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Sparkling wines produced using the ancestral method, also known as Pét-Nats, are gaining more and more market share these days. However, scientific information on these wines is very scarce. The aim of this study was therefore to compare the physicochemical composition and sensory characteristics of a representative selection of commercial sparkling wines produced using the ancestral and traditional methods. Ancestral sparkling wines were more heterogeneous than traditional sparkling wines, as some of them showed lower internal pressure, higher turbidity, higher color intensity and lower effervescence. These differences are probably due to the fact that the protocol for making sparkling wines using the ancestral method is not as well defined as that for traditional sparkling wines. However, the ancestral method has the advantage of being able to work with riper grapes and a lower sulfur dioxide dosage. [ABSTRACT FROM AUTHOR]

The aim of this work was to study the cooperage potential of the oak species Quercus pyrenaica, which is widespread throughout the Iberian Peninsula. A red wine of 2016 vintage was aged in new barrels made from Quercus pyrenaica, Quercus petraea and Quercus alba for 12 months. This process was repeated with a similar red wine from the subsequent vintage using the same barrels in order to compare the performances of the new Q. pyrenaica barrels and Q. pyrenaica barrels that had been used for one year with equivalent Q. petraea and Q. alba barrels. The results indicate that Q. pyrenaica releases levels of β-methyl-γ-octalactone similar to those released by Q. alba and clearly higher than Q. petraea, whereas it releases levels of ellagitannins similar to Q. petraea and clearly higher than Q. alba. These data indicate that Q. pyrenaica is more similar to American oak from an aromatic point of view, since it provides mainly coconut notes, but is more similar to French oak in terms of wine structuration. Moreover, based on the preferences of a trained panel, the wines aged in the Q. pyrenaica barrels were ranked in second position, just behind the wines aged in the Q. petraea barrels and ahead of those aged in the Q. alba barrels. Consequently, Q. pyrenaica seems to have characteristics midway between the two most commonly used oak species for cooperage, confirming its high potential in this regard.

This communication studies some possible strategies to reduce or even to replace sulfur dioxide in winemaking. Specifically, the aim of this work was to study the protective effect against oxidation of a commercial inactivated dry yeast (IDY) with very high level of glutathione, and of a selected non-Saccharomyces yeast, Metschnikowia pulcherrima strain in comparison with sulfur dioxide.

One of the problems that most seriously affects oenology today is enzymatic browning, especially when grapes are infected by grey rot. We studied the capacity of glutathione (GSH) and a specific inactivated dry yeast rich in glutathione (IDY-GSH) to protect white grape must from browning compared to that of sulphur dioxide (SO2). The results indicate that SO2 drastically reduces the oxygen consumption rate (by around 72%), protects hydroxycinnamic acids from oxidation and prevents grape must against browning even in the presence of laccase. Specifically, the presence of SO2 reduced the colour's blue–yellow component (b*) by around 91% in control conditions and around 76% in the presence of laccase. GSH, pure or in the form of IDY-GSH, also reduces the oxygen consumption rate (by 23% and 36%, respectively) but to a lesser extent than SO2. GSH also favours the formation of grape reaction product (GRP) from hydroxycinnamic acids and effectively protects grape must against browning in healthy grape conditions. Specifically, the presence of GSH reduced b* by around 81% in control conditions. Nevertheless, in the presence of laccase, it was not effective enough, reducing b* by around 39% in the case of pure GSH and 24% in the case of IDY-GSH. Therefore, both forms of GSH can be considered as interesting alternative tools to SO2 for preventing browning in white grape must, but only when the grapes are healthy. [ABSTRACT FROM AUTHOR]

Fermented beverages, particularly wines, exhibit variable concentrations of organic and phenolic acids, posing challenges in their accurate determination. Traditionally, enzymatic methods or chromatographic analyses, mainly high-performance liquid chromatography (HPLC), have been employed to quantify these compounds individually in the grape must or wine. However, chromatographic analyses face limitations due to the high sugar content in the grape must. Meanwhile, phenolic acids, found in higher quantities in red wines than in white wines, are typically analyzed using HPLC. This study presents a novel method for the quantification of organic acids (OAs), glycerol, and phenolic acids in grape musts and wines. The approach involves liquid-liquid extraction with ethyl acetate, followed by sample derivatization and analysis using gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) detection mode. The results indicated successful detection and quantification of all analyzed compounds without the need for sample dilution. However, our results showed that the method of adding external standards was more suitable for quantifying wine compounds, owing to the matrix effect. Furthermore, this method is promising for quantifying other metabolites present in wines, depending on their extractability with ethyl acetate. Fermented beverages, particularly wines, exhibit variable concentrations of organic and phenolic acids, posing challenges in their accurate determination. Traditionally, enzymatic methods or chromatographic analyses, mainly high-performance liquid chromatography (HPLC), have been employed to quantify these compounds individually in the grape must or wine. The approach of this proposed method involves (i) methoximation of wine compounds in a basic medium, (ii) acidification with HCl, (iii) liquid-liquid extraction with ethyl acetate, and (iv) silyl derivatization to analyze samples with gas chromatography-mass spectrometry (GC-MS) in ion monitoring detection mode (SIM). The results indicated successful detection and quantification of all analyzed compounds without the need for sample dilution. However, our results showed that the method of adding external standards was more suitable for quantifying wine compounds, owing to the matrix effect. Furthermore, this method is promising for quantifying other metabolites present in wines, depending on their extractability with ethyl acetate. In other words, the proposed method may be suitable for profiling (targeted) or fingerprinting (untargeted) strategies to quantify wine metabolites or to classify wines according to the type of winemaking process, grape, or fermentation. [ABSTRACT FROM AUTHOR]

