Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Int J Food Microbiol ; 342: 109077, 2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33550155

RESUMO

Cocoa pulp fermentation is a consequence of the succession of indigenous yeasts, lactic acid bacteria and acetic acid bacteria that not only produce a diversity of metabolites, but also cause the production of flavour precursors. However, as such spontaneous fermentations are less reproducible and contribute to produce variability, interest in a microbial starter culture is growing that could be used to inoculate cocoa pulp fermentations. This study aimed to generate robust S. cerevisiae strains by thermo-adaptive evolution that could be used in cocoa fermentation. We evolved a cocoa strain in a sugary defined medium at high temperature to improve both fermentation and growth capacity. Moreover, adaptive evolution at high temperature (40 °C) also enabled us to unveil the molecular basis underlying the improved phenotype by analysing the whole genome sequence of the evolved strain. Adaptation to high-temperature conditions occurred at different genomic levels, and promoted aneuploidies, segmental duplication, and SNVs in the evolved strain. The lipid profile analysis of the evolved strain also evidenced changes in the membrane composition that contribute to maintain an appropriate cell membrane state at high temperature. Our work demonstrates that experimental evolution is an effective approach to generate better-adapted yeast strains at high temperature for industrial processes.

2.
Food Microbiol ; 94: 103650, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33279075

RESUMO

The positive impact of certain non-Saccharomyces yeasts on the aromatic profile of wines has been well documented in literature and their industrial use in association with S. cerevisiae is now recommended. Competition between non-Saccharomyces species and Saccharomyces cerevisiae for various nutrients, especially nitrogen sources, greatly impacts the production of aroma compounds. In this study, we further explored the impact of different nitrogen nutrition strategies on the production of carbon and sulphur volatile compounds of three non-Saccharomyces strains, namely Pichia burtonii, Kluyveromyces marxianus, Zygoascus meyerae sequentially inoculated with S. cerevisiae in Sauvignon blanc and Shiraz grape musts. Nitrogen additions were implemented according the specific requirement of each species. At the end of fermentation, we observed specific metabolic signatures for each strain in response to the nature of the nitrogen source suggesting strain-specific metabolic fluxes present. Overall, these results confirmed and further explored the interconnection between nitrogen sources and aroma metabolism (including that of higher alcohols, fatty acids, esters and volatile sulphur compounds), and their variations according to species and the nature of the nitrogen source. The knowledge generated provides new insights to modulate the aroma profile of wines produced with non-Saccharomyces species.

3.
Artigo em Inglês | MEDLINE | ID: mdl-33355112

RESUMO

Nitrogen is among the essential nutriments that govern interactions between yeast species in the wine environment. A thorough knowledge of how these yeasts assimilate the nitrogen compounds of grape juice is an important prerequisite for a successful co- or sequential fermentation. In the present study, we investigated the efficiency of 18 nitrogen sources for sustaining the growth and fermentation of two Starm. bacillaris strains displaying metabolic properties, compared to the reference yeast S. cerevisiae The analysis of growth and fermentation parameters provided a comprehensive picture of Starm. bacillaris preferences with respect to nitrogen sources for sustained growth and fermentation. Important differences were observed in S. cerevisiae regarding rates, final population and CO2 production. In particular, Lys and His supported substantial Starm. bacillaris growth and fermentation contrary to S. cerevisiae, while only 3 nitrogen sources, Arg, NH4+ and Ser, promoted S. cerevisiae growth more efficiently than that of Starm. bacillaris strains. Furthermore, Starm. bacillaris strains displayed a higher fermentative activity than S. cerevisiae during the first phase of culture with Gly or Thr, when the former species consumed solely fructose. Finally, no correlation has been shown between the ability of nitrogen sources to support growth and their fermentation efficiency. The specificities of Starm. bacillaris regarding nitrogen sources preferences are related to its genetic background, but further investigations are needed to elucidate the molecular mechanisms involved. These data are essential elements to be taken into account in order to make the best use of the potential of the two species.IMPORTANCE Mixed fermentations combining non-Saccharomyces and S. cerevisiae strains are increasingly implemented in the wine sector as they offer promising opportunities to diversify the flavour profile of end-products. However, competition for nutrients between species can cause fermentation problems, which is a severe hindrance to the development of these approaches. With the knowledge provided in this study on the nitrogen preferences of Starm. bacillaris, winemakers will be able to set up a nitrogen nutrition scheme adapted to the requirement of each species during mixed fermentation, through must supplementation with relevant nitrogen compounds. This will prevent nitrogen depletion or competition between yeasts for nitrogen sources, and consequently potential issues during fermentation. The data of this study highlight the importance of an appropriate nitrogen resource management during co- or sequential fermentation for fully exploiting the phenotypic potential of non-Saccharomyces yeasts.

