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Function of yeast species and strains in wine flavour
Abstract
The diversity and the composition of the yeast micropopulation significantly contribute to the sensory characteristics of wine. The growth of each wine yeast species is characterized by a specific metabolic activity, which determines concentrations of flavour compounds in the final wine. However, it must be underlined that, within each species, significant strain variability has been recorded. The wide use of starter cultures, mainly applied to reduce the risk of spoilage and unpredictable changes of wine flavour, can ensure a balanced wine flavour, but it may also cause a loss of characteristic aroma and flavour determinants. Thus, the beneficial contribution from the yeast increases when starter cultures for winemaking are selected on the basis of scientifically verified characteristics and are able to complement and optimise grape quality and individual characteristics. Here we report the characterization of a large number of strains of different wine yeast species, isolated from spontaneous wine fermentations and included in the culture collection of the Basilicata University.
... 2 Various aromatic compounds (ethyl esters, acetates, higher alcohols, and fatty acids) are synthesized by the metabolic activity of yeasts, transforming aromatic precursors present in the grape juice or producing new aromatic compounds. 3 Due to different compositions of the grape juice, different wines can be produced under the influence of the same yeast, while the quality of the wine is a result of the interaction between the composition of the grape juice and the yeast. 3 According to the literature, the yeast strain is an important factor that strongly influences the aroma and quality of wine. ...
... 3 Due to different compositions of the grape juice, different wines can be produced under the influence of the same yeast, while the quality of the wine is a result of the interaction between the composition of the grape juice and the yeast. 3 According to the literature, the yeast strain is an important factor that strongly influences the aroma and quality of wine. [2][3][4][5][6][7][8][9] The yeast S. cerevisiae is mainly used in the industry to perform alcoholic fermentation, while S. bayanus has a minor application in wine production. ...
... 3 According to the literature, the yeast strain is an important factor that strongly influences the aroma and quality of wine. [2][3][4][5][6][7][8][9] The yeast S. cerevisiae is mainly used in the industry to perform alcoholic fermentation, while S. bayanus has a minor application in wine production. Data in the literature show that the yeasts used in the experiments significantly influenced the synthesis of various ethyl esters and acetates. ...
Krstač and Žižak are autochthonous grape varieties grown in Montenegro. Although international varieties are more popular, the autochthonous varieties are very important, especially for countries developing tourism. The fermentation aromas produced during alcoholic fermentation contribute significantly to wine quality. The effects of yeasts (Saccharomyces cerevisiae and Saccharomyces bayanus) and yeast nutrients (Fermaid E and Fermaid O) on aromatic compounds in wines were investigated. Using GC/FID-MS analysis, aroma compounds in Krstač and Žižak wines were characterized and quantified. Wines produced with the addition of yeast and yeast nutrients had mostly lower total alcohol content than wines obtained by spontaneous fermentation of Krstač and Žižak varieties. The results of this study showed that the concentration of compounds depends on the yeast strains. The yeast S. cerevisiae (ICV) provided a higher content of higher alcohols, while S. bayanus produced a higher concentration of esters and (medium chain) fatty acids. Total ester content ranged from 3.34 to 11.97 mg/l for Krstač wines and 8.51 to 13.68 mg/l for Žižak wines. Among all wines, Krstač and Žižak wines produced with S. bayanus and Fermaid E addition had the highest concentration of total esters. The yeast nutrients Fermaid E and O emphasized different characteristics of the yeasts. They had a statistically significant effect on the content of ethyl and acetate esters. The highest overall scores were obtained for ICVE and BayE Krstač wines (18.1 out of 20 points) and Žižak ICVE wine (18.2 out of 20 points).
... compounds, the Sc group was positively correlated with some volatile compounds, and FAJ was only correlated with a small number of volatile compounds. Each yeast has its characteristics, and the differences in the activities of each enzyme in the glycolysis process of different yeasts make each strain different, leading to differences in the metabolism of sugar, acid, glycerol, and aroma components [34,35]. The characteristics of the different strains and the interactions between the strains, as well as the combined effects between substances, give cider its complex flavor characteristics. ...
... Each yeast has its characteristics, and the differences in the activities of each enzyme in the glycolysis process of different yeasts make each strain different, leading to differences in the metabolism of sugar, acid, glycerol, and aroma components [34,35]. The characteristics of the different strains and the interactions between the strains, as well as the combined effects between substances, give cider its complex flavor characteristics. ...
Cider flavor has a very important impact on the quality. Solid-phase microextraction-gas chromatography–mass spectrometry (SPME-GC-MS) combined with gas chromatography–ion mobility spectrometry (GC-IMS) tested different kinds of non-Saccharomyces yeasts and Saccharomyces cerevisiae (S. cerevisiae) co-inoculated for the fermentation of cider to determine differences in aroma material, and the determination of odor activity value (OAV) is applied less frequently in research. Through Rhodotorula mucilaginosa, Debaryomyces hansenii, Zygosaccharomyces bailii, and Kluyveromyces Marxianus, four different strains of non-Saccharomyces yeast fermented cider, and it was found that, in both the chemical composition and flavor of material things, compared with monoculture-fermented cider using S. cerevisiae, all differences were significant. Co-inoculated fermentation significantly improved the flavor and taste of cider. As in the volatile compounds of OVA > 1, octanoic acid (Sc 633.88 μg/L, co-inoculation fermented group 955.49 μg/L) provides vegetable cheese fragrance and decanoic acid, ethyl ester (Sc 683.19 μg/L, co-inoculation fermented group 694.98 μg/L) a creamy fruity fragrance, etc., and the average content increased after co-inoculated fermentation. Phenylethyl alcohol, which can produce a rose scent, was relatively abundant in cider samples and varied greatly among the groups. Moreover, the contents of ethyl lactate and 1-butanol in the Sc+Rm (ciders fermented by S. cerevisiae and R. mucilaginosa) were the highest of all of the cider samples. Different types of non-Saccharomyces yeast produced cider with different flavor characteristics. This study demonstrates that different species of non-Saccharomyces yeast do have an important impact on the characteristics of cider and that co-inoculation with non-Saccharomyces yeast and S. cerevisiae for cider fermentation may be a strategy to improve the flavor of cider.
... After washing 1.0 kg of glutinous rice, it was soaked for 15 h. The steamed rice was cooled to [30][31][32][33][34][35] • C in an ultraclean bench (Suzhou Antai Air Technology Co., LTD, Suzhou City, Jiangsu Province, China). Approximately 600 mL of water was poured into the glutinous rice to disperse the rice, while adding 0.7% FMQ and IQ separately. ...
... However, after adding 2% FMQ to IQ for Huangjiu fermentation, the percentage of bacterial genera changed noticeably, which may be associated with the environmental changes. Amylase, protease, and β-glucosidase could be secreted by Saccharomycopsis, which facilitates the glycation of starch [31]. Saccharomycopsis was identified as the main microbial community in JIUYAO of Shaoxing-jiu and exerted a vital influence on fermentation activity and flavor characteristics [32]. ...
In recent years, intensified Qu (IQ) has been gradually applied to brewing in order to improve the aroma of Huangjiu (Chinese rice wine). In this study, Saccharomyces cerevisiae and Wickerhamomyces anomalus solutions were added to Fengmi Qu (FMQ) from Fangxian, China to produce IQ, and brewing trial was conducted. High-throughput sequencing (HTS) was used to analyze the microbial community in fermentation broth of IQ (IQFB). Headspace solid-phase microextraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC-MS) and sensory evaluation were performed to analyze volatile aroma compounds (VACs) in sample without Qu and both fermentation broths. The results showed that Pediococcus, Cronobacter, Enterococcus, Weissella, and Acinetobacter and Saccharomycopsis, Wickerhamomyces, and Saccharomyces were dominant bacterial and fungal groups, respectively. A total of 115 VACs were detected, and the content of esters including ethyl acetate, isoamyl acetate, and so on was noticeably higher in IQFB. The finding of sensory evaluation reflected that adding pure yeast to Qu could enhance fruit and floral aromas. Correlation analysis yielded 858 correlations between significant microorganisms and different VACs. In addition, prediction of microbial community functions in IQFB revealed global and overview maps and carbohydrate metabolism to be the main one. This study is advantageous for further regulation of the fermentation process of Huangjiu by microbial means.
... This leads to the production of other main metabolites such as glycerol and organic acids. In addition, several minor volatile compounds are formed, which are important for the sensory characteristics of wine and, in particular, give wine its vinous character (Romano et al., 2003). At the same time, grape derived aroma contributors get transformed by yeast's metabolism as well. ...
... Yeast utilizes the nutrients contained in grape must, which are mainly hexoses, nitrogen and lipid sources, for proliferation, whereas ethanol, CO2 and various minor metabolites are produced as byproducts. Many of these metabolites are volatile with sensorial properties, which give wine its vinous character (Romano et al., 2003). Although the flavor and aroma profile of wine is influenced by vine environment and management techniques, the choice of yeast strain plays a central role (Robinson et al., 2011). ...
The yeast Saccharomyces cerevisiae plays a vital role in the production of aroma compounds, such as esters, higher alcohols and organic acids, and the conversion of grape-derived aroma precursors during wine fermentation. To identify the genomic and metabolic bases for these processes, a cross was performed between two wine yeast strains selected because of their different nitrogen requirement during fermentation. 130 F2-segregants were genotyped by whole genome sequencing and individually phenotyped during wine fermentation by measuring extracellular metabolites using HPLC and GC-MS. Intracellular metabolic fluxes were estimated by constraint-based modeling. Quantitative trait locus (QTL) mapping was used to identify allelic variants influencing variations in the aroma profile and metabolic fluxes. More than 80 QTLs explaining variation in 59 quantitative traits were detected. These traits consisted of general fermentation parameters, substrate consumption, the production of main metabolites and fermentative aromas and the metabolism of grape aroma compounds. The applicability of QTL mapping to detect regions influencing intracellular fluxes (f-QTLs) was furthermore demonstrated. Found QTLs were dissected and genes with allele specific contributions to the phenotype were identified. These results emphasize the genomic and metabolic complexity of yeast aroma formation. In addition, the identification of genetic determinants increases knowledge about the links between genetic variation and industrial traits and provides a valuable foundation for the development of optimized strains by marker-assisted selection breeding strategies.
... Each strain has its own metabolic characteristics, different from those of the other strains, exerting a profound influence on the aromatic balance of wine [8][9][10][11][12][13]. Several studies have demonstrated that different strains of S. cerevisiae, employed as starters, produce strain-specific metabolites [14,15] and can impact the chemical and aromatic profiles of wine, resulting in greater complexity and aromatic diversity [1]. Differences in the diversity of wines may also depend on the cultivar applied, the winery, and the fermentation conditions [16]. ...
... Among them, isoamyl alcohol is the most represented (over 50%) and the main responsible compound for the fragrant component. Strains of S. cerevisiae can produce high amounts of isoamyl alcohol in a strain-specific fashion [14]. After higher alcohols, esters are the second most important component of volatile aromas in wine. ...
The present research is aimed at investigating the potential of two commercial Saccharomyces cerevisiae strains (EC1118 and AWRI796) to generate wine-specific volatile molecule fingerprinting in relation to the initial must applied. To eliminate the effects of all the process variables and obtain more reliable results, comparative fermentations on interlaboratory scale of five different regional red grape musts were carried out by five different research units (RUs). For this purpose, the two S. cerevisiae strains were inoculated separately at the same level and under the same operating conditions. The wines were analyzed by means of SPME-GC/MS. Quali-quantitative multivariate approaches (two-way joining, MANOVA and PCA) were used to explain the contribution of strain, must, and their interaction to the final wine volatile fingerprinting. Our results showed that the five wines analyzed for volatile compounds, although characterized by a specific aromatic profile, were mainly affected by the grape used, in interaction with the inoculated Saccharomyces strain. In particular, the AWRI796 strain generally exerted a greater influence on the aromatic component resulting in a higher level of alcohols and esters. This study highlighted that the variable strain could have a different weight, with some musts experiencing a different trend depending on the strain (i.e., Negroamaro or Magliocco musts).
... Therefore, these fermentations depend on both the wild yeasts present in must and the winery processing equipment, for the purpose of ensuring a correct, controlled and complete fermentation, as well as to enhance the wine sensory characteristics. Thus, modern winemaking is based on the use of selected yeast strains, mainly active dry yeasts of the Saccharomyces cerevisiae strain [1][2][3]. Wine fermentation is a very competitive scenario for microorganisms. Each strain of S. cerevisiae can have its own contribution to the wine sensory characteristics, and not all of them are equally adapted to all fermentation styles [4]. ...
