The varietal thiols 3-mercaptohexan-1-ol (3MH), 3-mercaptohexyl acetate (3MHA), and 4-mercapto-4-methylpentan-2-one (4MMP) are key aroma compounds in wine due to the tropical notes they impart. They are released by yeast during alcoholic fermentation from different precursors. However, a large part of 3MH origin remains unknown. In this study, we focused on dipeptide forms arising from glutathione S-conjugates to 3MH and 4MMP. Using labelled tracers, we showed in spiked must the release of varietal thiols from 4 different compounds. We highlighted the interconversion between different forms of precursors under defined enological conditions. Cysteinyl-glycine S-conjugates are partially degraded into cysteine S-conjugates, contrary to γ-glutamyl-cysteine S-conjugates. Glutathione S-conjugate to 3MH can be partially degraded to γ-glutamyl-cysteine S-conjugate to 3MH. For the first time, all these labeled forms of precursors were found to release 3MH or 4MMP between 0.17 and 1% molar conversion yield. Two different yeasts were compared without any significant difference.

硫醇3-巯基己-1-醇（3MH），乙酸3-巯基己酯（3MHA）和4-巯基-4-甲基戊烷-2-酮（4MMP）是葡萄酒中的关键香气化合物，因为它们具有热带气息。 。它们在酒精发酵过程中由酵母从不同的前体中释放出来。但是，3MH起源的很大一部分仍是未知的。在这项研究中，我们集中于谷胱甘肽S -3MH和4MMP共轭物产生的二肽形式。使用标记的示踪剂，我们证明了必须从4种不同的化合物中释放出各种巯基硫醇。我们着重说明了在定义的酶学条件下不同形式的前体之间的相互转化。与γ-谷氨酰-半胱氨酸相反，半胱氨酸-甘氨酸S-缀合物被部分降解为半胱氨酸S-缀合物S-共轭物。与3MH结合的谷胱甘肽S-结合物可以部分降解为与3MH结合的γ-谷氨酰-半胱氨酸S-结合物。首次发现所有这些标记形式的前体均在0.17％至1％的摩尔转化率之间释放3MH或4MMP。比较了两种不同的酵母，没有任何显着差异。