4.
Microorganisms ; 8(6)2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32560056

RESUMO

Non-Saccharomyces yeast strains have become increasingly prevalent in the food industry, particularly in winemaking, because of their properties of interest both in biological control and in complexifying flavour profiles in end-products. However, unleashing the full potential of these species would require solid knowledge of their physiology and metabolism, which is, however, very limited to date. In this study, a quantitative analysis using 15N-labelled NH4Cl, arginine, and glutamine, and 13C-labelled leucine and valine revealed the specificities of the nitrogen metabolism pattern of two non-Saccharomyces species, Torulaspora delbrueckii and Metschnikowia pulcherrima. In T. delbrueckii, consumed nitrogen sources were mainly directed towards the de novo synthesis of proteinogenic amino acids, at the expense of volatile compounds production. This redistribution pattern was in line with the high biomass-producer phenotype of this species. Conversely, in M. pulcherrima, which displayed weaker growth capacities, a larger proportion of consumed amino acids was catabolised for the production of higher alcohols through the Ehrlich pathway. Overall, this comprehensive overview of nitrogen redistribution in T. delbrueckii and M. pulcherrima provides valuable information for a better management of co- or sequential fermentation combining these species with Saccharomyces cerevisiae.

5.
Front Microbiol ; 11: 305, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32184771

RESUMO

Non-Saccharomyces yeasts are currently widely used in winemaking to enhance aroma profile diversity among wines. The use of Metschnikowia pulcherrima in sequential inoculation with S. cerevisiae was compared to the inoculation of a pure culture of S. cerevisiae. Moreover, various concentrations of sugar, nitrogen and lipids were tested in synthetic must to assess their impact on fermentation and its outcomes using a Box-Behnken design. Due to its phenotypic specificities, early inoculation with M. pulcherrima led to important modifications, first altering the fermentation kinetics. This may relate, at least in part, to the depletion of some nitrogen sources by M. pulcherrima during the first part of fermentation. Beyond these negative interactions on fermentation performance, comparisons between pure cultures and sequentially inoculated cultures revealed changes in the distribution of carbon fluxes during fermentation in presence of M. pulcherrima, resulting in a positive impact on the production of central carbon metabolites and aromas. Furthermore, the expression of varietal thiols was strongly increased as a consequence of positive interactions between the two species. The mechanism of this release still needs to be investigated. Significant differences in the final concentrations of fermentative and varietal aromas depending on the initial must composition were obtained under both inoculation strategies. Interestingly, the response to changes in nutrient availability varied according to the inoculation modality. In particular, a greater incidence of lipids on the production of fatty acids and their ethyl esters derivatives was found during sequential fermentation compared with pure culture, to be viewed in combination with the metabolic characteristics of M. pulcherrima regarding the production of volatile compounds from acetyl-CoA. Overall, the importance of managing nutrient availability under M. pulcherrima/S. cerevisiae sequential inoculation in order to derive the maximum benefit from the potentialities of the non-Saccharomyces species while carrying out fermentation to dryness was highlighted.

