Multispectral fluorescence sensitivity to acidic and polyphenolic changes in Chardonnay wines – The case study of malolactic fermentation

International audience; In this study, stationary and time-resolvedfluorescence signatures, were statistically and chemometrically analyzed among three typologies of Chardonnay wines (A, B and C) with the objectives to evaluate their sensitivity to acidic and polyphenolic changes. For that purpose, a dataset was built using Excitation Emission Matrices of fluorescence (N = 103) decomposed by a Parallel Factor Analysis (PARAFAC), andfluorescence decays (N = 22), mathematically fitted, using the conventional exponential modeling and the phasor plot representation. Wine PARAFAC component C4 coupledwith its phasor plot g and s values enable the description of malolactic fermentation (MLF) occur…

Exopolysaccharide produced by Weissella confusa: Chemical characterisation, rheology and bioactivity

Abstract The purpose of this study was to characterise the production of exopolysaccharide (EPS) by indigenous lactic acid bacteria (LAB) isolated from traditional Algerian dairy products and to evaluate their possible use in agri-foods. Among the collection of isolated strains, the strain Weissella confusa (W4) was selected for its ability to produce EPS once exposed to a sucrose culture medium. EPS produced were first isolated with a standardised method and further characterised in terms of molecular size, antioxidant activity, and rheological properties. Its direct implication in the texture and syneresis of acid milk gel was evaluated offering interesting industrial applications for its…

.) Clone-dependent expression of grapevine esca disease.

International audience; The occurrence of grapevine trunk diseases (GTDs) increases gradually within vineyards, leading to important economic losses. Several factors could affect grapevine susceptibility to GTDs, especially climate, vine age, soil fertilization, and also rootstock, cultivar and clone. For a cultivar, the level of disease expression can vary with region and from year to year. In this context, our objective was to assess if the expression of esca disease, one of the most widespread GTDs, was also clone-dependent. Two clones (76 and 95) of the “Chardonnay” cultivar, grown in the same plot, were compared according to their developmental and physiological traits, metabolome, and…

Impact of oak tannin selection and barrel toasting on the oxidative stability of dry white wine

International audience; The article focuses on the impact of selecting barrel toasting and oak tennin on the dry white wine's oxidative stability. It reports that the management of the barrel ageing is the most important step for the production of premium quality wines and its role in the micro-oxygenation and enrichment of odorant compounds. The oak wood contains the antioxidant capacity. The barrel ageing on the oxidative stability of white wine includes experimental setup, analysis and chemical profiles.

Clone-Dependent Expression of Esca Disease Revealed by Leaf Metabolite Analysis

International audience; Grapevine trutk diseases, especially Esca, are of major concern since they gradually alter vineyards worldwide and cause heavy economic losses. The expression of Esca disease symptoms depends on several factors, including the grapevine cultivar. In this context, a possible clone-dependent expression of the Esca disease was studied. Two clones of 'Chardonnay' grown in the same plot were compared according to their developmental and physiological traits, metabolome, and foliar symptom expression. Analysis of their leaf metabolome highlighted differences related to symptom expression. Interestingly, the content of a few specific metabolites exhibited opposite variations…

Influence of regionality and maturation time on the chemical fingerprint of whisky.

International audience; Understanding the chemical composition of whisky and the impact of each step in the manufacturing process provides a basis for responding to the challenges of producing high quality spirits. In this study, the objective was to discriminate whiskies according to their geographical origin and authenticate the maturation time in cask based on the non-volatile profiles. The combination of FT-ICR-MS and chemometrics allowed the distinction of whiskies from four geographical origins in Scotland (Highlands, Lowlands, Speyside and Islay). Statistical modeling was also used to discriminate whiskies according to the maturation time in cask and reveal chemical markers associate…

Fluorescence fingerprinting of bottled white wines can reveal memories related to sulfur dioxide treatments of the must.

