An Infrared Laser Sensor for Monitoring Gas-Phase CO2 in the Headspace of Champagne Glasses under Wine Swirling Conditions.

In wine tasting, tasters commonly swirl their glasses before inhaling the headspace above the wine. However, the consequences of wine swirling on the chemical gaseous headspace inhaled by tasters are barely known. In champagne or sparkling wine tasting, starting from the pouring step, gas-phase carbon dioxide (CO2) is the main gaseous species that progressively invades the glass headspace. We report the development of a homemade orbital shaker to replicate wine swirling and the upgrade of a diode laser sensor (DLS) dedicated to monitoring gas-phase CO2 in the headspace of champagne glasses under swirling conditions. We conduct a first overview of gas-phase CO2 monitoring in the headspace of a champagne glass, starting from the pouring step and continuing for the next 5 min, with several 5 s swirling steps to replicate the natural orbital movement of champagne tasters. The first results show a sudden drop in the CO2 concentration in the glass headspace, probably triggered by the liquid wave traveling along the glass wall following the action of swirling the glass.

Unveiling Carbon Dioxide and Ethanol Diffusion in Carbonated Water-Ethanol Mixtures by Molecular Dynamics Simulations.

The diffusion of carbon dioxide (CO2) and ethanol (EtOH) is a fundamental transport process behind the formation and growth of CO2 bubbles in sparkling beverages and the release of organoleptic compounds at the liquid free surface. In the present study, CO2 and EtOH diffusion coefficients are computed from molecular dynamics (MD) simulations and compared with experimental values derived from the Stokes-Einstein (SE) relation on the basis of viscometry experiments and hydrodynamic radii deduced from former nuclear magnetic resonance (NMR) measurements. These diffusion coefficients steadily increase with temperature and decrease as the concentration of ethanol rises. The agreement between theory and experiment is suitable for CO2. Theoretical EtOH diffusion coefficients tend to overestimate slightly experimental values, although the agreement can be improved by changing the hydrodynamic radius used to evaluate experimental diffusion coefficients. This apparent disagreement should not rely on limitations of the MD simulations nor on the approximations made to evaluate theoretical diffusion coefficients. Improvement of the molecular models, as well as additional NMR measurements on sparkling beverages at several temperatures and ethanol concentrations, would help solve this issue.

Does the Temperature of the prise de mousse Affect the Effervescence and the Foam of Sparkling Wines?

The persistence of effervescence and foam collar during a Champagne or sparkling wine tasting constitute one, among others, specific consumer preference for these products. Many different factors related to the product or to the tasting conditions might influence their behavior in the glass. However, the underlying factor behind the fizziness of these wines involves a second in-bottle alcoholic fermentation, also well known as the prise de mousse. The aim of this study was to assess whether a low temperature (13 °C) or a high temperature (20 °C) during the in-bottle fermentation might have an impact on the effervescence and the foaming properties (i.e., collar height and bubble size) of three French sparkling wines (a Crémant de Loire and two Champagne wines), under standard tasting conditions. Our results showed that sparkling wines elaborated at 13 °C and served in standard tasting conditions (i.e., 100 mL, 18 °C) had better ability to keep the dissolved CO2 (between 0.09 and 0.30 g/L) in the liquid phase than those elaborated at 20 °C (with P < 0.05). Most interestingly, we also observed, for the Crémant de Loire and for one Champagne wine, that the lower the temperature of the prise de mousse, the smaller (with P < 0.05) the bubbles in the foam collar throughout the wine tasting.

Chemical messages in 170-year-old champagne bottles from the Baltic Sea: Revealing tastes from the past.

