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Contribution by Saccharomyces cerevisiae yeast to fermentative flavor compounds in wines from cv. Albariño
Abstract
A comparative study was made of the fermentation products of Spanish Albariño wines produced with spontaneous yeast flora and an indigenous selected Saccharomyces cerevisiae strain (Alb16). The content of fermentative volatile compounds was determined by gas-chromatography-FID. Fifteen compounds (5 alcohols, 7 esters and 3 acetates) were identified in the two Albariño wines studied. Higher alcohols, ethyl esters (except ethyl hexanoate and ethyl octanoate) and acetates were in greater concentration in the spontaneous fermentation wine than in that with selected Alb16 strain. Principal components analysis showed good separation between the different wines.
... Terpenes are flavour compounds that are present in many grape varieties, including Albariño, and occur as free and bound (glycosylated) forms (Vilanova & Sieiro, 2006). Both forms can be modified to various degrees during alcoholic and malolactic fermentation (Swiegers, Bartowsky, Henschke, & Pretorius, 2005). ...
... Albariño is an aromatic white cultivar of Vitis vinifera, which is mainly grown in north-western Spain and northern Portugal. This cultivar has been the subject of several studies (Carballeira Lois, Cortés Dieguez, Gil de la Peña, & Fernandez Gomez, 2001;Dieguez, Lois, Gomez, & de la Peña, 2003;Fernandez et al., 1999;Gil, 2000;Oliveira, Faria, Sá, Barros, & Araújo, 2006;Oliveira, Oliveira, Baumes, & Maia, 2008;Vilanova, Genisheva, Masa, & Oliveira, 2010;Vilanova & Sieiro, 2006), which have focused on grape and wine characterisation. However, the effect of must YAN on wine composition is unknown. ...
... In order to determine the impact of nitrogen concentration on wine volatiles elaborated during fermentation of Albariño, a clarified must (YAN of 250 mg N/L) was supplemented with DAP to achieve a range of YAN concentrations from 250 to 450 mg N/L before inoculation. Albariño, which was sourced from Galicia (Spain), where it represents an important commercial variety, is characterised by a significant terpenoid content and floral sensory character (Vilanova & Sieiro, 2006). This variety can therefore provide additional new information on the role of nitrogen supplementation in the elaboration of floral aroma compounds, for optimised fermentation of 'floral' varieties. ...
Vitis vinifera cv. Albariño is an aromatic variety characterised by terpenes present largely as glycosidic flavour precursor compounds, which depends on fermentation to reveal its aromatic varietal potential. Clarified Albariño must containing 250 mg N/L (control) was supplemented with diammonium phosphate to 350 and 450 mg N/L before fermentation with a high-nitrogen-demand wine strain of Saccharomyces cerevisiae (M05). Ammonium supplementation had a significant effect on the chemical composition (titratable acidity and ethanol) and volatile profile of Albariño wines. Varietal compounds in the free fraction (limonene, linalool, a-terpineol, a-ionone and b-damascenone) and bound (limonene, linalool and a-terpineol), as well as most yeast-derived fermentation products (including esters, higher alcohols and volatile acids) were associated with moderate nitrogen concentrations. Free b-ionone, bound geraniol, bound a-ionone, bound b-damascenone and 1-hexanol were associated with high nitrogen concentrations. OAV wines made with moderate nitrogen exhibited a higher total odorant activity, driven by ethyl esters, terpenes and C 13-norisoprenoids, resulting in fruity and floral aroma attributes.
... The utilisation of YAN by different wine strains of Saccharomyces cerevisiae has been studied by several authors and quantitative and qualitative differences have been observed in wine aromatic composition (Albers, Larsson, Liden, Niklasson, & Gustafsson, 1996; Barbosa, Falco, Mendes-Faia, & Mendes-Ferreira, 2009; Bely, Rinaldi, & Dubourdieu, 2003; Carrau, Medina, Farina, Boido, & Dellacassa, 2010; Carrau et al., 2008; Garde-Cerdán & Ancin-Azpilicueta, 2008; Hernandez-Orte, Bely, Cacho, & Ferreira, 2006; Torrea, Fraile, Garde, & Ancin-Azpilicueta, 2003; Torrea et al., 2011; Unterfrauner, Kobler, & Rauhut, 2009; Vilanova et al., 2007). Terpenes are flavour compounds that are present in many grape varieties, including Albariño, and occur as free and bound (glycosylated ) forms (Vilanova & Sieiro, 2006). Both forms can be modified to various degrees during alcoholic and malolactic fermentation (Swiegers, Bartowsky, Henschke, & Pretorius, 2005 ). ...
... Albariño is an aromatic white cultivar of Vitis vinifera, which is mainly grown in north-western Spain and northern Portugal. This cultivar has been the subject of several studies (Carballeira Lois, Cortés Dieguez, Gil de la Peña, & Fernandez Gomez, 2001; Dieguez, Lois, Gomez, & de la Peña, 2003; Fernandez et al., 1999; Gil, 2000; Oliveira, Faria, Sá, Barros, & Araújo, 2006; Oliveira, Oliveira, Baumes, & Maia, 2008; Vilanova, Genisheva, Masa, & Oliveira, 2010; Vilanova & Sieiro, 2006), which have focused on grape and wine characterisation. However, the effect of must YAN on wine composition is unknown. ...
... In order to determine the impact of nitrogen concentration on wine volatiles elaborated during fermentation of Albariño, a clarified must (YAN of 250 mg N/L) was supplemented with DAP to achieve a range of YAN concentrations from 250 to 450 mg N/L before inoculation. Albariño, which was sourced from Galicia (Spain), where it represents an important commercial variety, is characterised by a significant terpenoid content and floral sensory character (Vilanova & Sieiro, 2006). This variety can therefore provide additional new information on the role of nitrogen supplementation in the elaboration of floral aroma compounds, for optimised fermentation of 'floral' varieties. ...
a b s t r a c t Vitis vinifera cv. Albariño is an aromatic variety characterised by terpenes present largely as glycosidic fla-vour precursor compounds, which depends on fermentation to reveal its aromatic varietal potential. Clar-ified Albariño must containing 250 mg N/L (control) was supplemented with diammonium phosphate to 350 and 450 mg N/L before fermentation with a high-nitrogen-demand wine strain of Saccharomyces cerevisiae (M05). Ammonium supplementation had a significant effect on the chemical composition (titratable acidity and ethanol) and volatile profile of Albariño wines. Varietal compounds in the free frac-tion (limonene, linalool, a-terpineol, a-ionone and b-damascenone) and bound (limonene, linalool and a-terpineol), as well as most yeast-derived fermentation products (including esters, higher alcohols and volatile acids) were associated with moderate nitrogen concentrations. Free b-ionone, bound geraniol, bound a-ionone, bound b-damascenone and 1-hexanol were associated with high nitrogen concentra-tions. OAV wines made with moderate nitrogen exhibited a higher total odorant activity, driven by ethyl esters, terpenes and C 13 -norisoprenoids, resulting in fruity and floral aroma attributes.
... Most research associated with flavour implications of uninoculated fermentations has focussed on the metabolic diversity of Saccharomyces and non-Saccharomyces isolates (Ciani and Maccarelli 1998, Rojas et al. 2003, Romano et al. 2003a, Clemente-Jimenez et al. 2004, Jolly et al. 2006, but only some studies have reported significant differences in the chemical composition of wines made by indigenous yeasts when compared to those made by inoculation with pure cultures (Lema et al. 1996, Egli et al. 1998, Nurgel et al. 2002b, Jolly et al. 2003. Although such studies have also described differences in some volatile compounds (Romano et al. 1997, Nurgel et al. 2002b, Vilanova and Sieiro 2006, the overall wine aroma composition has not been addressed. ...
... Even though the concentrations of higher alcohols were greater for uninoculated fermentations, they were below the threshold value (300 mg/L) considered by some authors to be detrimental for wine quality (Rapp and Mandery 1986), and therefore might contribute to the overall sensory complexity of these wines. Increased concentrations of higher alcohols have also been observed by others in Chardonnay wines made with indigenous yeasts (Herjavec et al. 2003, Vilanova andSieiro 2006). ...
... This character is not necessarily linked to wine quality. Some authors have suggested that better overall quality is achieved by using selected strains of S. cerevisiae (Romano et al. 1998), others have observed good quality wines with indigenous yeasts (Herjavec et al. 2003, Vilanova andSieiro 2006), whereas some reports have described very high or very low quality scores for wild yeast fermented Chardonnay and Riesling wines, depending on the taster (Egli et al. 1998). Nevertheless, atypical flavours not normally achieved with conventional S. cerevisiae create wines with new and interesting aroma profiles that differ from each other and from inoculated yeast wines. ...
Background and Aims: Winemakers are constantly searching for new techniques to modulate wine style. Exploiting indigenous yeasts present in grape must is re-emerging as a commercial option in New World wine regions. Wines made with indigenous or ‘wild’ yeasts are perceived to be more complex by showing a greater diversity of flavours; however, the chemical basis for the flavour characteristics is not yet defined. In order to evaluate techniques for making wine with the ‘wild yeast fermentation’ character more reliably, it is necessary to define the salient chemical characteristics of such wines.Methods and Results: Pairs of Chardonnay wines were prepared from the same must and subjected to similar fermentation conditions in the wineries of origin, except for the mode of inoculation. Reference wines were made by inoculation with a Saccharomyces cerevisiae starter culture, whereas companion wines were allowed to undergo fermentation with the indigenous microflora. Of all wine chemicals analysed, only yeast-derived volatile fermentation products showed significant differences between the yeast treatments.Conclusions: Inoculated wines were associated with the esters ethyl hexanoate and 3-methylbutyl acetate and formed a clear cluster by principal component analysis. By comparison with inoculated wines, ‘wild’ yeast fermented wines showed high variability in volatile compounds that contribute to wine aroma, with higher concentrations of 2-methylpropanol, 2-methylbutanoic acid, ethyl 2-methylpropanoate, ethyl decanoate and ethyl dodecanoate potentially being sensorially important.Significance of the Study: This study shows that yeast-derived volatile fermentation products are a key difference between inoculated and uninoculated ferments and provides a chemical basis for the ‘wild yeast fermentation’ character.