6.
Food Microbiol ; 85: 103287, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500707

RESUMO

Wine-related non-Saccharomyces yeasts are becoming more widely used in oenological practice for their ability to confer wine a more complex satisfying aroma, but their metabolism remains unknown. Our study explored the nitrogen utilisation profile of three popular non-Saccharomyces species, Torulaspora delbrueckii, Metschnikowia pulcherrima and Metschnikowia fructicola. The nitrogen source preferences to support growth and fermentation as well as the uptake order of different nitrogen sources during wine fermentation were investigated. While T. delbrueckii and S. cerevisiae strains shared the same nitrogen source preferences, Metschnikowia sp. Displayed a lower capacity to efficiently use the preferred nitrogen compounds, but were able to assimilate a wider range of amino acids. During alcoholic fermentation, the non-Saccharomyces strains consumed different nitrogen sources in a similar order as S. cerevisiae, but not as quickly. Furthermore, when all the nitrogen sources were supplied in the same amount, their assimilation order was similarly affected for both S. cerevisiae and non-Saccharomyces strains. Under this condition, the rate of nitrogen source consumption of non-Saccharomyces strains and S. cerevisiae was comparable. Overall, this study expands our understanding about the preferences and consumption rates of individual nitrogen sources by the investigated non-Saccharomyces yeasts in a wine environment. This knowledge provides useful information for a more efficient exploitation of non-Saccharomyces strains that improves the management of the wine fermentation.


Assuntos
Fermentação , Nitrogênio/metabolismo , Vinho/microbiologia , Leveduras/crescimento & desenvolvimento , Leveduras/metabolismo , Aminoácidos/metabolismo , Metschnikowia/crescimento & desenvolvimento , Odorantes , Saccharomyces cerevisiae , Torulaspora/crescimento & desenvolvimento
7.
Int J Food Microbiol ; 316: 108441, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-31778839

RESUMO

Even though non-Saccharomyces yeasts were regarded as spoilage microorganisms for a long time, their abilities to improve and diversify the aromatic profile of wines are now well recognized. Consequently, their use in combination with S. cerevisiae strains during winemaking has attracted substantial attention over the last decade. However, our limited understanding of the metabolism and physiology of these species remains a barrier to promoting efficient exploitation of their full potential. In this study, we further explored the metabolism involved in the production of fermentative volatile compounds of two commercial non-Saccharomyces strains, T. delbrueckii Biodiva™ and M. pulcherrima Flavia®, in comparison with the reference wine yeast S. cerevisiae Lalvin EC1118®. After growing these strains in the presence of 24 different N-compounds, particular attention was paid to the influence of the nitrogen source on the profile of aroma compounds synthesized by these yeasts (higher alcohols and acids, medium-chain fatty acids and their acetate or ethyl esters derivatives). A comprehensive analysis of the dataset showed that these three species were able to produce all the fermentative aromas, regardless of the nitrogen source, demonstrating the key contribution of the central carbon metabolism to the formation of volatile molecules. Nevertheless, we also observed some specific phenotypic traits for each of the strains in their assimilation capacities for the various nitrogen nutrients as well as in their response to the nature of the nitrogen source in terms of the production of volatile molecules. These observations revealed the intricacy and interconnection between the networks involved in nitrogen consumption and aroma production. These differences are likely related to the genetic backgrounds of the strains. Overall, this study expands our understanding of the metabolic processes responsible for the formation of volatile compounds during wine fermentation and their variations according to species and the nature of the nitrogen source. This knowledge provides a new platform for the more efficient exploitation of non-Saccharomyces strains during winemaking, improving the management of the fermentation.


Assuntos
Nitrogênio/metabolismo , Odorantes , Saccharomycetales/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Fermentação , Odorantes/análise , Fenótipo , Saccharomyces cerevisiae/metabolismo , Saccharomycetales/classificação , Especificidade da Espécie , Compostos Orgânicos Voláteis/análise , Vinho/análise , Vinho/microbiologia
8.
Environ Microbiol ; 21(11): 4076-4091, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31336027

RESUMO

In grape must, nitrogen is available as a complex mixture of various compounds (ammonium and amino acids). Wine yeasts assimilate these multiple sources in order to suitably fulfil their anabolic requirements during alcoholic fermentation. Nevertheless, the order of uptake and the intracellular fate of these sources are likely to differ between strains and species. Using a two-pronged strategy of isotopic filiation and RNA sequencing, the metabolic network of nitrogen utilization and its regulation in Kluyveromyces marxianus were described, in comparison with those of Saccharomyces cerevisiae. The data highlighted differences in the assimilation of ammonium and arginine between the two species. The data also revealed that the metabolic fate of certain nitrogen sources differed, thereby resulting in the production of various amounts of key wine aroma compounds. These observations were corroborated by the gene expression analysis.