... The concentration of total alcohols after MLF was higher in wines made with Sc2 and Sc4 yeasts than when Sc1 and Sc3 yeasts were inoculated. Among the factors that affect the formation of alcohols in the fermentation, yeast strain is one of the main parameters [1,26]. However, due to the different evolution of these compounds during aging, after 6 and 9 months in a bottle, it was the wines made with Sc2 and Sc3 yeast, respectively, that showed higher levels of total alcohols (Figure 3a). ...
Volatile and phenolic compounds play a key role in the sensory properties of wine, especially aroma and color. During fermentation, yeasts produce enzymes that affect the skin’s phenolic compounds extraction and synthesize some of the most important wine volatile compounds. Generally, selected yeasts of the Saccharomyces cerevisiae (Sc) strains are inoculated, which are responsible for carrying out the wine fermentation, enhancing and highlighting its sensory characteristics and contributing to help achieve the wine typicity, according to the winemaker’s criteria. After fermentation, all wines require aging in a bottle to modulate their composition and stability over time. Thus, four different Sc strains (Sc1–Sc4) were inoculated into tanks with Tempranillo grapes to carry out, in duplicate, their fermentation and subsequent aging in bottles (9 months), comparing the aromatic and phenolic composition between them. Results showed differences in the fermentation process (kinetic, ethanol yield), CI, TPI and content of alcohols, esters, anthocyanins, flavonols and flavanols in wines from the different Sc strains studied. Moreover, in the content in wines of most groups of aromas and phenols, except for total acetate esters and flavonols, aging in a bottle had more influence than the yeast strain used for fermentation.
... Wine results from a complex biochemical process that starts with grape harvesting, followed by alcoholic and malolactic fermentation, wine ageing and bottling (Romano et al., 2003). Different microorganisms, and particularly yeasts, are involved and play a key role in the production of wine, mostly in alcoholic fermentation (Padilla et al., 2016). ...
... Some strains of apiculate yeast (Hanseniaspora ssp.) can bring undesirable characteristics such as accentuated acetic acid production. In addition to apiculate yeasts and fermentative yeasts, deteriorating yeasts such as Brettanomyces intermedia and Pichia membranifaciens may appear after fermentation, causing serious defects in the final product (Romano et al., 2003;Ramírez-Castrillón et al., 2017). More and more, the regional microbiota has been assessed for the production of wines, bringing local characteristics to the final product and defining a fermentative "terroir". ...
Considering the influence of natural yeasts on wine production and the organoleptic properties of the final product, the objective of the present study was to evaluate the diversity of yeasts in Cabernet-Sauvignon and Merlot (Vitis vinifera L.) grown in the highlands of the Northeast region of Rio Grande do Sul State, “Serra Gaúcha”, Brazil. Grape samples were collected from commercial vineyards between February and March in the 2017, 2018 and 2019 vintages. One hundred sixty-six isolated yeasts were classified at the species level by D1/D2 domain of 26S rRNA sequencing. A total of 31 yeast species were identified. The most prevalent species were Hanseniaspora uvarum, Issatchenkia terricola, Saturnispora diversa and Starmerella bacillaris. These same yeasts were the most frequent regardless of the year evaluated. The results indicated that there is a great diversity of yeast species in grapes cultivated in the highlands of Southern Brazil. However, the yeast communities remain similar in Cabernet-Sauvignon and Merlot grapes the analysed parameters (grape variety/vintage) are not interfering in the yeast populations found in the region highlands of Rio Grande do Sul, “Serra Gaúcha”, Brazil. This study enabled the knowledge of the yeast populations present in the region and their variations during the harvesting of wine grapes, showing that there is a majority pattern of species independent of the harvest.
... The potential enological use of non-Saccharomyces yeasts has gained interest during recent years, due to their natural presence in musts, to their ability to produce secondary compounds impacting the sensory characteristics of wines, as well as to their possible use for production of low alcohol wines [1][2][3]. The role of various non-Saccharomyces yeasts in natural must fermentation has been investigated in order to assess the effect of using specific strains individually or in combinations in wine aroma (quality and complexity), as well as in alcohol content [4,5]. ...
... Different letters in the same series indicate significant differences between means (p < 0.05). Scale used desirable (7-9), acceptable (4-6) and undesirable(1)(2)(3). ...
The objective of this study was to explore the use of non-Saccharomyces yeasts, individually or in mixed culture, with Saccharomyces cerevisiae for the vinification of must originating from the native white wine grape cultivar Savvatiano (Vitis vinifera L.). Savvatiano is the most planted grape cultivar in Greece, cultivated predominantly in Central Greece. Grapes were harvested during October 2020, were pressed, and the must after cold settlement was inoculated with a. Saccharomyces cerevisiae, b. Metschnikowia pulcherrima, and c. mixed culture, in sequential inoculation (M. pulcherrima, followed by S. cerevisiae after 7 days). The progress of fermentations was monitored and the finished wines were analyzed for the main wine parameters, as well as sensory attributes by a panel of experts. The results of this study provide useful data in order to further explore the effect of mixed culture use on fermentation of musts originating from native grape varieties with low aromatic intensity.
... The treatment conditions with a lethality rate of about 80% were set as the mutation conditions [21]. During UV irradiation, the cell suspension (OD600 = 1.2) was spread on the YPD agar plate by the gradient dilution coating plate method, and irradiated with UV (20 W) at a distance of 50 cm for 0, 10,20,30,40,50,60,70,80,90, 100, 110, and 120 s. After irradiation, the plates were immediately shielded from light and incubated at 28 • C in the dark for 48 h. ...
... Aldehydes provide a floral, green apple aroma, while some acids and volatile phenols enhance wine aroma complexity; however, excessive amounts of these volatile aroma substances can cause undesirable and unanticipated odors [39]. Furthermore, wine can present different aroma characteristics and styles due to variation in metabolic pathways, enzymatic activity, and yeast strain metabolite type and content [40]. For example, the mono-culture fermentation of Torulaspora delbrueckii produces lower levels of volatile acids than Saccharomyces cerevisiae [41]. ...
Although using non-Saccharomyces yeasts during alcoholic fermentation can improve the wine aroma, most of them are not ethanol tolerant; therefore, in 2017, this study screened 85 non-Saccharomyces yeasts isolated and identified from 24 vineyards in seven Chinese wine-producing regions, obtaining Pichia terricola strain H5, which displayed 8% ethanol tolerance. Strain H5 was subjected to ultraviolet (UV) irradiation and diethyl sulfate (DES) mutagenesis treatment to obtain mutant strains with different fermentation characteristics from the parental H5. Compared with strain H5, the UV-irradiated strains, UV5 and UV8, showed significantly higher ethanol tolerance and fermentation capacity. Modified aroma profiles were also evident in the fermentation samples exposed to the mutants. Increased ethyl caprate, ethyl caprylate, and ethyl dodecanoate content were apparent in the UV5 samples, providing the wine with a distinctly floral, fruity, and spicy profile. Fermentation with strain UV8 produced a high ethyl acetate concentration, causing the wine to present a highly unpleasant odor. To a certain extent, UV irradiation improved the ethanol tolerance and fermentation ability of strain H5, changing the wine aroma profile. This study provides a theoretical basis for the industrial application of non-Saccharomyces yeasts that can improve wine flavor.
... The sensory profile of wine is affected mainly by the grapevine variety and microbial strain involved in the process [5]. However, the others factors, such as grape ripening level and grape sanitary conditions, harvesting method, fining procedures, and bottling, also have an essential impact on the sensory characteristics of the final product [5][6][7][8][9][10]. ...
... The sensory profile of wine is affected mainly by the grapevine variety and microbial strain involved in the process [5]. However, the others factors, such as grape ripening level and grape sanitary conditions, harvesting method, fining procedures, and bottling, also have an essential impact on the sensory characteristics of the final product [5][6][7][8][9][10]. A wide range of commercial wine yeast strains mainly of Saccharomyces cerevisiae species, being the dominant microflora during fermentation, is used worldwide in the industry. ...
Many commercial strains of the Saccharomyces cerevisiae species are used around the world in the wine industry, while the use of native yeast strains is highly recommended for their role in shaping specific, terroir-associated wine characteristics. In recent years, in Poland, an increase in the number of registered vineyards has been observed, and Polish wines are becoming more recognizable among consumers. In the fermentation process, apart from ethyl alcohol, numerous microbial metabolites are formed. These compounds shape the wine bouquet or become precursors for the creation of new products that affect the sensory characteristics and quality of the wine. The aim of this work was to study the effect of the grapevine varieties and newly isolated native S. cerevisiae yeast strains on the content of selected wine fermentation metabolites. Two vine varieties-Regent and Seyval blanc were used. A total of 16 different yeast strains of the S. cerevisiae species were used for fermentation: nine newly isolated from vine fruit and seven commercial cultures. The obtained wines differed in terms of the content of analyzed oenological characteristics and the differences depended both on the raw material (vine variety) as well as the source of isolation and origin of the yeast strain used (commercial vs. native). Generally, red wines characterized a higher content of tested analytes than white wines, regardless of the yeast strain used. The red wines are produced with the use of native yeast strains characterized by higher content of amyl alcohols and esters.
... Pursuing microbiological complexity in wines through spontaneous fermentations has yielded positive outcomes in terms of fostering diversity of species and strains associated with the terroir (Börlin et al., 2020;Mas and Portillo, 2022). This microbial diversity may result in added complexity to the wine's sensorial perception (Alexandre 2020;Esteve-Zarzoso et al., 1998;Gamero et al., 2016;Romano et al., 2003). However, the effectiveness of this fermentation method has been undermined by issues of contamination and fermentation interruption, unpredictable results, or formation of biogenic amine during fermentation (Capece et al., 2012;Tristezza et al., 2013;Vázquez et al., 2023). ...
... Different yeast strains can produce different tastes and aromas in wine, and wine makers often select specific strains to achieve desirable characteristics. At present, there are approximately 150 species of yeast generally involved in the wine fermentation process, including 25 genera, among which are the genera Saccharomyces, Candida, Pichia, Hanseniaspora, Schizosaccharomyces, Dekkera, Metschnikowia, and Zygosaccharomyces, including ten genera of yeasts [75,76]. Saccharomyces sp. is an essential microorganism in the grape fermentation process. ...
The diversity of alcohol beverage microorganisms is of great significance for improving the brewing process and the quality of alcohol beverage products. During the process of making alcoholic beverages, a group of microorganisms, represented by yeast and lactic acid bacteria, conducts fermentation. These microorganisms have complex synergistic or competitive relationships, and the participation of different microorganisms has a major impact on the fermentation process and the flavor and aroma of the product. Strain selection is one of the key steps. Utilizing scientific breeding technology, the relationship between strains can be managed, the composition of the alcoholic beverage microbial community can be improved, and the quality and flavor of the alcoholic beverage products can be increased. Currently, research on the microbial diversity of alcohol beverages has received extensive attention. However, the selection technology for dominant bacteria in alcohol beverages has not yet been systematically summarized. To breed better-quality alcohol beverage strains and improve the quality and characteristics of wine, this paper introduces the microbial diversity characteristics of the world’s three major brewing alcohols: beer, wine, and yellow wine, as well as the breeding technologies of related strains. The application of culture selection technology in the study of microbial diversity of brewed wine was reviewed and analyzed. The strain selection technology and alcohol beverage process should be combined to explore the potential application of a diverse array of alcohol beverage strains, thereby boosting the quality and flavor of the alcohol beverage and driving the sustainable development of the alcoholic beverage industry.
... In wine and beer production, selecting starter cultures is a common practice to improve control over fermentation performance , fla vour, and the creation of specific products (Carrasco et al. 2001, Fernández-Espinar et al. 2001, Romano et al. 2003, Ribéreau-Gayon et al. 2006, Torrens et al. 2008, Chambers and Pretorius 2010, Schuller 2010, Garofalo et al. 2016, Capozzi et al. 2017, Berbegal et al. 2018, Vilela 2021 In br e wing, S. cerevisiae str ains dominate ale pr oduction, while S. pastorianus (a hybrid of S. cerevisiae and S. eubayanus ) is pr ominent in la ger pr oduction. Commerciall y offer ed str ains also include S. cerevisiae and S. uvarum (Stewart et al. 2013, Gibson et al. 2017. ...
