terclim by ICS banner
IVES 9 IVES Conference Series 9 A NEW STRATEGY AND METHODOLOGY FOR THE CHARACTERIZATION OF POLYPHENOLS IN FINING PRECIPITATE

A NEW STRATEGY AND METHODOLOGY FOR THE CHARACTERIZATION OF POLYPHENOLS IN FINING PRECIPITATE

Abstract

Polyphenols are secondary metabolite widely distributed in plant kingdom such as in fruits, in grapes and in wine. During the winemaking process, polyphenols are extract from the skin and seed of the berries. Fining is an important winemaking step just before bottling which has an impact on wine stabi-lization and clarification. Most the time, fining agent are animal or vegetal protein while some of them can be synthetic polymer like PVPP or natural origin like bentonite. The aim of this study was better understand colloidals phenomenons involved in fining process and determine how polyphenols content and composition are impact by finning.

Different type and composition of fining agent were used during the investigation on each wine. Some of them were based on animal proteins, vegetal proteins, PVPP or bentonite alone while some mix with PVPP and vegetal proteins, PVPP and animal protein, and a mix with PVPP, vegetal proteins and bentonite were also used. On the wine before and after fining monomeric and total anthocyanins, monomeric, dimeric and total tannins, mDP (mean degree of polymerization), flavonol and phenolic acids content were measured. However in order to determine more precisely the content and composition of polyphenol lost during fining, a new strategy have been develop based on the re-solubilisation of the fining precipitate using some organic solvent.

For these experiments, this new method highlight some drastic differences between fining agents. Indeed, depending of the fining agent the amount and the composition of the polyphenols present in the fining precipitate change. For example, some fining agent don’t remove anthocyanins while some other precipitate mainly the p-coumarolylated anthocyanins. Moreover, important differences are also observed for condensed tannins according to the nature of the fining agent. Indeed, fining agent without PVPP were able to precipitate monomeric or dimeric condensed tannins. Moreover, some fining agent are more selective of oligomeric tannins while some has tendency to precipitate tannins with higher mDP.

This new methodology allow a more precise and clear identification of the polyphenol precipitated by fining agent and will help to better understand impact of the fining the organoleptic properties of the wine. Similarly, a better characterization of the fining precipitate will also help better understanding the colloidal structure of the wine.

DOI:

Publication date: February 9, 2024

Issue: OENO Macrowine 2023

Type: Article

Authors

Gauthier Lagarde¹, Manon ferreira¹, Sandra Vanbrabant¹, Soizic Lacampagne¹, Arnaud Massot², Virginie Moine², Pierre-Louis Teissedre¹ and Michael Jourdes*,1

1. Université de Bordeaux, Bordeaux INP, Bordeaux Sciences Agro, UMR 1366 OENOLOGIE, ISVV, 33140 – Villenave d’Ornon
2. Biolaffort, 11 Rue Aristide Berges, 33270 Floirac, Gironde, France

Contact the author*

Keywords

Fining, Precipitate, Condensed tannins, Anthocyanin

Tags

IVES Conference Series | oeno macrowine 2023 | oeno-macrowine

Citation

Related articles…

PROGRESS OF STUDIES OF LEES ORIGINATING FROM THE FIRST ALCOHOLIC FERMENTATION OF CHAMPAGNE WINES

Champagne wines are produced via a two-step process: the first is an initial alcoholic fermentation of grape must that produces a still base wine, followed by a second fermentation in bottle – the prise de mousse – that produces the effervescence. This appellation produces non-vintage sparkling wines composed of still base wines assembled from different vintages, varieties, and regions. These base wines, or “reserve wines,” are typically conserved on their fine lies and used to compensate for quality variance between vintages (1). Continuously blending small amounts of these reserve wines into newer ones also facilitates preserving the producer’s “house style.”

ACIDIC AND DEMALIC SACCHAROMYCES CEREVISIAE STRAINS FOR MANAGING PROBLEMS OF ACIDITY DURING THE ALCOHOLIC FERMENTATION

In a recent study several genes controlling the acidification properties of the wine yeast Saccharomyces cerevisiae have been identified by a QTL approach [1]. Many of these genes showed allelic variations that affect the metabolism of malic acid and the pH homeostasis during the alcoholic fermentation. Such alleles have been used for driving genetic selection of new S. cerevisiae starters that may conversely acidify or deacidify the wine by producing or consuming large amount of malic acid [2]. This particular feature drastically modulates the final pH of wine with difference of 0.5 units between the two groups.

YEAST DERIVATIVE PRODUCTS: CHARACTERIZATION AND IMPACT ON RIBOFLAVIN RELEASE DURING THE ALCOHOLIC FERMENTATION

Light-struck taste (LST) is a wine fault that can occur in white and sparkling wines when exposed to light. This defect is mainly associated to the formation of methanethiol and dimethyl disulfide due to light-induced reactions involving riboflavin (RF) and methionine [1]. The presence of RF in wine is mainly due to the metabolism of yeast [2] which fermenting activity can be favoured by using yeast derivative products (YDPs) as nutrients. Nonetheless, a previous study showed the addition of YDPs before the alcoholic fermentation (AF) led to higher concentrations of RF in wines [3]. Due to the widespread use of YDPs in the winemaking process, this study aimed to understand the possible relation between the content of RF in wine and the YDP adopted as nutrient for AF.

SENSORY DEFINITION OF A TECHNICAL UNAVOIDABLE TRANSFER OF AROMA COMPOUNDS VIA SEALING IN A BOTTLING LINE IN ORDER TO PREVENT PROSECUTION DUE TO FRAUDULENT AROMATIZATION OF A SUBSEQUENTLY FILLED WINE

In 2020, 12% of all bottled German wines were aromatized, which may increase further due to rising popularity of dealcoholized wines. As sealing polymers of a bottling line absorb aroma compounds and may release them into regular wines in the next filling¹, this unintentional carry-over bears the risk to violate the legal ban of any aromatization of regular wine. However, following EU legislation, German food control authorities accept a technical unavoidable transfer of aroma compounds, if this is of no sensory significance.

PHENOTYPIC DIVERSITY AND BIO-PROTECTION CAPABILITY OF METSCHNIKOWIA SP. IN OENOLOGY

Nowadays, the trend is to reduce the use of chemical inputs in the food sector, including in oenology. One of the inputs widely used in the wine making process are sulfites, for its several properties: antimicrobial and antioxidiant. This use isn’t without consequences on consumer’s health and environment, it can lead for example to allergic reactions and pollution. To limit the addition of chemical inputs, microbial alternatives are used. It consists to inoculate in grape must, a micro-organism able to inhibit the growth of the negative indigenous flora during the phase before the fermentation and to guarantee the sensory qualities of wines.