Assuntos
Compostos de Amônio/metabolismo , Kluyveromyces/metabolismo , Nitrogênio/metabolismo , Saccharomyces cerevisiae/metabolismo , Aminoácidos/metabolismo , Fermentação , Perfilação da Expressão Gênica , Kluyveromyces/genética , Redes e Vias Metabólicas/fisiologia , Saccharomyces cerevisiae/genética , Vitis/microbiologia , Vinho/microbiologia
9.
Food Res Int ; 122: 392-401, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31229092

RESUMO

The use of Starmerella bacillaris in combination with Saccharomyces cerevisiae is considered as a state-of-the-art biological application to modulate wine composition. This application implies a detailed understanding of yeast-yeast interactions during mixed fermentations and their effect on the composition of the resulting wines. In this context, ten commercial S. cerevisiae strains were used as partners of an indigenous, previously characterized Starm. bacillaris strain in order to get a better insight into the impact of S. cerevisiae strain employed. The different combinations of strains tested influenced the growth dynamics, the fermentation behavior and, as a consequence, wine composition in a couple-dependent manner. In addition, wines produced from mixed fermentations had significantly lower levels of ethanol, acetic acid and ethyl acetate, and showed higher amounts of glycerol, higher alcohols and esters compared to pure S. cerevisiae control fermentations. This study reveals the importance of S. cerevisiae strain choice on the chemical composition of the wines produced from mixed culture fermentations with Starm. bacillaris.


Assuntos
Fermentação , Saccharomyces cerevisiae/metabolismo , Saccharomycetales/metabolismo , Compostos Orgânicos Voláteis/análise , Vinho/análise , Acetatos/análise , Ácido Acético/análise , Análise de Alimentos , Manipulação de Alimentos , Glicerol/análise , Vinho/microbiologia
10.
J Agric Food Chem ; 66(44): 11739-11747, 2018 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-30350960

RESUMO

Since Saccharomyces cerevisiae strains display no to weak pectinase activity, the utilization of external pectinase is a common practice in winemaking to enhance the extraction of compounds located in the grape berry skins during maceration. In this study, the activity of the native endopolygalacturonase of a Kluyveromyces marxianus strain, isolated from grape juice, was characterized in Shiraz grape must during alcoholic fermentation with or without prefermentative cold maceration. The wines made with K. marxianus had a higher methanol concentration, more free-run wine, an altered volatile compound profile, and displayed pectinase activity in cell-free wine samples. Moreover, the results strongly suggest that K. marxianus' pectinase released polygalacturonic acid soluble fragments, unlike fungal pectinases, which mostly release monomers. Overall, this study shows that K. marxianus is an effective pectinase producer in wine with potential benefits for wine properties.


Assuntos
Aromatizantes/química , Proteínas Fúngicas/metabolismo , Kluyveromyces/enzimologia , Poligalacturonase/metabolismo , Vinho/análise , Fermentação , Aromatizantes/metabolismo , Proteínas Fúngicas/genética , Kluyveromyces/genética , Metanol/análise , Metanol/metabolismo , Odorantes/análise , Poligalacturonase/genética , Vitis/metabolismo , Vitis/microbiologia , Vinho/microbiologia
11.
Food Microbiol ; 76: 29-39, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30166153

RESUMO

During alcoholic fermentation, many parameters, including the nitrogen composition of the must, can affect aroma production. The aim of this study was to examine the impact of several types of nitrogen sources added at different times during fermentation. Nitrogen was added as ammonium or a mixture of amino acids at the beginning of fermentation or at the start of the stationary phase. These conditions were tested with two Saccharomyces cerevisiae strains that have different nitrogen requirements. The additions systematically reduced the fermentation duration. The aroma production was impacted by both the timing of the addition and the composition of the nitrogen source. Propanol appeared to be a metabolic marker of the presence of assimilable nitrogen in the must. The production of ethyl esters was slightly higher after the addition of any type of nitrogen; the production of higher alcohols other than propanol was unchanged, and acetate esters were overproduced due to the overexpression of the genes ATF1 and ATF2. Finally the parameter affecting the most the synthesis of beneficial aromas was the addition timing: The supply of organic nitrogen at the beginning of the stationary phase was more favorable for the synthesis of beneficial aromas.