Archaeochemistry as the application of the most recent analytical techniques to ancient samples now provides an unprecedented understanding of human culture throughout history. In this paper, we report on a multiplatform analytical investigation of 170-y-old champagne bottles found in a shipwreck at the bottom of the Baltic Sea, which provides insight into winemaking practices used at the time. Organic spectroscopy-based nontargeted metabolomics and metallomics give access to the detailed composition of these wines, revealing, for instance, unexpected chemical characteristics in terms of small ion, sugar, and acid contents as well as markers of barrel aging and Maillard reaction products. The distinct aroma composition of these ancient champagne samples, first revealed during tasting sessions, was later confirmed using state-of-the-art aroma analysis techniques. After 170 y of deep sea aging in close-to-perfect conditions, these sleeping champagne bottles awoke to tell us a chapter of the story of winemaking and to reveal their extraordinary archaeometabolome and elemental diversity in the form of chemical signatures related to each individual step of champagne production.

Differential responses of three grapevine cultivars to Botryosphaeria dieback.

Botryosphaeria dieback is a fungal grapevine trunk disease that represents a threat for viticulture worldwide due to the decreased production of affected plants and their premature death. This dieback is characterized by a typical wood discoloration called brown stripe. Herein, a proteome comparison of the brown striped wood from Botryosphaeria dieback-affected standing vines cultivars Chardonnay, Gewurztraminer, and Mourvèdre was performed. The transcript analysis for 15 targeted genes and the quantification of both total phenolics and specific stilbenes were also performed. Several pathogenesis-related proteins and members of the antioxidant system were more abundant in the brown striped wood of the three cultivars, whereas other defense-related proteins were less abundant. Additionally, total phenolics and some specific stilbenes were more accumulated in the brown striped wood. Strongest differences among the cultivars concerned proteins of the primary metabolism, which looked to be particularly impaired in the brown striped wood of 'Chardonnay'. Low abundance of some proteins involved in defense response probably contributes to make global response insufficient to avoid the symptom development. The differential susceptibility of the three grapevine cultivars could be linked to the diverse expression of various proteins involved in defense response, stress tolerance, and metabolism.

Flowering as the most highly sensitive period of grapevine (Vitis vinifera L. cv Mourvèdre) to the Botryosphaeria dieback agents Neofusicoccum parvum and Diplodia seriata infection.

Botryosphaeria dieback is a fungal grapevine trunk disease that currently represents a threat for viticulture worldwide because of the important economical losses due to reduced yield of affected plants and their premature death. Neofusicoccum parvum and Diplodia seriata are among the causal agents. Vine green stems were artificially infected with N. parvum or D. seriata at the onset of three different phenological stages (G stage (separated clusters), flowering and veraison). Highest mean lesion lengths were recorded at flowering. Major proteome changes associated to artificial infections during the three different phenological stages were also reported using two dimensional gel electrophoresis (2D)-based analysis. Twenty (G stage), 15 (flowering) and 13 (veraison) differentially expressed protein spots were subjected to nanoLC-MS/MS and a total of 247, 54 and 25 proteins were respectively identified. At flowering, a weaker response to the infection was likely activated as compared to the other stages, and some defense-related proteins were even down regulated (e.g., superoxide dismutase, major latex-like protein, and pathogenesis related protein 10). Globally, the flowering period seemed to represent the period of highest sensitivity of grapevine to Botryosphaeria dieback agent infection, possibly being related to the high metabolic activity in the inflorescences.

Losses of Yeast-Fermented Carbon Dioxide during Prolonged Champagne Aging: Yes, the Bottle Size Does Matter!

