Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 504
Filtrar
1.
Food Microbiol ; 100: 103838, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34416971

RESUMO

Hybridisation is an important evolutionary mechanism to bring about novel phenotypes and may produce new hybrids with advantageous combinations of traits of industrial importance. Within the Saccharomyces genus, Saccharomyces jurei is a newly discovered species and its biotechnological potential has not yet been fully explored. This yeast was found to be able to grow well in unhopped wort and at low temperatures, qualities necessary in good candidates for fermented bevarages. Here, we analysed its fermentation and aroma profile and created novel non-GMO hybrids between S. jurei and S. cerevisiae ale yeasts to develop new starter strains with interesting flavours for the craft brewing and beverage industry in general. Pilot beer fermentations with specific hybrids showed a good fermentation performance, similar to the ale parent strain, while eliminating the hyper-attenuation characteristic and a more complex flavour profile. This study exploits the genetic diversity of yeasts and shows how inter-specific hybridisation and clone selection can be effectively used in brewing to create new products and to eliminate or increase specific traits.


Assuntos
Cerveja/análise , Saccharomyces/genética , Saccharomyces/metabolismo , Cerveja/microbiologia , Fermentação , Aromatizantes/análise , Aromatizantes/metabolismo , Microbiologia de Alimentos , Humanos , Hibridização Genética , Odorantes/análise , Saccharomyces/crescimento & desenvolvimento , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Paladar
2.
Appl Environ Microbiol ; 87(18): e0061221, 2021 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-34232060

RESUMO

Lambic beers are beers produced through spontaneous fermentation and maturation in wooden barrels. The production process of lambic beers differs from the production processes of lagers and ales in process technology, environmental parameters, and the use of specific raw materials. Moreover, every lambic beer production process is unique in terms of microbiology and flavor formation because of its dependence on the spontaneous inoculation of microorganisms coming from the environmental air (contacting the open coolship and other brewery equipment) and the inner surfaces of the barrels. Several factors influence the inter- and intraspecies microbial successions during lambic beer wort fermentation and maturation and determine the final quality of the end products. The possibility to manually acidify the wort, the presence of species-specific metabolic traits, the environmental temperature, the co-occurrence of lactic acid bacteria and acetic acid bacteria, as well as yeasts, and the quality of the wooden barrels all determine the progress and outcome of the lambic beer production process. Further alterations in quality and flavor of lambic beers can be achieved by blending practices and additional bottle refermentations. This results in a vast array of lambic-derived beer products (e.g., gueuze) with complex taste and aroma profiles and specific characteristics, which separate them from most other commercially available beers.


Assuntos
Cerveja/microbiologia , Microbiota , Fermentação , Microbiologia de Alimentos
3.
Food Microbiol ; 99: 103806, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34119099

RESUMO

The increasing interest in novel beer productions focused on non-Saccharomyces yeasts in order to pursue their potential in generating groundbreaking sensory profiles. Traditional fermented beverages represent an important source of yeast strains which could express interesting features during brewing. A total of 404 yeasts were isolated from fermented honey by-products and identified as Saccharomyces cerevisiae, Wickerhamomyces anomalus, Zygosaccharomyces bailii, Zygosaccharomyces rouxii and Hanseniaspora uvarum. Five H. uvarum strains were screened for their brewing capability. Interestingly, Hanseniaspora uvarum strains showed growth in presence of ethanol and hop and a more rapid growth than the control strain S. cerevisiae US-05. Even though all strains showed a very low fermentation power, their concentrations ranged between 7 and 8 Log cycles during fermentation. The statistical analyses showed significant differences among the strains and underlined the ability of YGA2 and YGA34 to grow rapidly in presence of ethanol and hop. The strain YGA34 showed the best technological properties and was selected for beer production. Its presence in mixed- and sequential-culture fermentations with US-05 did not influence attenuation and ethanol concentration but had a significant impact on glycerol and acetic acid concentrations, with a higher sensory complexity and intensity, representing promising co-starters during craft beer production.


