Macrowine 2021
IVES 9 IVES Conference Series 9 Crown procyanidin: a new procyanidin sub-family with unusual cyclic skeleton in wine

Crown procyanidin: a new procyanidin sub-family with unusual cyclic skeleton in wine

Abstract

Condensed tannins (also called proanthocyanidins) are a widely distributed throughout in plants kingdom and are one of the most important classes of secondary metabolites, in addition, they are part of the human diet. In wine, they are extracted during the winemaking process from grape skins and seeds. These compounds play an important role in red wine organoleptic characteristics such as color, bitterness and astringency. Condensed tannins in red wine are oligomers and polymers of flavan-3-ols unit such as catechin, epicatechin, epigallocatechin and epicatechin-3-O-gallate. The monomeric units can be linked among them with direct interflavanoid linkage or mediated by aldehydes. During our investigation on red wine condensed tannins, three surprisingly polar tannins oligomers (one tetramer and two pentamers) were detected by HPLC-UV-MS (Tof) and their concentrations remained stable during wine aging. The objective of this study was (1) to develop a purification method for these three oligomers of condensed tannins observed in red wine, (2) to determine their structures by high resolution mass spectrometry, chemical depolymerization strategy, as well as NMR, (3) to quantify them in various red wine and to estimate their organoleptic properties. The new procyanidin tetramer and the two new procyanidin pentamers have been purified by a “three steps-two gels” strategy with the first step of C-18 Solid Phase Extraction, the second step of TSK-40S Gel Filtration Chromatography and the last step of C-18 HPLC semi-preparative. Their fragmentation pattern obtained by MS/MS analysis using a high resolution mass spectrometry revealed that these three compounds belong to the procyanidin family. Moreover the inter-flavanoid linkages, sub-units information as well as overall configuration of the tetramer were established by 1D and 2D NMR. The structure of the tetramer have been determined to be a symmetric procyanidin with four sub-units of (−)-epicatechin link together by B-type interflavanoid linkage in the following sequence of Unit 1-(4-8)-Unit 2-(4-6)-Unit 3-(4-8)-Unit 4 (4-6)-Unit 1 with the first unit linked with the last unit via the forth interflavanoid linkage C6-C4 to form the macrocyclic structure. Since such carbon skeleton has never been reported before for procyanidins in wine, neither in plants kingdom, we decide to name this new group of procyanidins “crown procyanidins”. This new procyanidin sub-family has been quantified in three different red wines (merlot, cabernet sauvignon and shiraz) with various vintages (from 1991 to 2011). The concentration of the crown procyanidin remains stable in wine during ageing and their concentration shows higher stability than linear B-type procyanidins which their content decrease during aging. Moreover, a strong correlation between these new procyanidin and the red wine astringency level has been observed.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Article

Authors

Michael Jourdes*, Liming Zeng, Pere Pons-Mercadé, Pierre-Louis Teissedre, Stéphanie Krisa, Tristan Richard

*UMR 1219 OEnologie

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Effect of ageing with Specific Inactivated Dry Yeasts on the volatile composition of Sauvignon Blanc and Carménère wines

Úbeda-Aguilera, C a, b, Peña-Neira, A.b Del Barrio-Galán, R.b, c a Biomedical Sciences Institute, Science Faculty, Universidad Autónoma de Chile, Chile. b Department of Agro-Industry and Enology, Faculty of Agronomical Sciences, University of Chile, Post Office Box 1004, Santa Rosa 11315, La Pintana, Santiago, Chile c Lallemand Inc. Chile y Compañía Limitada, Rosario Norte 407, piso 6, Las Condes, Santiago, Chile The wine is a complex matrix made up of several compounds which can interact among themselves throughout the wine ageing process, thereby modifying their sensorial characteristics. It is well known that during ageing of wines on lees, polysaccharides (mainly mannoproteins) can be released and can interact with the aromatic fraction modifying its volatility.

Effect of post-harvest ozone treatments on the skin phenolic composition and extractability of red winegrapes cv Nebbiolo and Barbera

Wine industry is looking forward for innovative, safe and eco-friendly antimicrobial products allowing the reduction of chemical treatments in the grape defense and the winemaking process that can affect negatively the quality of the product. Ozone has been tested in food industry giving good results in preventing fungi and bacteria growth on a wide spectrum of vegetables and fruits, due to its oxidant activity and ability to attack numerous cellular constituents. Ozone leaves no chemical residues on the food surface, decomposing itself rapidly in oxygen. Gaseous ozone has been already tested for table grapes storage and on wine grapes during withering.

Metabolomics of grape polyphenols as a consequence of post-harvest drying: on-plant dehydration vs warehouse withering

A method of suspect screening analysis to study grape metabolomics, was developed [1]. By performing ultra-high performance liquid chromatography (UHPLC) – high-resolution mass spectrometry (HRMS) analysis of the grape extract, averaging 320-450 putative grape compounds are identified which include mainly polyphenols. Identification of metabolites is performed by a new HRMS-database of putative grape and wine compounds expressly constructed (GrapeMetabolomics) which currently includes around 1,100 entries.

Assessing the effect of oak derived aromas on mouthfeel perception in Chardonnay wine

Mouthfeel is an important quality parameter for Chardonnay wines, particularly those aged in oak. While research on mouthfeel has traditionally focused on the impact of non-aromatic compounds, the role of aroma compounds has largely been over looked. However, in wine as well as other food interactions between retronasal aroma and mouthfeel have been noted. The goal of this research was to investigate the impact of wine aroma on the perception of mouthfeel. Because of the importance of oak aging in the development of Chardonnay mouthfeel, the impact of oak aromas on perceived mouthfeel was explored. Aroma compounds associated with oak (ethyl palmitate, eugenol, furfural, isoeugenol, syringaldehyde, vanillin and whiskey lactone) were added to two different Chardonnay wines; one with no oak influence and one fermented in neutral oak. Low and high concentrations of the compounds were added based on concentrations typically found in barrel aged Chardonnay wine.

Quantification of the production of hydrogen peroxide H2O2 during wine oxidation

Chemical studies aiming at assessing how a wine reacts towards oxidation usually focus on the characterization of wine constituents, such as polyphenols, or oxidation products. As an alternative, the key oxidation intermediate hydrogen peroxide H2O2 has never been quantified, although it plays a pivotal role in wine oxidation. H2O2 is obtained from molecular oxygen as the result of a first cascade of oxidation reactions involving metal ions and polyphenols. The produced H2O2 then reacts in a second cascade of oxidation to produce reactive hydroxyl radicals that can attack almost any chemical substrate in wine.