For the first time, Excitation Emission Matrix (EEM) fluorescence spectroscopy was combined with parallel factor statistical analysis (PARAFAC) and applied to a set of 320 dry white wines of the Chardonnay grape variety. A four component PARAFAC model (C1, C2, C3 and C4) best explained the variability of fluorescence signatures of white wines. Subtle changes were observed in EEMs of white wines from two different vintages (2006 and 2007), where different concentrations of sulfur dioxide (0, 4, and 8 g·hL(-1)) were added to the grape must at pressing. PARAFAC results clearly indicated that sulfur dioxide added to the must subsequently influenced white wine chemistry into three distinct sulfu…

MOOC : "Open Wine University 2"

Plan du cours Semaine 1 : Introduction Entre sol et climat Micro-organismes du vin Premiers pas en dégustation + support sur la vinification des vins blancs et des vins rouges Semaine 2 : Le vin en danger ? Climat et viticulture Principales maladies et ravageurs de la vigne Economie mondiale du vin après la crise du phylloxéra Semaine 3 : Façonner le vin Géologie et sols des terroirs bourguignons Vin et diversité microbienne Marchés du vin Semaine 4 : Maîtriser son terroir Construction du terroir de la vigne Vinification des vins spéciaux : l'exemple de la production de vins jaunes du Jura Défauts du vin Semaine 5 : Mettre le vin à table Mise en bouteille du vin Vieillissement du vin Le vin…

The Antioxidant Potential of White Wines Relies on the Chemistry of Sulfur-Containing Compounds: An Optimized DPPH Assay

The DPPH (2,2-Diphenyl-1-picrylhydrazyl) assay is an easy and efficient method commonly used to determine the antioxidant capacity of many food matrices and beverages. In contrast with red wines, white wines are poorer in antioxidant polyphenolics, and the more hydrophilic sulfur-containing compounds in them may contribute significantly to their antioxidant capacity. The modification of the classical DPPH method, with a methanol-buffer and the measure of EC20 (quantity of sample needed to decrease the initial DPPH concentration by 20%) has shown that sulfur-containing compounds such as cysteine (0.037 &plusmn

Chemical Transfers Occurring Through Oenococcus oeni Biofilm in Different Enological Conditions

International audience; Chardonnay wine malolactic fermentations were carried out to evaluate the chemical transfers occurring at the wood/wine interface in the presence of two different bacterial lifestyles. To do this, Oenococcus oeni was inoculated into must and wine in its planktonic and biofilm lifestyles, whether adhering or not to oak chips, leading to three distinct enological conditions: (i) post-alcoholic fermentation inoculation in wine in the absence of oak chips, (ii) post-alcoholic fermentation inoculation in wine in the presence of oak chips, and (iii) co-inoculation of both Saccharomyces cerevisiae and O. oeni directly in Chardonnay musts in the presence of oak chips. Classi…

Molecular and Macromolecular Changes in Bottle-Aged White Wines Reflect Oxidative Evolution–Impact of Must Clarification and Bottle Closure

This article is part of the Research Topic "The Chemistry of Wine Ageing" Adresse de correspondance: Institut Universitaire de la Vigne et du Vin, Dijon, France PMCID: PMC5897750; International audience; Chardonnay wines from Burgundy, obtained from musts with three levels of clarification (Low, Medium and High) during two consecutive vintages (2009 and 2010) and for two kinds of closures (screw caps and synthetic coextruded closures) were analyzed chemically and sensorially. Three bottles per turbidity level were opened in 2015 in order to assess the intensity of the reductive and/or oxidative aromas (REDOX sensory scores) by a trained sensory panel. The chemical analyses consisted in poly…

Inoculation of Torulaspora delbrueckii as a bio-protection agent in winemaking

International audience; In oenology, bio-protection consists in adding bacteria, yeasts or a mixture of microorganisms on grape must before fermentation in order to reduce the use of chemical compounds such as sulphites. More particularly, non-Saccharvinyces yeasts are used as a total or partial alternative to sulphites. However, scientific data capable of proving the effectiveness of adding these yeasts on grape must is lacking. This study reports the analysis of antimicrobial and antioxidant effects of one non-Saccharamyces yeast, Torulaspora delbruecicii, inoculated at the beginning of the white winemaldng process in two Burgundian wineries as an alternative to sulphiting. The implantati…

Capillary Electrophoresis in Wine Science

International audience; Capillary electrophoresis appeared to be a powerful and reliable technique to analyze the diversity of wine compounds. Wine presents a great variety of natural chemicals coming from the grape berry extraction and the fermentation processes. The first and more abundant after water, ethanol has been quantified in wines via capillary electrophoresis. Other families like organic acids, neutral and acid sugars, polyphenols, amines, thiols, vitamins, and soluble proteins are electrophoretically separated from the complex matrix.Here, we will focus on the different methodologies that have been employed to conduct properly capillary electrophoresis in wine analysis.Two examp…

How Chemical and Sensorial Markers Reflect Gentian Geographic Origin in Chardonnay Wine Macerated with Gentiana lutea Roots?

