among phenolic compounds, tannins have been widely associated to the taste of beverages (namely astringency and bitterness). Furthermore, phenolic acids and anthocyanins may also influence bitterness and the latter are also responsible for beverages' color. Thus, it is necessary to perform molecular studies to better understand the effect of fining agents in the overall phenolic composition of beverages and the resulting organoleptic changes. The molecular interactions between these three classes of phenolic compounds and a yeast protein extract (YPE), designed as a new fining agent, was studied. The binding affinities were assessed by fluorescence quenching at two temperatures (21 °C and 37 °C) and in two reaction media (water and wine model solution). The size of aggregates formed was characterized by Dynamic Light Scattering and the selectivity of protein interaction was analyzed by electrophoresis. Overall, pentagalloylglucoside (tannin) showed the highest binding affinity for YPE, followed by malvidin 3-glucoside (anthocyanin), p-coumaric acid (phenolic acid) and gallic acid (phenolic acid). The studied temperatures and solvents affected the interaction affinities as well as the aggregates' size. Binding selectivity of proteins from YPE was not found. These results open new perspectives to control the fining process by using the YPE as a fining agent taking into account the further effect in the organoleptic properties of beverages.
酚类化合物在澄清过程中会部分去除，这可能会影响饮料的感官特性。在酚类化合物中，单宁与饮料的味道（即涩味和苦味）广泛相关。此外，酚酸和花青素也可能影响苦味，而后者也负责饮料的颜色。因此，有必要进行分子研究，以更好地了解澄清剂对饮料整体酚类成分的影响以及由此产生的感官变化。研究了这三类酚类化合物与酵母蛋白提取物（YPE）之间的分子相互作用，YPE 被设计为一种新型澄清剂。在两个温度（21°C 和 37°C）和两个反应介质（水和葡萄酒模型溶液）下通过荧光猝灭评估结合亲和力。通过动态光散射表征形成的聚集体的大小，并通过电泳分析蛋白质相互作用的选择性。总的来说，五没食子酰葡萄糖（单宁）对 YPE 的结合亲和力最高，其次是矢车菊素 3-葡萄糖苷（花青素）、对香豆酸（酚酸）和没食子酸（酚酸）。研究的温度和溶剂会影响相互作用亲和力以及聚集体的大小。未发现 YPE 中蛋白质的结合选择性。这些结果为通过使用 YPE 作为澄清剂来控制澄清过程提供了新的视角，同时考虑到对饮料感官特性的进一步影响。
