Macrowine 2021
IVES 9 IVES Conference Series 9 Understanding sweetness of dry wines: first evidence of astilbin isomers in red wines and quantitation in a one-century range of vintages

Understanding sweetness of dry wines: first evidence of astilbin isomers in red wines and quantitation in a one-century range of vintages

Abstract

The gustatory balance of wines relies on sweetness, bitterness and sourness. In dry wines, sweetness does not result from the presence of residual sugar as in sweet wines, but is due to other non-volatile compounds. Such taste-active compounds are released during winemaking, by grapes, yeasts or oak wood and belong numerous chemical families [1]. Beyond this diversity, stereochemistry of molecules can also influence their sensory properties [2]. However, the molecular determinants associated with this taste have only been partially elucidated. Astilbin (2R, 3R) was recently reported to contribute to wine sweetness [3]. As its aglycon contains two stereogenic centers, three other stereoisomers may be present: neoisoastilbin (2S, 3R), isoastilbin (2R, 3S), and neoastilbin (2S, 3S). These compounds have already been observed in natural products, but never in wine. This work aimed at assaying their presence for the first time in wines as well as their taste properties.The isomers were synthesized from astilbin and purified by semi-preparative HPLC. Their content was assayed by developing a UHPLC-Q-Exactive quantification method. The method was applied to screen astilbin and isomers in various wines, especially in different vintages from the same estate. Sensory analysis highlighted the sweet taste of these stereoisomers whose intensity varied according to their configuration. Quantification results revealed that while young wines contained higher concentrations of astilbin than the old ones, the concentrations of the other isomers, mainly neoastilbin, were higher in the old wines, suggesting their formation over time.These results highlight the contribution of astilbin isomers in wine sweetness. More generally, this study brings new insights to understand the chemical origin of wine taste.

DOI:

Publication date: September 17, 2021

Issue: Macrowine 2021

Type: Article

Authors

Marie Le Scanff , Syntia FAYAD, Axel MARCHAL, 

Unité de recherche Œnologie, EA 4577, USC 1366 INRA, ISVV, Université de Bordeaux, F33882 Villenave d’Ornon, France 

Contact the author

Keywords

sweetness, sensory analysis, taste, isomers, wines

Citation

Related articles…

EFFECTS OF INDUCED SUNBURN DAMAGES ON WHITE WINE PROPERTIES

Climate change is a great challenge for the environment and affects the wine industry as well. Sunburn damage of sensitive grapes increase with severe heat periods. Besides significant loss of yield sunburn, modifies sensory properties of the wines and may cause climate-related off-flavours. To initiate sunburn in a controlled way, in 2021 sunburn was directly induced in the vineyard with the GrapeBurner device, exposing grapes of the varieties Riesling and Pinot Blanc with UV and IR radiation. This device was first assembled by Kai Müller of the university in Geisenheim and consists of a carriage with 6 UV/IR lamps. A 15 min irradiation was applied in early September at 60°Oe. Due to the colder season in 2021 the grapes were not harmed by previous sunburn damage.

Capture depletion of grapevine DNA: an approach to advance the study of microbial community in wine

The use of next-generation sequencing (NGS) has helped understand microbial genetics in oenology. Current studies mainly focus on barcoded amplicon NGS but not shotgun sequencing, which is useful for functional analyses. Since the high percentage of grapevine DNA conceals the microbial DNA in must, the majority of sequencing data is wasted in bioinformatic analyses. Here we present capture depletion of grapevine whole genome DNA.

French AOC positioning and their concepts and extension to other products

Constitue une appellation d’origine “la dénomination géographique d’un pays, d’une région ou d’une localité servant à désigner un produit qui en est originaire, et dont la qualité ou les caractères sont dus exclusivement ou essentiellement au milieu géographique, comprenant les facteurs naturels et les facteurs humains …”

Zonificación vitícola y aplicación a la D.O. Montilla-Moriles, usando como referencia la variedad ‘Pedro Ximenes’

Se señalaron 28 parcelas, en la zona de D.O. Montilla-Moriles, repartidas por toda la superficie de viñedo, de ellas 12 se localizan en las Zonas de calidad Superior, en los términos municipales de Montilla

Exploring the genetic diversity of leaf flavonoids content in a set of Iberian grapevine cultivars: preliminary results

The use of grapevine genetic diversity is a way to mitigate the negative impacts of climate change on viticulture systems. Leaf epidermal flavonoids (including flavonols and anthocyanins) are involved in plant defense mechanisms against environmental stresses, like high temperatures or excessive solar radiation [1,2]. Among other factors, they modulate light absorption, which reduces photoinhibition processes in photosynthetic tissues [1]. Therefore, the identification of grapevine cultivars with an increased content on leaf epidermal flavonoids arises as a potential avenue to improve grapevine tolerance to some detrimental environmental stresses.