... The essence of a wine's flavour is formed during alcoholic fermentation. Ethanol and glycerol are the most abundant alcohols, followed by higher alcohols and esters, the combinations of which affect the final aroma of a wine (Vilanova & Sieiro, 2006). The total higher alcohol content varied from 116 to 363 mg/l, the highest levels being observed with Banginapalli mango cultivar. ...
... However, when above 400 mg/l, they have a negative influence on quality (Swiegers & Pretorius, 2005). The highest ethanol concentration was found in the wines from Alphonso (10.3%) and Banginapalli (10.0%), and, to a great extent, the fresh fruity aromas of wines derive from the mixture of esters produced by the yeast during fermentation (Vilanova & Sieiro, 2006). Esters are particularly important compounds in the aroma of young wines, and, in the present study, the highest concentration of total esters was found in the wine obtained from Banginapalli (44 mg/l), Raspuri (37 mg/l) and Alphonso (28 mg/l). ...
This investigation deals with the antioxidant and sensory properties of mango wine produced from different mango varieties. The highest phenolic content was recorded in wines produced from Alphonso (537 mg/l), Banginapalli (456 mg/l) and Sindhoora (490 mg/l) mango fruit varieties. The antiradical activity varied from 27.57% to 36.70% ascorbic acid equivalents, the antioxidant activity varied from 73.90% to 85.95% gallic acid equivalents and the reducing power varied from 0.71 to 2.90 μm/l ascorbic acid equivalents. From the liquid chromatography–mass spectrometer (LC–MS) analysis, 11 phenolic compounds were identified in Alphonso wine. Based on nine-point hedonic scale for the evaluation of organoleptic properties, the wines made from Alphonso and Banginapalli varieties have been found to have better sensory properties. A significant correlation was not observed between the panellist and the instrumental results.La presente investigación trata sobre las propiedades antioxidantes y sensoriales del vino de mango producido con diferentes variedades. El contenido más alto de fenólicos se registró en vinos producidos con variedades de mango Alphonso (537), Banginapalli (456) and Sindhoora (490 mg/l). La actividad antiradical varió entre 27,57 y 36,70% equivalentes de ácido ascórbito, la actividad antioxidante entre 73,90 y 85,95% equivalentes de ácido gálico y el poder reductor entre 0,71 y 2,90 μm/l equivalentes de ácido ascórbico. Del análisis LC–MS se identificaron once components fenólicos en el vino elaborado con Alphonso. Basándose en la escala hedónica de nueve puntos para la evaluación de las cualidades organolépticas, los vinos producidos con las variedades Alphonso y Banginapalli resultaron tener mejores propiedades sensoriales. No se observó una correlación significativa entre los resultados de panelistas e instrumentales.
... Esters produced by yeasts during fermentation affect wine flavour because they impart fruity and floral aroma to wine. 3 The fact that ester composition of wines is strain dependent has been reported. 38,39 In particular, the influence of yeast strains on ester composition of wine was studied for Albariño, 7,25,27,28 and recently for Treixadura wines. 14,19 Our results confirmed those findings, especially with strain XG3, which produced wines with the highest content of ethyl esters for both cultivars, Albariño and Godello. ...
... These results are in agreement with those reported by several authors who distinguished wines from spontaneous fermentations and wines from inoculated processes. 7,8,27,42 On the other hand, the location in the same quadrant of wines made with QA 23, despite of the cultivar, confirmed that commercial strains promote wine standardisation. In contrast, the results highlighted that fermentation with autochthonous strains modulated the chemical characteristics of wine and preserved their varietal typicality. ...
Yeasts responsible for fermentation have an important repercussion on wine quality. This study presents the influence of two autochthonous strains of Saccharomyces cerevisiae (XG1 and XG3), a commercial yeast (QA23) and spontaneous fermentation on the chemical and sensory properties of wines from Godello and Albariño.
All the yeasts showed normal fermentative kinetics and were able to lead fermentations; therefore, they were responsible for wine chemical and sensory characteristics. Significant differences were found at the chemical level depending on yeast strain and variety. Albariño wines from XG1 and XG3 presented low total acidity and glycerol content. Godello wines from QA23 had higher total acidity but lower alcohol content than those from XG1, XG3 and spontaneous fermentation. QA23 wines presented a greater amount of higher alcohols and 2-phenylethanol for both grapevine cultivars, whereas XG3 and spontaneous fermentations yielded wines with a higher concentration of esters, mainly ethyl lactate, and fatty acids. These differences were detected at the sensory level; thus, Albariño made with XG3 and Godello from spontaneous fermentation were the most appreciated wines.
XG3, an autochthonous strain of S. cerevisiae, constitutes a useful tool to elaborate wines with singular characteristics.
... La importancia de cada compuesto depende de la correlación entre la concentración química y el umbral de percepción. Para que se tenga en cuenta, la concentración química debe ser más alta que el umbral de percepción (Valor de actividad olorosa, OAV) (Vilanova y Vilariño, 2006). Los aromas de los vinos elaborados con uvas de Albariño, tienen tres tipos de compuestos aromáticos. ...
... El efecto de S. cerevisiae en la vinificación ha sido estudiado por diversos autores, observándose diferencias significativas en los compuestos volátiles tales como alcoholes superiores y ésteres (Vilanova y Masneuf-Pomarède, 2005; Vilanova y Sieiro, 2006) entre Vinos Albariño fermentados de forma espontánea y Vinos Albariño fermentados de manera controlada con cepas de S. cerevisiae. El papel de dicha levadura en la hidrólisis de los precursores glicoconjugados, y por tanto, su capacidad de liberación de los compuestos volátiles varietales, no estaba del todo claro. ...
... Esters, alcohols, acids, aldehydes, ketones, hydrocarbons, sulfur compounds and volatile phenols are the main volatiles detected in beer, they being able to influence their aroma and flavor both individually and in a synergistic or antagonistic way (Pinho et al., 2006). Different strains of S. cerevisiae can produce significantly different flavor profiles when fermenting the same substrate and this is a consequence of two factors: the differential ability of yeast strains to release varietal volatile compounds from their non-volatile precursors, and the differential ability to de novo synthesize yeast-derived volatile compounds (Vilanova and Sieiro, 2006). ...
This study investigated the influence of three Saccharomyces cerevisiae strains, selected from different matrices - CHE-3 (cherry), P4 (sourdough) and TA4-10 (grape must) - on characteristics of Italian Grape Ale (IGA) beers obtained at microbrewery scale. A multidisciplinary approach, combining results from analysis of chemical, volatile and organoleptic profiles of the beers, was adopted to underline the relationships between yeast starter and the quality of final products. Detection volatile organic compounds (VOCs) by Gas-Chromatography coupled with Mass Spectrometry (GC-MS) after extraction carried out by head-space micro-extraction (HS-SPME) revealed that the beer obtained by P4 strain differed from the others for its higher concentrations of esters, alcohols, and terpenes as confirmed by PCA (principal component analysis) and Cluster heatmap. Furthermore, sensorial analysis and consumer test showed that this sample differed from others by more pronounced notes of “fruity smell and floral” and “olfactory finesse,” and it was the most appreciated beer for smell, taste, and overall quality. Conversely, CHE-3 was the sample with the lowest concentrations of the identified volatiles and, together TA4-10, showed the highest scores for smoked, yeast, malt, and hop notes. As far as we know, these are the first results on the application of indigenous S. cerevisiae strains in the production of craft IGA beers analyzed through a complex multivariate approach.
... To the best of our knowledge, there is little available information in the scientific literature that addresses the impact of amphorae on the dynamics of alcoholic fermentation [1]; furthermore, no studies have been conducted to investigate the effectiveness of commercial yeast starters or S. cerevisiae biodiversity of spontaneous wine fermentations carried out in these vessels. In general, during the spontaneous fermentation of wine, the development of different indigenous S. cerevisiae strains has been widely and demonstrated, and this biodiversity plays an active role in the definition of the sensorial characteristics of the final product [9,[15][16][17]. Moreover, indigenous S. cerevisiae strains might be better adapted than commercial starters to peculiar fermentative conditions [18][19][20][21]. ...
The use of earthenware amphorae in winemaking can give wines unique attributes enhancing their typicity. Therefore, in this study, spontaneous and inoculated in-amphora fermentations of Trebbiano Toscano grape must were monitored to assess the Saccharomyces cerevisiae strains occurring in each fermentation as well as the chemical characteristics of the wines. Strain typing via Interdelta analyses pointed out that the commercial starters did not dominate, showing 24% and 13% implantation percentages, and that 20 indigenous strains were present at different percentages, ranging from 2 to 20%, in inoculated and spontaneous fermentations. The assessment of the technical characteristics of the indigenous strains via fermentations at lab and pilot scale (20 L amphorae) and the sensory analysis of the experimental wines allowed for the selection of two indigenous strains to be used as starter cultures in comparison to a commercial strain in 300-L-amphorae vinifications in the cellar. The observed fermentative performances and sensory analysis of the experimental wines highlighted that one indigenous S. cerevisiae strain dominated the process and conferred distinctive sensory characteristics to the Trebbiano Toscano wine, demonstrating its effectiveness in managing the in-amphora fermentations. In addition, the results demonstrated the ability of amphorae to protect the polyphenolic compounds from oxidation during wine ageing. Indeed, the concentration of both hydroxycinnamic acids and flavonols decreased, with an average reduction of 30% and 14%, respectively, while hydroxybenzoic acids remained unchanged.
... Different strains of S. cerevisiae can produce significantly different flavour profiles when fermenting the same must. This is a consequence of the ability of wine yeast stains to both release varietal volatile compounds from grape precursors and synthesise de novo yeast-derived volatile compounds [77,[128][129][130]. Molina et al. (2009) showed that musts fermented by two strains differed in sensory perception and descriptive analysis [131]. ...
