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Sulfur dioxide is the most used additive today for preventing browning in grape musts and wines. However, since wine consumers are increasingly interested in healthier wines, the wine industry is keen to reduce its use. Some promising alternatives to sulfur dioxide have been proposed in recent years, including glutathione, both pure and in the form of inactivated yeasts, and Metschnikowia pulcherrima used as a bioprotective agent. Some information exists about the protective effect against oxidation of glutathione but there is very few about the use of bioprotection for that purpose. Supplementation with glutathione, regardless of the commercial form, reduced oxygen consumption and browning intensity when laccase was not present in the grape juice. Metschnikowia pulcherrima also reduced browning intensity in the absence of laccase but increased the total oxygen consumption. However, in the presence of laccase, glutathione and Metschnikowia pulcherrima were not effective enough to adequately prevent the grape juice from browning. Glutathione, both pure and in the form of inactivated yeasts, and Metschnikowia pulcherrima are interesting tools for protecting grape must against browning, and thus reducing the use of sulfur dioxide.

Background The aim of this work was to study the influence of grape berry morphology, especially the seed weight percentage, on the tannin concentration and astringency of red wine. Clusters of Tempranillo, Garnacha, Merlot, and Cabernet Sauvignon were characterized and their seeds were extracted and macerated in a model wine solution. In parallel, we elaborated three types of wines of each cultivar. One wine was made with only grape juice, one wine was made adding the appropriate proportion of seeds to the grape juice, and the last wine was elaborated with the complete destemmed and crushed berries. Results Merlot and Cabernet Sauvignon grapes, which have higher percentage of seed weight with respect to the berry weight than Tempranillo and Garnacha grapes originated wines with higher tannin concentration and astringency than Tempranillo and Garnacha wines. Conclusion The main conclusion of this study is that the seed weight percentage with respect to the berry weight is one of the main determinants of the final tannin concentration and astringency of red wines., The aim of this work was to study the influence of grape berry morphology, especially the seed weight percentage, on the tannin concentration and astringency of red wine.

International audience; The aim of this paper is to develop a synthetic model reproducing more realistically the conditions of grape juice to study browning caused by laccase from Botrytis cinerea. The laccase browning kinetics were measured by monitoring the increase in absorbance at 420 nm over time in the presence of different substratesone monophenol: 4-hydroxybenzoic acid; three orthodiphenols: caftaric acid, (+)-catechin and (−)-epicatechin; and one triphenol: gallic acid. The results indicate that orthodiphenols are better substrates than triphenols and that monophenols do not appear to be reactive. Of the orthodiphenols, (+)-catechin showed the greatest browning intensity, followed in decreasing order by (−)-epicatechin and caftaric acid. These results confirm that sulfur dioxide, ascorbic acid and glutathione really do protect grape juice against laccase browning. The effectiveness of ascorbic acid and glutathione also confirm that both antioxidants can be useful tools for reducing doses of sulfur dioxide in winemaking, especially when grey rot is present.

Sparkling wines elaborated using the traditional method undergo a second fermentation in the bottle. This process involves an aging time in contact with the lees, which enriches the wine in various substances, especially proteins, mannoproteins and polysaccharides, thanks to the autolysis of the yeasts. As a result of this yeast autolysis, sparkling wines benefit from better integration of carbon dioxide and a clear sensory improvement, especially in the case of long aging. This chapter synthetizes the main results that our research group has obtained about the influence of yeasts autolysis on sparkling wines composition and quality during last years, making special emphasis on the capacity of the lees to release proteins and polysaccharides as well as on their capacity to consume oxygen and thus protect the sparkling wines from oxidation.

The interaction between stomach porcine mucin and 3 oenological tannins (extract of ellagitannins from oak, extract of gallotannins from gall nuts and extract of proanthocyanidins from grape seeds) was measured by Surface Plasmon Resonance (SPR). These tannins were analysed and their astringency was determined using the Astringency Index method and by tasting. The interaction constants were determined using a Biacore SPR device (1:1 Langmuir binding model). The results indicate that the ellagitannins are more astringent than gallotannins and those, in turn, are more astringent than seed proanthocyanidins if the richness of the commercial extracts is considered. The astringency index of these tannins had high correlation and regression coefficients with their kinetic and thermodynamic dissociation constants. This data support a hypothesis that astringency depends not only on the thermodynamic tendency to form the complex between tannins and salivary proteins but also probably on the time required to dissociate the complex.

