Beyond the production of positive aromas during alcoholic fermentation, Saccharomyces cerevisiae metabolism also results in the formation of volatile compounds detrimental to wine quality, including a wide range of volatile sulfur compounds (VSCs). The formation of these VSCs during wine fermentation is strongly variable and depends on biological and environmental factors. First, the comparison of the VSCs profile of 22 S. cerevisiae strains provided a comprehensive overview of the intra-species diversity in VSCs production: according to their genetic background, strains synthetized from 1 to 6 different sulfur molecules, in a 1- to 30-fold concentration range. The impact of fermentation parameters on VSCs production was then investigated. We identified yeast assimilable nitrogen, cysteine, methionine and pantothenic acid contents – but not SO₂ content – as the main factors modulating VSCs production. In particular, ethylthioacetate and all the VSCs deriving from methionine catabolism displayed a maximal production at yeast assimilable nitrogen concentrations around 250 mg/L; pantothenic acid had a positive impact on compounds deriving from methionine catabolism through the Ehrlich pathway but a negative one on the production of thioesters. Overall, these results highlight those factors to be taken into account to modulate the formation of negative VSCs and limit their content in wines.

中文翻译：

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如何调节葡萄酒发酵过程中负挥发性硫化合物的形成？

除了在酒精发酵过程中产生积极的香气外，酿酒酵母的代谢还会导致对葡萄酒质量不利的挥发性化合物的形成，包括各种挥发性硫化合物 (VSC)。在葡萄酒发酵过程中这些 VSC 的形成变化很大，取决于生物和环境因素。一、22株酿酒酵母VSCs谱的比较菌株提供了 VSC 生产中种内多样性的全面概述：根据其遗传背景，菌株由 1 到 6 种不同的硫分子合成，浓度范围为 1 到 30 倍。然后研究了发酵参数对 VSC 生产的影响。我们确定了酵母可同化的氮、半胱氨酸、甲硫氨酸和泛酸含量——但未确定 SO ₂内容 – 作为调节 VSCs 生产的主要因素。特别是，硫代乙酸乙酯和所有源自甲硫氨酸分解代谢的 VSC 在酵母可同化氮浓度约为 250 mg/L 时表现出最大产量；泛酸对通过 Ehrlich 途径产生的蛋氨酸分解代谢产生的化合物产生积极影响，但对硫酯的产生产生负面影响。总体而言，这些结果强调了在调节负 VSC 的形成和限制其在葡萄酒中的含量时需要考虑的因素。