When it comes to champagne tasting, dissolved CO2 is a key compound responsible for the very much sought-after effervescence in glasses. Nevertheless, the slow decrease of dissolved CO2 during prolonged aging of the most prestigious cuvees raises the issue of how long champagne can age before it becomes unable to form CO2 bubbles during tasting. Measurements of dissolved CO2 concentrations were done on a collection of 13 successive champagne vintages stored in standard 75 cL bottles and 150 cL magnums showing prolonged aging ranging from 25 to 47 years. The vintages elaborated in magnums were found to retain their dissolved CO2 much more efficiently during prolonged aging than the same vintages elaborated in standard bottles. A multivariable exponential decay-type model was proposed for the theoretical time-dependent concentration of dissolved CO2 and the subsequent CO2 pressure in the sealed bottles during champagne aging. The CO2 mass transfer coefficient through the crown caps used to seal champagne bottles prior to the 2000s was thus approached in situ with a global average value of K ≈ 7 × 10-13 m3 s-1. Moreover, the shelf-life of a champagne bottle was examined in view of its ability to still produce CO2 bubbles in a tasting glass. A formula was proposed to estimate the shelf-life of a bottle having experienced prolonged aging, which combines the various relevant parameters at play, including the geometric parameters of the bottle. Increasing the bottle size is found to tremendously increase its capacity to preserve dissolved CO2 and therefore the bubbling capacity of champagne during tasting. For the very first time, a long time-series dataset combined with a multivariable model indicates that the bottle size plays a crucial role on the progressive decay of dissolved CO2 experienced by champagne during aging.

Physiological changes in green stems of Vitis vinifera L. cv. Chardonnay in response to esca proper and apoplexy revealed by proteomic and transcriptomic analyses.

Among grapevine trunk diseases, esca proper and apoplexy commonly represent a threat for viticulture worldwide. To retrieve further information about the mechanisms activated in apoplectic and esca proper-affected plants, a two-dimensional gel electrophoresis (2-DE) based analysis was conducted on green stems from 26-year-old standing vines. Symptomatic and asymptomatic stems from both apoplectic (A) and esca proper-affected (E) plants compared to control (without visual symptom since 10 years) stems were studied. Thirty-three differentially expressed proteins were identified by nanoLC-MS/MS and included into three groups conceptually defined as proteins involved in (i) metabolism and energy, (ii) stress tolerance, and (iii) defense response. For nine of them, expression of the relative mRNA's was also monitored by qRT-PCR. Proteome variations were specifically related to apoplexy and esca proper but were more similar in asymptomatic stems than in the symptomatic ones. Remarkable quantitative differences were noted for several proteins in symptomatic stems according to the expressed form, A and E. Results further indicate that similar responses are likely activated in asymptomatic stems but a various quantitative expression is triggered upon onset of apoplexy or esca proper symptoms while both kind of plants are infected by the same pathogenic fungi.

Metabolomics reveals simultaneous influences of plant defence system and fungal growth in Botrytis cinerea-infected Vitis vinifera cv. Chardonnay berries.

Botrytis cinerea is a fungal plant pathogen of grape berries, leading to economic and quality losses in wine production. The global metabolite changes induced by B. cinerea infection in grape have not been established to date, even though B. cinerea infection is known to cause significant changes in chemicals or metabolites. In order to better understand metabolic mechanisms linked to the infection process and to identify the metabolites associated with B. cinerea infection, (1)H NMR spectroscopy was used in global metabolite profiling and multivariate statistical analysis of berries from healthy and botrytized bunches. Pattern recognition methods, such as principal component analysis, revealed clear metabolic discriminations between healthy and botrytized berries of botrytized bunches and healthy berries of healthy bunches. Significantly high levels of proline, glutamate, arginine, and alanine, which are accumulated upon plant stress, were found in healthy and botrytized berries of botrytized bunches. Moreover, largely degraded phenylpropanoids, flavonoid compounds, and sucrose together with markedly produced glycerol, gluconic acid, and succinate, all being directly associated with B. cinerea growth, were only found in botrytized berries of botrytized bunches. This study reports that B. cinerea infection causes significant metabolic changes in grape berry and highlights that both the metabolic perturbations associated with the plant defence system and those directly derived from fungal pathogen growth should be considered to better understand the interaction between metabolic variation and biotic pathogen stress in plants.

Unraveling different chemical fingerprints between a champagne wine and its aerosols.

