 IVES 9 IVES Conference Series 9 Alternative fate of varietal thiols in wine: identification, formation, and enantiomeric distribution of novel 1,3-oxathianes

Alternative fate of varietal thiols in wine: identification, formation, and enantiomeric distribution of novel 1,3-oxathianes

Abstract

AIM: This study aimed to explore an alternative fate of varietal thiols by identifying and characterising cis-2-methyl-4-propyl-1,3-oxathiane (cis-2-MPO) and cis-2,4,4,6-tetramethyl-1,3-oxathiane (cis-TTMO) in wine. Elucidating these new pathways could aid in explaining the loss of varietal thiols and would further our understanding of the stereochemical relationships between oxathianes and varietal thiols.

METHODS: GC-MS was used to identify cis-2-MPO,1 and a stable isotope dilution assay (SIDA) was developed to quantify its enantiomers after separation with a chiral β-cyclodextrin GC column.2 Varietal thiols and their enantiomers were analysed by SIDA with HPLC-MS/MS to determine their relationship with cis-2-MPO. Production of cis-2-MPO and its correlation with 3-SH, 3-SHA, and acetaldehyde was studied by profiling the evolution of these volatiles during alcoholic fermentation (AF) of Sauvignon blanc (SB) juice fermented with J7, VIN13, and their co-inoculum.3

RESULTS: cis-2-MPO, derived from 3-SH and acetaldehyde, was identified and then measured at up to 460 ng/L (equivalent to 385 ng/L of 3-SH) in a set of wines. Analysis of (2R,4S)-2-MPO and (2S,4R)-2-MPO, arising from thiol enantiomers (3S)-3-SH and (3R)-3-SH, showed respective concentrations of up to 250 and 303 ng/L. The enantiomeric ratio of (2R,4S)-/(2S,4R)-2-MPO was 43:57 whereas that of (3S)-/(3R)-3-SH in the same wines was 51:49.2 Strong correlations were revealed for both 3-SH and cis-2-MPO and their related enantiomeric pairs.The AF study showed cis-2-MPO was produced from an early stage of AF and reached a peak of 847 ng/L (VIN13 ferment) before gradually declining to 50-65 ng/L. Its evolution profile was identical to that of acetaldehyde and 3-SHA, with moderate to strong correlations found for the analytes.Additionally, cis-TTMO, derived from 4-MSPOH and acetaldehyde, was identified in wine as a single enantiomer at concentrations of up to 28 ng/L (equivalent to 23 ng/L of 4-MSPOH). An aroma detection threshold of 14.9 µg/L was determined for cis-TTMO, and this new volatile was described as ‘citrus’, ‘green’, ‘sweet/caramel’, and ‘mango’, shifting toward ‘onion/sweaty’ and ‘sulfurous’ at higher concentrations.2

CONCLUSIONS

The knowledge gained helps rationalise the fate of varietal thiols via the production of oxathianes in wine, and reveals the stereochemical links between these related compounds. A chemical formation pathway to oxathianes was verified and may also apply to other thiols bearing the 1,3-sulfanylalkanol substitution through the reaction with acetaldehyde.

DOI:

Publication date: September 13, 2021

Issue: Macrowine 2021

Type: Article

Authors

Xingchen Wang

Department of Wine Science and Waite Research Institute, The University of Adelaide (UA), PMB 1, Glen Osmond, SA 5064, Australia,Liang, CHEN, Université de Bordeaux, Unité de Recherche Œnologie, EA 4577, USC 1366 INRAE, Institut des Sciences de la Vigne et du Vin, 33882, Villenave d’Ornon cedex, France Dimitra L., CAPONE, Department of Wine Science and Waite Research Institute, Australian Research Council Training Centre for Innovative Wine Production, UA, PMB 1, Glen Osmond, SA 5064, Australia Aurélie, ROLAND, SPO, Univ Montpellier, INRAE, Institut Agro, Montpellier, France David W., JEFFERY, Department of Wine Science and Waite Research Institute, Australian Research Council Training Centre for Innovative Wine Production, UA, PMB 1, Glen Osmond, SA 5064, Australia

Contact the author

Keywords

3-sulfanylhexan-1-ol, 4-methyl-4-sulfanylpentan-2-ol, acetaldehyde, chiral stationary phase, odour detection threshold, sauvignon blanc, stable isotope dilution assay, gas chromatography–mass spectrometry

Citation

Risposte enologiche del Nero d’Avola su suoli a diverso grado di salinità

Vengono riportati i risultati enologici di uno studio condotto sul Nero d’Avola in un tipico ambiente viticolo siciliano, in cui insistono suoli che presentano un diverso grado di salinità.

The bottleneck/cork interface: A key parameter for wine aging in bottle

The shelf life of wine is a major concern for the wine industry. This is particularly true for wines intended for long cellaring, which are supposed to reach their peak after an ageing period ranging from a few months to several years, or even decades. Low, controlled oxygen inputs through the closure system are generally necessary for the wine to evolve towards its optimum organoleptic characteristics. Our previous studies have already shown that the interface between the cork and the bottleneck plays a crucial role in the transfer of oxygen into the bottled wine.

Optimization of a tool to determine the oxygen avidity of a wine through the kinetics of consumption by its phenolic and aromatic fractions (PAFs)

Wine oxidation phenomena during the different processes of winemaking, aging and storage are closely related to the presence of oxygen and to the wine’s capacity for consumption.

Vinhos de talha: to pitch or not to pitch

In Alentejo, south of Portugal there is a traditional way of fermenting wines in clay vessels, known as “Vinhos de Talha”. Clay vessels were traditionally impermeabilized using pine pitch, creating a barrier between the fermenting must and the clay. Due to this unusual production technology that uses of clay vessels, instead of inox or wood vessels, “Vinhos de Talha” present unique characteristics increasingly appreciated by national and international consumers when compared with wine obtained by the said traditional methods of winemaking. Although the positive consumers feedback, there is little literature about the physical-chemical characteristics of these wines (Martins et al, 2018; Cabrita et al, 2018). This work aims to characterize the volatile composition of white wines produced in clay vessels with different coatings and to contribute to the knowledge and preservation of these wines that are a unique cultural heritage. Wine samples were produced during 2019 vintage from white grapes, using the traditional technology associated to these wines.

Acumulación de materia seca, orientada a valorar la fijación de carbono, en función del aporte de riego y la pluviometría, en Cabernet-Sauvignon a lo largo de 15 años

The vineyard is capable of fixing carbon in its permanent structure from atmospheric carbon dioxide, through the process of gas exchange and the performance of photosynthesis. The photosynthetic capacity of the vineyard depends on the water resources that the plant may have at its disposal, so the amount of dry matter, derived from the processed photosynthates, that it can store will depend on the water regime of the crop, both in the annually renewable organs as in permanent parts.