Assuntos
Nitrogênio/farmacologia , Odorantes/análise , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Vinho/microbiologia , Acetiltransferases/efeitos dos fármacos , Acetiltransferases/genética , Álcoois/metabolismo , Aminoácidos/metabolismo , Aminoácidos/farmacologia , Compostos de Amônio/metabolismo , Compostos de Amônio/farmacologia , Meios de Cultura/síntese química , Ésteres/metabolismo , Fermentação , Cinética , Nitrogênio/metabolismo , Proteínas/efeitos dos fármacos , Proteínas/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/efeitos dos fármacos , Proteínas de Saccharomyces cerevisiae/genética , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/metabolismo , Vinho/análise
12.
AMB Express ; 8(1): 130, 2018 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-30097818

RESUMO

Saccharomyces cerevisiae × Saccharomyces kudriavzevii hybrids are typically used for white wine fermentation because of their cryotolerance. One group of these hybrids presents a unique ability to release thiol varietal aroma products as well as excessive amounts of acetic acid under specific conditions, which is detrimental for wine organoleptic quality. The aim of this work is to better assess the effects of lipids, sugar concentrations and temperature on the production of acetic acid and thiols during wine fermentation. To this end, we used a Box-Behnken experimental design and response surface modeling on the production of acetic acid and thiols in S. cerevisiae × S. kudriavzevii hybrids from the Eg8 family during fermentation of a synthetic must. We showed that these hybrids produced lower levels of acetic acid when the initial lipid concentration was increased, whereas they produced greater levels when the initial sugar concentration was high. Moreover, we found that lipids had a positive impact on the final concentrations of 4-methyl-4-mercaptopentan-2-one and 3-mercaptohexan-1-ol (3MH), giving box tree and citrus flavors, respectively. The increase of 3MH was concomitant with a decrease of 3-mercaptohexyl acetate (3MHA) characterized by a passion fruit aroma, indicating that lipid addition reduces the rate of 3MH acetylation into 3MHA. These results highlight the key role of lipid management in acetic acid metabolism and thiol release by S. cerevisiae × S. kudriavzevii hybrids and underline its technological interest in alcoholic fermentation to avoid the overproduction of volatile acidity while favoring the release of volatile thiols.

13.
Appl Environ Microbiol ; 84(16)2018 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-29858207

RESUMO

Over the last few years, the potential of non-Saccharomyces yeasts to improve the sensory quality of wine has been well recognized. In particular, the use of Starmerella bacillaris in mixed fermentations with Saccharomyces cerevisiae was reported as an appropriate way to enhance glycerol formation and reduce ethanol production. However, during sequential fermentation, many factors, such as the inoculation timing, strain combination, and physical and biochemical interactions, can affect yeast growth, the fermentation process, and/or metabolite synthesis. Among them, the availability of yeast-assimilable nitrogen (YAN), due to its role in the control of growth and fermentation, has been identified as a key parameter. Consequently, a comprehensive understanding of the metabolic specificities and the nitrogen requirements would be valuable to better exploit the potential of Starm. bacillaris during wine fermentation. In this study, marked differences in the consumption of the total and individual nitrogen sources were registered between the two species, while the two Starm. bacillaris strains generally behaved uniformly. Starm. bacillaris strains are differentiated by their preferential uptake of ammonium compared with amino acids that are poorly assimilated or even produced (alanine). Otherwise, the non-Saccharomyces yeast exhibits low activity through the acetaldehyde pathway, which triggers an important redistribution of fluxes through the central carbon metabolic network. In particular, the formation of metabolites deriving from the two glycolytic intermediates glyceraldehyde-3-phosphate and pyruvate is substantially increased during fermentations by Starm. bacillaris This knowledge will be useful to better control the fermentation process in mixed fermentation with Starm. bacillaris and S. cerevisiaeIMPORTANCE Mixed fermentations using a controlled inoculation of Starmerella bacillaris and Saccharomyces cerevisiae starter cultures represent a feasible way to modulate wine composition that takes advantage of both the phenotypic specificities of the non-Saccharomyces strain and the ability of S. cerevisiae to complete wine fermentation. However, according to the composition of grape juices, the consumption by Starm. bacillaris of nutrients, in particular of nitrogen sources, during the first stages of the process may result in depletions that further limit the growth of S. cerevisiae and lead to stuck or sluggish fermentations. Consequently, understanding the preferences of non-Saccharomyces yeasts for the nitrogen sources available in grape must together with their phenotypic specificities is essential for an efficient implementation of sequential wine fermentations with Starm. bacillaris and S. cerevisiae species. The results of our study demonstrate a clear preference for ammonium compared to amino acids for the non-Saccharomyces species. This finding underlines the importance of nitrogen sources, which modulate the functional characteristics of inoculated yeast strains to better control the fermentation process and product quality.