A wine’s aroma profile is an important part of the criteria affecting wine acceptability by consumers. Its characterisation is complex because volatile molecules usually belong to different classes such as alcohols, esters, aldehydes, acids, terpenes, phenols and lactones with a wide range of polarity, concentrations and undesirable off-aromas. This review focused on mechanisms and conditions of the formation of individual aroma compounds in wine such as esters and higher alcohols by yeast during fermentation. Additionally, aroma losses during fermentation are currently the subject of many studies because they can lead to a reduction in wine quality. Principles of aroma losses, their prevention and recovery techniques are described in this review.
... Wine quality is strongly influenced by the yeast strain used for fermentation. The influence of various Saccharomyces cerevisiae strains on sensory properties of wine was described [1,2]. At the time when application of commercial pure cultures of wine yeasts is a common oenological practice of modern winemaking, some producers are still using traditional spontaneous fermentation with autochthonous yeasts. ...
Controlled fermentation with a pure Saccharomyces cerevisiae culture is a frequent practice in modern wineries. Use of other fermentation strategies could positively influence the aroma of the wine product. However, the background and application of these approaches are often very difficult and complex. The use of axenic S. cerevisiae culture originating from the particular terroir remains the best compromise for modern winemaking. In our research, 48 S. cerevisiae strains from 7 viticultural regions of Czech Republic and Slovakia were isolated, identified and studied. For the first time, newly-bred vine varieties Devín, Pálava, Moravian Muscat and Dunaj were used for isolation of new yeast strains. The aim of this work was to find a convenient method for identification and selection of autochthonous S. cerevisiae yeasts. Isolated strains were identified using conventional microbiological tests, sequencing of the internal transcribed spacer region and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). From the results of this research, the selection of 17 yeast strains for potential use as a starter culture in the production of typical wines was performed. Six of them, namely, PAC34, PAE58, PAG63, DUH135, PAH48 and DEH53, were isolated from newly-bred varieties.
... The major persistence of Aureobasidium pullulans and the clear dominance of Hanseniaspora spp. in wine N may be related to both higher alcohols and terpenes production. Increased concentration of higher alcohols have been previously observed by several authors in different wines fermented by non-Saccharomyces yeast (Herjavec, Podgorski, Redzepovic, & Mirosevic, 2003;Varela et al., 2009;Vilanova & Sieiro, 2006) having a very active synthetic or Ehrlich pathway for aminoacids metabolism. Moreover, a recent study (Davis, Boundy-Mills, & Landolt, 2012) showed that the major headspace volatiles emitted by Aureobasidium pullulans isolated from apples, were 2-methyl-1-butanol, 3-methyl-1-butanol, and 2-phenylethanol. ...
Natural (N) as well as starter inoculated (S, inoculated with Saccharomyces cerevisiae M3–5; CZS, Candida zemplinina T13, Zygosaccharomyces bailii NS113 and Saccharomyces cerevisiae M3–5) fermentations of Falanghina must from dehydrated grape were monitored. Culture dependent analyses and amplicon-based high-throughput sequencing targeting 18S rRNA and 16S rRNA genes were used to monitor the fungal and bacterial communities (8 sampling points during 65 days). The resulting wines were subject to both sensory evaluation and volatile organic compounds analysis. Fungal community of un-inoculated musts (N) at beginning of the fermentation was mainly represented by Aureobasidium, Cladosporium, Sclerotinia, while Candida, Debaryomyces, Hanseniaspora, Metschnikowia, Pichia, Saccharomyces and Zygosaccharomyces showed a very low occurrence. The dominance of Hanseniaspora vineae and/or Hanseniaspora uvarum was clear up to 29th days of fermentation. S. cerevisiae occurred in all the phases but become dominant only at the end of the process. The odour profiles as evaluate by Quantitative Descriptive Analysis (QDA) highlighted a significant impact of the fungal populations on the olfactory profiles of the wines. Raisins, dried fruits, Sherry and liqueur were stronger in both S and CZS, while N was mostly discriminated by solvent/chemical and floral features. Outcomes underpin the impact of microbiota on the chemical and odour traits of Falanghina passito wines.
... In addition, the predominant strains can sometimes persist in alcoholic fermentations carried out in the same winery in consecutive years and can be described as "recurring" strains ( Gutièrrez et al., 1999;Bisson, 2012). Since S. cerevisiae strains, participating in alcoholic fermentations, may differently affect the chemical and sensory qualities of resulting wines (Fleet, 2003;Romano et al., 2003;Villanova and Sieiro, 2006;Lopandic et al., 2007;Barrajón et al., 2011;Knight et al., 2015;Bokulich et al., 2016;Callejon et al., 2016), it is of great importance to assess whether the predominant strains retain the dominant behavior after their isolation from grape must fermentations. Furthermore, it could be noteworthy to investigate whether the predominance of these S. cerevisiae strains on others results from a different adaptation capability (fitness advantage) to some stress factors of oenological interest. ...
Different Saccharomyces cerevisiae strains are simultaneously or in succession involved in spontaneous wine fermentations. In general, few strains occur at percentages higher than 50% of the total yeast isolates (predominant strains), while a variable number of other strains are present at percentages much lower (secondary strains). Since S. cerevisiae strains participating in alcoholic fermentations may differently affect the chemical and sensory qualities of resulting wines, it is of great importance to assess whether the predominant strains possess a “dominant character.” Therefore, the aim of this study was to investigate whether the predominance of some S. cerevisiae strains results from a better adaptation capability (fitness advantage) to the main stress factors of oenological interest: ethanol and temperature. Predominant and secondary S. cerevisiae strains from different wineries were used to evaluate the individual effect of increasing ethanol concentrations (0-3-5 and 7% v/v) as well as the combined effects of different ethanol concentrations (0-3-5 and 7% v/v) at different temperature (25–30 and 35°C) on yeast growth. For all the assays, the lag phase period, the maximum specific growth rate (μmax) and the maximum cell densities were estimated. In addition, the fitness advantage between the predominant and secondary strains was calculated. The findings pointed out that all the predominant strains showed significantly higher μmax and/or lower lag phase values at all tested conditions. Hence, S. cerevisiae strains that occur at higher percentages in spontaneous alcoholic fermentations are more competitive, possibly because of their higher capability to fit the progressively changing environmental conditions in terms of ethanol concentrations and temperature.
... Generally, yeast strains play a central role during vinification since their metabolism has a differing impact on modulation of taste and flavor and on overall composition of wine (Liu, Lu, Duan, & Yan, 2016;Alvarez-P erez et al., 2012). Furthermore, during fermentation of the same must different yeast strains can produce significantly different aroma profiles of wines due to their various capacity to synthesize volatile compounds and differential ability of releasing varietal volatile compounds from non-volatile grape precursors (Ugliano, Bartowsky, McCarthy, Moio, & Henschke, 2006;Vilanova & Sieiro, 2006;Zott et al., 2011). The final aroma composition of the wine depends on the changes that occur during aging, when the loss of fresh and fruity attributes in white wines typically occurs primarily due to oxidation and esterification reactions (Recamales, Gallo, Hernanz, Gonz alez-Miret, & Heredia, 2011). ...
The aim of the research was characterization and improvement of aroma of white wine Vitis vinifera L. Pošip by application of several enological practices, either individually or in combinations. The effect of pre-fermentative maceration, indigenous yeast strain and antioxidant additions (higher sulfur dioxide and glutathione) was examined, and compared to conventional white wine production: reductive pressing, commercial yeast strain and typical doses of free sulfur dioxide (35 mg/L). The most significant aroma contributors were esters and higher alcohols (fermentation aroma), as well as varietal aroma compounds such as linalool, β-damascenone and thiols (3SH and 3SHA). Furthermore, results showed that pre-fermentative maceration affected the higher concentrations of several aroma compounds, primarily those important for varietal character of wines: terpenes, norisoprenoids and varietal thiols. Fermentation by indigenous yeasts resulted in higher concentrations of different compounds, especially of i-amyl acetate which contributes to desirable fruity, banana-like odors. Furthermore, during 12 months’ aging, most of the aroma compounds significantly decreased, but in wines bottled with antioxidant additions (higher free sulfur dioxide, glutathione and their combination) their slower decrease was observed. The most notable protective effect was observed using the combination of higher free sulfur dioxide (50 mg/L) with glutathione (20 mg/L).
... Sacch. cerevisiae strains develop during wine fermentation which play an active role in the characteristics of wine (Vilanova andSieiro 2006, Capece et al. 2013). ...
... These findings suggest that specific native strains could be associated with a terroir, a term that classically includes only grape variety, climate and soil as fundamental factors determining the typical nature of wines (Van Leeuwen and Seguin, 2006) and that might be revised including also a " microbial aspect " (Bokulich et al., 2014; Taylor et al., 2014). Since it is well established that chemical and sensory properties of some wines reflect their geographic origin (Villanova and Sieiro, 2006; Callejon et al., 2010) it was interesting to determine whether regionally defined S. cerevisiae genotypes actually exhibit specific metabolic profiles (or phenotypes) able to modulate the wine quality, thus contributing to terroir-associated wine characteristics. Indeed, in a recent study Knight et al. (2015) demonstrated significant correlation between the region of isolation of S. cerevisiae and aroma profile in wines. ...
Numerous studies, based on different molecular techniques analyzing DNA polymorphism, have provided evidence that indigenous Saccharomyces cerevisiae populations display biogeographic patterns. Since the differentiated populations of S. cerevisiae seem to be responsible for the regional identity of wine, the aim of this work was to assess a possible relationship between the diversity and the geographical origin of indigenous S. cerevisiae isolates from two different Italian wine-producing regions (Tuscany and Basilicata). For this purpose, sixty-three isolates from Aglianico del Vulture grape must (main cultivar in the Basilicata region) and from Sangiovese grape must (main cultivar in the Tuscany region) were characterized genotypically, by mitochondrial DNA restriction analysis and MSP-PCR by using (GIG)(5) primers, and phenotypically, by determining technological properties and metabolic compounds of oenological interest after alcoholic fermentation. All the S. cerevisiae isolates from each region were inoculated both in must obtained from Aglianico grape and in must obtained from Sangiovese grape to carry out fermentations at laboratory-scale. Numerical analysis of DNA patterns resulting from both molecular methods and principal component analysis of phenotypic data demonstrated a high diversity among the S. cerevisiae strains. Moreover, a correlation between genotypic and phenotypic groups and geographical origin of the strains was found, supporting the concept that there can be a microbial aspect to terroir. Therefore, exploring the diversity of indigenous S. cerevisiae strains can allow developing tailored strategies to select wine yeast strains better adapted to each viticultural area.