Scotch Whisky, a product of high importance to Scotland, has gained global approval for its distinctive qualities derived from the traditional production process which is defined in law. However, ongoing research continuously enhances Scotch Whisky production and is fostering a diversification of flavour profiles. To be classified as Scotch Whisky, the final spirit needs to retain the aroma and taste of “Scotch”. While each production step contributes significantly to whisky flavour—from malt preparation and mashing to fermentation, distillation, and maturation—the impact of yeast during fermentation is crucially important. Not only does the yeast convert the sugar to alcohol, it also produces important volatile compounds, for example esters and higher alcohols, that contribute to the final flavour profile of whisky. The yeast chosen for whisky fermentations can significantly influence whisky flavour, so the yeast strain employed is of high importance. This review explores the role of yeast in Scotch Whisky production and its influence on flavour diversification. Furthermore, an extensive examination of non-conventional yeasts employed in brewing and winemaking is undertaken to assess their potential suitability for adoption as Scotch Whisky yeast strains, followed by a review of methods for evaluating new yeast strains.
... Nowadays, in the beer industry, there are a few yeast species that are the most employed for fermentation, corresponding to commercial strains, but some artisanal producers employ spontaneous fermentation, with high variability and sometimes unpredictable results in terms of organoleptic properties. The study of the last type of beer production showed that there are different S. cerevisiae strains capable of wort fermentation (Pataro et al., 2000;Canonico et al., 2014;Larroque et al., 2021) and they are highly variable, showing different polymorphisms that could alter yeast metabolism, producing different profiles of secondary compounds which increase the diversity of flavor and aroma in the final product (Cabrera et al., 1988;Giudici et al., 1990;Pretorius, 2000;Fleet, 2003;Romano et al., 2003;Siesto et al., 2013;Cardoso et al., 2021). In addition, the different industries of fermentation beverages looking for new S. cerevisiae strains capable of fermenting more and adding different flavors in other alcoholic beverages such as wine (Rainieri and Pretorius, 2000;Suárez-Lepe and Morata, 2012;Ilieva et al., 2017;Costantini et al., 2019Zhang et al., 2023, sparkling wine (Garofalo et al., 2018) and cider (Suárez-Valles et al., 2005;Kanwar and Keshani., 2016) and some studies have been carried out in beer (Lorca et al., 2022;Wauters et al., 2023). ...
Introduction
Beer is one of the most consumed alcoholic drinks in the world, and this industry is a growing market that demands different properties to satisfy new consumers. The yeasts are used in different fermented beverages to contribute to new flavors. However, yeast strains used in the beer industry are limited so far, thus the diversity of flavors is very restricted. Therefore, the use of native yeast strains has been taking more importance with the purpose of conferring differentiated organoleptic properties to the product. Based on this observation the potentiality of native Saccharomyces cerevisiae strains obtained from different localities in Chile was researched.
Methods
In this work was selected those strains that produced the highest ethanol concentration (nearly 6% v/v), consumed the highest amounts of sugars, and produced the lowest amounts of organic acids in the resulting beers. Finally, we did a beer tasting to select those strains that added different flavors to the final beer compared with a commercial strain used.
Results and discussion
In this study, two native strains that produced fruity descriptors are described, which could be used in the future in brewing, craft or industrial production.
... Fermentations dominated by Hanseniaspora and Lachancea presented 47.37 ± 16.98% and 16.65 ± 6.54% of unconsumed sugars, respectively (Figure 2B, Additional File 1), due to their limited fermentative capacity and ethanol tolerance, preventing them to complete the fermentation process [54][55][56]. In addition, approximately half of SO2 treatments did not even start the fermentation (data not shown), mostly in Lachancea or Hanseniaspora dominated samples. ...
Background
Connecting the composition and function of industrial microbiomes is a major aspiration in microbial biotechnology. Here, we address this question in wine fermentation, a model system where the diversity and functioning of fermenting yeast species is determinant of the flavor and quality of the resulting wines.
Results
First, we surveyed yeast communities associated with grape musts collected across wine appellations, revealing the importance of environmental (i.e., biogeography) and anthropic factors (i.e., farming system) in shaping community composition and structure. Then, we assayed the fermenting yeast communities in synthetic grape must under common winemaking conditions. The dominating yeast species defines the fermentation performance and metabolite profile of the resulting wines, and it is determined by the initial fungal community composition rather than the imposed fermentation conditions. Yeast dominance also had a more pronounced impact on wine meta-transcriptome than fermentation conditions. We unveiled yeast-specific transcriptomic profiles, leveraging different molecular functioning strategies in wine fermentation environments. We further studied the orthologs responsible for metabolite production, revealing modules associated with the dominance of specific yeast species. This emphasizes the unique contributions of yeast species to wine flavor, here summarized in an array of orthologs that defines the individual contribution of yeast species to wine ecosystem functioning.
Conclusions
Our study bridges the gap between yeast community composition and wine metabolite production, providing insights to harness diverse yeast functionalities with the final aim to producing tailored high-quality wines.
... The local S. cerevisiae EZ2 strain, originating from a V. amurensis-producing area, can be used as a new type of ferment in V. amurensis wine brewing. At present, most V. amurensis wines are fermented using commercial yeasts, which do not effectively highlight their characteristics (Romano et al., 2003). Therefore, it is of great practical significance to utilize novel brewing yeasts with excellent characteristics, such as the EZ2 strain. ...
... In most parts of the world, cider is an alcoholic beverage that is the result of fermentation made from pressed apple juice, effectively following the same process as wine. Most cider production processes rely on various strains of S. cerevisiae that allow rapid and reliable fermentation, reduce the risk of sluggish or stuck fermentation, and prevent microbial contamination [5]. Yeasts are the prominent organisms involved in cider production and determine several characteristics of the cider, including the flavor, through a range of mechanisms and activities [6]. ...
The study was conducted in Completely Randomized Design with eight treatments replicated three times. The treatments were T1 (Indian olive 500 g +250 ml water +150 g sugar), T2 (Indian olive 500 g +250 ml water +200 g sugar), T3 (Indian olive 500 g +250 ml water +250 g sugar), T4 (Indian olive 500 g +250 ml water +300 g sugar), T5 (Indian olive 500 g +250 ml water +150 g sugar +1.5 g yeast), T6 (Indian olive 500 g +250 ml water +200 g sugar +1.5 g yeast), T7 (Indian olive 500 g +250 ml water +250 g sugar +1.5 g yeast) and T8 (Indian olive 500 g +250 ml water +300 g sugar +1.5 g yeast). Total soluble solids, pH and specific gravity decreased while alcohol content, acidity and sensory qualities increased with increasing length of fermentation. From the above experiment, it is concluded that treatment T5 was found superior in respect to parameters like total soluble solids, pH, acidity, alcohol content, and specific gravity. Whereas the highest score for organoleptic parameters like color and appearance, aroma, taste, and overall acceptability were recorded in T6. Treatment T6 also recorded highest in terms of gross return, the net return and cost-benefit ratio. Since Indian olive contains numerous nutritional and medicinal properties and is still underutilized, the production of cider from this fruit can to help reduce post-harvest losses and help in value addition of this crop. This study showed that acceptable cider can be produced from Indian olive using yeast (Saccharomyces cerevisiae).
... • Improving the conversion of reducing sugar can result in greater yield and productivity of alcohol when the fresh juice is fed with a culture of inoculum containing an influential alcohol producer. However, it is preferable to avoid using different starter cultures of native yeasts because they have been shown to Fig. 11 Process modifications for improved Feni production significantly alter the chemical composition and concentration of flavor components depending on the yeast strain's metabolic activity [14,15]. It can be achieved to produce Feni consistently in terms of aromas and alcohol content by maximizing the quantity and age of the inoculum culture. ...
The cashew tree (Anacardium occidentale), which originated in Brazil but is now grown in many countries, including India, goes by the common name of the cashew nut. In addition to being a delectable snack in many areas of the world, cashew nuts are also rich in protein, fiber, and minerals, including iron, magnesium, and zinc. The cashew nut develops right beneath the pseudo-fruit (cashew apple) of the cashew plant. Although cashew apples are a very good source of vitamin C and have excellent antioxidant properties, they are usually discarded and not used to make any valuable products since they are so readily perishable. However, the alcoholic drink Feni is made in the Indian state of Goa using discarded ripe cashew apples. Feni has gained extensive popularity due to its unique natural taste, aroma, and high alcohol concentration. Traditionally, cashew Feni production is a relatively laborious and lengthy process that does not require specialized equipment. It is a four-step process consisting of the harvesting of cashew apples, juice extraction through stomping with feet, natural fermentation in earthen pots, and subsequent distillation and condensation in a clay still over a low wood fire. The distilled Feni is then aged for a couple of months and bottled. Over time, due to the underlying drawbacks of the conventional production process, like economic unfeasibility, modifications in its steps have been made by many Feni manufacturers. In this chapter, three such case studies have been elaborately discussed, highlighting some of the process upgradation made by Feni producers to the traditional process. Moreover, the authors examine potential modifications proposed in this chapter to individual steps of the existing process to enhance its yield and augment its economics. In the end, the utilization of residual cashew pulp waste after juice extraction to produce value-added products, including bioethanol, is discussed.
Keywords: Cashew apple; Fermentation; Feni; Mass balance; Waste valorization; Value-added products
... In general, the yeasts most used in wine making are Saccharomyces cerevisiae, due to 64 their adaptability to the medium (musts rich in sugars, low pH, tolerance to ethanol and 65 sulfur dioxide) (Romano et al., 2003). However, studies show that yeasts from non- It is in this context that this work is inserted, that is, to produce Gewürztraminer wines This preprint research paper has not been peer reviewed. ...
... In general, yeast starter cultures that are precisely chosen for the winemaking process based on features that have been scientifically proven complement and optimize the quality of the wine's distinctive qualities Swiegers, et al. [3]. Many different strains of Saccharomyces cerevisiae are currently used in the majority of cider production because they enable quick and dependable fermentation lower the danger of slow or blocked fermentation, and guard against microbial contamination Romano, et al. [4]. ...
The study was conducted in Completely Randomized Design (CRD) with 7 treatments replicated thrice. The treatments were T1 (pomegranate juice 1ltr + 0.5 g yeast + 500 g sugar), T2 (pomegranate juice 1ltr + 1g yeast + 500g sugar), T3 (pomegranate juice 1ltr + 1.5g yeast + 500g sugar), T4 (pomegranate juice 1ltr + 2g yeast + 500 g sugar), T5 (pomegranate juice 1ltr + 2.5g yeast + 500g sugar), T6 (pomegranate juice 1ltr + 3g yeast + 500g sugar), T7 (pomegranate juice 1ltr + 3.5g yeast + 500g sugar). The pomegranate juice was fermented using Saccharomyces cerevisiae. The cider was assessed for the physico-chemical changes that occurred throughout its 90 days of storage, as well as its sensory quality using a 9-point Hedonic scale that was put to the test on a panel of five experts. With longer fermentation times, the alcohol level, acidity, and sensory qualities increased while total soluble solids, pH, and specific gravity decreased. From the above treatments, it is concluded that treatment T6 was found superior in respect of the parameters like Total Soluble Solids, Acidity, pH, Alcohol content, Specific gravity, Color and Appearance, Taste, Aroma and Overall acceptability. In terms of cost benefit ratio, the highest net return, Cost Benefit Ratio was also found in the same treatment.
... The selected yeast strains should assure rapid fermentation onset, satisfactory breakdown of sugars, and avoid stuck fermentations, while mitigating the production of other undesirable secondary metabolites, such as acetic acid (Capozzi et al., 2015). Additionally, these strains might improve wine sensory quality (Romano et al., 2003). Even though several species of yeasts exist, the most widely used in winemaking is Saccharomyces cerevisiae, due to its high ethanol tolerance and dominance throughout the alcoholic fermentation (Petruzzi et al., 2017). ...
The objective of this work was to evaluate the effect of different commercial strains of Saccharomyces cerevisiae on the characteristics of Sauvignon Blanc wines produced in the Campanha Gaúcha region. The must obtained by mechanical destemming and crushing was treated with 150 mg L of potassium metabisulfite and pectolitic enzymes and subject to enzymatic hidrolisis and débourbage for 24h00 at 4°C. The must was divided into glass fermenters of 4,6 L, in triplicate for each of the four treatments, which were defined by the inoculation of 25g hL-1 of dry yeast: T1 - Zymaflore X5® (Laffort, Bordeaux, France); T2 - AWRI 796 (AB Biotek, Sydney, Australia); T3 - Maurivim PDM (AB Biotek, Sydney, Australia); T4 - 50% Zymaflore X5® + 50% AWRI 796. The wines were analyzed, regarding: ethanol; reducing sugars; total acidity; volatile acidity; pH; dry matter; and ash. The most significant differences were observed in: ethanol; reducing sugars; pH; dry matter. Among the treatments inoculated with single strains, T1 showed higher ethanol and lower reducing sugars content. T3 presented results similar to T1. T2 resulted in higher content of reducing sugars and consequently lower ethanol levels. The mixed fermentation (T4) achieved the lowest levels of reducing sugars among the treatments. It suggests that mixed fermentations could be an alternative to produce drier wines.
