Macrowine 2021
IVES 9 IVES Conference Series 9 New acylated flavonols identified in the grape skin of Vitis vinifera cv. Tannat and their wines

New acylated flavonols identified in the grape skin of Vitis vinifera cv. Tannat and their wines


Flavonols are a class of flavonoid compounds derived from plant secondary metabolism. There they play different roles like antioxidants, internal regulators and UV screenings. In red wines, flavonols have increasingly received consideration by part of scientific and winemakers according their properties began to arise known. Among these stand out wine colour stabilization and their value as bioactive compounds. In this work the complete series of the acetylated and p-coumaroylated derivatives of the 3-O-glycosides of methoxylated flavonols, namely isorhamnetin, laricitrin and syringetin, have been identified in grapes and their respective wines from Vitis vinifera cv. Tannat. The assignments were based on their UV-vis and MSn spectral data. Firstly, the MS2 fragmentation pattern of each tentatively identified flavonol glycoside derivative showed a main signal attributable to the expected flavonol aglycone, together with a weak signal corresponding to the intermediate loss of the acyl moiety. The structures of the flavonol aglycones were confirmed by their respective MS3 experiments that matched with those obtained from authentic standards of the three aglycones. In addition, the DAD on-line UV-vis spectra of the suggested flavonol-3-O-(p-coumaroyl)-glucosides closely matched the sum of the respective spectra of the flavonol-3-O-glucoside and that of p-coumaric acid. Interestingly, the presence of these new flavonol derivatives was limited to the minority flavonols. Being acylation a final step in the flavonoid synthesis, our findings suggest a very high specificity of the acyltransferases implied for the flavonol glycoside substrate that in this case would be related to the presence of methoxyl groups in the B ring of the flavonol. The fact that these compounds have been found in Tannat, a Vitis vinifera with scarce cultivation around the world, may indicate that the implied acyltransferases could be little spread among grape varieties. Nevertheless it could be associated to other factors like growth environmental conditions, or to the sensitivity of the analytical technique employed, or others factors, which should be further considered and studied. These results give evidences of new flavonol derivatives in grapes and wines, and expose a case of substrate specificity of the enzymes implied in their synthesis.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster


Isidro Hermosín-Gutíerrez*, Diego Piccardo, Gustavo González Neves, Guzmán Favre, Sergio Gómez-Alonso

*Universidad de Castilla-La Mancha

Contact the author


IVES Conference Series | Macrowine | Macrowine 2016


Related articles…

Effect of nanofiltration on the chemical composition and wine quality

In Enology the conventional processes of filtration for clarification and stabilization are giving place to alternative membrane processes, including nanofiltration (NF). Furthermore, the increased alcohol content in wines recorded in recent years became an important issue for all the main wine producing countries. Among techniques available to the wine industry to reduce the ethanol content, NF is certainly one of the newest. This study is focused on the evaluation of NF influence on wine physical-chemical composition, including mineral content, which in accordance to our best knowledge is a novelty.

Effect of concentration and competition between different fungicide residues on the adsorption efficiency of activated vegetal fibres for treatment of wine

Vineyards are strongly exposed to fungal diseases, attacks from insects and competition with weeds. Most treatments used on grape vines contain synthetic active substances, which may be transferred to the wine. Such pesticides have a negative image because many active substances are potential health hazards. A specific oenological treatment allowing the reduction of pesticide residues in wine based on activated vegetable fibres (AVF) is under examination by the International Organisation for Vine and Wine. This technique works efficiently and alters the wine only little (Lempereur et al. 2014).

Impact of heating must before fermentation on Chardonnay wines

Prefermentation steps of white winemaking are very important for controlling the stability and the sensory attributes of wines. Usually musts are clarified by cold settling to prevent the start of the fermentation, before racking big lees and thus limiting the appearance of vegetable or reduction off flavour while favouring an aromatic expression with low turbidity. Besides, to reach the protein stability, some white wines further require a bentonite fining, sometimes associated with negative effects on the sensory quality. This study aims to know the impact of musts heating after pressing on a Chardonnay wine in northern conditions by comparison with a classic cold racking of the must.

Partial dealcoholisation of red wine by reverse osmosis-evaporative perstraction: impact on wine composition

Around the world, the alcohol content of wine has been steadily increasing; partly as a consequence of climate change, but also due to improvements in viticultural management practices and winemaking techniques [1,2]. Concurrently, market demand for wines with lower alcohol levels has increased as consumers seek to reduce alcohol intake for social and/or health reasons [3]. As such, there is increasing demand for both innovative methods that allow winemakers to produce ‘reduced alcohol wines’ (RAW) and a better understanding of the impact of such methods on the composition of RAW. This study therefore aimed to investigate compositional changes in two red wines resulting from partial alcohol removal following treatment by one such method, involving a combination of reverse osmosis and evaporative perstraction (RO-EP).

New biological tools to control and secure malolactic fermentation in high pH wines

Originally, the role of the malolactic fermentation (MLF) was simply to improve the microbial stability of wine via biological deacidification. However, there is an accumulation of evidence to support the fact that lactic acid bacteria (LAB) also contribute positively to the taste and aroma of wine. Many different LAB enter into grape juice and wine from the surface of grape berries, cluster stems, vine leaves, soil and winery equipment. Due to the highly selective environment of juices and wine, only a few types of LAB are able to grow.