... These findings suggest that specific native strains could be associated with a terroir, a term that classically includes only grape variety, climate and soil as fundamental factors determining the typical nature of wines (Van Leeuwen and Seguin, 2006) and that might be revised including also a " microbial aspect " (Bokulich et al., 2014; Taylor et al., 2014). Since it is well established that chemical and sensory properties of some wines reflect their geographic origin (Villanova and Sieiro, 2006; Callejon et al., 2010) it was interesting to determine whether regionally defined S. cerevisiae genotypes actually exhibit specific metabolic profiles (or phenotypes) able to modulate the wine quality, thus contributing to terroir-associated wine characteristics. Indeed, in a recent study Knight et al. (2015) demonstrated significant correlation between the region of isolation of S. cerevisiae and aroma profile in wines. ...
Numerous studies, based on different molecular techniques analysing DNA polymorphism, have provided evidence that indigenous Saccharomyces cerevisiae populations display biogeographic patterns. Since the differentiated populations of S. cerevisiae seem to be responsible for the regional identity of wine, the aim of this work was to assess a possible relationship between the diversity and the geographical origin of indigenous S. cerevisiae isolates from two different Italian wine-producing regions (Tuscany and Basilicata). For this purpose, sixty-three isolates from Aglianico del Vulture grape must (main cultivar in the Basilicata region) and from Sangiovese grape must (main cultivar in the Tuscany region) were characterized genotypically, by mitochondrial DNA restriction analysis and MSP-PCR by using (GTG)5 primers, and phenotypically, by determining technological properties and metabolic compounds of oenological interest after alcoholic fermentation. All the S. cerevisiae isolates from each region were inoculated both in must obtained from Aglianico grape and in must obtained from Sangiovese grape to carry out fermentations at laboratory-scale. Numerical analysis of DNA patterns resulting from both molecular methods and principal component analysis of phenotypic data demonstrated a high diversity among the S. cerevisiae strains. Moreover, a correlation between genotypic and phenotypic groups and geographical origin of the strains was found, supporting the concept that there can be a microbial aspect to terroir. Therefore, exploring the diversity of indigenous S. cerevisiae strains can allow developing tailored strategies to select wine yeast strains better adapted to each viticultural area.
... Sacch. cerevisiae strains develop during wine fermentation which play an active role in the characteristics of wine (Vilanova andSieiro 2006, Capece et al. 2013). ...
... The fruit wine industry is also interested in food grade microorganisms, particularly some special yeast strains that are able to produce unique flavours, which are dependent on two aspects of yeast starters: (1) their capability in releasing volatile compounds from flavour precursors of fruits, e.g. mangosteen and (2) their different capacity to synthesise yeast-derived volatile compounds (Wondra & Boveric 2001;Swiegers et al. 2006;Ugliano et al. 2006;Vilanova & Sieiro 2006). On the other hand, the sensory characters of wines fermented with different Saccharomyces cerevisiae would be significantly changed due to their remarkably varied flavour profiles despite the same fermentation. ...
Mangosteen fruit is fermented with five different strains (i.e. GRE (Y1), Lalvin RC212 (Y2), Lalvin D254 (Y3), CGMCC2.23 (Y4) and CGMCC2.4 (Y5)) of the yeast Saccharomyces cerevisiae to make mangosteen wines. A total of 36 volatile compounds of the mangosteen wines were identified by gas chromatography-mass spectrometry and gas chromatography-pulsed flame photometric detection. A total of 35 odour-active compounds were identified by gas chromatography-olfactometry analysis and by the detection frequency (DF) method. The compounds with high DF values included ethyl octanoate, ethyl hexanoate and 3-methyl-2-butene-1-thiol. Principal component analysis was used to characterise the differences of the flavour profiles of those mangosteen wines. The result demonstrated that the samples could be divided into three groups that were associated closely with aroma-active compounds.
... From the quantitative perspective, alcohols were the largest group of the volatile compounds in persimmon wines. During fermentation, different yeast strains contributed considerably to the differences in higher alcohol profiles and concentrations in fruit wines (Vilanova & Sieiro 2006). The alcohol concentration of fruit wines was an important parameter that reflects the fermentation capacity of yeast strains due to their close correlation with yeast metabolism (Romano et al. 2003). ...
This study evaluated the effects of five strains (IFFI 1346, IFFI 1363, CICC 31482, D254 and CGMCC2.346) of the yeast Saccharomyces cerevisiae on the aromatic profiles of fermented persimmon (Diospyros kaki L.f.) musts. A total of 50 and 60 compounds were identified in persimmon wine by stir bar sorptive extraction coupled with gas chromatography-mass spectrometry. According to odour activity values (OAVs), 26 detected compounds showed an OAV above 1. Principal component analysis explained the distribution of these persimmon wines on the basis of volatile compounds with OAV>1. The volatile compounds with high OAV included ethyl hexanoate, ethyl octanoate, methyl decanoate, linalool and geraniol. Quantitative descriptive analysis was employed. The result showed that persimmon wines fermented with strains IFFI 1363 and D254 were strongly correlated with persimmon, aroma harmony, fruity, fusel and taste balanced, fullness, hedonic scale. Therefore, the two yeast strains could be used as starter culture for persimmon wine production.
... The essence of a wine's flavor is formed during alcoholic fermentation. Ethanol and glycerol are the most abundant alcohols, followed by higher alcohols and esters, the combinations of which affect the final aroma of a wine [40]. Arrizon et al. [5] indicated that acetaldehyde is directly correlated with yeast metabolism in alcoholic fermentation because this compound is produced by decarboxylation of pyruvate, which is the direct product of glycolysis. ...
Two yeast groups, S5: Saccharomyces (S.) cerevisiae BCRC21686 and S. cerevisiae BCRC21962, and S6: S. cere-visiae BCRC21824 and S. cerevisiae BCRC21962, were used to ferment Monostroma (M.) nitidum hydrolysate (MNH) solution under various conditions, such as (1) M. nitidum powder; (2) carbon source; (3) nitrogen source; and (4) yeast group inoculation concentrations, respectively, at 25°C in a 10-day M. nitidum wine study. First, the 2.5% M. nitidum powder particles in the MNH solution elicited better alcohol content than the other concentrations did. Then, the 15% sucrose and 0.500% proline in the MNH solution produced good alcohol content in a carbon source and a nitrogen source, respectively. The S5 and S6 groups also showed improved alcohol content in the yeast group inoculation concentration of 4%. Therefore, we combined these conditions to out carry M. nitidum wine fermentation on days 0, 5, 7, 10, 14, 18, or 21. The M. nitidum wines with 10%, 15%, or 20% sucrose ferment showed good alcohol and compositional changes after 7, 10, or 14 days, respectively. During the 3 months of aging, the influence on the alcohol content, pH value, titratable acidity, reducing sugar content and residual sugar content caused by storage temperatures at 15°C and 25°C on the components of M. nitidum wines were not observed. The M. nitidum wines aged at 25°C showed lower Hunter L, a, and b values than did the M. nitidum wines aged at 15°C. Overall, sensory evalua-tions showed the best M. nitidum wines were fermented with 20% sucrose added to the M. nitidum wine substrate at 25°C and then aged at 15°C for 3 months. M. nitidum wine can be further studied in the field of M. nitidum wine manufacturing.
... Saccharomyces cerevisiae is highly tolerant to ethanol and highly competitive for growth in media with high sugar concentration (Querol, Barrio, Huerta, & Ramón, 1992) and is the main species of yeast in winemaking. Different strains of S. cerevisiae can produce significantly different flavour profiles when fermenting the same must and this is a consequence of three factors: i) the difference in winemaking conditions; ii) the differential ability of wine yeast strains to release varietal volatile compounds from grape precursors; iii) the strain-specific capability to de novo synthesise yeast-derived volatile compounds (Vilanova & Sieiro, 2006). ...
... In the past years, strains of Saccharomyces cerevisiae have been selected for their enological properties and have been used as starters in winemaking to carry out alcoholic fermentation with success. The native and starter strains of S. cerevisiae, involved in fermentation, play an important role in the characteristics of wine (King et al., 2008;Lambrechts & Pretorius, 2000;Thorhgate, 1998;Vilanova & Sieiro, 2006). In fact the composition and the sensory quality of the resulting wine are due to the diversity of S. cerevisiae strains and to their dominance in fermentation (La Jeune, Enry, Demuyter, & Lollier, 2006;Torrens et al., 2008;Wondra & Boveric, 2001). ...
The growth of selected, indigenous Saccharomyces cerevisiae added as starters (SRS1, MS72 and RT73) was monitored during Montepulciano d'Abruzzo wine production. In all the fermentations the addition of the starter, caused a decrease of the non-Saccharomyces yeasts. When strains MS72 and RT73 were used as starters they were detected in the first phases of fermentations, while strain SRS1 competed successfully with native yeasts during all the process. Wines obtained by fermentation with the indigenous starters showed some different characteristics, according to the chemical and sensory analyses. This study highlighted that among selected starters with high fermentative capacity, some are able to dominate better than other natural wine yeast biota, whereas some strains can interact and survive besides native yeast populations during the fermentation. As a consequence, the dominance character can have a positive or negative effect on wine quality and has to be considered in the frame of yeast selection in order to improve or characterize traditional wines. Winemakers could choose among different degrees of yeast dominance to modulate the interaction among starter and native wine yeast population.