... Active dry yeast such as S. cerevisiae has been selected and differentiated from other yeast according to different characteristics such as high and low temperature tolerance, production and tolerance to SO 2 , ethanol tolerance, pH tolerance, nitrogen requirements, and H 2 S production. However, it must be underlined that, within each species, significant strain variability has been recorded [16]. It has been reported that the type of yeast strain selected is a factor strongly affecting alcoholic fermentation, and, therefore, the quality of the wine [14]. ...
The current investigation briefly reviews previous studies about the fate of pesticides used in wine grape production during the alcoholic fermentation process, and how these could affect the correct functioning of yeast. The present review discusses the fact that yeasts could be used as a biological tool for pesticide dissipation, diminishing the concentration present in the grapes during the production process. The previous have never been directly boarded by other authors. The first part explores the influences of pesticides on yeasts and elucidates their effect on the fermentation process; also, some examples are analyzed of molecular studies involving the effect of pesticides on yeast. The second part discusses the effect of yeast on pesticide residues and their capacity to reduce its concentration during the alcoholic fermentation process, which varies among the different pesticides. In addition, this review discusses the mechanism by which yeast cells adsorb and/or degrade pesticides. In the last part, some examples of using yeasts as a possible remediation tool in wine and how the industry could use this to ensure consumers that a product is without pesticide residues are also discussed. This review shows that there is a natural capacity for the reduction of pesticide residue concentration by yeasts, and the effects of pesticides on yeast development is a variable phenomenon. This information guides advancement in pesticide removal from wine.
... The total time of AF increased in sequential fermentations. According to the literature, the slower kinetics in sequential fermentations may be due to nutritional competition between non-Saccharomyces and S. cerevisiae (Balmaseda et al., 2018;Belda et al., 2015;Martín-García et al., 2020;Romano et al., 2003). Additionally, depending on the combination of T. delbrueckii and S. cerevisiae strains, differences were observed between the four T. delbrueckii strains (Fig. 1, Table SD2). ...
The use of Torulaspora delbrueckii in the alcoholic fermentation (AF) of grape must is increasingly studied and used in the wine industry. In addition to the organoleptic improvement of wines, the synergy of this yeast species with the lactic acid bacterium Oenococcus oeni is an interesting field of study. In this work, 60 strain combinations were compared: 3 strains of Saccharomyces cerevisiae (Sc) and 4 strains of Torulaspora delbrueckii (Td) in sequential AF, and four strains of O. oeni (Oo) in malolactic fermentation (MLF). The objective was to describe the positive or negative relationships of these strains with the aim of finding the combination that ensures better MLF performance. In addition, a new synthetic grape must has been developed that allows the success of AF and subsequent MLF. Under these conditions, the Sc-K1 strain would be unsuitable for carrying out MLF unless there is prior inoculation with Td-Prelude, Td-Viniferm or Td-Zymaflore always with the Oo-VP41 combination. However, from all the trials performed, it appears that the combinations of sequential AF with Td-Prelude and Sc-QA23 or Sc-CLOS, followed by MLF with Oo-VP41, reflected a positive effect of T. delbrueckii compared to inoculation of Sc alone, such as a reduction in L-malic consumption time. In conclusion, the obtained results highlight the relevance of strain selection and yeast-LAB strain compatibility in wine fermentations. The study also reveals the positive effect on MLF of some T. delbrueckii strains.
... At the early stages of fermentation, low ethanol-tolerant non-Saccharomyces species usually are predominant and start the fermentation process, especially yeasts belonging to the genera Hanseniaspora [5]. Wine strains of this genus are endowed with the ability to produce fermentation metabolites [6,7] and numerous extracellular enzymes [8], which can affect the quality and aromatic characteristics of wine. The alcohol that progressively accumulates in the medium exerts a selective pressure on the low ethanol-tolerant yeasts; further, they are quickly replaced by Saccharomyces wine strains, which, when present, complete the fermentation process [2,9]. ...
The type and quantity of precursor amino acids present in grape must that are used by wine yeasts affect the organoleptic and health properties of wine. The aim of this work was to conduct a preliminary screening among Saccharomyces and non-Saccharomyces indigenous strains, which were previously isolated from different Italian regional grape varieties. This was performed in order to evaluate their decarboxylase activity on certain important amino acids—such as arginine, proline, serine, and tyrosine—that are present in grape must. In particular, a qualitative test on 122 wine yeasts was performed on a decarboxylase medium using arginine, proline, serine, and tyrosine as precursor amino acids. Our results showed a considerable variability among the microbial species tested for this parameter. Indeed, Saccharomyces cerevisiae strains exhibited a high decarboxylase capability of the four amino acids tested; moreover, only 10% of the total (i.e., a total of 81) did not show this trait. A high recovery of decarboxylation ability for at least one amino acid was also found for Zygosaccharomyces bailii and Hanseniaspora spp. These findings can, therefore, promote the inclusion of decarboxylase activity as an additional characteristic in a wine yeast selection program in order to choose starter cultures that possess desirable technological traits; moreover, this also can contribute to the safeguarding of consumer health.
... Nowadays, in the beer industry, there are a few yeast species that are the most employed for fermentation, corresponding to commercial strains, but some artisanal producers employ spontaneous fermentation, with high variability and sometimes unpredictable results in terms of organoleptic properties. The study of the last type of beer production showed that there are different S. cerevisiae strains capable of wort fermentation (Pataro et al., 2000;Canonico et al., 2014;Larroque et al., 2021) and they are highly variable, showing different polymorphisms that could alter yeast metabolism, producing different profiles of secondary compounds which increase the diversity of flavor and aroma in the final product (Cabrera et al., 1988;Giudici et al., 1990;Pretorius, 2000;Fleet, 2003;Romano et al., 2003;Siesto et al., 2013;Cardoso et al., 2021). In addition, the different industries of fermentation beverages looking for new S. cerevisiae strains capable of fermenting more and adding different flavors in other alcoholic beverages such as wine (Rainieri and Pretorius, 2000;Suárez-Lepe and Morata, 2012;Ilieva et al., 2017;Costantini et al., 2019Zhang et al., 2023, sparkling wine (Garofalo et al., 2018) and cider (Suárez-Valles et al., 2005;Kanwar and Keshani., 2016) and some studies have been carried out in beer (Lorca et al., 2022;Wauters et al., 2023). ...
... In fact, it is considered the main responsible for the alcoholic fermentation (Ribéreau, 1985). However, some studies have shown that although non-Saccharomyces yeasts are active for short periods in the fermentation, they contribute significantly to the aromatic quality of the final beverage (Romano et al., 2003,). ...
Abstract Mezcal is a traditional alcoholic beverage in Mexico obtained from fermentation of juices, coming from mature agave pineapples, and their subsequent distillation, Agave cupreata juice as natural sugar source is the commonly used. This study aims to investigate mezcal production from Agave cupreata juice by optimizing fermentation at flask level temperature; initial content sugar; pH and initial cell concentration, using single strains, factorial fractional design was applied and for fermentation at bioreactor level 2.5 Liters a Simplex centroid design was developed to determine the most appropriate yeast consortium for producing mezcal. The fermentation process was carried out for 52 h with varied input variables, and all the models showed significant p-values for interaction of variance (< 0.05). It was produced at an optimized temperature of 32.5 °C, initial quantity sugar of 14 °Brix, pH of 5.5 and stirring agitation of 150 rpm was found that it is possible to reach ethanol concentration levels of about 5.9, 5.2, 7.3 and 4.9% v/v for S. cerevisiae, C. lusitaniae, K. marxianus and Z. bailii, respectively. Therefore K. marxianus and Z. bailii strains reached the highest production of ethanol. Fermentation broths from the mixture design were distilled and rectified determining alcohol concentration; mixtures of K. marxianus and Z. bailii reached ethanol content in their distillates, about 42.82% v/v. The developed models could predict the quality of mezcal developed from Agave cupreata using a yeast consortium.
... Alcoholic fermentation is the result of yeast converting sugars into ethanol [5,6]. During the fermentation process, yeast metabolises the sugars available in the substrate, which leads to the production of volatile (e.g., alcohols, esters, and fatty acids) and nonvolatile compounds (e.g., malic acid), which influence both the final aroma and flavour of the cider [6][7][8][9][10]. The development of flavour in ciders is similar to wine, where, through a long history of fermentation research, studies have identified which flavour influencing compounds are: (a) grape-derived, (b) grapederived then altered by yeast, and (c) the result of the primary metabolism of yeast [11]. ...
During the fermentation of apple juice, yeast metabolism creates complex biosynthetic pathways which produce a range of compounds responsible for the organoleptic qualities of cider. In this study, basic cider quality parameters were measured to investigate the influence of six yeast strains on cider made from three apple varieties (‘Pink Lady’, ‘Sturmer’, and ‘Bulmer’s Norman’). Measurement of pH, titratable acidity, and total phenolic content revealed that yeast can influence cider attributes, albeit variety and season dependent. Descriptive sensory analysis using a trained sensory panel was conducted on cider made from ‘Pink Lady’ apples and the same six yeast strains. The sensory panel significantly differentiated the yeast strains on the attributes of ‘fresh apple’, ‘earthy’ and ‘pear’. Identifying the variety specific influence of individual yeast strains on chemical and sensory characteristics of apple cider will provide cider makers with an enhanced understanding when choosing yeast strains.
... The detection of formaldehyde in most alcoholic beverages such as whiskey, wine and beer does not preclude its undesirability as a health risk [42], and its presence should be regulated to prevent adverse effects if consumed in large quantities. On the other hand, the esters are produced from higher alcohols [44] and ethyl alcohol through catalysis by yeast alcohol acetyltransferase, alcohol dehydrogenase or other enzymatic activities by S. cerevisiae and yeasts such as the non-fermenting yeast species H. guilliermondii and P. kudriavzevii [45,46]. Esters are known to decline in concentration post fermentation and during storage due to non-enzymatic degradation [44]. ...
Marula wine is traditionally produced through a spontaneous fermentation process and has a huge economic potential in Africa. The current study investigated the contributing microbiota and the metabolites produced during the wine fermentation process. Microbial communities were analyzed by selective cultivation and identified by biotyping and rDNA sequencing. Sugars and volatile compounds were determined with the high performance liquid chromatography and gas chromatography, respectively. Different Lactobacillus spp. were present throughout the fermentation process but dominated the earlier stages of fermentation, together with non-Saccharomyces yeasts, whereas Saccharomyces cerevisiae and acetic acid bacteria dominated the latter stages. Sucrose, glucose and fructose were detected during the early stages, while ethanol and butanol were present during the latter stages of fermentation. Interestingly, acetic acid and formic acid were detected in relatively high amounts at the latter stages of fermentation. Lactobacillus spp. and S. cerevisiae were identified as the primary contributing microbiota, and Acetobacter aceti and Acetobacter pasteuriannus were associated with the off taste and spoilage of the marula wine.
... The compounds formed during alcoholic fermentation differ depending on species and strains of yeasts. This significantly impacts volatile composition (Fleet, 2003;Romano et al., 2003). Alcoholic beverage may be spontaneously fermented by indigenous yeasts or specific strains of those inoculated. ...
The attachment, biofilm formation and control of biofilm formed by Vibrio parahaemolyticus (VP) ATCC 17802 on four stainless steel (SS) coupons which are different in type or finishing, 316L, 304, 430 with 2B finish and 304 with BA finish, were studied. SS coupons were subjected to surface roughness measurement using Atomic Force Microscope and Scanning Electron Microscope. The surface of 316L/2B was the roughest surface while 403/2B and 304/BA were the least roughness surface. VP were able to attach on all SS surfaces immediately after contact. They tended to attach on the rougher surface of the SS samples better than the smoother ones. They could be released from surfaces into liquid medium and grew very fast, after contact. Attached cells formed multilayer clumps within 72 h. Cells in biofilms survived on all SS surfaces under dry condition for more than 72 h. The 0.02% benzalkonium chloride (BAC) completely eliminate 8 log10 CFU mL⁻¹ planktonic cells immediately after contact, but it took more than 1 min to eliminate viable cells of 24 and 72h biofilms from 304/2B and 316L/2B. The viable cells in biofilm on the rougher surfaces showed more resistance to the BAC than those on the smoother ones.