As champagne or sparkling wine is poured into a glass, the myriad of ascending bubbles collapse and radiate a multitude of tiny droplets above the free surface into the form of very characteristic and refreshing aerosols. Ultrahigh-resolution MS was used as a nontargeted approach to discriminate hundreds of surface active compounds that are preferentially partitioning in champagne aerosols; thus, unraveling different chemical fingerprints between the champagne bulk and its aerosols. Based on accurate exact mass analysis and database search, tens of these compounds overconcentrating in champagne aerosols were unambiguously discriminated and assigned to compounds showing organoleptic interest or being aromas precursors. By drawing a parallel between the fizz of the ocean and the fizz in Champagne wines, our results closely link bursting bubbles and flavor release; thus, supporting the idea that rising and collapsing bubbles act as a continuous paternoster lift for aromas in every glass of champagne.

Densities, Viscosities, Thermal Expansivities, and Isothermal Compressibilities of Carbonated Hydroalcoholic Solutions for Applications in Sparkling Beverages.

Densities, viscosities, isothermal compressibilities, and thermal expansivities of carbonated hydroalcoholic solutions relevant for sparkling beverages are evaluated by molecular dynamics simulations as a function of temperature and alcoholic degree. They are compared with available experimental data, among which new measurements of densities and viscosities are performed in that respect. The OPC water model seems to yield the most accurate results, and the choice of CO2 model has little influence on the results. Theoretical densities obtained with the OPC model typically deviate by ∼2 kg m-3 from experimental data. At low alcoholic degrees (<9% EtOH vol), experimental viscosities lie in between theoretical values derived from the Stokes-Einstein formula and the calculation of transverse current autocorrelation functions, but at higher alcoholic degrees (≥9% EtOH vol), the Stokes-Einstein relation leads to viscosities in quantitative agreement with experiments. Isothermal compressibilities estimated with a fluctuation formula roughly extend from 0.40 to 0.49 GPa-1 in close agreement with the experimental range of values. However, thermal expansivities are found to significantly overestimate experimental data, a behavior that is partly attributed to the low temperature of maximum density of the OPC model. Despite this discrepancy, our molecular model seems to be suitable for describing several transport and thermodynamic properties of carbonated hydroalcoholic solutions. It could therefore serve as a starting point to build more realistic models for carbonated beverages, from fizzy drinks to sparkling wines.

Recent Progress in the Analytical Chemistry of Champagne and Sparkling Wines.

The strong interplay between the various parameters at play in a bottle and in a glass of champagne or sparkling wine has been the subject of study for about two decades. After a brief overview of the history of champagne and sparkling wines, this article presents the key steps involved in the traditional method leading to the production of premium modern-day sparkling wines, with a specific focus on quantification of the dissolved CO2 found in the sealed bottles and in a glass. Moreover, a review of the literature on the various chemical and instrumental approaches used in the analysis of dissolved and gaseous CO2, effervescence, foam, and volatile organic compounds is reported.

How Many CO2 Bubbles in a Glass of Beer?

The number of bubbles likely to form in a glass of beer is the result of the fine interplay between dissolved CO2, tiny particles or glass imperfections acting as bubble nucleation sites, and ascending bubble dynamics. Experimental and theoretical developments about the thermodynamic equilibrium of dissolved and gas-phase carbon dioxide (CO2) were made relevant to the bottling and service of a commercial lager beer, with 5% alcohol by volume and a concentration of dissolved CO2 close to 5.5 g L-1. The critical radius and the subsequent critical concentration of dissolved CO2 needed to trigger heterogeneous nucleation of CO2 bubbles from microcrevices once the beer was dispensed in a glass were derived. The subsequent total number of CO2 bubbles likely to form in a single glass of beer was theoretically approached as a function of the various key parameters under standard tasting conditions. The present results with the lager beer were compared with previous sets of data measured with a standard commercial Champagne wine (with 12.5% alcohol by volume and a concentration of dissolved CO2 close to 11 g L-1).

How Does Gas-Phase CO2 Evolve in the Headspace of Champagne Glasses?