... Rapid information regarding the composition and dynamics of yeast flora occurring throughout the vinification process helps to control fermentation and consequently wine quality. During the fermentations, it's widely demonstrated that different Saccharomyces cerevisiae strains develop and this strain variety plays an active role in the characteristics of wine (Lambrechts and Pretorius, 2000;Vilanova and Sieiro, 2006;King et al., 2008). This diversity of wild yeasts can produce high quality and unique-flavoured wines (Callejon et al., 2010). ...
... Thus, wine made with XG5 showed a higher content of 2-phenylethyletanol and a lower amount of acetates and ethyl lactate. These results are in agreement with those reported by several authors; who distinguished wines from spontaneous fermentation and wines from inoculated processes (Egli et al., 1998;Lema et al., 1996;Nurgel et al., 2002;Varela et al., 2009;Vilanova and Sieiro, 2006). ...
The fermentative ability of five autochthonous Saccharomyces cerevisiae strains (XG1, XG2, XG3, XG4 and XG5) and their influence on the chemical composition and sensory properties of Treixadura wines were evaluated. The inoculated strains have successfully led and completed the fermentations. Wines obtained from different yeasts showed significant differences in total and volatile acidity. Regarding volatile compounds, significant differences among wines were found for acetates, ethyl esters, acetoin, 1-hexanol, and fatty acids. Wines from spontaneous fermentation and those made with yeasts XG3 and XG4 were clearly separated through principal component analysis. Chemical composition influenced sensory properties of wines, especially at the olfactory level. Different connotations of fruity notes predominated depending on the strain. The wine from strain XG4 was the most appreciated by panelists. Our results confirmed that autochthonous S. cerevisiae strains are useful tools in winemaking because they allow obtaining singular wines from a given variety.
... The presence of ethyl lactate was observed in the headspace of fermented beverages with yeast UFLA CA1174 and spontaneous fermentation. Vilanova & Sieiro (2006) observed that lower concentrations of ethyl lactate were produced in wines fermented with selected yeasts. As the production of ethyl lactate increased in beverages fermented spontaneously, the authors attributed this observation to the fermentation process. ...
The aim of this study was to evaluate the contribution of yeast to the volatile profile of beverages obtained by the fermentation of lychee must through inoculated (Saccharomyces cerevisiae strains UFLA CA116, UFLA CA1183 and UFLA CA1174) and spontaneous fermentation. Higher alcohols and esters were the primary volatiles detected by SPME/GC–MS. A Principal Component Analysis indicated similarities between UFLA CA116 and UFLA CA1183 and between UFLA CA1174 and spontaneous fermentation. Changing the yeast strain used in the fermentation process has the potential to modulate the volatile profile of fermented beverages. The beverage produced by the inoculation of yeast CA1183 showed the most complex aroma profile compared to the other beverages.
... Different strains of S. cerevisiae can produce significantly different flavour profiles when fermenting the same must. This is a consequence of both, the differential ability of wine yeast stains in releasing varietal volatile compounds from grape precursors, as well as the differential capacity to synthesise de novo yeast-derived volatile compounds (Swiegers, Francis, Herderich, & Pretorius, 2006;Ugliano, Bartowsky, McCarthy, Moio, & Henschke, 2006;Vilanova & Sieiro, 2006;Wondra & Boveric, 2001). Therefore, the selection of the proper yeast strain can be critical for the development of the desired wine style. ...
The specific impact of the yeast strain on the wine flavour and aroma has not been well characterised yet because this effect is usually combined with other variables during the winemaking. In this study, the contribution to wine flavour of two Saccharomyces cerevisiae strains widely used in wine production, VIN13 and EC1118, was evaluated after fermentation at 15 °C. Chemical defined grape juice media fermented with the EC1118 strain showed higher solvent, fatty and pineapple aroma attributes, while that fermented with the VIN13 strain exhibited higher banana, fruity, yeasty and green attributes. Sensorial and chemical analyses evidenced that the production of flavour-active compounds is significantly affected by the yeast strain, as well as by the temperature of fermentation, as shown by comparing the former data with those from fermentations carried out at 28 °C under identical culture conditions.
... Several studies have clearly shown the effects of indigenous and inoculated yeast populations on the wine volatile composition (Mateo et al., 2001; Nurgel et al., 2003). From Atlantic viticulture, a comparative study was made of the fermentation products of Spanish Albariño wines produced with spontaneous yeast flora and an indigenous selected Saccharomyces cerevisiae strain (Vilanova & Sieiro, 2006a). The gas chromatography data showed that the wines differed in their volatiles contents. ...
... The employment of native, indigenous, selected local strains of S. cerevisiae as starters seems to be preferable [2, 22, 40] , because these strains are adapted to all the conditions associated with a speciWc wine-production area [23] and are thus able to control the indigenous microXora during the fermentation process more eYciently. Moreover, there is a growing demand to select, among the fermentative yeast Xora, autochthonous yeast strains that ensure the maintenance and/or the improvement of the typical oenological and sensory characteristics which could be considered representative of an oenological region [29, 44, 56, 59]. In the present study, we propose a strategy to select S. cerevisiae strains from a large number of strains by key parameters indicative of their technological and qualitative characteristics. ...
The aim of the present study was to establish a new procedure for the oenological selection of Saccharomyces cerevisiae strains isolated from natural must fermentations of an important Italian grape cultivar, denoted as "Negroamaro". For this purpose, 108 S. cerevisiae strains were selected as they did not produce H(2)S and then assayed by microfermentation tests. The adopted procedure made it possible to identify 10 strains that were low producers of acetic acid and hydrogen sulphide and showed that they completed sugar consumption during fermentation. These strains were characterized for their specific oenological and technological properties and, two of them, strains 6993 and 6920, are good candidates as industrial starter cultures. A novel protocol was set up for their biomass production and they were employed for industrial-scale fermentation in two industrial cellars. The two strains successfully dominated the fermentation process and contributed to increasing the wines' organoleptic quality. The proposed procedure could be very effective for selecting "company-specific" yeast strains, ideal for the production of typical regional wines. "Winery" starter cultures could be produced on request in a small plant just before or during the vintage season and distributed as a fresh liquid concentrate culture.
... Different strains of Saccharomyces can produce significant flavour differences when fermenting the same must. This is a consequence of both the differential ability of wine yeast strains to release varietal volatile precursors and the different ability to synthesise the novo yeastderived volatile compounds (Callejón et al. 2010;Swiegers et al. 2006;Vilanova et al. 2006;Wondra et al. 2001). Therefore, the selection of the proper yeast strain may be critical for the development of the desired wine style (Callejón et al. 2010;Molina et al. 2009). ...
Wine production in most countries is based on the use of commercial strains leading to the colonisation of the wineries by these strains with the consequent reduction of autochthonous biodiversity. This implies that wine styles could therefore become standardised. The vineyard could be an important source of native yeasts of oenological interest. For this reason the objective of this study was to compare two agronomic conditions with the aim of preserving yeast biodiversity in the vineyard. A three year sampling plan was designed to evaluate the influence of different agronomic parameters on the biodiversity of fermentative grape yeasts. Thus two vineyards, one organic and one conventional, with three different grape varieties (Shiraz, Grenache and Barbera) were chosen. In total, 27 samples were collected from both vineyards. Of these, 1080 colonies were isolated and a total of 9 species were identified. The strains identified as Saccharomyces cerevisiae were genotyped by microsatellite analysis obtaining nine different electrophoretic patterns. Classical ecology indexes were used to obtain the richness (S), the biodiversity (H') and the dominance (D) of the species studied. The results indicated a clear influence on grape associated yeast diversity of the phytosanitary treatment used in the vineyard. This is the first time that classical ecology indexes have been used to study the ecology of the spontaneous fermentation of grape musts and the species Candida sorbosa and Pichia toletana have been described in vineyards of the Madrid winegrowing region.
... Although these secondary metabolites are often formed only in trace amounts, their concentrations determine the distinct aroma of these beverages because their perception threshold is very low. The main fermentation-derived secondary metabolites which contribute to the wine aroma are aldehydes, higher alcohols, esters and fatty acids (Lilly et al., 2006a;Vilanova & Sieiro, 2006). The individual secondary metabolites and their impact on perception are listed in Table 6.1. ...