Malolactic fermentation (MLF) in wine is driven by the lactic acid bacterium Oenococcus oeni in most cases. Although this bacterium is resistant to wine stress conditions, it often faces difficulties completing MLF. Previous studies indicate that yeast mannoproteins may improve O. oeni growth and survival in wine. However, very little is known about this topic. This study evaluated the effect of the addition of mannoprotein extracts to culture media on O. oeni growth and its survival to stress conditions and MLF performance. Three commercial mannoprotein extracts were characterized in terms of polysaccharide and protein richness and were used for O. oeni culture media supplementation. The addition of mannoprotein extracts improved the survival of the two evaluated O. oeni strains, PSU-1 and VP41, after acid shock (pH 3.2) in comparison to that of the control. The transcriptional response of four genes involved in mannose metabolism was different depending on the strain, indicating the complexity of sugar metabolism in O. oeni. PSU-1 cells grown with two of the mannoprotein extracts performed faster MLF compared with the control condition, indicating that mannoprotein addition may improve the performance of O. oeni starter cultures, although this effect depends on the strain. [ABSTRACT FROM AUTHOR]

This study investigates the impact of inoculating Torulaspora delbrueckii (Td) strains during the initial phase of carbonic maceration (CM) vinification, aiming to enhance the fermentative process and unique characteristics of CM wines. CM is a winemaking technique where whole bunches (without destemming and crushing) are enclosed in tanks filled with carbon dioxide, inducing intracellular fermentation. This study compares the effects of two Td strains on the MLF performance and sensory characteristics of CM wines using both inoculated and spontaneous MLF strategies. Although general physicochemical parameters remained consistent across conditions, organoleptic attributes showed significant differences due to T. delbrueckii presence. T. delbrueckii introduction during CM resulted in wines with increased anthocyanin content and a particular volatile profile. Isoamyl acetate, a key aroma in CM wines, was notably elevated, especially in the TdP strain. Sensory evaluations also revealed distinctions, with TdV wines displaying more pronounced aromas of red fruit, banana, and grass. Regarding MLF, T. delbrueckii presence notably enhanced performance, particularly in spontaneous MLF cases, accelerating fermentation completion. Inoculating the Oenococcus oeni strain OoVP41 also shortened MLF duration. These findings highlight the potential of Td strains to improve MLF efficiency and sensory attributes in CM wines. Using T. delbrueckii strains strategically enables winemakers to optimize MLF and improve sensory profiles, offering an opportunity to produce higher-quality CM wines. [ABSTRACT FROM AUTHOR]

Grapes of Tempranillo, Garnacha Tinta and Merlot at very high maturity level were used for red microvinifications using a conventional Saccharomyces cerevisiae strain (Lalvin EC 1118®) and new S. cerevisiae strain generated using adaptive evolution-based strategies (IONYS™WF). All microvinifications were performed by triplicate and at low (16°C) and at high (27°C) temperatures. The results show that all the wines fermented with IONYS™WF, independently of the fermentation temperature and grape cultivar have significant lower ethanol content (average 0.60 %), higher glycerol content (average of 5.6 g/L), higher titratable acidity (average of 1.3 g of tartaric acid/L) and lower pH (average of 0.1 units) than their corresponding controls. It seems therefore that IONYS™WF strain can be a useful tool to mitigate the excess of ethanol and the lack of acidity that unfortunately many wines present nowadays. Moreover, the high glycerol production can also be an interesting contribution inasmuch as this compound increases mouthfeel and smooth astringency.

The effect as copigment of (-)-epicatechin and five different oenological tannins has been measured in a model wine solution containing malvidine-3-monoglucoside. The results show that all oenological tannins exert a positive effect on the color of the malvidine solution, increasing the global absorptivity spectrum and changing the Cielab coordinates. Specifically, supplementation with oenological tannins increase a* and b* and decreases L*. Overall, the effect as copigments of all oenological tannins was higher than that of (−)-epicatechin.