The chemical space perceived by a consumer of champagne or other sparkling wines is progressively modified all along tasting. Real-time monitoring of gas-phase CO2 concentration was performed, through a CO2-diode laser sensor, along a two-dimensional array of nine points in the headspace of three types of glasses poured with champagne. Two original glasses with distinct headspace volumes were compared with the standard INAO tasting glass. For each of the three glass types, a kind of temperature-dependent CO2 fingerprint was revealed and discussed as a function of the glass geometry and headspace volume. Moreover, a simple model was developed, which considers the rate of decrease of the concentration of gas-phase CO2 in the headspace of a glass after the pouring process as being mainly ruled by natural air convection in ambient air. The timescale which controls the rate of decrease of gas-phase CO2 was found to highly depend on the ratio of the headspace volume to the open aperture of the glass.

Monitoring gas-phase CO2 in the headspace of champagne glasses through combined diode laser spectrometry and micro-gas chromatography analysis.

During Champagne or sparkling wine tasting, gas-phase CO2 and volatile organic compounds invade the headspace above glasses, thus progressively modifying the chemical space perceived by the consumer. Gas-phase CO2 in excess can even cause a very unpleasant tingling sensation perturbing both ortho- and retronasal olfactory perception. Monitoring as accurately as possible the level of gas-phase CO2 above glasses is therefore a challenge of importance aimed at better understanding the close relationship between the release of CO2 and a collection of various tasting parameters. Here, the concentration of CO2 found in the headspace of champagne glasses served under multivariate conditions was accurately monitored, all along the 10 min following pouring, through a new combined approach by a CO2-Diode Laser Sensor and micro-gas chromatography. Our results show the strong impact of various tasting conditions (volume dispensed, intensity of effervescence, and glass shape) on the release of gas-phase CO2 above the champagne surface.

Unveiling CO2 heterogeneous freezing plumes during champagne cork popping.

Cork popping from clear transparent bottles of champagne stored at different temperatures (namely, 6, 12, and 20 °C) was filmed through high-speed video imaging in the visible light spectrum. During the cork popping process, a plume mainly composed of gaseous CO2 with traces of water vapour freely expands out of the bottleneck through ambient air. Most interestingly, for the bottles stored at 20 °C, the characteristic grey-white cloud of fog classically observed above the bottlenecks of champagne stored at lower temperatures simply disappeared. It is replaced by a more evanescent plume, surprisingly blue, starting from the bottleneck. We suggest that heterogeneous freezing of CO2 occurs on ice water clusters homogeneously nucleated in the bottlenecks, depending on the saturation ratio experienced by gas-phase CO2 after adiabatic expansion (indeed highly bottle temperature dependent). Moreover, and as observed for the bottles stored at 20 °C, we show that the freezing of only a small portion of all the available CO2 is able to pump the energy released through adiabatic expansion, thus completely inhibiting the condensation of water vapour found in air packages adjacent to the gas volume gushing out of the bottleneck.

Evidence for protein degradation by Botrytis cinerea and relationships with alteration of synthetic wine foaming properties.

Botrytis cinerea is an important fungal pathogen particularly dreaded in the cool climate vineyard. It is responsible for important damage, especially the decrease in foamability of sparkling wines, such as Champagne. Different studies have shown that proteins are largely involved in the stabilization of Champagne foam despite their low concentration. Other works demonstrated changes in the electrophoretic characteristics of must proteins originating from botrytized grapes, although the cause of such alterations was never explained. In the first part of this study, results showed the release by B. cinerea of 3.5 mg/L total proteins in a synthetic liquid medium. Among these proteins, the presence of a protease activity on bovine serum albumin (BSA) and must proteins was demonstrated by using a colorimetric method and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In the model wine, the Bradford method showed a BSA loss of 66% after 24 h and a loss of 96% after 120 h. In the same model wine, the soluble must protein concentration decreased by 35% after 1 week and by 53% after 2 weeks while the control showed no protein loss. B. cinerea proteases were then able to degrade BSA and must proteins and were above all active at must and wine pH and in the presence of ethanol and SO(2). The second part of this work was dedicated to the relationship between the presence of B. cinerea proteases and its effects on the synthetic wine foaming properties. The addition of a B. cinerea culture medium (1/33 v/v) to the synthetic wine containing 21 mg/L soluble grape proteins induced a decrease in foamability by 60% after 1 week. For BSA in the model wine, the foamability decreased by 32% after 24 h and by 95% after 120 h, as shown by the colorimetric method. These experiments demonstrate for the first time the relationship between B. cinerea protease activity and the decrease in wine foaming properties.