ENGLISH ABSTRACT: The production of glycerol by Saccharomyces cerevisiae under anaerobic conditions is essential for maintaining the intracellular redox balance thereby allowing continuous energy generation through conversion of sugars into ethanol. In addition, glycerol can act as an osmolyte and is synthesized to maintain turgor pressure under hyperosmotic conditions. The production of ethanol from sugars can be a redox-neutral process, where the NAD+ (nicotinamide adenine dinucleotide) that is consumed during the glycolytic conversion of glyceraldehyde-3-phosphate to pyruvate is later regenerated by the reduction of acetaldehyde to ethanol. However, in particular the redirection of metabolic flux of pyruvate to biomass formation leads to excess NADH formation. The intracellular redox balance in these conditions is then primarily maintained through formation of glycerol which is control by two main enzymes, namely Gpd1p and Gpd2p. Deletion of the genes coding for these two proteins leads to accumulation of NADH and renders the cells incapable of maintaining their fermentative ability and growth under anaerobic conditions. The goal of this study was to investigate the growth, fermentative ability and metabolite synthesis of various gpd1Δgpd2Δ double mutant (DM) strains in which the redox balancing potential was partially restored through expression of native or heterologous genes. Strains were constructed by introducing alternative NADH oxidizing pathways or manipulating existing pathways to favour the oxidation of excess NADH. More specifically, the modifications included (i) sorbitol formation; (ii) establishing a pathway for propane-1,2-diol formation; and (iii) increasing ethanol formation. Apart from genetically manipulating the gpd1Δgpd2Δ double mutant, the addition of pyruvate during growth was also investigated. The experiments were carried out under oxygen limited conditions in a high sugar medium and the fermented product was analyzed for total sugar consumed, biomass and primary and secondary metabolites formed by the different strains. The relationships between sugar consumption, growth and metabolite production by different strains were investigated by comparing the data generated from the different strains by using multivariate data analysis tools. Analysis of the pathways involved in the production of primary (acids, ethanol and other metabolites) and secondary metabolites (aroma compounds) were also carried out in order to establish flux modification in comparison to the wild type (WT) strain. The results revealed that these manipulations improved the fermentative capacity of the gpd1Δgpd2Δ double mutant, suggesting a partial recovery of NAD+ regeneration ability, albeit not to the extent of the WT strain. As expected a significant correlation was found between sugar consumption and ethanol and biomass formation. Ethanol yields but not final concentrations were increased by the genetic manipulations. Sorbitol by DM(srlD) and DM(SOR1) strains and propane-1,2-diol by DM(gldA, GRE3, mgsA) strain were formed in significant amounts although at lower molar yields than glycerol. Furthermore, by genetic manipulation the yield of secondary metabolites (isobutanol, isoamyl alcohol, 2-phenyl ethanol and isobutyric acid) was increased whereas the ethyl acetate concentration and yield decreased. The results indicate that aroma compound properties of wine yeasts could be favourably changed by manipulating the glycerol synthesizing pathway. The addition of pyruvate during the growth of gpd1Δgpd2Δ double mutant contributes to excess NADH re-oxidation through additional ethanol formation. AFRIKAANSE OPSOMMING: Die produksie van gliserol deur Saccharomyces cerevisiae onder anaërobiese toestande is noodsaaklik vir die onderhouding van die intrasellulêre redoksbalans en maak dus ononderbroke energie-ontwikkeling tydens die omsetting van suikers in etanol moontlik. Daarbenewens kan gliserol as ‘n osmoliet optree en word dit gesintetiseer om turgordruk onder hiperosmotiese toestande te onderhou. Die produksie van etanol uit suikers kan ‘n redoksneutrale proses wees, waar die NAD+ (nikotinamiedadenien-dinukleotied) wat tydens die glikolitiese omskakeling van gliseraldehied-3-fosfaat na piruvaat verbruik word, later deur die reduksie van asetaldehied na etanol regenereer word. Die nasending van die metaboliese vloeiing van piruvaat na biomassavorming lei egter na ‘n oormaat NADH-vorming. Onder hierdie toestande word die intrasellulêre redoksbalans dan hoofsaaklik deur die vorming van gliserol onderhou. Laasgenoemde word veral deur twee ensieme beheer, naamlik Gpd1p en Gpd2p. Die delesie van die gene wat vir hierdie twee proteïene enkodeer, lei tot ‘n akkumulasie van NADH en veroorsaak dat die selle nie hulle gistingsvermoë en groei onder anaërobiese toestande kan onderhou nie. Die doelwit van hierdie studie was om die groei, gistingsvermoë en metabolietsintese van verskeie gpd1Δgpd2Δ dubbelmutant (DM) rasse te ondersoek waarin die redoksbalanseringspotensiaal gedeeltelik herstel is deur die uitdrukking van inheemse of heteroloë gene. Rasse is gekonstrueer deur alternatiewe NADH-oksiderende weë in te voer of deur bestaande weë te manipuleer om die oksidasie van oormaat NADH te bevoordeel. Meer spesifiek het die modifikasies die volgende ingesluit: (i) sorbitolvorming; (ii) die vestiging van ‘n weg vir propaan-1,2-diol-vorming; en (iii) die verhoging van etanolvorming. Buiten die genetiese manipulering van die gpd1Δgpd2Δ dubbelmutant, is die byvoeging van piruvaat tydens groei ook ondersoek. Die eksperimente is onder suurstofbeperkte toestande in ‘n hoë-suiker medium uitgevoer en die gegiste produk is ondersoek vir totale suikerverbruik, biomassa en primêre en sekondêre metaboliete wat deur die verskillende rasse gevorm is. Die verhoudings tussen suikerverbruik, groei en metabolietproduksie deur die verskillende rasse is ondersoek deur die data wat deur die verskillende rasse gegeneer is deur middel van meerveranderlike data-analise te vergelyk. Analise van die weë wat in die produksie van primêre (sure, etanol en ander metaboliete) en sekondêre metaboliete (aromaverbindings) betrokke is, is ook uitgevoer om die verandering in vloei te bepaal in vergelyking met die wildetipe (WT) ras. Die resultate het gewys dat hierdie manipulasies die gistingsvermoë van die gpd1Δgpd2Δ-dubbelmutant verbeter het, wat ‘n gedeeltelike herstel van NAD+- regenerasievermoë voorstel, hoewel nie tot dieselfde mate as in die WT-ras nie. Soos verwag, is ‘n beduidende korrelasie tussen suikerverbruik en etanol- en biomassavorming gevind. Etanolopbrengs is deur genetiese manipulasies verhoog, maar nie die finale konsentrasies van etanol nie. Sorbitol is in beduidende hoeveelhede deur die DM(srlD) en DM(SOR1)-rasse gevorm en propaan-1,2-diol deur die DM(gldA, GRE3, mgsA) -rasse, hoewel teen laer molare opbrengste as gliserol. Verder is die opbrengs van sekondêre metaboliete (isobutanol, iso-amielalkohol, 2-fenieletanol en isobottersuur) deur genetiese manipulasie verhoog, terwyl die etielasetaatkonsentrasie en -opbreng verlaag is. Die resultate dui aan dat die aromaverbindingseienskappe van wyngiste voordelig verander kan word deur die gliserolsintetiseringsweg te manipuleer. Die byvoeging van piruvaat tydens die groei van die gpd1Δgpd2Δ-dubbelmutant dra by tot uitermate NADH-reoksidasie tydens die bykomende vorming van etanol. Thesis (PhD (Science) (Viticulture and Oenology. Wine Biotechnology))--University of Stellenbosch, 2010.
... Different strains of S. cerevisiae can produce significantly different flavour profiles when fermenting the same must. This is a consequence of both the differential ability of wine yeast strains to release varietal volatile compounds from grape precursors and the differential ability to synthesise de novo yeast-derived volatile compounds [12][13][14][15]. Therefore, selecting the proper yeast strain can be critical for the development of the desired wine style [7]. ...
Organic wines were produced at pilot scale to select the best autochthonous and commercial yeast strains to obtain wines with high organoleptic qualities. We tested the behaviour of five S. cerevisiae yeast strains and determined their volatile composition and organoleptic characteristics by sensory analysis. A total of 51 volatile compounds were quantified in the wines produced. The concentration of most of the volatile compounds was significantly influenced depending on which yeast strain was inoculated. The differences observed in the volatile composition of the wines appear to be quantitative rather than qualitative. In general, acetals were the most abundant group of volatile compounds in all the samples studied, followed by alcohols without ethanol. The highest contents of volatile compounds were found in two of the wines produced by autochthonous yeast strains. The results obtained in the sensory analysis suggest that autochthonous yeast produced wines of higher organoleptic quality because this sample gave the highest value for the general impression attribute.
... Therefore, in the wine-making industry the growth of undesirable yeasts is controlled by addition of sulphur dioxide to musts and inoculation with selected strains of Saccharomyces cerevisiae [20,21,28]. Analysis obtained from spontaneous and inoculated fermentations has shown signiWcant diVerences in the chemical composition and sensory properties of wine [4,10,33]. ...
This work describes the influence of yeast population on the chemical characteristics of wine obtained by spontaneous and inoculated fermentation of must from Vitis vinifera Lado, a minor white grapevine autochthonous to Galicia (NW Spain). The study was carried out for two consecutive years. The results showed that musts derived from Lado presented a high acidity though the potential alcohol level was acceptable. The genetic diversity of S. cerevisiae strains isolated from spontaneous fermentations was low, probably due to must characteristics, although these did not interfere with the implantation of the commercial strains used. Analyses showed that the wines subsequently produced had high alcoholic levels and very high acidities (pH 3.0) as was expected from must composition. Wines obtained from spontaneous fermentations had a lower alcohol content but higher total acidity than those from inoculated fermentations. Monovarietal wines produced from Lado were poorly evaluated in sensorial tests because of their unbalanced structure and sourness; however, when they were mixed with other autochthonous white varieties with less acidity, the resulting wines were well accepted.
Saccharomyces yeasts from different origins and species fermented in a semi-synthetic must containing aroma precursor of cv. Albariño and polyfunctional mercaptans precursors. The resulting wines were subjected to accelerate anoxic aging. Afterward, aroma profiles were analyzed by distinct gas chromatography methodologies.
Cryotolerant strains showed better fermentation performances with significant differences in volatile and non-volatile fermentation products than Saccharomyces cerevisiae (S. cerevisiae). We suggested that the highest levels γ-butyrolactone and diethyl succinate in Saccharomyces uvarum (S. uvarum) strains, together with their substantial succinic acid yields, could be related to greater flux through the GABA shunt. These strains also had the highest production of β-phenylethyl acetate, geraniol, and branched-chain ethyl esters. The latter compounds were highly increased by aging, while acetates and some terpenes decreased. S. kudriavzevii strains showed a remarkable ability to release polyfunctional mercaptans, with SK1 strain yielding up to 47-fold and 8-fold more 4-methyl-4-mercaptopentan-2-one (4MMP) than S. cerevisiae and S. uvarum strains, respectively. The wild S. cerevisiae beer isolate showed a particular aroma profile due to the highest production of ethyl 4-methylvalerate (lactic and fruity notes), γ-octalactone (coconut), and furfurylthiol (roasted coffee). The latter compound is possibly produced from the pentose phosphate pathway (PPP). Since erythritol, another PPP intermediate was largely produced by this strain.
The effect of four commercial Saccharomyces cerevisiae strains (D254, VIC, BV818, and RV100) on the volatile profile of wax apple (Syzygium samarangense) wine was investigated in this study. Alcohols and esters were the most two abundant groups of identified volatiles in wax apple wines. However, different S. cerevisiae strains possess various capacities in releasing/synthesizing volatiles with varied mRNA levels of genes involved in volatiles metabolism during wax apple wine fermentation. VIC, which yielded the highest total concentration of volatiles and largest number of volatiles with odor activity value (OAV) > 1, could be used as a starter culture to produce wax apple wine characterized with intense aroma. D254 and RV100, which produced the greatest variety of volatiles and scored the highest in global aroma, respectively, could be used to enhance the wine complexity. Four wax apple wines could be differentiated by their main volatile compounds.