This study shows the monitoring of the physical, chemical and sensorial changes that occur in the sparkling wine along 18 months of aging due to different typology yeast-derived products; dry inactivated yeast from Saccharomyces (Saccharomyces cerevisiae) and non-Saccharomyces (Torulaspora delbrueckii) yeast strains, yeast autolysate, and yeast protein extract tested at two different doses. The addition of 5 g/hL yeast protein extract and inactivated yeast from T. delbrueckii helped to preserve esters in wines with 9 and 18 months of aging on lees. The addition of yeast autolysate achieved greater polysaccharide enrichment and gave rise to sparkling wines with the highest antioxidant activity. Effects on foaming properties were quite different depending on the aging time. Despite this, sparkling wines treated with 10 g/hL of yeast autolysate and Optimum White™ generally exhibited the highest foamability and foam stability. Further experiments with higher doses are needed to observe clear effects on sensory profile.

Onologische Tannine werden aus unterschiedlichen Grunden in der Weinherstellung verwendet (Versari et al., 2013; Vignault et al., 2018), insbesondere jedoch wegen ihrer hemmenden Eigenschaften gegenuber der Aktivitat der Laccase. Die Verwendung ist besonders in denjenigen Jahrgangen sinnvoll, die von der Botrytis-Traubenfaule betroffen sind, um die Weine vor Braunfarbung zu schutzen. Dieser Anti-Laccase-Effekt der Tannine beruhte bis vor Kurzem nur auf Beobachtungen, ohne wissenschaftliche Beweise. Die OIV hatte aus diesem Grund eine spezielle Arbeitsgruppe gegrundet, die sich mit der praktischen Anwendung onologischer Tannine beschaftigt. Die Ergebnisse dieser Untersuchungen werden in diesem Artikel vorgestellt und zeigen die Effektivitat, mit der onologische Tannine die Laccaseaktivitat inhibieren und somit die Farbe der Weine schutzen (Vignault et al., 2019; Vignault et al., 2020).

Biodiversity loss is a worldwide problem, and the vine is probably one of the most affected species. The number of cultivated varieties of vine has decreased in recent years, and the local varieties of each region have been displaced by other varieties that have expanded internationally due to globalization of markets. This work focuses on the characterization and identification of 111 accessions from the Balearic Archipelago by microsatellite analysis, using 20 molecular markers. A total of 58 different genotypes were identified. Twenty-nine names commonly used in the Islands are considered new synonyms. Seventeen cases of mislabeling and 5 unknown molecular profiles were described. Of the 58 varieties identified, 16 have been proposed as local varieties (Argamusa, Callet, Callet cas Concos blanco, Callet cas Concos negro, Epero de gall, Excursach, Fogoneau, Gafarro, Giro ros, Gorgollasa, Manses de Tibbus together with its mutation, Manses de Tibbus-1, Manto negro, Sabate and Valent blanc). This local population has also been compared with a world population in order to study their singularity. In all cases these 16 local varieties behaved like an own subpopulation being very distant respect to the other populations. These results also suggest that local varieties have had a great influence of Iberian Peninsula varieties over the years and a slight Italian influence. Finally, it is suggested that most of the crossing related to these local varieties have been carried out in Balearic Islands.

The foam of two base wines was overflowed by carbon dioxide sparging, and the foam wine was recovered. The foam wine (FW), original wine (CW), and the remainder fraction (RW) were analyzed to determine foam properties, chemical composition, and some physical properties. In general, FW had better foam parameters, higher density, and lower surface tension and viscosity than CW and RW. FW wines also tended to have higher concentrations of proteins and lower concentrations of ethanol, higher alcohols, titratable acidity, and esters. The improved foam properties in the FW wines were likely due to low levels of foam-negative factors (ethanol and fatty acids) and high levels of foam-positive factors (proteins).