... Independently of the fermentation protocol, volatile acids were slightly higher in wines produced with C. famata WB-1 and H. uvarum S-2, but still, in all produced wines, this level was far below the limits proposed by the OIV (1.2 g/L of acetic acid). Although different non-Saccharomyces yeasts (such as Candida krusei, Candida stellate, Hansaniaspora uvarum/Kloeckera apiculate, Pichia anomala, Saccharomycodes ludwigii) are known as the producers of higher amount of acetic acid [43], this characteristic also depends on sugar concentration, nitrogen source, pH, and must composition [44]. Comi and co-workers [45] reported that from forty-nine apiculate strains, just a few produced acetic acid above 1 g/L. ...
The enological potential of two previously characterized indigenous yeast isolates, Hanseniaspora uvarum S-2 and Candida famata WB-1, in pure and sequential inoculation with commercial yeast Saccharomyces cerevisiae QA23 were analyzed in industrial-scale vinification of the grape variety Tamjanika. Their contribution to the quality and aroma profile was investigated by quantifying volatile compounds and wine sensory evaluation. Both yeast isolates were able to complete alcoholic fermentation, to reduce ethanol concentration up to 1.06% v/v (in monoculture) in comparation to S. cerevisiae QA23, and to enhance aroma and sensory profile. Based on calculated odor activity values (OAV), p-cymene, ethyl hexanoate, ethyl octanoate, and ethyl decanoate were the major aroma volatile compounds in all Tamjanika wine samples. Analyzed yeast strains significantly affected relative contribution of volatile compounds and can be considered responsible for the differences and uniqueness of the obtained wine samples. Besides confirmation of good enological and fermentative characteristics, selected isolates can be characterized as high ester-producing strains with potential to enhance the floral and fruity aromas of wine. The present study represents a further step toward the use of indigenous yeast isolates at industrial-scale fermentation in order to ensure the regional signature of Tamjanika wine.
... In addition, strains CLI 194, CLI 457, CLI 691, and CLI 1028 also exceeded these values. The concentration obtained by the H. valvyensis CLI 194 strain (189.91 mg L −1 ) is noteworthy since, despite having been described as a low producer of higher alcohols, its concentration is a quarter higher than that of S-04 [73,74]. On the other hand, the values obtained by the other two Hanseniaspora strains (CLI 3 and CLI 512) are lower than those of the control strain. ...
The use of non-Saccharomyces yeasts in brewing is a useful tool for developing new products to meet the growing consumer demand for innovative products. Non-Saccharomyces yeasts can be used both in single and in mixed fermentations with Saccharomyces cerevisiae, as they are able to improve the sensory profile of beers, and they can be used to obtain functional beers (with a low ethanol content and melatonin production). The aim of this study was to evaluate this capacity in eight non-Saccharomyces strains isolated from Madrid agriculture. For this purpose, single fermentations were carried out with non-Saccharomyces strains and sequential fermentations with non-Saccharomyces and the commercial strain SafAle S-04. The Wickerhamomyces anomalus strain CLI 1028 was selected in pure culture for brewing beer with a low ethanol content (1.25% (v/v)) for its fruity and phenolic flavours and the absence of wort flavours. The best-evaluated strains in sequential fermentation were CLI 3 (Hanseniaspora vineae) and CLI 457 (Metschnikowia pulcherrima), due to their fruity notes as well as their superior bitterness, body, and balance. Volatile compounds and melatonin production were analysed by GC and HPLC, respectively. The beers were sensory-analysed by a trained panel. The results of the study show the potential of non-Saccharomyces strains in the production of low-alcohol beers, and as a flavour enhancement in sequential fermentation.
... Collection of S. cerevisiae wine strains from spontaneous fermentations has demonstrated the existence of such strong polymorphism within this species [30]. Therefore, the production level of by-products is considered as an individual strain characteristic, underlining the importance of characterizing strains for industrial purposes [31]. ...
The aromatic complexity of a wine is mainly influenced by the interaction between grapes and fermentation agents. This interaction is very complex and affected by numerous factors, such as cultivars, degree of grape ripeness, climate, mashing techniques, must chemical–physical characteristics, yeasts used in the fermentation process and their interactions with the grape endogenous microbiota, process parameters (including new non-thermal technologies), malolactic fermentation (when desired), and phenomena occurring during aging. However, the role of yeasts in the formation of aroma compounds has been universally recognized. In fact, yeasts (as starters or naturally occurring microbiota) can contribute both with the formation of compounds deriving from the primary metabolism, with the synthesis of specific metabolites, and with the modification of molecules present in the must. Among secondary metabolites, key roles are recognized for esters, higher alcohols, volatile phenols, sulfur molecules, and carbonyl compounds. Moreover, some specific enzymatic activities of yeasts, linked above all to non-Saccharomyces species, can contribute to increasing the sensory profile of the wine thanks to the release of volatile terpenes or other molecules. Therefore, this review will highlight the main aroma compounds produced by Saccharomyces cerevisiae and other yeasts of oenological interest in relation to process conditions, new non-thermal technologies, and microbial interactions.
... It is widely known that the ordinary practice in wine-making facilities regarding the utilization of yeasts performing alcoholic fermentation refers to the employment of commercial "optimized" Saccharomyces cerevisiae strains, which results in the production of highly "homogenous" types of wines [20,21]. On the other hand, the use of "indigenous" ("local", viz. ...
In modern wine-making technology, there is an increasing concern in relation to the preservation of the biodiversity, and the employment of “new”, “novel” and wild-type Saccharomyces cerevisiae strains as cell factories amenable for the production of wines that are not “homogenous”, expressing their terroir and presenting interesting and “local” sensory characteristics. Under this approach, in the current study, several wild-type Saccharomyces cerevisiae yeast strains (LMBF Y-10, Y-25, Y-35 and Y-54), priorly isolated from wine and grape origin, selected from the private culture collection of the Agricultural University of Athens, were tested regarding their biochemical behavior on glucose-based (initial concentrations ca 100 and 200 g/L) shake-flask experiments. The wild yeast strains were compared with commercial yeast strains (viz. Symphony, Cross X and Passion Fruit) in the same conditions. All selected strains rapidly assimilated glucose from the medium converting it into ethanol in good rates, despite the imposed aerobic conditions. Concerning the wild strains, the best results were achieved for the strain LMBF Y-54 in which maximum ethanol production (EtOHmax) up to 68 g/L, with simultaneous ethanol yield on sugar consumed = 0.38 g/g were recorded. Other wild strains tested (LMBF Y-10, Y-25 and Y-35) achieved lower ethanol production (up to ≈47 g/L). Regarding the commercial strains, the highest ethanol concentration was achieved by S. cerevisiae Passion Fruit (EtOHmax = 91.1 g/L, yield = 0.45 g/g). Subsequently, the “novel” strain that presented the best technological characteristics regards its sugar consumption and alcohol production properties (viz. LMBF Y-54) and the commercial strain that equally presented the best previously mentioned technological characteristics (viz. Passion Fruit) were further selected for the wine-making process. The selected must originated from red and white grapes (Assyrtiko and Mavrotragano, Santorini Island; Greece) and fermentation was performed under wine-making conditions showing high yields for both strains (EtOHmax = 98–106 g/L, ethanol yield = 0.47–0.50 g/g), demonstrating the production efficiency under microaerophilic/anaerobic conditions. Molecular identification by rep-PCR carried out throughout fermentations verified that each inoculated yeast was the one that dominated during the whole bioprocess. The aromatic compounds of the produced wines were qualitatively analyzed at the end of the processes. The results highlight the optimum technological characteristics of the selected “new” wild strain (S. cerevisiae LMBF Y-54), verifying its suitability for wine production while posing great potential for future industrial applications.
... The compounds formed during alcoholic fermentation differ depending on species and strains of yeasts. This significantly impacts volatile composition (Fleet, 2003;Romano et al., 2003). Alcoholic beverage may be spontaneously fermented by indigenous yeasts or specific strains of those inoculated. ...
Autochthonous yeasts associated with pineapple fermentation were isolated and their fermentation behaviours were investigated for development of specific culture in pineapple winemaking. Autochthonous yeast isolates, Saccharomycodes ludwigii and Hanseniaspora uvarum, were selected due to their generated products of alcohol and 2-phenylethyl acetate, respectively. The fermentation kinetic parameters of selected autochthonous yeasts as single and co-cultures in chaptalized pineapple juice were investigated comparing to commercial Saccharomyces cerevisiae. The ethanol production rate of S'codes ludwigii (0.104%(v/v)/h) during the initial stage of fermentation was relatively slower compared to those of S. cerevisiae (0.129%(v/v)/h) but increased during middle through final stages with similar ethanol content to the commercial S. cerevisiae (~12%(v/v)). In pineapple juice, fructose was firstly assimilated, S'codes ludwigii (K = 0.405) and S. cerevisiae (K = 0.552), while glucose was secondly used, S'codes ludwigii (K = 0.281) and S. cerevisiae (K = 0.217) for first-order kinetic model. In co-cultures, the two isolated strains displayed synergistic behaviours during fermentation. S'codes ludwigii supported the growth of H. uvarum so that it generated more desirable volatile organic compounds (VOCs) at an early stage. Interestingly, the VOCs could not be produced in co-cultures of H. uvarum with the commercial strains. Then, S'codes ludwigii further completed the alcoholic fermentation through final stage. The fermentation performances of co-cultured autochthonous yeasts demonstrated a new approach for successful pineapple winemaking over S. cerevisiae. In addition, growth kinetics and fermentation behaviour, as observed in this study, could be a key information in development of potential substrates and strains for future alcoholic fermentation.
... However, poor reproducibility and decreased acidity are the drawbacks of this process (Montaño et al., 2004). Lactic acid bacteria are employed in the production of garlic, whereas yeast and mold are generally used as starter cultures in fermented foods (Blandino et al., 2003;Romano et al., 2003). ...
S‐allyl cysteine (SAC), which is the most abundant bioactive compound in black garlic (BG; Allium sativum), has been shown to have antioxidant, anti‐apoptotic, anti‐inflammatory, anti‐obesity, cardioprotective, neuroprotective, and hepatoprotective activities. Sulfur compounds are the most distinctive bioactive elements in garlic. Previous studies have provided evidence that the concentration of SAC in fresh garlic is in the range of 19.0–1736.3 μg/g. Meanwhile, for processed garlic, such as frozen and thawed garlic, pickled garlic, fermented garlic extract, and BG, the SAC content increased to up to 8021.2 μg/g. BG is an SAC‐containing product, with heat treatment being used in nearly all methods of BG production. Therefore, strategies to increase the SAC level in garlic are of great interest; however, further knowledge is required about the effect of processing factors and mechanistic changes. This review explains the formation of SAC in garlic, introduces its biological effects, and summarizes the recent advances in processing methods that can affect SAC levels in garlic, including heat treatment, enzymatic treatment, freezing, fermentation, ultrasonic treatment, and high hydrostatic pressure. Thus, the aim of this review was to summarize the outcomes of treatment aimed at maintaining or increasing SAC levels in BG. Therefore, publications from scientific databases in this field of study were examined. The effects of processing methods on SAC compounds were evaluated on the basis of the SAC content. This review provides information on the processing approaches that can assist food manufacturers in the development of value‐added garlic products.
... In the last decades, a wide number of molecular and physiological studies demonstrated the high genotypic and phenotypic diversity of S. cerevisiae wine strains (Romano et al., 2008;Csoma et al., 2010;Mercado et al., 2011;Capece et al., 2013;Tristezza et al., 2013;Legras et al., 2018;Peter et al., 2018). This biodiversity is strictly associated with a significant high technological variability (Pretorius, 2000) and is of great importance for a successful strain selection and the development of new starters able to modulate the organoleptic quality of wine (Romano et al., 2003). ...