Assuntos
Cerveja/microbiologia , Hanseniaspora/metabolismo , Mel/microbiologia , Ácido Acético/análise , Ácido Acético/metabolismo , Cerveja/análise , Etanol/metabolismo , Fermentação , Microbiologia de Alimentos , Hanseniaspora/crescimento & desenvolvimento , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Resíduos/análise , Leveduras/crescimento & desenvolvimento , Leveduras/metabolismo
4.
Food Microbiol ; 99: 103813, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34119100

RESUMO

Tyramine is one of the most toxic biogenic amines and it is produced commonly by lactic acid bacteria in fermented food products. In present study, we investigated the influence of selected nisin-producing Lactococcus lactis subsp. lactis strains and their cell-free supernatants (CFSs) on tyramine production by four Lactobacillus and two Lactiplantibacillus strains isolated from cheese and beer. Firstly, we examined the antimicrobial effect of the CFSs from twelve Lactococcus strains against tested tyramine producers by agar-well diffusion assay. Six Lactococcus strains whose CFSs showed the highest antimicrobial effect on tyramine producers were further studied. Secondly, we investigated the influence of the selected six Lactococcus strains and their respective CFSs on tyramine production by tested Lactobacillus and Lactiplantibacillus strains in MRS broth supplemented with 2 g.L-1 of l-tyrosine. Tyramine production was monitored by HPLC-UV. The tyramine formation of all tested Lactobacillus and Lactiplantibacillus strains was not detected in the presence of Lc. lactis subsp. lactis CCDM 71 and CCDM 702, and their CFSs. Moreover, the remainder of the investigated Lactococcus strains (CCDM 670, CCDM 686, CCDM 689 and CCDM 731) and their CFSs decreased tyramine production significantly (P < 0.05) - even suppressing it completely in some cases - in four of the six tested tyramine producing strains.


Assuntos
Antibacterianos/farmacologia , Cerveja/microbiologia , Queijo/microbiologia , Meios de Cultura/farmacologia , Lactobacillaceae/efeitos dos fármacos , Lactobacillus/efeitos dos fármacos , Lactococcus lactis/química , Tiramina/farmacologia , Antibacterianos/análise , Antibacterianos/metabolismo , Cromatografia Líquida de Alta Pressão , Meios de Cultura/química , Meios de Cultura/metabolismo , Lactobacillaceae/crescimento & desenvolvimento , Lactobacillaceae/isolamento & purificação , Lactobacillus/crescimento & desenvolvimento , Lactobacillus/isolamento & purificação , Lactococcus lactis/metabolismo , Tiramina/análise , Tiramina/metabolismo
5.
World J Microbiol Biotechnol ; 37(7): 125, 2021 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-34173085

RESUMO

Ethyl-acetate is important for the flavor and aroma of the alcoholic beverages, therefore, there have been extensive efforts toward increasing its production by engineering yeast strains. In this study, we reported a new approach to breed non-genetic modified producing yeast strain with higher ethyl-acetate production for beer brewing. First, we demonstrated the positive effect of higher acetic acid concentration on inducing the expression of acetyl-CoA synthetase (ACS). Then, we applied adaptive laboratory evolution method to evolve strain with higher expression level of ACS. As a result, we obtained several evolved strains with increased ACS expression level as well as ethyl-acetate production. In 3 L scale fermentation, the optimal strain EA60 synthesized more ethyl-acetate than M14 at the same time point. At the end of fermentation, the ethyl-acetate production in EA60 was 21.4% higher than M14, while the other flavor components except for acetic acid were changed in a moderate degree, indicating this strain had a bright prospect in industrial application. Moreover, this study also indicated that ACS1 played a more important role in increasing the acetic acid tolerance of yeast, while ACS2 contributed to the synthesis of cytosol acetyl-CoA, thereby facilitating the production of ethyl-acetate during fermentation.


