Macrowine 2021
IVES 9 IVES Conference Series 9 Influence of toasting oak wood on ellagitannin structures

Influence of toasting oak wood on ellagitannin structures

Abstract

Ellagitannins (ETs) have been reported to be the main phenolic compounds found in oak wood. These compounds, belonging to the hydrolysable tannin class of polyphenols, are esters of hexahydroxydiphenic acid (HHDP) and a polyol, usually glucose or quinic acid. They own their name to their capacity to be hydrolysed and liberate ellagic acid and they have an impact on astringency and bitterness sensation, which is strongly dependant on their structure. The toasting phase is particularly crucial in barrels fabrication and influences wood composition. Burning the inner oak wood barrels surface with an open fire inducing severe changes in ellagitannins structures and compositions. Up to now thermal ellagitannin products or the reaction mechanisms underlying the ellagitannin degradation are not well searched, thus the goal of the present study is to research oak wood ellagitannin changes during toasting. For this purpose a purification protocol was established, 100 mg ellagitannins crude extract was fractionated on Toyopearl TSK HW-40 (F) gel from Tosoh Corp, ellagitannins were eluted in the acetone/water fraction. This fraction was fractionated for two times on a C-18 column. The final fraction containing only the eight principal ellagitannins was dry-heated in a lab oven for 60 min at 220 °C. After cooling, it was further fractionated on C-18 column and separated by means of preparative HPLC before being injected in UPLC/TOF-MS. Reduction process is occuring during toasting whereas oxydation can occur without heating; Thus vescalagin, is reduced into deoxyvescalagin whereas castalagin oxidation form is presented before and after toasting. Additionally to deoxyvescalagin, other ellagitannin derivatives which showed [M-H]-ion peak at m/z 1055.0631, 1041.0792, 1011.0756 and 971.0456 were produced by the toasting and identified for the first time. LC-MS/MS analyses gave strong evidence that decarboxylations as well as ellagic acid loss are the key steps in ellagitanin thermal degradation.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster

Authors

Kleopatra Chira*, Michael Jourdes, Pierre Louis Teissedre

*Institut des sciences de la vigne et du vin

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Intelligent article to control the internal pressure in continue in bottles

An intelligent packaging might, among others, provide information and allow monitoring of the quality of the packed product or its surrounding environment. A recent project on micro-flow wine bottles closed with aluminium screw cap and tightness liner, highlighted the importance of monitoring the internal overpressure continuously, in real-time and at least for 72 hours, since the internal pressure on the tightness liner and the micro-flow are related. Real-time and continuous measurements are not the standard methods of measurement of the overpressure, yet. The most used equipment for the determination of the pressure in wine bottle is the aphrometer, a destructive device that supplies a single value of pressure.

Study of the content of amino acids and biogenic amines in sparkling red wines

The production of red sparkling wines is lower in Spain in comparison with the winemaking of white or rosé sparkling wines. In red sparkling wine processing it is essential to obtain suitable base wines that should have moderate alcohol content, high acidity, good color values, an adequate mouth-feel and a sweet tannin. Grapes for sparkling wine production have to be harvested at low maturity stages, with lower alcohol contents and higher acidities, which will that the phenolic maturity of the grapes is also low, showing green tannins. This paper analyses different treatments in order to minimize these inconveniences: cold maceration-prefermentation and delestage to elaborate the grapes with lower maturity, must nanofiltration, and the partial osmosis of the wines made from grapes with an adequate maturity degree.

Petrolomics-derived data interpretation to study acetaldehyde-epicatechin condensation reactions

During red wine ageing or conservation, color and taste change and astringency tends to reduce. These changes result from reactions of flavan-3-ols and/or anthocyanins among which condensation reactions with acetaldehyde are particularly important. The full characterization of these reactions has not been fully achieved because of difficulties in extracting and separating the newly formed compounds directly from wine. Model solutions mimicking food products constitute a simplified medium for their exploration, allowing the detection of the newly formed compounds, their isolation, and their structure elucidation.

Moscatel vine-shoot extracts as grapevine biostimulant to increase the varietal aroma of Airén wines

There is a growing interest in the exploitation of vine-shoots waste, since they are often left or burned. Sánchez-Gómez et al. [1] have shown that vines-shoots aqueous extracts have significant contents of bioactive compounds, among which several polyphenols and volatiles are highlighted. Recent studied had demonstrated that the chemical composition of vine-shoots is enhanced when vine-shoots are toasted
[2,3]. The application of vegetable products in the vineyards has led to significant changes towards a more “Sustainable Viticulture”. An innovative foliar application for Airén vine-shoot extracts have been carried out to the vineyard. It has been shown that they act as grape biostimulants, improving certain wine quality characteristics [4].

Molecular cloning and characterization of UDP-glucose: furaneol glucosyltransferase gene from Japanese

2,5-Dimethyl-4-hydroxy-3(2H)-furanone (furaneol) is an important aroma compound in fruits, such as pineapple and strawberry, and is reported to contribute to the strawberry-like note in some wines. Several grapevine species are used in winemaking, and furaneol is one of the characteristic aroma compounds in wines made from American grape (Vitis labrusca) and its hybrid grape, similar to methyl anthranilate. Muscat Bailey A is a hybrid grape variety [V. labrusca (Bailey) x V. vinifera (Muscat Hamburg)], and its wine is one of the most popular in Japan. The inclusion of Muscat Bailey A in the ‘International List of Vine and Varieties and their Synonyms’ managed by the ‘International Organisation of Vine and Wine (OIV)’ in 2013 has further fueled its popularity among winemakers and researchers worldwide.