This paper reports on a common experiment performed by 17 Research Units of
the Italian Group of Microbiology of Vine and Wine (GMVV), which belongs to the
Scientific Society SIMTREA, with the aim to validate a protocol for the characterization
of wine strains of Saccharomyces cerevisiae. For this purpose, two commercial
S. cerevisiae strains (EC 1118 and AWRI796) were used to carry out inter-laboratoryscale
comparative fermentations using both synthetic medium and grape musts
and applying the same protocol to obtain reproducible, replicable, and statistically
valid results. Ethanol yield, production of acetic acid, glycerol, higher alcohols, and
other volatile compounds were assessed. Moreover, the Fourier transform infrared
spectroscopy was also applied to define the metabolomic fingerprint of yeast cells
from each experimental trial. Data were standardized as unit of compounds or yield per
gram of sugar (glucose and fructose) consumed throughout fermentation, and analyzed
through parametric and non-parametric tests, and multivariate approaches (cluster analysis, two-way joining, and principal component analysis). The results of experiments
carried out by using synthetic must showed that it was possible to gain comparable
results from three different laboratories by using the same strains. Then, the use of the
standardized protocol on different grape musts allowed pointing out the goodness and
the reproducibility of the method; it showed the main traits of the two yeast strains
and allowed reducing variability amongst independent batches (biological replicates) to
acceptable levels. In conclusion, the findings of this collaborative study contributed to
the validation of a protocol in a specific synthetic medium and in grape must and showed
how data should be treated to gain reproducible and robust results, which could allow
direct comparison of the experimental data obtained during the characterization of wine
yeasts carried out by different research laboratories.
As the fourth staple food crop in the world, potatoes can provide enough energy, protein, and nutrients necessary for humans. However, the population growth and negative effects of climate change call for improved potato yields and resilience. Genetic engineering is a convenient way to improve potato varieties and create new germplasm resources. Agrobacterium tumefaciens mediated transformation is a stable and widely used method for genetic improvement. In this study, a simple and efficient transgenic system was built by testing different potato materials, explants type, selection medium, selection agent, A. tumefaciens EHA105 strain carried different vectors. The results shown this simple system produced positive transformed seedlings in about 40 days. The lower ploidy change ratio for tetraploid variety Desiree compared to diploid recipient. Both SEG and SE could function as a single regeneration medium. Leaf discs explants is eligible. The concentration of 20μg/L is suitable for chlorsulfuron selection. The positive transgenic efficiency of tetraploid recipient Desiree is up to 68.79%, This simple and fast transgenic system provides a powerful tool for supporting basic research on potato functional genes and creating new potato materials for genetic engineering breeding.
Low fermentation temperatures are usually employed to obtain high-quality wines. This is especially interesting for white wine production since it prevents the loss of volatile compounds and a browning appearance; however, available fermentative yeasts do not usually tolerate low temperatures. Therefore, an interesting place to find new yeasts with cryotolerance is the Antarctic continent. From soil samples collected in Antarctica, 125 yeasts were isolated, of which 25 exhibited fermentative activity at 10 °C. After a fingerprinting assay, we classified the candidates into nine isotypes and sequenced internal transcribed spacer regions for their identification. These yeasts were identified as part of the Mrakia genus. Sugar and alcohol tolerance tests showed that some of these Antarctic soil yeasts were able to grow up to 9% alcohol, and 25% sugar was reached; however, they exhibited longer latency periods compared to the control Saccharomyces cerevisiae. The optimal growing temperature for the isolated Antarctic yeasts was between 10 °C and 15 °C. A comprehensive analysis of the results obtained showed that the isolates 10M3-1, 4M3-6, and 4B1-35 could be good candidates for fermentation purposes due to their alcohol, sugar tolerance, and growth features. Our results prove that it is possible to isolate fermentative yeasts from Antarctic soil with promising characteristics for their potential use in the wine production industry.
Elaeocarpus sylvestris, an evergreen tree widely distributed in Jeju Island, South Korea, contains polyphenolic compounds (phenols and flavonoids) exhibiting antioxidant, antiviral, and antibacterial activities. This study examines the antimicrobial, antioxidant, and cytotoxicity profiles of E. sylvestris extracts. Leaf extract (LE) and branch extract (BE) of E. sylvestris obtained using 60% methanol were filtered and concentrated. The antimicrobial efficacy of these extracts against foodborne pathogens and lactic acid bacteria was examined. The antioxidant property was tested along with assays to assess cytotoxicity and effects on cell proliferation. The extracts were also subjected to antioxidant assays and tested for cytotoxicity and effects on cell proliferation using human skin fibroblasts (Detroit 551). LE completely inhibited the growth of Staphylococcus aureus and Listeria monocytogenes at 100 mg/mL. Seven strains of lactic acid bacteria were susceptible to the whole extracts. LE significantly suppressed the growth of Weisella confusa, Pediococcus acidilactici, and Leuconostoc mesenteroides (p < 0.05). Yeasts (Pichia anomala and Pichia fermentans) exhibited significantly higher growth rates than lactic acid bacteria. Both extracts (100 mg/mL) significantly decreased H2O2 formation (>50%). The confluency of Detroit 551 cells was 68.07–87.52% at concentrations of 0–50 μg/mL for 24 h. In total, 130 metabolites were identified in BE and 128 in LE, including metabolites with potential benefits for skin improvement and photoprotection. A methanolic extract of E. sylvestris could be a promising source of natural bioactive materials for both microbial biocontrol and functional skin care cosmetics, with a wide range of applications in the food, cosmetic, and pharmaceutical industries.
Msalais is a traditional wine produced from naturally fermented boiled local grape juice in China. It has characteristic dried fruit and caramel odors, mainly attributed to aromatic compounds, such as furaneol and 5-methylfurfural. However, it is unclear how microbes involved in the natural fermentation of Msalais contribute to this characteristic aroma. Here, we analyzed the Msalais-fermenting microbes and aromatic compounds formed during natural Msalais fermentation by using high-throughput sequencing and gas chromatography–mass spectrometry, respectively. The analysis revealed that Saccharomyces cerevisiae, Kazachstania humilis, Lactobacillus plantarum, and Lactobacillus farraginis are the dominant and key functional species that produce high amounts of furaneol and 5-methylfurfural during Msalais fermentation. Of these, K. humilis and L. farraginis are rarely detected during regular wine fermentation. The identified functional species could be used to control typical aromatic characteristics of Msalais.
Wine is a highly complex mixture of components with different chemical natures. These components largely define wine's appearance, aroma, taste, and mouthfeel properties. Among them, aroma is among the most important indicators of wine's sensory characteristics. The essence of winemaking ecosystem is the process of metabolic activities of diverse microbes including yeasts, lactic acid bacteria, and molds, which result in wines with complicated and diversified aromas. A better understanding of how these microbes affect wine's aroma is a crucial step to producing premium quality wine. This study illustrates existing knowledge on the diversity and classification of wine aroma compounds and their microbial origin. Their contributions to wine characteristics are discussed, as well. Furthermore, we review the relationship between these microbes and wine aroma characteristics. This review broadens the discussion of wine aroma compounds to include more modern microbiological concepts, and it provides relevant background and suggests new directions for future research.
As a metaphor, lemons get a bad rap; however the proverb 'if life gives you lemons, make lemonade' is often used in a motivational context. The same could be said of Hanseniaspora in winemaking. Despite its predominance in vineyards and grape must, this lemon-shaped yeast is underappreciated in terms of its contribution to the overall sensory profile of fine wine. Species belonging to this apiculate yeast are known for being common isolates not just on grape berries, but on many other fruits. They play a critical role in the early stages of a fermentation and can influence the quality of the final product. Their deliberate addition within mixed-culture fermentations shows promise in adding to the complexity of a wine and thus provide sensorial benefits. Hanseniaspora species are also key participants in the fermentations of a variety of other foodstuffs ranging from chocolate to apple cider. Outside of their role in fermentation, Hanseniaspora species have attractive biotechnological possibilities as revealed through studies on biocontrol potential, use as a whole-cell biocatalyst and important interactions with Drosophila flies. The growing amount of 'omics data on Hanseniaspora is revealing interesting features of the genus that sets it apart from the other Ascomycetes. This review collates the fields of research conducted on this apiculate yeast genus.
The flavor is one of the sensory attributes that panelists assess and its complexity brings several discussions regarding the definition of its concept. Some authors describe the flavor as a sum of perceptions resulting from the stimulation of the senses by the food/beverage in the digestive and respiratory tracts; other authors define flavor as a combination of taste and mouthfeel. There is a tendency to consider the relevance of the relationship between the flavor and the chemical food/beverage matrix. Acids, alcohols, volatile compounds, and other chemical substances are responsible for distinctive sensations in the mouth promoting different tastes and mouthfeel. In addition, the synthesis path of the chemical substances that respond to flavor compounds is based on relevant biochemical phenomena. In this context, alcoholic fermentation is considered one of the most essential biochemical reactions providing the formation of a set of volatile compounds responsible for influencing the flavor. Wine and mezcal are examples of alcoholic beverages that present several chemical compounds responsible for their complex flavor due to the several biochemical reactions that occur during their production. Esters, higher alcohols, carbonyl compounds, and oak flavors such as lactones, furanic compounds, and methoxyphenols are responsible for providing the complex flavor that differentiates the wines. Other factors such as the intrinsic features of the grape cultivar and the grape vintage also influence the wine flavor. The most relevant biochemical pathway that produces the chemical compounds that respond to wine flavor is the synthesis of different enzymes produced by the different yeasts responsible for alcoholic fermentation. Also, mezcal is produced by different species of maguey and its cooking is the first step that generates caramel and smoky notes related to furans, alcohols, aldehydes, ketones, phenols, and terpenes. The chemical composition of the mezcal depends on the maguey species, age, the chemical composition of the maguey, and the practice of each producer. The use of autochthonous yeasts during alcoholic fermentation and the conditions used for the biochemical reaction respond to the mezcal flavor differences. In summary, biochemical reactions have substantial importance for the flavor complexity of wine and mezcal since the different flavor nuances are explained by the different chemical composition of the grape and maguey, respectively, the conditions used during the process, and the yeasts involved in the alcoholic fermentation. The study of biochemical pathways will be helpful for wineries and mezcal producers to elucidate the mechanism of the reactions involving the synthesis of specific chemical compounds and their respective flavor notes, producing a safe beverage with quality and high acceptance.
Some endogeneous and exogeneous enzymes participate in the brewery and winery technologies. Industrial enzymes provide quantitative advantages (increased juice yields) and qualitative advantages (enhanced extraction and flavor) for processing (shorter maceration, settling, and filtration time). This review aims to explain the flow process of brewing and wine-making, discuss different enzymes used in brewery and wine-making industry. Also, this chapter summarizes the key enzymes used at different stages of wine-making and brewing, and the challenges of the exogeneous, commercial and immobilized enzymes. Finally, the use of immobilized enzymes is presented as a significant strategy to improve catalyst during brewing and wine-making.
A malt beverage is a fermented drink that is generally made from cereal grain such as barley that has been malted that involves germinating the grain in water followed by drying. This process converts the starch of the cereals to fermentable sugar, which is fermented by yeast to produce alcohol. Malting is an important process which assists the breakdown of cell wall of the grains and also contributes to the tastes and aroma of the drinks produced from it. Depending upon the alcohol content, the alcoholic beverages can be categorized as beer, wine, and distilled liquor. Beer is an example of such product, which is the most common malt-based alcoholic beverage in the world. It is an alcoholic beverage with low content of ethanol usually 1–10%, which is produced by the fermentation of malted barley along with hops (Humulus lupulus). Normally fermentation is achieved by yeasts Saccharomyces cerevisiae. The Saccharomyces cerevisiae is used to produce ale via warm fermentation, while the Saccharomyces pastorianus is used to produce lager at low temperature. Hops are used to give bitter taste to beer and also act as a preservative. Wine is a fruit-based fermented product made from grapes and wide variety of other fruits. Most wines are made from grapes belonging to the genus Vitis vinifera, which are rich in anthocyanins, hence giving color to these grapes. The unique composition of fruit juice gives wine its characteristic taste and aroma. Distilled liquors are produced by distillation of fermented drinks made of grains, fruits, or vegetables and contain higher percentage of alcohol compared to beer and wine. Examples of distilled liquors include whisky made from distillation of fermented grain mash; other examples include brandy derived from fermentation of wines or any fruit. Though alcohol production has been for thousands of years, there’s a lot more to alcohol production than just conversion of sugar to alcohol, it involves a complex process that have to take in to account the flavor, aroma, and even color of the finished product.KeywordsAlcoholBeerWineDistilled alcoholFermentation
Saccharomyces cerevisiae
The behavior of four Saccharomyces cerevisiae strains and Torulaspora delbrueckii toward fermentation of sterile musts from Pedro Ximénez grapes in different degrees of ripeness is studied. Ethanol production by the four Saccharomyces strains was similar and higher than that of T. detbrueckii particularly in those musts of
high glucose content devoted to sherry wine making. However, the Saccháromyces strains, especially cerevisiae A and cerevisrae B, produced more volatile acidity. Regarding the aromaÚc fraction, neither cerevisiae A nor chevalieri stood out in any respect, while the remaining yeast investigated showed unlike behavior and yielded significantly different amounts of various compouñds and fractions.