The analytical and sensory analysis of wines aged in barrels of French and American oak with three different levels of toasting was performed to determine the relationship between the volatile substances released by oak wood and sensory appreciation by a trained panel. For that purpose, a discolored white wine of Macabeo and a red wine of Cabernet Sauvignon from 2012 vintage were aged for 12 months in new barrels. Similar wines from the following vintage were aged in the same barrels for knowing how the use of the barrels affects their capacity to release volatile substances and its organoleptic impact. A significant correlation was found between the appreciation of coconut and smoked/toasted notes by the panel and the theoretical sensory impact of β-methyl-γ-octalactone and volatile phenols, respectively, in two different wines aged in new oak barrels. Vanillin correlated significantly in only one of the wines tasted. The panelists generally preferred wines aged in medium-toasted new barrels for both oak species. In a triangle test, tasters could distinguish between wines aged in new American and French oak barrels when the toasting level was light or medium but not when it was heavy. They were also able to distinguish between wines aged in new and 1-year-used barrels. It can be concluded that the botanical origin of the oak, the toasting level of the staves and the number of times that the barrels have been used previously have a real impact on the volatile composition of the wine and in its sensory impact.

International audience; Enzymatic parameters (KM and Vmax), residual activity, effect of bentonite and electrophoresis characterization of laccase in the presence of different oenological tannins (OT) were investigated in relation to B. cinerea negative effects in grapes and musts. Five OT were tested (gallotannin, ellagitannin, quebracho, grape-skin and grape-seed) in comparison with ascorbic acid (AA), sulfur dioxide (SO2) and bentonite. We added OT, AA, SO2 and bentonite to botrytized must obtained by inoculation of grapes with B. cinerea strain 213. Laccase activity was measured by the syringaldazine method at different concentrations of substrate. Enzymatic parameters were determined using Michaelis-Menten and Lineweaver-Burk plots. The B. cinerea strain was also grown in a liquid medium for laccase production. Molecular weight of laccases and effect of OT upon these laccases were studied by SDS-PAGE. Results confirm that bentonite, contrary to OT, did not permit to reduce laccase activity. Regardless the tannin considered, Vmax, KM and laccase activity were reduced and gallotannin, grape-skin and grape-seed tannin presented the greatest ability. Efficiency of grape-seed tannin addition in order to reduce the laccase activity, was comparable to that of AA or SO2 at the typical doses employed in oenology for each one. Oenological tannins appear to be excellent processing aids to prevent laccase effects and contribute to reduce the use of SO2 in grapes and musts.

International audience; Aim: The aim of the study was to evaluate the effects of five different oenological tannins on the color of a malvidin-3-O-monoglucoside solution, and thereby assess the effectiveness of these tannins as copigments.Methods and results: Solutions containing malvidin-3-O-glucoside and different doses of copigments were prepared. The malvidin-3-O-glucoside concentration of the solutions, and color parameters, were measured after 1 and 7 days.Conclusions: On days 1 and 7, a decrease in lightness and hue, and an increase in chroma, absorption at 520 nm and wavelength of maximal absorption were observed in solutions containing the oenological tannins. A decrease in malvidin-3-O-glucoside concentration in the tannin-containing solutions compared with the control solution was detected on day 7. The extent of this decrease depended on the specific tannin. Some changes in color parameters on day 7 compared with day 1 were observed, which were probably due to the formation of new pigments. The total color difference between the different malvidin-3-O-glucoside solutions and a pure white solution was calculated to estimate the effectiveness of the different tannins as copigments.Significance and impact of the study: These results prove that supplementation with oenological tannins is a viable option for improving the color of red wines. A copigmentation index is proposed for measurement of the effectiveness of copigments.

This communication actualizes the status of the research of the OIV working group on oenological tannins with the purpose of deepening the knowledge of the mechanisms and functionalities of oenological tannins in winemaking. The obtained results confirm that oenological tannins really exert an effect as copigments and that they really protect the wine color against the negative effect of the enzyme laccase present in grapes affected by the infection of Botrytis cinerea.

