exhibits extraordinary positive oenological characteristics contributing to the aroma and texture of wines, especially by its ability to produce great concentrations of benzenoid and phenylpropanoid compounds compared with conventional yeasts. Consequently, in practice, sequential inoculation of and allows to improve the aromatic quality of wines. In this work, we evaluated the impact on wine aroma produced by increasing the concentration of phenylalanine, the main amino acid precursor of phenylpropanoids and benzenoids. Fermentations were carried out using a Chardonnay grape juice containing 150 mg N/L yeast assimilable nitrogen. Fermentations were performed adding 60 mg/L of phenylalanine without any supplementary addition to the juice. Musts were inoculated sequentially using three different strains isolated from Uruguayan vineyards and, after 96 h, was inoculated to complete the process. At the end of the fermentation, wine aromas were analysed by both gas chromatography–mass spectrometry and sensory evaluation through a panel of experts. Aromas derived from aromatic amino acids were differentially produced depending on the treatments. Sensory analysis revealed more floral character and greater aromatic complexity when compared with control fermentations without phenylalanine added. Moreover, fermentations performed in synthetic must with pure revealed that even tyrosine can be used in absence of phenylalanine, and phenylalanine is not used by this yeast for the synthesis of tyrosine derivatives.

中文翻译：

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苯丙氨酸对葡萄酒发酵过程中葡萄汉逊酵母香气代谢的影响

表现出非凡的积极酿酒学特征，有助于葡萄酒的香气和质地，特别是与传统酵母相比，它能够产生高浓度的苯环和苯丙烷化合物。因此，在实践中，顺序接种可以提高葡萄酒的芳香质量。在这项工作中，我们评估了增加苯丙氨酸浓度对葡萄酒香气的影响，苯丙氨酸是苯丙素和苯类化合物的主要氨基酸前体。使用含有 150 mg N/L 酵母可同化氮的霞多丽葡萄汁进行发酵。添加 60 mg/L 苯丙氨酸进行发酵，无需向果汁中添加任何补充。使用从乌拉圭葡萄园分离出的三种不同菌株依次接种葡萄汁，并在 96 小时后接种以完成该过程。发酵结束时，专家小组通过气相色谱-质谱法和感官评估对葡萄酒香气进行分析。根据处理的不同，源自芳香族氨基酸的香气产生差异。与未添加苯丙氨酸的对照发酵相比，感官分析显示出更多的花香特征和更高的芳香复杂性。此外，在纯合成葡萄汁中进行的发酵表明，即使在没有苯丙氨酸的情况下也可以使用酪氨酸，并且该酵母不使用苯丙氨酸来合成酪氨酸衍生物。