Assuntos
Compostos de Amônio/metabolismo , Fermentação , Nitrogênio/metabolismo , Fenótipo , Saccharomycetales/metabolismo , Vinho/microbiologia , Aminoácidos/metabolismo , Carbono/metabolismo , Glicerol/metabolismo , Saccharomyces cerevisiae/metabolismo , Vinho/análise
14.
FEMS Yeast Res ; 18(5)2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29741618

RESUMO

Saccharomyces cerevisiae is currently the most important yeast involved in food fermentations, particularly in oenology. However, several other yeast species occur naturally in grape must that are highly promising for diversifying and improving the aromatic profile of wines. If the nitrogen requirement of S. cerevisiae has been described in detail, those of non-Saccharomyces yeasts remain poorly studied despite their increasingly widespread use in winemaking. With a view to improving the use of non-Saccharomyces yeasts in winemaking, we explored the fermentation performances, the utilisation of nitrogen sources and the volatile compound production of 10 strains of non-conventional yeasts in pure culture. Two different conditions were tested: one mimicking the grape juice's nitrogen composition and one with all the nitrogen sources at the same level. We highlighted the diversity in terms of nitrogen preference and amount consumed among the yeast strains. Some nitrogen sources (arginine, glutamate, glycine, tryptophan and γ-aminobutyric acid) displayed the largest variations between strains throughout the fermentation. Several non-Saccharomyces strains produced important aroma compounds such as higher alcohols, acetate and ethyl esters in significantly higher quantities than S. cerevisiae.


Assuntos
Fermentação , Nitrogênio/metabolismo , Odorantes/análise , Vinho/microbiologia , Leveduras/metabolismo , Acetatos/análise , Álcoois/análise , Ésteres/análise , Saccharomyces cerevisiae
15.
Food Res Int ; 109: 298-309, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29803453

RESUMO

The use of mixed fermentations with Starmerella bacillaris and Saccharomyces cerevisiae is gaining attention in recent years due to their ability to modulate the metabolites production of enological interest. In the present study, four of the most popular planted red grape varieties (Cabernet sauvignon, Merlot, Pinot noir and Shiraz) were fermented using the aforementioned species and two different inoculation protocols (inoculation of S. cerevisiae after 24 and 48 h from the Starm. bacillaris inoculation), in order to evaluate their impact on the volatile composition and chromatic characteristics of wines. Analysis from chemical composition showed that titratable acidity and glycerol content exhibited marked differences among wines after fermentation. For volatile compounds, mixed fermented wines using an inoculation delay of 48 h led to reduction of volatile compounds (mainly esters). A shorter 24 h delay produced wines with higher values of color intensity than pure fermented wines. The differences observed between the inoculation protocols can be explained by the growth dynamics of both species during fermentation. These findings suggest that mixed fermentations posed a great potential in reducing metabolites which are considered negative for wine quality (mainly ethyl acetate and volatile fatty acids) and with an improvement of the chromatic profile of the wines.


