Modulation of Volatile Thiol Release during Fermentation of Red Musts by Wine Yeast

Abstract

During the alcoholic fermentation of grape sugars, wine yeast produces a range of secondary metabolites that play a critical role in the aroma profile of wines. One of the most impactful yeast-modified compound families, particularly in white wines, are the ‘fruity’ polyfunctional thiols, which include 3-mercaptohexan-1-ol (3-MH) and 4-mercapto-4-methylpentan-2-one (4-MMP). While the formation and stylistic contribution of these thiols have been extensively researched in white wines, little is known about the conditions leading to their formation in red wines. In this study, we explored the ability of yeast strains to modulate the release of these aroma compounds during the fermentation of two red musts. In laboratory-scale Pinot Noir fermentations, the formation of 3-MH strongly correlated with yeast β-lyase activity, particularly with the presence of certain genotypes of the flavour-releasing gene IRC7. Subsequent production of Grenache wine at the pilot scale, with detailed compositional and sensory analysis, was undertaken to confirm laboratory-scale observations. A commercial wine strain used for expressing ‘fruity’ thiols in Sauvignon Blanc was shown to produce wines that exhibited more intense red fruit aromas. These results reveal an opportunity for winemakers to shape red wine aroma and flavour by using yeasts that might typically be considered for white wine production.

Unravelling copper effect on the production of varietal thiols during Colombard and Gros Manseng grape juices fermentation by Saccharomyces cerevisiae

“…The consumption of precursors across all the conditions was in average 55 and 65% for Colombard and Gros Manseng, respectively. These values are lower than the majority of those observed in red grape must of Pinot noir with precursors consumption (G3SH + Cys3SH + CysGly3SH) ranging from 4 to 99.5% with an average of 76% for the 11 AWRI yeast strains studied (Cordente et al, 2022) with an initial content of 1,176, 129.7 and 24.9 μg/l for G3SH, Cys3SH and CysGly3SH, respectively. In Merlot juices with an initial precursor content between 2028 and 9,855 μg/l, consumption ranged from 13 to 47% if considering only Cys3SH and G3SH (Concejero et al, 2016).…”

“…Considering the difference observed for precursors consumption, conversion yield for total aroma (reduced + oxidized) and all precursors were in average, respectively, 3.282 ± 0.001, 3.013 ± 0.001, 3.123 ± 0.001, 3.184 ± 0.001% for ‘Control’, ‘Cu1’, ‘Cu2’, ‘Cu3’ modalities for Colombard. These figures are in the upper range of those encountered in natural conditions, i.e., from 0.08 to 4.4% ( Roland et al, 2011b ; Bonnaffoux et al, 2018 ; Cordente et al, 2022 ), even if to date comparisons with other research works remain difficult as calculation methods for conversion yield are not always identical. Based on the results presented here, copper could not be correlated with thiol conversion yield during fermentation from a yeast metabolism point of view.…”

Influence of amino acids, and their interaction with volatiles and polyphenols, on the sensory properties of red wine

“…Oak‐derived aroma compound were quantified according to Pollnitz et al (2004), except all compounds were analysed by liquid–liquid extraction‐GC/MS using an Agilent 6890 GC, coupled to an Agilent 5973 MS and equipped with a Gerstel MPS2. Volatile sulfur compounds were analysed according to Siebert et al (2010) and Cordente et al (2022) utilising static HS‐GC/SCD on an Agilent 7890B GC, coupled to an Agilent 8355 SCD and equipped with a Gerstel MPS2 XL (Lasersan). Polyfunctional thiols were analysed by HPLC/MS/MS after derivatisation and SPE as described by Capone et al (2015) and Cordente et al (2022) using an Exion UHPLC coupled to a 6500 QTrap+ (Sciex, Mulgrave, Vic., Australia).…”

“…Volatile sulfur compounds were analysed according to Siebert et al (2010) and Cordente et al (2022) utilising static HS‐GC/SCD on an Agilent 7890B GC, coupled to an Agilent 8355 SCD and equipped with a Gerstel MPS2 XL (Lasersan). Polyfunctional thiols were analysed by HPLC/MS/MS after derivatisation and SPE as described by Capone et al (2015) and Cordente et al (2022) using an Exion UHPLC coupled to a 6500 QTrap+ (Sciex, Mulgrave, Vic., Australia).…”

The Role of Potent Thiols in “Empyreumatic” Flint/Struck-Match/Mineral Odours in Chardonnay Wine

“…Te set of 71 survey wines, including the subset of 24 wines were analysed for polyfunctional thiols (including PMT and 2FMT) by HPLC/MS/MS after derivatisation with 4,4′-dithiodipyridine (Acros Termo Fisher Scientifc, Tebarton, SA, Australia) and SPE as described by Capone et al [31] and Cordente et al [32] using an Exion UHPLC coupled to a 6500 QTrap+ (Sciex, Mulgrave, Vic., Australia).…”