The aim of this study was to develop high quality no-sugar-added apple cider. Physicochemical characteristics of the apple cider fermented using a co-culture of Saccharomyces cerevisiae Fermivin and non-Saccharomyces yeasts (Pichia anomala JK04 and Issatchenkia orientalis KMBL5774) were investigated after freeze concentration (FC) until alcohol content reached 12% (v/v). Compared with others, JK04 cider showed delayed alcohol fermentation. Soluble solid, reducing sugar, total acidity, and total phenolic compounds including free-sugar content of JK04 cider were considerably increased after FC compared to those of other ciders. Malic acid content was the highest among organic acids in all ciders after FC, while lactic acid content remained unchanged. Methanol, acetaldehyde, and fusel oil content of all ciders increased after FC; but it was lower than the standard of Korean Food Standards Codex. Hue value decreased in Fermivin and JK04 ciders but increased in 5774 cider. Intensity values of all ciders increased. L and a values in all ciders decreased, whereas b value increased remarkably. In total, 20 types of volatile aromatic compounds were detected. High molecular weight compounds increased while low molecular weight compounds decreased after FC. JK04 cider got the highest color and flavor scores, while 5774 cider got the highest taste and overall preferences scores. Therefore, these data show that non-Saccharomyces yeasts and freeze concentration can be used to improve the overall quality of apple cider. Copyright © The Korean Society of Food Preservation. All rights reserved.
This study investigated the volatile composition and color attributes of mulberry wine fermented by three yeast strains, including Red Fruit (RF), Red Vintage (RV), and ES488 (ES). Results showed different yeasts altered the physicochemical properties, volatile composition, and color attributes of the samples. The highest contents of total phenol and total anthocyanins were observed in ES wine and RF wine, respectively. Higher level on alcohols, terpenes, and benzenes together with lower concentration on carbonyl compounds was observed in RV wine. Esters were the most abundant volatiles, and the total esters' concentration was similar among these samples. The primary aroma in mulberry wine was floral and caramel flavors. The RV wine exhibited higher level on the fruity and chemical aromas. Additionally, the RV wine possessed higher brightness, lower red color, and color intensity. Color contribution from the copigmented and polymerized anthocyanins was significantly improved in RV wine and ES wine, respectively.
Practical applications
Different yeast strains during mulberry wine fermentation played an important role in affecting the composition of volatiles and color attributes, which further determines the overall quality of mulberry wine. The findings from this study could provide useful reference on optimizing mulberry wine fermentation through selecting suitable yeast strains.
The use of yeast starters indigenous to each winegrowing area is today a worldwide oenological practice aiming to imprint a differential character to the wine. This chapter summarizes the research carried out towards the design and development of indigenous wine yeast starters from Argentinean Patagonia that are currently nonexistent in the market. The results shown include diversity and criteria for Saccharomyces and non-Saccharomyces wild yeast strain selection as well as their contribution to the physicochemical and sensorial qualities of wines when they are used either singly or in combined forms. The advantages of these indigenous starters over the foreign commercial ones to imprint a differential character on regional wines are also discussed.
The long-time studies on wine yeasts have determined a wide diffusion of inoculated fermentations by commercial starters, mainly of Saccharomyces. Although the use of starter cultures has improved the reproducibility of wine quality, the main drawback to this practice is the lack of the typical traits of wines produced by spontaneous fermentation. These findings have stimulated wine-researchers and wine-makers towards the selection of autochthonous strains as starter cultures. The objective of this study was to investigate the biodiversity of 167 S. cerevisiae yeasts, isolated from spontaneous fermentation of grapes. The genetic variability of isolates was evaluated by PCR amplification of inter-δ region with primer pair δ2/δ12. The same isolates were investigated for characteristics of oenological interest, such as resistance to sulphur dioxide, ethanol and copper and hydrogen sulphide production. On the basis of technological and molecular results, 20 strains were chosen and tested into inoculated fermentations at laboratory scale. The experimental wines were analyzed for the content of some by-products correlated to wine aroma, such as higher alcohols, acetaldehyde, ethyl acetate and acetic acid. One selected strain was used as starter culture to perform fermentation at cellar level. The selection program followed during this research project represents an optimal combination between two different trends in modern winemaking: the use of S. cerevisiae as starter cultures and the starter culture selection for specific fermentations.
Persimmon contains high levels of vitamins and phenolic compounds, as well as soluble solids, necessary for the fermentation of persimmon wine. Co-fermentation of persimmon wine was carried out using a mixed culture of Pichia anomala JK04, a Korean indigenous yeast that improves wine quality and flavor, and Saccharomyces cerevisiae Fermivin, an industrial wine yeast, in the following ratios: 9:1 (v/v), 5:5 (v/v), 1:9 (v/v) and 0:10 (v/v). During fermentation, the alcohol contents increased more slowly in samples of mixed culture than in samples of the single culture of S. cerevisiae Fermivin. The alcohol contents of all samples reached 12~13% (v/v) after 15 days. All samples of the mixed culture showed greater variety in flavor and taste than S. cerevisiae Fermivin only. In the sensory evaluation, mixed culture samples had higher scores in terms of flavor and overall preference than the single culture samples. Therefore, P. anomala JK04 is thought to improve the wine flavor of Korean domestic persimmon wine.
In this study, a recombinant Saccharomyces cerevisiae strain EKD13 overproducing mannoproteins has been used to obtain Albariño white wines. The inoculated strain prevailed and produced complete fermentation of the must, as also occurred in the case of spontaneous (non-inoculated) fermentation and in the must inoculated with the S. cerevisiae EC1118 strain. The analytical study of the wines obtained showed that the most important chemical differences among the wines produced with EKD-13, corresponded to the high concentration of mannoproteins, 2-phenyl ethanol and tyrosol. These differences were attributed to the expression, during must fermentation, of genes modified in the recombinant EKD-13 strain. The results obtained imply that this strain could be potentially useful to produce wines rich in mannoproteins that have distinctive characteristics compared to other similar wines, modifying the sensorial and technological parameters of the wines obtained.
For improving local wine aroma and quality, microvinifications of Cabernet Sauvignon must inoculated with twelve autochthonous strains of Saccharomyces cerevisiae, isolated and preselected from four viticultural regions in China, were carried out. Chemical and aromatic compositions of young wines were determined after alcoholic fermentation. Variance statistical analysis showed that chemical compositions and aroma concentrations quantified were significantly influenced by the strains used. A series of correlations, positive or negative, were observed among important volatile metabolites (esters, alcohols and fatty acids). Principal Component Analysis (PCA) of active aroma compounds, which contents were higher than thresholds, distinguished wines prepared into four groups according to the yeasts applied for microvinifications. The results of the sensory evaluation indicated that the wines produced by autochthonous yeast CC17 (CGMCC No.3284), which was the best producer of ethyl and isoamyl esters, have the highest sensory assessment because these wines are characterized by fruity aroma, and have the highest score for the color, astringency and flavor complexity. The relationships between sensory descriptors and volatile compounds of young Cabernet Sauvignon wines were studied by partial least squares regression (PLSR).
Sequence analysis of D1/D2 region of 26S rDNA was used for identification of different yeasts isolated from food-borne material. Then, their aromas compounds were detected and analyzed by SPME-GC-MS, another biology information technology. 12 yeast strains were grouped in 7 species belonging to 5 genera as follows: Saccharomyces cerevisiae, Torulaspora delbrueckii, Kluyveromyces marxianus, Pichia cactophila, Clavispora lusitaniae, Pichia membranifaciens, and Pichia kudriavzevii. Among all yeast strains, most of volatiles were similar, but contents were affected by different strains. Strain A1 (Saccharomyces cerevisiae) produced relatively higher aromas compounds than S6 (Kluyveromyces marxianus). The result of GC-MS showed ethyl octanoate and phenylethyl acetate were high-impact flavors by strain A1 and S6, respectively. In conclusion, it is a reliable identification system to indentify food-borne yeasts at species level using 26S rDNA sequencing and phenotypic studies. SPME-GC/MS analysis highlights aroma compounds can be used for pre-screening potential edible yeast strains effectively.
The use of selected yeast strains with improved or novel properties may promote wines with special and original quality attributes. In this paper, changes in the chemical composition (aroma compounds and polyphenols) and sensorial properties of Albariño white wines elaborated with the same must and selected yeast (named as 1, 2 and 3) have been studied in comparison with wines subjected to non-inoculated fermentation (control wine). The results indicated that yeast strain can significantly influence the aroma and polyphenol composition of the wines. Wines elaborated with strain 1 had a higher concentration of terpenes and norisoprenoids, which are compounds closely associated with the fruity and fresh character of Albariño white wines. These same wines had a lower concentration of flavan-3-ols, closely associated with the astringency and bitterness of the wine and the lowest browning potential. The formal sensory analysis conducted by 8 trained judges showed that wines elaborated with strain 1 were preferred by the tasting panel. Therefore, the selection of yeast strains could offer the possibility to modulate sensorial attributes related with the aroma and phenol composition in Albariño white wines.