Sparkling wines elaborated with a traditional method need to age in the bottle in contact with wine lees because yeast autolysis enriches the wines in colloids and improves their effervescence, foam and aromatic complexity. It is generally considered that lees protect the wine against oxidation because they consume small amounts of oxygen that can permeate the crown cap. However, to our knowledge there is no specific study on this subject using lees from real sparkling wine. Therefore, the oxygen consumption rate (OCR) of the lees of sparkling wines from the first to the ninth year of aging time was measured using a noninvasive fluorescence measurement method. The results indicate that lees really consume oxygen and that their OCR tended to decrease with the wine aging time. These data suggest that the lees’ capacity to protect against oxidation decreases over time, which could affect the ability of sparkling wines to age properly.

This work studied how different grape maturity levels and cluster treatments affect the color and phenolic composition of Grenache wines. Specifically, five treatments were undertaken at a microvinification scale for three maturity levels : Control (destemmed and crushed grapes), Whole Berry, Whole Cluster, Crushed Cluster and Submerged Cap. The first three treatments were also reproduced with large-scale wine fermentation in oak barrels but only with well-ripened grapes. The results indicated that the total polyphenol index (TPI), anthocyanin and proanthocyanidin concentrations, as well as the mean degree of polymerization were higher in all the treatments when the grapes were riper. Submerged Cap generated maximum color and polyphenolic extraction at the three maturity levels. Whole Berry wines were the most similar to the controls. The presence of stems (Crushed Cluster and Whole Cluster treatments) produced wines with a significantly higher pH at all maturity levels and with lower color intensity when the grapes were less ripe. The presence of stems also significantly increased the TPI in almost all cases.

In a previous study, we reported that sequential inoculation of Torulaspora delbrueckii (strain TD291) and a specific strain of Saccharomyces cerevisiae during the first fermentation increased the protein concentration and improved the foaming properties of a base wine. Since effervescence and foam of sparkling wines are key quality factors, the interest of this practice for sparkling wine industry is obvious. In this paper, we study whether the foaming properties of the sparkling wines produced from the base wines obtained by sequential inoculation with these strains of T. delbrueckii and S. cerevisiae remain better than those of their controls produced from base wines fermented only with S. cerevisiae. The obtained results confirmed that sequential inoculation in the production of the base wine originated sparkling wines with significantly higher maximum heights of foam than conventional inoculation, probably because autolysis of the T. delbrueckii (strain TD291) cells in the base wine released higher amounts of proteins, especially of the low molecular weight fraction.

The aim of this paper is to study the real influence of seeds and stems on wine composition, astringency, and bitterness. A decolored grape juice and a grape juice macerated for 4 days from the same Cabernet Sauvignon grapes were fermented with or without supplementation with 100% seeds, 300% seeds, or 100% stems. Once alcoholic fermentation had finished, the wines were analyzed and tasted. The presence of seeds and stems increased the concentration of flavan-3-ol monomers with respect to the controls. However, the seeds mainly released (+)-catechin and (-)-epicatechin, whereas the stems mainly released (+)-catechin and (+)-gallocatechin. The seeds and stems also released proanthocyanidins; those from seeds have a lower mDP and a high percentage of galloylation, whereas those from stems have a higher mDP and a relatively high percentage of prodelphinidins. The presence of seeds and stems brought about a slight but significant increase in pH and lowered titratable acidity and ethanol content. The presence of seeds boosted color intensity, whereas stems had the opposite effect. Finally, both seeds and stems increased wine astringency and bitterness.

A collection of 338 grapevine accessions from 24 countries planted on the estates of Bodegues Sumarroca (AOC Penedes) was genotyped with 20 microsatellite markers. A total of 294 different molecular profiles were obtained; 28 of them are presented for the first time. Twenty-six accession names are considered new synonyms and are commonly used in several regions.

