IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 New insights on thiol precursors catabolism by yeast during wine fermentation: identification of the N-Acetyl-L-Cysteine conjugate

New insights on thiol precursors catabolism by yeast during wine fermentation: identification of the N-Acetyl-L-Cysteine conjugate

Abstract

Understanding the catabolism of thiol precursors is essential for understanding the revelation of varietal thiols in wine. For many years, knowledge of these precursors has been limited to the S-conjugates of glutathione, cysteine (Cys3SH) and the dipeptides g-GluCys and CysGly, without being able to explain the full origin of 3-sulfanylhexan-1-ol (3SH) in wines. Cysteine was the one considered as the final intermediate before the revelation of 3SH by yeast. Inspired by the glutathione detoxification pathway of xenobiotics, we identified the 3-S-(N-Acetyl-Cysteinyl)hexan-1-ol (NAC3SH) as a new metabolite, by developing (a) a dedicated organic synthesis strategy, (b) a targeted LC-MS/MS analysis method and (c) filiation studies under oenological conditions.In practice, we synthesized NAC3SH by Michael addition of N-Acetyl-L-Cysteine onto trans-2-hexenal in 50/50 water/acetonitrile followed by reduction with NaBH4 in situ. After purification by preparative HPLC, the two diastereomers of NAC3SH were successfully isolated. Characterization was done by both 1D and 2D homonuclear 1H and heteronuclear 1H /13C NMR spectroscopy and quantification by 1D 1H NMR (qNMR). An analytical method for NAC3SH was developed by LC-MS/MS using Cys3SH-d2 as internal standard. The resolution of the two diastereomers could not be achieved under our conditions and they were therefore analyzed in 50/50 equimolar mixture. The method has been validated and showed very satisfactory analytical performances (accuracy = 102%, linearity: R2 = 0.976, LOQ = 6.9 µg/L, LOD = 23 µg/L, repeatability: CV).

DOI:

Publication date: June 23, 2022

Issue: IVAS 2022

Type: Article

Authors

Dournes Gabriel¹, Sachot Somaya¹, Le-Guernevé Christine¹, Suc Lucas1, Mouret Jean-Roch¹ and Roland Aurélie¹  

¹SPO, Univ Montpellier, INRAE, Institut Agro, Montpellier, France

Contact the author

Keywords

thiol precursors, varietal thiol, grape, wine

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

DNA-free genome editing confers disease resistance in grapevine varieties

The grapevine is facing significant challenges due to climate change, as rising temperatures impact its physiological traits and disrupt plant phenology.

Read More

Vine response to compost addition on a sandy-loam soil in the north-east of italy. Effects on root system, vegetative growth, yield and grape quality of Cabernet-Sauvignon cv

In this study two different compost types and two application methods were studied over 5 years (2009-2013) on mature Cabernet Sauvignon vines grown in a commercial vineyard in the AOC Piave area, northeastern Italy.

Read More

Trace-level analysis of phosphonate in wine and must by ion chromatography with inductively coupled plasma mass spectrometry (IC-ICP-MS).

Phosphonic acid and especially potassium dihydrogen phosphonate are widely used to restrain the ubiquitous pressure of grapevine downy mildew in viticulture. Nevertheless, phosphonic acid and its derivatives have been banned in organic viticulture in October 2013, because they have been classified as plant protection products since then.

Read More

Techniques to study graft union formation in grapevine 

Grapevines are grown grafting in most viticultural regions. Grapevine rootstocks are either hybrids or pure species of different American Vitis spp. (particularly V. berlandieri, V. rupestris and V. riparia), which are primarily used to provide root resistance to the insect pest Phylloxera. In addition to Phylloxera resistance, ideally grapevine rootstocks should be resistant to other soil borne pathogens and adapted to abiotic stress conditions. New rootstocks have the potential to adapt agriculture to climate change without changing the characteristics of the harvested product. However, high grafting success rates are an essential prerequisite.

Read More

Impact of Japanese beetles (Popillia japonica Newman) on the chemical composition of two grape varieties grown in Italy (Nebbiolo and Erbaluce)

The Japanese beetle, Popillia japonica Newman, is considered one of the most harmful organisms due to its ability to feed on more than 300 plant species. Symptoms indicative of adult beetles include feeding holes in host plants extending to skeletonization of leaves when population numbers are high. The vine is one of the species most affected by this beetle. However, the damaged plants, even if with difficulty, manage to recover, bringing the bunches of grapes to ripeness.

Read More