A Burgundian Chardonnay wine was enriched with Gentiana lutea root powders originating from two French mountain sites (Massif Central and Jura) in order to prepare semi-dry gentian aromatized Chardonnay wine-based drinks. These novel alcoholic beverages were chemically and sensorially characterized for evaluating if the gentian geographic origin influenced bitter and elemental and volatile composition and sensory profiles in the final products. For that, the chemical fingerprint of gentian powders and wines were carried by headspace solid phase microextraction gas chromatography coupled to mass spectrometry (HS&ndash

Impact of Oak Wood Barrel Tannin Potential and Toasting on White Wine Antioxidant Stability

International audience; Wines aged in oak wood barrels with various uniform tannin contents (which were classified according to their total ellagitannins contents as predicted by Near Infrared Spectroscopy on the untoasted wood) and different toasting levels (high precision toasting by radiation) were distinguished according to their overall abilities to resist against oxidation. Wine trials were carried out on two different vintages (2015, 2016) and three grape varieties (Sauvignon blanc, Sémillon, Chardonnay). Regardless of the vintage and the wine matrix, a relationship was established between wine oxidative stability (based on EPR spin trapping methodology) and oak barrel tannin potenti…

L'uB au coeur de la viticulture durable

SPEIPMUB; Ancrée au cœur d’une région viticole historique, l’université de Bourgogne soutient de multiples projets de recherche viti-vinicoles et s’investit dans la formation des futurs professionnels du secteur. Elle est d’ailleurs la seule université française à disposer d’un domaine expérimental, situé à Marsannay-la-Côte. En activité depuis 1955, il apporte à la fois un support pédagogique aux étudiants de l’institut Jules Guyot, qui y effectuent différentes manipulations en conditions réelles, et répond à des demandes d’expérimentations émanant des viticulteurs et vignerons de la région. Dans ce cadre, il teste de nouveaux produits, matériaux ou micro-organismes susceptibles de mieux p…

Sulfites and the Wine Metabolome

International audience; In a context of societal concern about food preservation, the reduction of sulfite input plays a major role in the wine industry. To improve the understanding of the chemistry involved in the SO2 protection, a series of bottle aged Chardonnay wines made from the same must, but with different concentrations of SO2 added at pressing were analyzed by ultrahigh resolution mass spectrometry (FT-ICR-MS) and excitation emission matrix fluorescence (EEMF).Metabolic fingerprints from FT-ICR-MS data could discriminate wines according to the added concentration to the must but they also revealed chemistry-related differences according to the type of stopper, providing a wine me…

Corrigendum to ‘Inoculation of Torulaspora delbrueckii as a bio-protection agent in winemaking’ [Food Research International, Inoculation of Torulaspora delbrueckii as a bio-protection agent in winemaking, Volume: 107 (2018), 451–461]

Measurement of white wines resistance against oxidation by Electron Paramagnetic Resonance spectroscopy

International audience; Free radical theory of aging hypothesizes that oxygen-derived radicals are responsible for the storage-related flavor instability in wine. In an optimal situation, a balanced-distribution exists between oxidants and antioxidants among wines intrinsic/extrinsic metabolites. Based on the kinetic study of POBN-1-hydroxyethyl spin adduct (POBN-1-HER) formation in wines initiated via the Fenton reaction, a novel tool based on EPR spin trapping methodology was developed to quantify wines resistance against oxidation. Antioxidant capacities of wines were evaluated according to POBN-1-HER maximum signal intensity (Imax POBN-1-HER) and rate formation (r(POBN-1-HER)) kinetic p…