An extensive survey of different methods of yeast strain identification (classical microbiological tests, whole-cell protein electrophoresis, chromosomal patterns, DNA hybridization and mitochondrial DNA restriction analysis) has been carried out in order to differentiate, with industrial purposes, strains present in the Alicante wine ecosystem. Only chromosomal patterns and mitochondrial DNA (mtDNA) restriction analysis show differences between strains. Both techniques are very complex to be used in bio technological industries. For this reason, we have developed a new, simple, unexpensive and rapid method based on mtDNA restriction analysis.
A rapid and efficient analytical method for the determination of glycerol in wines is described. This method utilizes high-performance thin layer chromatography (HPTLC) plates coupled with an automated multiple development system with an elution gradient based on acetonitrile–acetone–hexane on silica gel layers. The absence of clean-up procedures, sometimes only centrifugation, makes this method suitable also for the large-scale control of alcoholic beverages. In particular the capacity of different wine yeast species (Saccharomyces cerevisiae, Zygosaccharomyces bailii, Kloeckera apiculata and Saccharomycodes ludwigii) to produce glycerol was determined. Generally, the strains of S. cerevisiae produced elevated amounts of glycerol together with Z. bailii, whereas K. apiculata strains formed the lowest amounts of glycerol, exhibiting also a great strain variability.
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.
The dynamics of fungi, yeasts, and lactic acid bacteria during fermentation of four musts were studied. Fungi disappeared quickly in the fermenting must. The lactic acid bacteria population diminished during alcoholic fermentation, then they increased and performed malolactic fermentation. Yeasts grew quickly, reaching maximum populations at different times depending on the vinification treatment.
Gas chromatographic analysis by direct injection of samples yielded quantitative data on acetoin content. Ninety-six strains of Hanseniaspora guilliermondii and Kloeckera apiculata were investigated for the ability to produce acetoin in synthetic medium and in must. High-level production of acetoin was found to be a characteristic of both species. In synthetic medium, the two species were not significantly different with respect to sugar utilization and ethanol or acetoin production. In grape must, the two species were significantly different (P = 0.001) in acetoin production and K. apiculata exhibited a significantly negative correlation between acetoin production and either sugar consumption or ethanol production. Use of selected apiculate yeasts in mixed cultures with Saccharomyces cerevisiae seems promising for optimization of wine bouquet.
Riesling musts, with or without sulfur dioxide added, were fermented either with or without the addition of yeast. Uninoculated fermentations took much longer to finish than inoculated musts. There were no significant differences in growth of non-Saccharomyces yeasts in uninoculated musts with less than 50 mg l(-1) SO2 added. The starter culture was completely dominant over indigenous Saccharomyces cerevisiae and strongly inhibitory to non-Saccharomyces. Alcohol and acetaldehyde were greater in the inoculated treatments; titratable acidity and acetic acid were greater in the uninoculated fermentations. There were no statistically significant differences among any treatments in final pH, ammonia content, or colour (A(420)). Uninoculated fermentations had higher sensory scores (P > 0.95) for 'spicy', 'apple', 'melon', 'pear', and 'H2S', while inoculated wines had higher scores (P > 0.95) for 'paper', 'oxidized', and 'sweaty'. Sulfite treatment produced an assortment of significant sensory differences in the finished uninoculated wines, but in inoculated wines the additions of SO2 to the must had no significant effect on indigenous yeast populations or on flavour.
A study was conducted of the dynamics of Saccharomyces and non-Saccharomyces populations during alcoholic fermentation of Albarino musts from two enological subzones located in Galicia (Northwest Spain). Sixteen microvinifications were carried out (8 in each must, M and E) with five indigenous Saccharomyces cerevisiae strains, two commercial active dry strains, and the corresponding spontaneous fermentation. The volatile compounds in the resulting wines were measured using gas chromatography. The study of different physiological and biochemical characteristics allowed us to follow the evolution of the inoculated S. cerevisiae strains. The different cellular concentrations of these strains in the musts produced different growth rates during fermentation. The growth of non-Saccharomyces flora depended on the initial starter culture concentrations and on their growth rate during winemaking. Statistical analysis (factorial and cluster) of data obtained by gas chromatography created statistical relationships between the production of some components of wine aroma and the evolution of yeast flora during alcoholic fermentation.
Yeast strains, producing different amounts of secondary compounds, exert a definite influence on the flavour and aroma of the wines and impart their characteristics. This suggests that the use of a single strain for different types of wines is not appropriate, due to a potential uniformity of aromatic characteristics in the final products. In order to typify each product for the varietal and geographic characteristics, it becomes necessary to isolate natural autochtonous strains, which, in addition to the desirable technological characteristics, exhibit a metabolic profile corresponding to each wine. Thirty strains of Saccharomyces cerevisiae, isolated from different Aglianico grape cultivars, were tested for fermentation power, SO2-resistance, Cu-resistance and the production of secondary compounds. The results for each strain were transformed into individual functions of desirability (di), i.e. dimensionless values between 0 and 1, and then combined to obtain a response of total desirability (Dtot). The form of the transformation was subjectively selected according to the level of knowledge of the desired optimal response. The strains were tested in Aglianico fermentations and only three showed a Dtot value higher than 0.7. By comparing Dtot values of selected strains with Dtot values of experimental wines, an evident correspondence was found. This demonstrates the value of the selection method utilised.
The spontaneous alcoholic fermentation is characterized by the contribution of different Saccharomyces cerevisiae strains, which grow in succession or in combination throughout the fermentation process and exhibit different metabolic patterns. The formation of secondary compounds is a strain-specific characteristic and the strains are distinguishable in phenotypes through the production of different amounts of by-products. Natural fermentation is a source of indigenous Sacch. cerevisiae strains, which seem more suitable to be used as starter cultures for that particular wine because they were isolated from the original region and, consequently, better adapted to the particular vinification conditions of that enological area. Among the indigenous strains, the cultures for must fermentation should be chosen on the basis of aroma and flavour determinants typical of the wine under study. Successively, the selected cultures should be tested for the genetic segregation of traits under consideration in order to identify strains completely homozygous for the metabolic characteristics. Only a small proportion of natural wine strains is completely homozygous, the majority being heterozygous for one or more traits. In addition, a significant proportion of natural wine strains can sporulate on rich media, such as grape must, and, as a consequence, the progeny of such strains can exhibit differences in the levels of by-products, thereby affecting the organoleptic properties of the final product. Determination of the degree of strain stability overcomes this problem and allows the choice of the most suitable selected culture to be used in inoculated fermentation. The feature, »stability of metabolic phenotype in industrial strains«, represents a selective index, which ensures that the final product is always consistent with the own properties of each wine.
The formation of flavor in fermented beverages is due to various biosynthetic mechanisms. In wine, flavors arise as the result of compounds: 1. Originating from the native fruit (grap) 2. Which are formed or altered during the various processes employed in production 3. Which are developed or transformed by yeast during fermentation 4. Arise during the aging process In this review the results of investigations on the development of flavors in grape and wine will be discussed. Special attention will be devoted to the effects of specific processes in winemaking on the development of flavor.
Aroma compounds, as a result of their pronounced effect on the sensory organs, play a definitive role in the quality of the food and luxury products. As in the case with most food products, the aroma or "bouquet" of a wine is influenced by the action of several hundred different compounds. When dealing with wine aroma, a distinction is made among—(1) primary or grape aroma: aroma compounds as they occur in the undamaged plant cells of the grape; (2) secondary grape aroma: aroma compounds formed during the processing of the grapes (crushing, pressing, skin contact) and by chemical, enzymatic-chemical, and thermal reactions in grape must; (3) fermentation bouquet: aroma compounds formed during the alcoholic fermentation; (4) maturation bouquet: caused by chemical reactions during maturation of the wine. Numerous studies have shown that the monoterpene compounds form the axis for the sensory expression of the wine bouquet which is typical of its variety (primary or grape aroma) and that they can, therefore, be used analytically for varietal characterization. At present, more than 50 monoterpene compounds are known. Based on the quantitative determination of only 12 monoterpene substances the German white wines can be classified into three groups: "Riesling-type," "Muscat-type," and "Silvaner-WeiBburgunder-type." By including further components and by means of statistical methods, such as linear discriminant analysis, even the different varieties within the mentioned groups can be distinguished.
Historically, the fermentation of grape juice to wine has been carried out by indigenous yeasts found on the berry. However, in newer wine regions, e.g. the USA, inoculation with selected wine yeast strains is employed. Grape juice is high in nutritional factors and difficulties in fermentation usually arise from the inhibitory effects of the high concentration of sugar initially present and the ethanol produced. A secondary fermentation, brought about by indigenous or added lactic acid bacteria, converts malic acid to lactic acid and carbon dioxide and often occurs. This ‘malolactic’ fermentation is usually slow. For both yeast and bacterial fermentations strain selection is based more on fermentation performance than on sensory characteristics of the wine, with increased tolerance of the yeast to ethanol and of the bacteria to low pH being emphasized. Attempts to increase the malolactic fermentation rate have been made by cloning and transferring the malolactic gene from Lactobacillus to wine yeast. In early attempts to produce wines with enhanced or novel sensory characteristics a leucine-less mutant of a homothallic wine yeast has been obtained which does not produce isoamyl alcohol.
This article emphasises the importance of making quantitative measurements of the growth of yeast species during wine fermentations. Although such studies confirm Saccharomyces cerevisiae as the principal wine yeast, they show that indigenous species of Kloeckera and Candida make a more significant contribution to the fermentation than previously thought. Inoculation of grape juice with S. cerevisiae does not necessarily suppress growth of these indigenous species, nor does it ensure that the inoculated strain will become dominant over indigenous strains of S. cerevisiae. Factors that affect growth of yeasts during fermentation are examined along with the related aspects of stuck fermentations, killer‐yeast activity and yeast autolysis. The contribution of non‐Saccharomyces yeasts to wine quality warrants more serious consideration.
Must and wine from grapes harvested in two vintages (1986 and 1987) were anlyzed during vinification for physicochemical and microbiological characteristics. The 1986 vintage would be considered abnormal or poor vintage because of higher rainfall at harvest, and the 1987 one a normal vintage. Low reducing sugars and high volatile acidity at the beginning of the poor fermentation was observed as compared to normal vinification. The yeast population showed atypical evolution through the process since oxidative yeasts were isolated in the first stages of the poor vinification.
Riesling musts, with or without sulfur dioxide added, were fermented either with or without the addition of yeast. Uninoculated fermentations took much longer to finish than inoculated musts. There were no significant differences in growth of non-Saccharomyces yeasts in uninoculated musts with less than 50 mg l−1 SO2 added. The starter culture was completely dominant over indigenous Saccharomyces cerevisiae and strongly inhibitory to non-Saccharomyces. Alcohol and acetaldehyde were greater in the inoculated treatments ; titratable acidity and acetic acid were greater in the uninoculated fermentations. There were no statistically significant differences among any treatments in final pH, ammonia content, or colour (A420). Uninoculated fermentations had higher sensory scores (P > 0·95) for ‘spicy’, ‘apple’, ‘melon’, ‘pear’, and ‘H2S’, while inoculated wines had higher scores (P > 0·95) for ‘paper’, ‘oxidized’, and ‘sweaty’. Sulfite treatment produced an assortment of significant sensory differences in the finished uninoculated wines, but in inoculated wines the additions of SO2 to the must had no significant effect on indigenous yeast populations or on flavour.
Fifteen indigenous strains of Saccharomyces cerevisiae, differentiated by their genetic polymorphism, were compared in standard conditions for their respective ability to produce volatile compounds during the alcoholic fermentation of grape must. The results were processed using analysis of variance and of principal components. They exhibited significant differences between strains, in particular for the higher alcohols, fatty acid esters, acetates or acetaldehyde. On the basis of their analytical profile, five strains were selected and compared on the pilot scale. Overall, the pilot results confirmed laboratory findings. As the strain effect appears to be determinant on the aromatic composition of wine spirits, a programme of selection based on both intraspecific molecular characterisation and chromatographic analysis is carried out to obtain specific yeast strains for high-quality spirits.