Nowadays supplementing red wines with commercial inactive dry yeasts is a widespread practice in winemaking because it leads to better balanced wines through increased mouthfeel and smooth astringency. The aim of this article is to study, in a red wine and in a model wine solution, how supplementation with three commercial inactive dry yeasts affects chemical composition and astringency. This will give us a better understanding of the action mechanism involved. RESULTS The results suggest that this action mechanism is related to two different phenomena. The first is that inactive yeasts release polysaccharides and oligosaccharides which can increase mouthfeel and inhibit interactions between salivary protein and tannins. The second is that they have a direct effect on the precipitation or absorption of proanthocyanidins, especially the larger polymers, which have been described as the most astringent. CONCLUSION It can be concluded that supplementation with inactive yeasts is indeed a useful tool for smoothing the astringency of red wines. ? 2016 Society of Chemical Industry

The effect of the botanical origin, pH level and ethanol content of different oenological tannins on the color of malvidin-3-O-monoglucoside solution, including their effectiveness as copigments, was studied. Briefly, a model wine solution (4 g/L of tartaric acid, pH 3.5 and 12% ethanol) containing 50 mg/L of malvidin-3-O-monoglucoside was prepared and supplemented with 0.1, 0.2 and 0.4 g/L of commercial tannins using (&minus, )-epicatechin as reference control copigment. Six additional model wine solutions (12% ethanol at pH 3.1, 3.5 or 3.9, and 10%, 12% or 14% ethanol at pH 3.5) were prepared as previously described. Samples were stored under airtight conditions. After a week the full absorbance spectrum in the visible range (400&ndash, 800 nm) was measured and CIELAB color space was determined. These measurements, including an increase in a* (redness), a decrease in b* (yellowness) and a decrease in L* (lightness), indicated that all oenological tannins had a clear positive effect on color copigmentation. Moreover, hydrolysable tannins appeared to be better copigments than condensed tannins as the copigmentation effectiveness (Cp) was found to be between two to four times higher. The effects of these tannins were dose-dependent because a higher addition resulted in a greater impact on copigmentation. In general, an increase in pH and ethanol content resulted in a decrease of the effect of tannins on color. Independent of intrinsic wine conditions, hydrolysable tannins, more specifically gallotannin, remain the most effective in increasing red wine color. These results prove that supplementation with oenological tannins, especially hydrolysable tannins, could be an interesting tool for the improvement of the red wine color.

Aims: The aim of this research was to determine and quantify the ability of enological tannins to reduce laccase activity and, consequently, to protect wine color against enzymatic browning and/or oxidasic haze. Methods and results: Botrytized grape juice with laccase activity was obtained by inoculating Botrytis cinerea in healthy mature grapes. Laccase activity was determined in grape juice before and after supplementation with enological tannins using the syringaldazine method. White micro-fermentations were performed in the presence or not of laccase activity and supplemented or not with enological tannins in order to determine how the color was affected. Similarly, red micro-fermentations were performed using white grape juice supplemented with malvidin-3-O-glucoside. All enological tannins inhibited laccase activity and protected the wine color. Conclusion: Supplementation with enological tannins is an interesting tool to inhibit laccase activity and protect the color of white wines from browning and the color of red wines from oxidasic haze. Significance and impact of the study: This is the first scientific study evidencing the inhibitory effect of enological tannins on laccase activity in winemaking conditions. Keywords: enological tannins, Botrytis cinerea, grey mould, laccase activity, contact time, dose effect

© 2015 by the American Society for Enology and Viticulture. All rights reserved. Cabernet Sauvignon grapes were harvested at three different degrees of maturity (~three, five, and seven weeks postveraison) and used for micro-scale vinifications. For each maturity, four different maceration lengths (one, two, three, and four weeks) were applied in triplicate to assess the influence of both maceration length and grape maturity on the composition of wine polysaccharides. The total concentration of wine polysaccharides was estimated by high resolution size exclusion chromatography-refraction index detection and the polysaccharides then underwent acidic hydrolysis. The neutral monosaccharides released were analyzed by ion exclusion chromatography using an HPLC-RID chromatographic system. The total concentration of wine polysaccharides increases with maceration length and with grape maturity. Both yeast polysaccharides (mannoproteins, MP) and some grape polysaccharides (polysaccharides rich in arabinose and galactose, PRAGs) increase with maceration length. However, grape maturity affects PRAGs and MPs differently: while PRAGs increase with the grape’s maturity, the opposite appears to be true of yeast polysaccharides., The authors would like to thank CICYT ( AGL2007-66338 and AGL2011-29708-C02-01) and CDTI ( Project CENIT Demeter) for their financial support.

