Macrowine 2021
IVES 9 IVES Conference Series 9 Update knowledge about the presence of condensed tannins in grapes and their contributions to astringency perception

Update knowledge about the presence of condensed tannins in grapes and their contributions to astringency perception

Abstract

Condensed tannin is a principle group of polyphenol compounds derived from grape, greatly contributing to the bioactivity and the sensory perception of wine. Condensed tannins present as a heterogeneous mixture in nature involving various degrees of both polymerization and galloylation. Even though multiple attempts focusing on fractionation of grape condensed tannins by solid-phase have been conducted over the past decades, few individual tannins have been purified and identified. Hence, our knowledge on grape and wine condensed tannin moleculars has to be limited at the several known monomeric, dimeric and trimeric proanthocyanidins. In the present study, a rapid and effective approach was developed to isolate the galloylated proanthocyanidin from the non-galloylated forms in grape seed tannins and fractionate the non-galloylated proanthocyanidin according to their degree of polymerization by the technique of Centrifugal partition chromatography (CPC). The application of CPC on grape tannins fractionation is efficient, less-time consuming, less expensive and with higher recovery. More importantly, it could effectively isolate galloylated tannins at the beginning and eliminate its interference in the other fractions. After fractionation performed by the technique of CPC, the repurification was achieved by either preparative hydrophilic interaction chromatography or reversed phase high-performance liquid chromatography (HPLC). Eventually, a series of individual condensed tannins with certain degree of polymerization and galloylation from grape were isolated successively. Analyte identity and purity were examined by reversed-phase UPLC-DAD-ESI-Q-TOF and normal-phase HPLC-UV-Fluo-MS, respectively. The astringency perception contributions of the purified individual tannins were examined by the approach of salivary binding ability test. The results were observed by HPLC-Fluo and quantified by the difference of the amount of proanthocyanidins between before and after interaction.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster

Authors

Wen Ma*, Hua Li, Michael Jourdes, Pierre Waffo-Téguo, Pierre-Louis Teissedre

*ISVV

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Use of chitosan as a secondary antioxidant in juices and wines

Chitosan is a polysaccharide produced from the deacetylation of chitin extracted from crustaceous and fungi. In winemaking chitosan is mainly used in the clarification of grape juice and wine, stabilization of white wines, removal of metals and to prevent wine spoilage by undesired microorganisms. The addition of chitosan to model wine systems was able to retard browning, reduce levels of metallic ions (Fe and Cu) and to protect varietal thiols due to its antiradical activity1. The present experiment was planned in order to evaluate the use of chitosan as a secondary antioxidant at three different stages of Sauvignon blanc fermentation and winemaking. Sauvignon blanc juices from three different locations were obtained at a commercial winery in Marlborough, New Zealand. One lots of grapes was collected from a receival bin and pressed into juice with a water-bag press, and a further juice sample was collected from a commercial pressing operation. Chitosan (1 g/L, low molecular weight, 75 – 85% deacetylated) was added to the juice after pressing, after cold settling, after fermentation, or at all these stages. Controls without any chitosan additions were also prepared.

Identification of green, aggressive and hard character of wines by a chemo-sensory directed methodology

With climate change, it is progressively more often to obtain grapes with an acceptable content in sugars or acids but with immature tannins described as green, aggressive or hard (noted as GAH onwards). During winemaking, the oenologist has to make decisions related to the elaboration of such grapes based mainly on empirical experience, given the lack of objective criteria to this concern. An increase in the chemical and sensory knowledge of immature tannins would allow managing this GAH character of grapes with the maximum possible efficiency during winemaking processes. The present work aims at isolating and identifying the group of compounds responsible for the GAH character present in wines.

Fingerprinting the origin of rosé wines with a new high throughput polyphenomics method

Wine is a widely consumed alcoholic beverage with a high commercial value. More specifically, the worldwide consumption of rosé wine has increased by 20% since 2002[1]. But because of its high commercial value, it can become a subject of fraud, and authenticity control is necessarily required. More than one hundred polyphenols have been recently quantified in various rosé wines [2]. They are key components defining color, taste and quality of wines. Their amount and composition depend on many different factors such as grape variety, winemaking and age of the wine. In this study, the influence of geographic origin of some rosé French wines was investigated. An original and very fast UPLC-QTOF-MS method was developed and used to predict the geographic origin authenticity of rosé wines.

On the losses of dissolved CO2 from laser-etched champagne glasses under standard tasting conditions

Under standard champagne tasting conditions, the complex interplay between the level of dissolved CO2 found in champagne, its temperature, the glass shape, and the bubbling rate, definitely impacts champagne tasting by modifying the neuro-physico-chemical mechanisms responsible for aroma release and flavor perception. Based on theoretical principles combining heterogeneous bubble nucleation, ascending bubble dynamics and mass transfer equations, a global model is proposed (depending on various parameters of both the wine and the glass itself), which quantitatively provides the progressive losses of dissolved CO2 from laser-etched champagne glasses.

Effect of intra‐vineyard ripeness variation on the efficiency of commercial enzymes on berry cell wall deconstruction under winemaking conditions

Intra-vineyard variation grape berry ripening occurs within bunches, between bunches on the same vine and between vines. Although it is assumed that such variation also occurs at the grape berry cell wall level, no study to data has investigated in any depth. Here we have used a intra-vineyard panel design to investigate pooled bunches from six vines (per panel) in the context of a winemaking scenario. The dissected vineyard was harvested by separate panels, where each panel was then subjected to a standard winemaking procedure with or without the addition of three different enzyme preparations for maceration.