Determination of the grape invertase content (using PTA-ELISA) following various fining treatments versus changes in the total protein content of wine. relationships with wine foamability.

Proteins have proven to play a major role in the stabilization of foam in Champagne wines despite their low concentration that ranges from 4 to 20 mg/L. The aim of this study was to evaluate the effect of fining on total protein and grape invertase contents of champenois base wines and their foaming properties. Data showed that fining and especially the use of bentonite at doses ranging from 10 to 50 g/hL leads to a significant decrease in the total protein content of wines together with that of the grape invertase content, with such a decrease being very detrimental to the foaming properties of the treated wines in terms of foam height (HM) and foam stability (HS). Only a slight decrease in the total protein content, in the grape invertase concentration, and in the foam quality of wines was observed when using casein (10 and 20 g/hL) or bentonite combined with casein (both at 20 g/hL). Our study thus clearly establishes the good correlation existing between the wine protein concentration and its foaming properties. A remarkable correlation was observed between the decrease in the grape invertase content and the total protein content of wines, following bentonite treatments, suggesting that the grape invertase (which represents at least 10-20% of the wine proteins) follows a similar behavior upon fining to other proteins of Champagne wines, despite the high molecular mass and the highly glycosylated structure of this particular protein. Moreover, the decrease in total protein and grape invertase contents of wine after fining with bentonite was found to be correlated with a decrease in the foaming properties of the corresponding wines (with respectively R(2) = 0.89 and 0.95).

Precipitation of champagne base wine proteins prior to 2D electrophoresis.

Numerous methods have been employed to depict the protein content of wines. Among them, two-dimensional electrophoresis (2D-E) presents a powerful resolution, but has been poorly applied to wine. Furthermore, 2D-E was coupled with various extraction methods of proteins without any reference method for wine. Here, we describe a rapid method to extract proteins from a champagne base wine through ultrafiltration followed by precipitation with ethanol and trichloroacetic acid. More than 50 spots were visualized on 2D-gels (7 cm, pH 3-6) by colloidal Coomassie Brilliant Blue staining.

It's time to pop a cork on champagne's proteome!

Champagne is a world-renowned French sparkling wine, which undergoes many steps (fermentation, aging …) for its elaboration. Various compounds might evolve during this winemaking process and thus modify its final quality. Here, we report the first proteome analysis of two standard commercial Champagne wines, using the powerful Combinatorial Peptide Ligand Library (CPLL) technique. Indeed, wine proteins are present in small amounts but they are key compounds, likely to impact on both foam quality and aroma behavior. Forty-three unique gene products were retrieved in a single-varietal champagne and a blended champagne. Several proteins from Vitis vinifera together with seven yeast proteins were undoubtedly identified in these Champagne wines. BIOLOGICAL SIGNIFICANCE: The main advantage of CPLLs was the detection of low abundance proteins despite the absence of purification or pre-concentration step. It is an important fact to take into account, since Champagne wines generally contain a low amount of proteins (5-10mg/L) that implies to usually concentrate wine proteins before 1D or 2D electrophoresis. Most Champagne proteins are grape and yeast glycoproteins which are considered as good foam "promoters". Some of these proteins might also interact with wine aromas, and thus contribute to the overall quality of Champagne wines. This article is part of a Special Issue entitled: Proteomics of non-model organisms.