Background and Aims According to one of the classical postulates of viticulture, cultivars with smaller berries produce the best red wines. During grape development, some differences at berry level lead to a wide range of fruit heterogeneity at harvest. One source of heterogeneity at harvest is berry size. The aim of this work is to determine if berry size affects the colour and chemical composition of wine. Methods and Results Cabernet Sauvignon grapes were harvested at optimal ripeness, and screened by two sieves, to select three groups of grapes of large, medium and small size. Wines were made from each size class in triplicate, with the control being wine made from unselected grapes. The colour properties and composition of the phenolic substances of the wines were determined. Conclusions Wine colour showed the clearest trend in this experiment: the smaller the berries, the deeper the wine colour, as measured by the CIELab coordinates as well as by (wine) colour intensity. Moreover, stilbene concentration increased when berry size decreased, while pH did the opposite. Finally, wines made from small berries had a titratable acidity, total phenolic index and monomeric flavan-3-ol concentration higher than that of wines made from the large- and medium-sized berry sizes. Significance of the Study These data suggest that berry size classification in wineries would be an interesting tool for management of wine composition.

The use of non-Saccharomyces yeasts for the production of quality wine has become increasingly frequent in recent years. Several studies of the influence of Torulaspora delbrueckii and Metschnikowia pulcherrima on chemical composition have been reported, especially in aspects concerning aroma. The aim of this article was to study the influence of sequential inoculation of these non-Saccharomyces yeasts and Saccharomyces cerevisiae on the composition and quality of base wine for sparkling wine production. The results indicate that sequential inoculation with non-Saccharomyces yeasts may be an interesting tool for obtaining base wines with different characteristics. On the one hand, T. delbrueckii Biodiva™ strain increased glycerol concentration, reduced volatile acidity and exerted a positive effect on foaming properties improving foamability (Hm) and foam persistence (Hs). On the other hand, M. pulcherrima Flavia® strain also increased foam persistence (Hs) and changed the aromatic profile, increasing smoky and flowery notes.

BACKGROUND The aim of this paper is to determine the main factors that influence the foaming properties of base wines and sparkling wines and, in particular, the role played by the maturity of the grapes in the controlled designation of origin (CDO) Cava. Macabeo, Xarel.lo, Parellada and Chardonnay grapes were harvested at two different maturity levels in two vintages. The first harvest was selected because of its desirable titratable acidity and the second because of its optimal sugar concentration. The mono-varietal base wines and standard blends were transformed into sparkling wines and aged for 14 months. RESULTS The results indicate that the main factors affecting foam properties are ethanol content, high molecular weight polysaccharides and gluconic acid (which have a negative effect), and proteins (which have a positive effect). CONCLUSION The main conclusion of this study is that the foaming properties of wines can be improved if harvest dates are advanced. © 2014 Society of Chemical Industry

BACKGROUND: The blending of wine is a common practice in winemaking to improve certain characteristics that are appreciated by consumers. The use of some cultivars may contribute phenolic compounds that modify certain characteristics in blended wines, particularly those related to mouthfeel. The aim of this work was to study the effect of Carm ´ en ` ere, Merlot and Cabernet Franc on the phenolic composition, proanthocyanidin profile and mouthfeel characteristics of Cabernet Sauvignon blends. RESULTS: Significant differences in chemical composition were observed among the monovarietal wines. Separation using Sep-Pak C18 cartridges revealed differences in the concentration but not in the proportion of various proanthocyanidins. Blending reduced polyphenol concentration differences among the various monovarietal wines. Although no major overall differences were observed after blending the monovarietal wines, this oenological practice produced clear differences in mouthfeel characteristics in such a way that the quality of the perceived astringency was different. CONCLUSION: This study showed that the use of a particular wine variety (Cabernet Sauvignon) in a higher proportion in wine blending produced blends that were less differentiable from the monovarietal wine, owing to a suppression effect, producing an apparent standardization of the wines regarding chemical composition. c � 2013 Society of Chemical Industry