P. ROMANO, G. SUZZI, G. COMI AND R. ZIRONI. 1992. Ninety-six strains of apiculate wine yeasts were investigated for their ability to produce higher alcohols and acetic acid in synthetic medium. Less isoamyl alcohol and more n-propanol and isobutanol were formed by Hanseniaspora guilliermondii than by Kloeckera apiculata. The latter produced twice as much acetic acid as H. guilliermondii. The production of higher alcohols and acetic acid was found to be a characteristic of individual strains and was statistically significant. In a multivariate analysis of higher alcohol production two main groupings were formed at 86%S, corresponding to the taxa H. guilliermondii and K. apiculata. Strains that produced low amounts (50 mg/1) of acetic acid, comparable with that of Saccharomyces cerevisiae, were found in both species of apiculate yeasts.
The effects of temperature and pH on the survival and growth of Saccharomyces cerevisiae, Kloeckera apiculata, Candida stellata, Candida krusei, Candida pulcherrima and Hansenula anomala were examined during mixed culture in grape juice. At 25°C, pH 3.0 and pH 3.5, S. cerevisiae dominated the fermentation and the other species died off before fermentation was completed. Saccharomyces cerevisiae also dominated the fermentation at 20°C but there was increased growth and survival of the other species. At 10°C the fermentation was dominated by the growth of both S. cerevisiae and K. apiculata and there was extended growth and survival of C. stellata and C. krusei. Juices fermented at 10°C exhibited ethanol concentrations between 7.4 and 13.4% and populations of K. apiculata, C. stellata and C. krusei in the range 106-108 cells/ml. However, these species produced maximum ethanol concentrations in the range 2.7–6.6% when grown as single cultures in grape juice.
Twenty-six strains of yeasts, belonging to the genera Candida, Debaryomyces, Hanseniaspora, Hansenula, Kloeckera, Metschnikowia, Pichia, Saccharomyces and Torulaspora previously isolated from wines, were screened for the production of extracellular pectinases, amylases, lipases, proteases and β-glucosidases. Some strains of Candida species and Hanseniaspora uvarum/Kloeckera apiculata produced extracellular proteolytic or lipolytic activities. Most yeasts exhibited β-glucosidase activity, but particularly high activity was observed in strains of Pichia anomala/Candida pelliculosa (formerly Hansenula anomala) and Hanseniaspora uvarum/Kloeckera apiculata. The potential impact of these enzymes on wine quality is discussed.
A total of 78 strains of non-Saccharomyces yeasts were isolated: 30 strains of Kloeckera apiculata, 20 of Candida stellata, 8 of Candida valida and 20 of Zygosaccharomyces fermentati. The diversity of yeast species and strains was monitored by determining the formation of secondary products of fermentation, such as acetaldehyde, ethyl acetate and higher alcohols. Within each species, the strains were distinguishable in phenotypes through the production of different amounts of by-products. In particular, a great variability was found in C. stellata, where six different phenotypes were identified by means of the production of acetaldehyde, ethyl acetate, isobutanol and isoamyl alcohol. At different stages of the spontaneous fermentation different phenotypes of the non-Saccharomyces yeasts were represented, characterized by consistent differences in some by-products involved in the wine bouquet, such as acetaldehyde.
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.
The capacity to produce 2,3-butanediol by 90 strains of four different species of wine yeasts (Kloeckera apiculata, Saccharomyces cerevisiae, Saccharomycodes ludwigii, Zygosaccharomyces bailii) was tested in grape must by automated multiple development HPTLC. The total amount of 2,3-butanediol produced varied between 23mg l–1 and 857.7mg l–1 according to the yeast species. S. cerevisiae and Z. bailii behaved similarly, producing elevated amounts of 2,3-butanediol. K. apiculata and Sc. ludwigii, in contrast, were low producers. When considerable amounts of 2,3-butanediol were found, little acetoin was present; the amounts of butanediol and acetoin were characteristic of the individual species.
Forty-nine strains of Kloeckera apiculata, isolated from the Friuli region in Italy, were differentiated on the basis of fermentation behaviour and production of secondary compounds in two different grape musts at 18 C. The isolates exhibited a controlled production of acetic acid, only in a few cases more that 1 g/l. In Moscato grape must the strains exhibited a more uniform behaviour for the production of higher alcohols, ethyl acetate and acetoin than in red grapes. In general, higher levels of ethanol, glycerol and acetic acid were produced in red grape must fermentation. Apiculate strains behaved differently in the two musts, with different metabolic phenotypes dominating the fermentation process. The existence of different metabolic phenotypes correlated with the must composition underlines the need to perform a selection of indigenous apiculate yeasts to obtain the desired consistent products.
The (R)/(S) ratios of acetoin were always higher in wines obtained by Saccharomyces cerevisiae than in those obtained by Kloeckera apiculata. A significantly different behaviour was determined between the two species as regards contents and ratios of 2,3-butanediols: S.cerevisiae produced more (R,R)-2,3-butanediol (about 80%), whereas K.apiculata produced more meso-form (about 90%).
Secondary products in wines obtained by pure, mixed and sequential cultures of Saccharomyces cerevisiae, Hanseniaspora guilliermondii or Kloeckera apiculata were studied. Consistent differences in the composition were determined in wines fermented by sequential cultures. When S. cerevisiae was added to musts partially fermented by apiculate yeasts, its metabolism was significantly affected. In particular it synthesized high amounts of n-propanol and metabolized high quantities of acetoin, produced by apiculate yeasts
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.
Eighty-six strains of Saccharomyces cerevisiae were investigated for their ability to produce acetaldehyde in synthetic medium and in grape must. Acetaldehyde production did not differ significantly between the two media, ranging from a few mg/l to about 60 mg/l, and was found to be a strain characteristic. The fermentation temperature of 30 degrees C considerably increased the acetaldehyde produced. This study allowed us to assign the strains to different phenotypes: low, medium and high acetaldehyde producers. The low and high phenotypes differed considerably also in the production of acetic acid, acetoin and higher alcohols and can be useful for studying acetaldehyde production in S. cerevisiae, both from the technological and genetic point of view.
On the basis of the levels of secondary product formation four different phenotypes were represented among the 28 strains of Saccharomyces cerevisiae isolated during the spontaneous fermentation of grape juice. The genetic analysis indicated that four different strains, representing each phenotypic class, were derived, one from the other, by mutation. The spontaneous fermentation of a Malvasia must was dominated by different strains of Saccharomyces cerevisiae at different stages of fermentation.
Ninety-six strains of apiculate wine yeasts were studied for their ability to produce glycerol, acetaldehyde, ethyl acetate, sulphur dioxide and hydrogen sulphide in synthetic medium. Hanseniaspora guilliermondii produced smaller quantities of glycerol, acetaldehyde and hydrogen sulphide than Kloeckera apiculata, whereas the production of ethyl acetate and sulphur dioxide was found to be similar. Strains characterized by different capacities and properties were found for both species. The existence of apiculate strains differing in secondary compound production is of technological interest, as these yeasts constitute potential flavour producers. Selected strains of apiculate yeasts might favour an enhanced flavour formation and yield desirable characteristics to the final product.
The aroma of wine consists of 600 to 800 aroma compounds from which especially those, typical for the variety, are already present in the grapes. There are significant varietal differences between the aromagrams ('fingerprint patterns'). Thus the amount of some flavour compounds ('key substances') shows typical dependence on the variety. Especially monoterpene compounds play an important role in the differentiation of wine varieties. The German white wines can be differentiated into three groups only by quantitative determination of 12 monoterpenes ('terpene profile'). These groups are: 'Riesling type', 'Muscat type' and 'Silvaner-Weissburgunder type'. Such 'terpene profiles' are also useful for the separation of real Riesling wines from others called Riesling (e.g. Welschriesling, Kap Riesling, Emerald Riesling) but not produced from grapes of the variety Riesling. Including further components and by means of statistical methods (discriminant analysis) even the different varieties within the mentioned groups for instance the 'Riesling'-group (e.g. Riesling, Kerner, Ehrenfelser, Bacchus, Müller-Thurgau) can be separated from each other. An analytical characterization of the neutral ('Silvaner-type') grape varieties Silvaner, Ruländer (Pinot gris), Weissburgunder (Pinot blanc) is also possible with about 20 compounds (e.g. monoterpenes, alcohols). Computing at the same time free and glycosidically bound aroma components (monoterpenes, alcohols, norisoprenes) in discriminant analysis the characterization of the neutral grape varieties can be considerably improved. To identify compounds causing 'off-flavours' sniffing technique is the method of choice. The off-flavour is pinpointed during gas chromatographic separation of the complex aroma mixture by effluent sniffing. Once allocated, the chemical nature of the off-flavours is elucidated by spectroscopic methods. Substances contributing to the green pepper taint, the strawberry note, moussiness, corkiness, etc. in wine could be found in this way.
Yeasts are predominant in the ancient and complex process of winemaking. In spontaneous fermentations, there is a progressive growth pattern of indigenous yeasts, with the final stages invariably being dominated by the alcohol-tolerant strains of Saccharomyces cerevisiae. This species is universally known as the 'wine yeast' and is widely preferred for initiating wine fermentations. The primary role of wine yeast is to catalyze the rapid, complete and efficient conversion of grape sugars to ethanol, carbon dioxide and other minor, but important, metabolites without the development of off-flavours. However, due to the demanding nature of modern winemaking practices and sophisticated wine markets, there is an ever-growing quest for specialized wine yeast strains possessing a wide range of optimized, improved or novel oenological properties. This review highlights the wealth of untapped indigenous yeasts with oenological potential, the complexity of wine yeasts' genetic features and the genetic techniques often used in strain development. The current status of genetically improved wine yeasts and potential targets for further strain development are outlined. In light of the limited knowledge of industrial wine yeasts' complex genomes and the daunting challenges to comply with strict statutory regulations and consumer demands regarding the future use of genetically modified strains, this review cautions against unrealistic expectations over the short term. However, the staggering potential advantages of improved wine yeasts to both the winemaker and consumer in the third millennium are pointed out.
Yeast ecology, biogeography and biodiversity are important and interesting topics of research. The population dynamics of yeasts in several cellars of two Spanish wine-producing regions was analysed for three consecutive years (1996 to 1998). No yeast starter cultures had been used in these wineries which therefore provided an ideal winemaking environment to investigate the dynamics of grape-related indigenous yeast populations. Non-Saccharomyces yeast species were identified by RFLPs of their rDNA, while Saccharomyces species and strains were identified by RFLPs of their mtDNA. This study confirmed the findings of other reports that non-Saccharomyces species were limited to the early stages of fermentation whilst Saccharomyces dominated towards the end of the alcoholic fermentation. However, significant differences were found with previous studies, such as the survival of non-Saccharomyces species in stages with high alcohol content and a large variability of Saccharomyces strains (a total of 112, all of them identified as Saccharomyces cerevisiae) with no clear predominance of any strain throughout all the fermentation, probably related to the absence of killer phenotype and lack of previous inoculation with commercial strains.
The levels of yeasts and lactic acid bacteria that naturally developed during the vinification of two red and two white Bordeaux wines were quantitatively examined. Yeasts of the genera Rhodotorula, Pichia, Candida, and Metschnikowia occurred at low levels in freshly extracted grape musts but died off as soon as fermentation commenced. Kloeckera apiculata (Hanseniaspora uvarum), Torulopsis stellata, and Saccharomyces cerevisiae, the dominant yeasts in musts, proliferated to conduct alcoholic fermentation. K. apiculata and eventually T. stellata died off as fermentation progressed, leaving S. cerevisiae as the dominant yeast until the termination of fermentation by the addition of sulfur dioxide. At least two different strains of S. cerevisiae were involved in the fermentation of one of the red wines. Low levels of lactic acid bacteria (Pediococcus cerevisiae, Leuconostoc mesenteroides, and Lactobacillus spp.) were present in grape musts but died off during alcoholic fermentation. The malolactic fermentation developed in both red wines soon after alcoholic fermentation and correlated with the vigorous growth of at least three different strains of Leuconostoc oenos.
Principles and Practices of Winemaking Automated multiple development method for determination of glycerol produced by wine yeasts
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Flavor Microbiology Formation and occurrence of flavour com-pounds in wine and distilled alcoholic beverages
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Yeasts: growth during fermenta-tion
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Role of apiculate yeasts on organoleptic charac-teristics of wine Biodiversity and Biotech-nology of Wine Yeasts
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La purezza fermentativa in Saccharomyces cer-evisiae
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Wine and brandy Prescott and Dunn's Industrial Microbiology
- I Benda
Benda, I., 1982. Wine and brandy. In: Reed, G. (Ed.), Prescott and Dunn's Industrial Microbiology. Avi Technical Books, Westport, pp. 292 – 402.
Esiste un'interazione del lievito con il vitigno? Vignevini 7 – 8
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