The most mysterious aspect of wine is the endless variety of flavours that stem from a complex, completely non-linear system of interactions among many hundreds of compounds. In its widest sense, wine flavour refers to the overall impression of both aroma and taste components. Aroma is usually associated with odorous, volatile compounds; the bouquet of wine refers to the more complex flavour compounds which evolve as a result of fermentation, elevage and ageing. With the exception of terpenes in the aromatic grape varieties and alkoxypyrazines in the herbaceous cultivars, perceived flavour is the result of absolute amounts and specific ratios of many of these interactive compounds, rather than being attributable to a single "impact" compound. Without underestimating the complexity of these interactive effects or negating the definitive role played by the accumulated secondary grape metabolites in the varietal character of wine, this review will focus mainly on the contribution of yeast fermentation to the sensorial quality of the final product. Yeast and fermentation conditions are claimed to be the most important factors influencing the flavours in wine. Both spontaneous and inoculated wine fermentations are affected by the diversity of yeasts associated with the vineyard and winery. During the primary alcoholic fermentation of sugar, the wine yeast, Saccharomyces cerevisiae, together with other indigenous non-Saccharomyces species, produce ethanol, carbon dioxide and a number of by-products. Of these yeast-derived metabolites, the alcohols, acetates and C4-C8 1tfatty acid ethyl esters are found in the highest concentration in wine. While the volatile metabolites contribute tothe fermentation bouquet ubiquitous to all young wines, the production levels of these by-products are variable and yeast strain specific. Therefore, this article also highlights the importance of untapping the hidden wealth of indigenous yeast species present on grapes, and the selection and genetic development of yeast starter culture strains with improved flavour profiles. In the future, some winemakers may prefer to use mixtures of indigenous yeast species and tailored S. cerevisiae strains as starter cultures to reflect the biodiversity and stylistic distinctiveness of a given region. This will help winemakers to fullfil the consumer's demand for individual wines with intact local character and to ensure the survival of wine's most enthralling aspect - its endless variety.
This study was carried out to investigate the effect of addition of selected S. cerevisiae yeasts on cv. Kalecik karasi wines. Kalecik karasi grown in Middle Anatolia is a native grape variety of Vitis vinifera. Inoculation with the selected yeasts produced higher amounts of ethanol compared to spontaneous fermentation and repressed the non-Saccharomyces yeasts earlier. The total concentration of flavour compounds increased by using selected wine yeasts. Higher alcohols were abundant compounds and isoamyl alcohol levels varied from 75 to 132 mg/l. The addition of S. cerevisiae yeasts produced higher concentrations of 4-vinyl phenol and isoamyl acetate. Wines were also analysed by sensory evaluation. Those obtained with selected yeasts differed from the control wine in triangle test. The most preferred wine was the one produced by commercial S. cerevisiae in the ranking test.
The influence of different strains of Saccharomyces cerevisiae on the fermentation and sensory characteristics of wine was studied. Five strains were isolated from fermenting musts in the Rías Baixas region (NW Spain), and characterized by pulsed field gel electrophoresis. Each strain was assessed for pectinolytic and killer activity as well as for flocculation capacity. The strains were then used to ferment Albariño must on a laboratory scale. The wines produced, which showed significantly different (P<0.001) physicochemical parameters, were evaluated for aromatic quality by sensorial analyses. The wine obtained using one of the strains was given the highest rating by wine tasters, as its aroma was the most typical of the Rías Baixas wines.
The effect of inoculation with selected Saccharomyces cerevisiae strains was studied on fermentation and flavor compounds of wines made from Vitis vinifera L. cv. Emir grown in Central Anatolia, Turkey. Flavor compounds were analysed and identified by GC-FID and GC-MS, respectively. The total concentrations of flavor compounds did not increase with the addition of indigenous and commercial wine yeasts, but differences were noted in individual volatile compounds. Cluster and factor analyses of flavor compounds also showed that wines produced were different depending on the wine strain used. Wines were completely fermented to less than 1.4 g/l residual sugar. Yeasts other than S. cerevisiae survived longer than previously reported. Inoculation with selected strains increased the ethanol level.
The growth of yeasts that occur naturally in grape juice was quantitatively examined during the fermentation of four wines that had been inoculated with Saccharomyces cerevisiae. Although S. cerevisiae dominated the wine fermentations, there was significant growth of the natural species Kloeckera apiculata, Candida stellata, Candida colliculosa, Candida pulcherrima, and Hansenula anomala.
Volatile composition of red wines made from cv. Kalecik Karasι, a native grape variety of Vitis vinifera grown in Turkey, was investigated during two vintages. Volatile compounds were extracted with dichloromethane, and then analysed by gas chromatography–flame ionisation detection (GC/FID) and gas chromatography–mass spectrometry (GC/MS). Seventy-eight aroma compounds were identified. Isoamyl alcohol, ethyl hexanoate, ethyl octanoate, ethyl decanoate, isoamyl acetate, 2-phenyl ethanol and octanoic acid were potent aroma compounds on the basis of gas chromatography/olfactometry (GC/O) analysis and odour activity values (OAVS).
One hundred and fifteen Saccharomyces cerevisiae strains from Aglianico del Vulture, a red wine produced in Southern Italy, were characterized for the production of some secondary compounds involved in the aroma and taste of alcoholic beverages. The strains exhibited a uniform behaviour in the production levels of n-propanol, active amyl alcohol and ethyl acetate, whereas isobutanol, isoamyl alcohol and acetaldehyde were formed with a wide variability. Only five strains produced wines close to the reference Aglianico del Vulture wine for the traits considered. Of these, two strains were selected, underwent to tetrad analysis and the single spore cultures were tested in grape must fermentation. The progeny of one strain showed a significant metabolic variability, confirming the necessity to test starter cultures for the segregation of traits of technological interest. Our findings suggest the selection of specific strains for specific fermentations as a function of the vine variety characteristics in order to take the major advantage from the combination grape must/S. cerevisiae strain.
Albariño and Loureira grapes were collected during maturation in 1998 and free and bound volatile compounds from the grapes
were studied to estimate and compare their aromatic potential. After solid-phase extraction monoterpenols, norisoprenoids,
terpenic hydrocarbons, and some alcohols were detected and quantified by GC with FID.
The influence of the addition of different concentrated inocula of various strains of Saccahromyces cerevisiae to high sugar content must on both evolution of sugar concentration and the volatile composition of the wines were studied. Evolution of sugar content was characteristic of the yeast strain and one was incapable of finishing fermentation. Volatile compounds were analyzed by using fused silica capillary GC column. Application of cluster analysis to the data showed that differences in the volatile fraction are mainly due to the inoculated yeast strain, although concentration of higher alcohols increases directly as the inoculum concentration.
The use of selected yeasts for wine-making has clear advantages over the traditional spontaneous fermentation. We have designed a simple and effective procedure to select wine yeasts for industrial use based on technological characteristics of the yeasts. The procedure consists of just two steps. The first is a preselection based on resistance to sulfur dioxide, killer phenotype, growth at high temperature and low foam production. The second is a selection based on volatile acidity, ethanol production, and residual sugars. Most of the selected yeasts (66.6%) produced wines of greater acceptance than those from spontaneous fermentation.
Wines from four Galician white varieties (Albariño, Loureira, Treixadura and Dona Branca) with 1992 to 1995 vintages have been analysed, in order to obtain their characterisation by the aromatic index. Monoterpenes, higher alcohols, ethyl esters, fatty acids, acetates, volatile phenols and heavy sulphur compounds were analysed by gas chromatography alone and together with mass spectrometry. Flavour compositions were similar for each wine obtained from grapes harvested in different years. Comparisons between odour unit values (OUV) from each wine variety and from these vintages were similar. However, odour profiles of Galician wines from these years were clearly differentiated. A correct differentiation could be achieved between samples elaborated with different varieties, when principal component and linear discriminant analysis were applied to the OUV data.
A hundred strains of Saccharomyces cerevisiae were examined for the ability to produce higher alcohols. In the strains tested the production of higher alcohols was found to be an individual strain characteristic and, as such, was statistically significant. The characteristics of the strains used (flocculation ability, foaming ability, killer character, and non-H2S production) were found to be uncorrelated to isobutanol and isoamyl alcohol production, whereas the production of high levels of n-propanol was found to be related to inability to produce H2S. This, in turn, suggests a link to methionine biosynthesis.
Nine Saccharomyces cerevisiae and four Saccharomyces bayanus strains used in the production of Trebbiano wine were examined. The aim of this study is to evaluate the different abilities of various yeast strains in wine-making. The possibility of yeast discrimination on the basis of their volatile production is another possibility. Wine chemical analyses showed statistically significant differences depending on the yeast strain used. Some compounds such as 2-phenylethanol, 2-phenethyl acetate, ethyl lactate, 3-ethoxypropanol, and, to a lesser extent, diethyl succinate and propionic acid characterized examined Saccharomyces bayanus yeasts. Moreover, these strains did not produce any undesirable compounds, such as acetic acid and sulfur anhydride. For these reasons and because they synthesized malic acid, they could be more suitable for white wine production. The other yeasts showed great differences, which are difficult to correlate with the strain. However, some strains had peculiar characteristics, such as an uncommonly high concentration of n-propanol and 3-ethoxypropanol.
Terpenes and C(13) norisoprenoids are among the most important aromatic compounds found in a volatile and nonvolatile form in grapes. Aromatic typicity of a spirit could be attributed to these compounds despite the very important presence of volatile compounds produced during alcoholic fermentation. In this study, following a solid phase extraction stage, the determination of the varietal aromatic compounds by gas chromatography was performed on 15 samples of Galician orujo spirits. The results show that significant differences (p < 0.05) exist in the concentrations of varietal aromatic compounds in Galician spirits obtained from different varieties of grapes. alpha-Ionona is the varietal aromatic compound that is most likely to contribute to the aroma of all of the spirits studied. The spirits from Catalan Roxo are the most aromatic, with floral and fruity nuances, while the spirits from Godello were the less aromatic group as far as the varietal compounds studied are concerned. Spirits from Mencia and Treixadura show a similar profile, but the former has a more intensive aroma due to beta-pinene, citronellol, and alpha-ionone. Albariño spirits stand out because of their profile that is marked by the contributions of eugenol and linalool.
This chapter reviews the scientific knowledge of the role of microorganisms, especially yeast, in the development of wine flavor. Specific attention is given to the contribution of esters, higher alcohols, volatile thiols, volatile phenols, and monoterpenoids to the flavor profile. It is well known that grapes of different cultivars display characteristic aromas that are distinctive of the wines. However, it can be shown that although some volatile aroma substances arise from components of the grapes, many of these compounds are changed and a substantial portion of wine flavor substances are formed during yeast fermentation. Therefore, wine has more flavor than the grape juice it is fermented from, and the importance of yeast and other wine-related microorganisms is central to the development of wine flavor. Furthermore, different biosynthetic pathways are interactive during the formation of the aroma of alcoholic beverages, and different factors play their part in the formation of the total aroma.
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