Assuntos
Fermentação , Manipulação de Alimentos/métodos , Microbiologia de Alimentos/métodos , Frutas/microbiologia , Odorantes/análise , Saccharomyces cerevisiae/metabolismo , Saccharomycetales/metabolismo , Vitis/microbiologia , Compostos Orgânicos Voláteis/metabolismo , Vinho/microbiologia , Acetatos/metabolismo , Cor , Ácidos Graxos Voláteis/metabolismo , Olfato , Fatores de Tempo
16.
Food Chem ; 257: 350-360, 2018 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-29622221

RESUMO

Mixed fermentations with Starmerella bacillaris and Saccharomyces cerevisiae affect the chemical composition of wines, by modulating various metabolites of oenological interest. The current study was carried out to elucidate the effect of sequential inoculation of the above mentioned species on the production of white wines, especially on the chemical and aromatic characteristics of Chardonnay, Muscat, Riesling and Sauvignon blanc wines. Titratable acidity and glycerol content exhibited evident differences among the wines after fermentation. For volatile compounds, mixed fermentations led to a reduction of the total esters, including ethyl acetate, which is a compound responsible for wine deterioration. However, Sauvignon blanc wines fermented by mixed cultures contained significantly higher levels of esters and thiols, both associated with positive sensory attributes. These findings suggest that sequential inoculations possess great potential in affecting and modulating the chemical and aromatic profile of white wines, especially those produced from Sauvignon blanc grapes.


Assuntos
Saccharomyces cerevisiae/metabolismo , Saccharomycetales/metabolismo , Compostos Orgânicos Voláteis/análise , Vinho/análise , Acetatos/análise , Acetatos/isolamento & purificação , Reatores Biológicos , Cromatografia Gasosa , Ácidos Graxos/análise , Compostos de Sulfidrila/análise , Terpenos/análise , Compostos Orgânicos Voláteis/isolamento & purificação
17.
Front Microbiol ; 9: 196, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29487584

RESUMO

The sequential inoculation of non-Saccharomyces yeasts and Saccharomyces cerevisiae in grape juice is becoming an increasingly popular practice to diversify wine styles and/or to obtain more complex wines with a peculiar microbial footprint. One of the main interactions is competition for nutrients, especially nitrogen sources, that directly impacts not only fermentation performance but also the production of aroma compounds. In order to better understand the interactions taking place between non-Saccharomyces yeasts and S. cerevisiae during alcoholic fermentation, sequential inoculations of three yeast species (Pichia burtonii, Kluyveromyces marxianus, Zygoascus meyerae) with S. cerevisiae were performed individually in a synthetic medium. Different species-dependent interactions were evidenced. Indeed, the three sequential inoculations resulted in three different behaviors in terms of growth. P. burtonii and Z. meyerae declined after the inoculation of S. cerevisiae which promptly outcompeted the other two species. However, while the presence of P. burtonii did not impact the fermentation kinetics of S. cerevisiae, that of Z. meyerae rendered the overall kinetics very slow and with no clear exponential phase. K. marxianus and S. cerevisiae both declined and became undetectable before fermentation completion. The results also demonstrated that yeasts differed in their preference for nitrogen sources. Unlike Z. meyerae and P. burtonii, K. marxianus appeared to be a competitor for S. cerevisiae (as evidenced by the uptake of ammonium and amino acids), thereby explaining the resulting stuck fermentation. Nevertheless, the results suggested that competition for other nutrients (probably vitamins) occurred during the sequential inoculation of Z. meyerae with S. cerevisiae. The metabolic footprint of the non-Saccharomyces yeasts determined after 48 h of fermentation remained until the end of fermentation and combined with that of S. cerevisiae. For instance, fermentations performed with K. marxianus were characterized by the formation of phenylethanol and phenylethyl acetate, while those performed with P. burtonii or Z. meyerae displayed higher production of isoamyl alcohol and ethyl esters. When considering sequential inoculation of yeasts, the nutritional requirements of the yeasts used should be carefully considered and adjusted accordingly. Finally, our chemical data suggests that the organoleptic properties of the wine are altered in a species specific manner.

