Macrowine 2021
IVES 9 IVES Conference Series 9 First quantification of glut-3SH-SO3 and glut-3SH-al in juice and wine

First quantification of glut-3SH-SO3 and glut-3SH-al in juice and wine

Abstract

3-Sulfanylhexan-1-ol (3SH) is a key impact odorant of white wines such as Sauvignon Blanc.[1] In particular, the varietal characters of Sauvignon Blanc, especially from Marlborough New Zealand, are strongly influenced by the concentrations of 3SH.[2,3] Although only trace levels of 3SH are needed to impart perceptible aroma characters of passionfruit and grapefruit, the biogenesis of this compound during fermentation is not yet fully understood.[1,4] The polyfunctional varietal thiols can be produced during fermentation by metabolism of non-volatile precursors such as glutathione and cysteine conjugates of 3SH, however the routes by which these precursors are metabolised are complex, and not fully elucidated.[4]

One precursor of particular interest is the glutathione conjugate to the aldehyde form of 3SH, 3S-glutathionylhexanal (glut-3SH-al). The presence of the aldehyde functional group drastically changes the reactivity of the precursor in wine-like systems. Recent work by this group has shown that this compound can exist as tautomers in solution, suggesting possible new reaction pathways for the metabolism of glut-3SH-al. Additionally, the bisulfite adduct of glut-3SH-al (glut-3SH-SO3) has been identified in wine samples.[5,6] The interconversion of glut-3SH-al and glut-3SH-SO3 is of great interest as this equilibrium will be influenced by the concentrations of both glut-3SH-al and free SO2 in the sample. As such, it is thought that glut-3SH-SO3 may exist in finished wines as a potential reservoir for the release of 3SH which could extend the life of the fruity characters which are so desirable in young white wines.[6]

A method for the extraction and quantification of glut-3SH-al and glut-3SH-SO3 has been developed, using previously synthesised deuterated analogues of these compounds to ensure reliable quantification.[7] The compounds are separated using solid phase extraction (SPE), followed by oxime derivatisation and MRM analysis on an LC-QqQ. This method has been validated using standard addition of synthetic glut-3SH-al and was found to be linear up to 1000 ppb.

Using this method, we have analysed the glut-3SH-al and glut-3SH-SO3 content of laboratory scale synthetic grape media samples before, during, and after fermentation, as well as a selection of commercial wines and grape juices. With the SPE and LC-QqQ analysis described here, the glut-3SH-al and glut-3SH-SO3 content of a wide range of grape derived samples can be measured, a valuable piece of the puzzle in elucidating 3SH biogenesis.

DOI:

Publication date: September 7, 2021

Issue: Macrowine 2021

Type: Article

Authors

Jennifer Muhl

School of Chemical Sciences, The University of Auckland,Lisa PILKINGTON, School of Chemical Sciences, The University of Auckland  Bruno FEDRIZZI, School of Chemical Sciences, The University of Auckland  Rebecca DEED, School of Chemical Sciences, School of Biological Sciences, The University of Auckland

Contact the author

Keywords

3-sulfanylhexan-1-ol, Aroma Precursors, Analytical Method, Isotopic Labelling, LC-MS/MS

Citation

Related articles…

Effect of vineyard management strategy on the nutritional status of irrigated « Tempranillo » vineyards grown in semi-arid areas

The combination of cover crops with regulated deficit irrigation has been lately shown to be a good method to improve harvest quality in irrigated vineyards of Southern Europe with semiarid climate, as an alternative to the conventional management, that consists on mechanical tillage and irrigation from fruitset to veraison and from then on reduced, or even ended.

Spatio-temporal analysis of grapevine water behaviour in hillslope vineyards. the example of corton hill, Burgundy

Hillslope vineyards show various and complex water dynamics between soil and plants, and in order to gain further insight into this phenomenon, 8 grapevine plots were monitored during three vintages, from 2010 to 2013, on Corton Hill, Burgundy, France.

The role of soil water holding capacity and plant water relations in zone/terroir expression

The spatial variability in soil type and depth and water holding capacity is very high in many viticultural regions of the world. Differences in rooting depths and water extraction profiles and their seasonal dynamics add additional variability and it is extremely difficult to deduct direct causal relationships between these factors and fruit

INFLUENCE OF WINEMAKING VARIABLES AND VINEYARD LOCATIONS ON CHEMICAL AND SENSORY PROFILES OF SOUTH TYROLEAN PINOT BLANC

Pinot Blanc, an important grape variety grown in some mountain areas of Northern Italy such as South Tyrol over the last decades, with its cultivation covering 10.3% of the total vineyards, has compatible climatic conditions (e.g. heat requirements) which are normally found in the geographical areas of the mountain viticulture [1,2,3,4]. Climatic changes are hastening the growth of this variety at higher elevations, particularly for the production of high quality wine.

Report on the work carried out by the zoning group of the O.I.V.

La création officielle du groupe Experts Zonage Vitivinicole à l’O.I.V., qui s’inscrit dans la Commission Viticulture, est récente. Le Professeur Mario FREGONI en assure la présidence depuis 1998, assisté du vice-président et du secrétaire général Mario FALCETTI. Ils ont été confirmés dans leurs fonctions lors des sessions de mars 2001. Actuellement, le groupe d’experts Zonage Vitivinicole de l’O.I.V. se compose de 40 délégués, représentant 18 pays membres. La mise en place de ce groupe a tout d’abord été initiée par l’Instituto Agrario de San Michele (Italie) et l’Unité de Recherches Vigne et Vin du Centre INRA d’Angers (France). Une collaboration entre les chercheurs s’est installée très tôt, dès 1987.