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. [ABSTRACT FROM AUTHOR]

• Enzymatic parameters of laccase of B. cinerea in presence of oenological tannins were determined. • Electrophoretic characterization of laccase of B. cinerea in presence of oenological tannin was investigated. • Bentonite, contrary to oenological tannins, did not reduce laccase activity. • Gallotannin, skin and seed tannins were the greatest to reduce laccase activity. • Oenological tannins seem to be great tool to prevent laccase effects and reduce use of SO 2. Enzymatic parameters (K M and V max), 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 (SO 2) and bentonite. We added OT, AA, SO 2 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, V max , K M 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 SO 2 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 SO 2 in grapes and musts. [ABSTRACT FROM AUTHOR]

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 (−)-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 (400–800 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. [ABSTRACT FROM AUTHOR]

The kinetics of oxygen consumption by different oenological tannins were measured in a model wine solution using the non-invasive method based on luminiscence. The results indicate that the oxygen consumption rate follows second-order kinetics depending on tannin and oxygen concentrations. They also confirm that the oxygen consumption rate is influenced by temperature in accordance with Arrhenius law. The indications are that ellagitannins are the fastest oxygen consumers of the different oenological tannins, followed in decreasing order by quebracho tannins, skin tannins, seed tannins and finally gallotannins. This methodology can therefore be proposed as an index for determining the effectiveness of different commercial tannins in protecting wines against oxidation. [ABSTRACT FROM AUTHOR]

• Oxygen consumption rate of sparkling wine lees from the first to ninth year of aging was measured. • Results confirm that lees consume O 2 and can protect sparkling wines from oxidation. • The oxygen consumption rate of lees decreased overtime, especially after 3 years. • These data explain why only few sparkling wines can age more than 3 years. 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. [ABSTRACT FROM AUTHOR]

The chemical composition (CC), antioxidant capacity (AC) and oxygen consumption rate (OCR) of 36 different commercial tannins were measured. The CC was analyzed by total polyphenol index, Bate-Smith, methyl-cellulose, Folin-Ciocalteu, OIV official method and phloroglucinolisis. The AC was measured by different methods (ABTS, CUPRAC, DPPH, FRAP, ORAC) using Trolox as standard. The OCR was measured using a non-invasive method based on luminescence. The results indicate that it is possible to obtain differentiation between procyanidins/prodelphinidins, profisetinidins/prorobinetidins, gallotannins and ellagitannins by PCA based on their CC data. It is also possible to separate condensed from hydrolysable tannins by PCA based on their AC data. The results show that ellagitannins are the fastest oxygen consumers of the various oenological tannins, followed in descending order by condensed tannins and finally gallotannins. The combination of CC, AC and OCR analyses enable to classify tannins according to their effectiveness in protecting wines against oxidation. [ABSTRACT FROM AUTHOR]

Saccharomyces cerevisiae is a highly fermentative species able to complete the wine fermentation. However, the interaction with other non- Saccharomyces yeasts can determine the fermentation performance of S. cerevisiae. We have characterised three rare non- Saccharomyces yeasts (Cyberlindnera fabianii , Kazachstania unispora and Naganishia globosa), studying their impact on S. cerevisiae fitness and wine fermentation performance. Using a wide meta-taxonomic dataset of wine samples, analysed through ITS amplicon sequencing, we show that about a 65.07% of wine samples contains Naganishia spp., a 27.21% contains Kazachstania spp., and only a 4.41% contains Cyberlindnera spp; in all cases with average relative abundances lower than 1% of total fungal populations. Although the studied N. globosa strain showed a limited growth capacity in wine, both K. unispora and C. fabianii showed a similar growth phenotype to that of S. cerevisiae in different fermentation conditions, highlighting the outstanding growth rate values of K. unispora. In mixed fermentations with S. cerevisiae , the three yeast species affected co-culture growth parameters and wine chemical profile (volatile compounds, polysaccharides and proteins). K. unispora DN201 strain presents an outstanding capacity to compete with S. cerevisiae strains during the first stage of wine fermentation, causing stuck fermentations in both synthetic and natural grape musts. • The prevalence of Cyberlindnera spp. in wine populations is about 4% of samples. • The prevalence of Kazachstania spp. in wine populations is about 27% of samples. • The prevalence of Naganishia spp. in wine populations is about 65% of samples. • Kazachstania unispora DN201 caused stuck fermentations. • K.unispora DN201 has high nitrogen consumption rate and production of acetic acid. [ABSTRACT FROM AUTHOR]