18.
Food Res Int ; 107: 257-266, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29580483

RESUMO

Two different Metschnikowia strains (M. pulcherrima MP 346 or M. fructicola MF 98-3) were applied for the first time, during pre-fermentative cold maceration (PCM) in order to enhance the properties and stability of Sangiovese wine color. During the 2014 and 2015 vintages a total of eight wines were produced with 24 h of cold maceration (PCM 24 h) or 72 h (PCM 72 h), respectively. PCM was carried out in presence of MP 346 or MF 98-3 or pectic enzyme (Cuvée Rouge). The sequential inoculation of S. cerevisiae strain was carried out at the end of PCM. After 12 months in the bottle, the MP 346 and MF 98-3 wines contained much higher levels of total flavonoids than the Control sample for both vintages and regardless PCM duration. Moreover, in both vintages only MF 98-3 showed a higher color intensity than the Control sample after 12 months in the bottle. However, neither PCM duration nor the microbial/enzymatic treatment increased the level of anthocyanins at draining off. Both wines produced by the pre-fermentative inoculum with Metschnikowia strains (MP 346 and MF 98-3) retained their red hue, regardless the duration of pre-fermentative and fermentative macerations, while the Control wines were characterized by faster rates of color loss.


Assuntos
Antocianinas/análise , Manipulação de Alimentos/métodos , Metschnikowia , Pigmentos Biológicos/análise , Vitis , Vinho/análise , Antocianinas/metabolismo , Cor , Fermentação , Pigmentos Biológicos/metabolismo
19.
Food Microbiol ; 69: 179-188, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28941899

RESUMO

Starmerella bacillaris (synonym Candida zemplinina) is a non-Saccharomyces yeast that has been proposed as a co-inoculant of selected Saccharomyces cerevisiae strains in mixed culture fermentations to enhance the analytical composition of the wines. In order to acquire further knowledge on the metabolic interactions between these two species, in this study we investigated the impact of oxygen addition and combination of Starm. bacillaris with S. cerevisiae strains on the microbial growth and metabolite production. Fermentations were carried out under two different conditions of oxygen availability. Oxygen availability and strain combination clearly influenced the population dynamics throughout the fermentation. Oxygen concentration increased the survival time of Starm. bacillaris and decreased the growth rate of S. cerevisiae strains in mixed culture fermentations, whereas it did not affect the growth of the latter in pure culture fermentations. This study reveals new knowledge about the influence of oxygen availability on the successional evolution of yeast species during wine fermentation.


Assuntos
Ascomicetos/metabolismo , Oxigênio/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Vitis/microbiologia , Vinho/análise , Ascomicetos/crescimento & desenvolvimento , Etanol/análise , Etanol/metabolismo , Fermentação , Aromatizantes/análise , Aromatizantes/metabolismo , Saccharomyces cerevisiae/metabolismo , Vitis/metabolismo
20.
FEMS Yeast Res ; 17(5)2017 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-28810703

RESUMO

Yeast cryotolerance brings some advantages for wine fermentations, including the improved aromatic complexity of white wines. Naturally cold-tolerant strains are generally less adept at wine fermentation but fermentative fitness can potentially be improved through hybridization. Here we studied the potential of using hybrids involving Saccharomyces eubayanus and a S. cerevisiae wine strain for low-temperature winemaking. Through screening the performance in response to variable concentrations of sugar, nitrogen and temperature, we isolated one hybrid strain that exhibited the superior performance. This hybrid strain was propagated and dried in pilot scale and tested for the fermentation of Macabeu and Sauvignon blanc grape musts. We obtained highly viable active dry yeast, which was able to efficiently ferment the grape musts with superior production of aroma active volatiles, in particular, 2-phenylethanol. The genome sequences of the hybrid strains revealed variable chromosome inheritance among hybrids, particularly within the S. cerevisiae subgenome. With the present paper, we expand the knowledge on the potentialities of using S. eubayanus hybrids in industrial fermentation at beverages other than lager beer.


Assuntos
Quimera/genética , Quimera/metabolismo , Redes e Vias Metabólicas/genética , Saccharomyces/genética , Saccharomyces/metabolismo , Vinho/microbiologia , Metabolismo dos Carboidratos , Temperatura Baixa , Dessecação , Fermentação , Viabilidade Microbiana , Nitrogênio/metabolismo , Saccharomyces/efeitos da radiação , Compostos Orgânicos Voláteis/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...