Assuntos
Acetatos/metabolismo , Ácido Acético/metabolismo , Bebidas Alcoólicas/microbiologia , Coenzima A Ligases/metabolismo , Saccharomyces/metabolismo , Adaptação Biológica , Cerveja/microbiologia , Evolução Molecular Direcionada/métodos , Fermentação , Aromatizantes/metabolismo , Microbiologia Industrial/métodos , Laboratórios , Engenharia Metabólica , RNA Fúngico , Reação em Cadeia da Polimerase em Tempo Real , Saccharomyces/genética
6.
Folia Microbiol (Praha) ; 66(4): 525-541, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34097198

RESUMO

Customer demand for product diversity is the key driving force for innovations in the brewing industry. Specialty beers are regarded as a distinct group of beers different from two major types, lagers and ales, without established definitions or boundaries. Specialty beers, including low- to no-alcohol beer, low carbohydrate beer, gluten-free beer, sour beer, probiotic beer, and enriched beer, are exclusively brewed and developed keeping in mind their functionality, the health and wellbeing of the consumer, and emerging market trends. Compared with conventional beer-brewing, the production of specialty beers is technologically challenging and usually requires additional process steps, unique microorganisms, and special equipment, which in turn may incur additional costs. In addition, the maintenance of quality and stability of the products as well as consumer acceptability of the products are major challenges to successful commercialization. A harmonious integration of traditional brewing practices and modern technological approaches may hold potential for future developments. In the present review, latest developments in the fermentative production of selected specialty beers are discussed.


Assuntos
Cerveja , Indústria Alimentícia , Cerveja/microbiologia , Cerveja/normas , Fermentação , Indústria Alimentícia/tendências
7.
Food Chem ; 361: 130025, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34029908

RESUMO

The relative concentration of available inorganic elements is critical for yeast growth and metabolism and has potential to be a tool leading to directed yeast flavour formation during fermentation. This study investigates the influence of essential inorganic elements during alcoholic fermentation of brewers wort, fermented using three independent yeast strains, Saccharomyces pastorianus W34/70, and Saccharomyces cerevisiae strains M2 and NCYC2592 under a range of conditions replicated for each yeast strain. 10 treatments were applied: 1 control and 9 inorganic supplementations: standard brewers wort, ammonia-nitrogen, inorganic phosphate, potassium, magnesium, copper, zinc, iron, manganese and a composite mixture, Twenty-five chemical markers were evaluated by HPLC (ethanol, glycerol), and GC-MS (aroma). There was a significant change in volatile aroma compounds during fermentation, which was more prominent when supplemented with ammonia nitrogen, inorganic phosphate, potassium or magnesium (P < 0.05). Heavy metal ions mostly had a negative effect on the flavour formation.


Assuntos
Cerveja/microbiologia , Metais/farmacologia , Saccharomyces/metabolismo , Cerveja/análise , Cromatografia Líquida de Alta Pressão , Etanol/metabolismo , Fermentação/efeitos dos fármacos , Microbiologia de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Glicerol/metabolismo , Metais/metabolismo , Odorantes , Potássio/metabolismo , Potássio/farmacologia , Saccharomyces/efeitos dos fármacos , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo
8.
FEMS Yeast Res ; 21(4)2021 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-34037755

RESUMO

Yeast flocculation plays an essential role in industrial application. Appropriate flocculation of yeast cells at the end of fermentation benefits the cell separation in production, which is an important characteristic of lager yeast for beer production. Due to the complex fermentation environment and diverse genetic background of yeast strains, it is difficult to explain the flocculation mechanism and find key genes that affect yeast flocculation during beer brewing. By analyzing the genomic mutation of two natural mutant yeasts with stronger flocculation ability compared to the parental strain, it was found that the mutated genes common in both mutants were enriched in protein processing in endoplasmic reticulum, membrane lipid metabolism and other pathways or biological processes involved in stress responses. Further functional verification of genes revealed that regulation of RIM101 and VPS36 played a role in lager yeast flocculation under the brewing condition. This work provided new clues for improving yeast flocculation in beer brewing.


Assuntos
Cerveja/microbiologia , Fermentação , Floculação , Saccharomyces/genética , Evolução Molecular , Genoma Fúngico , Microrganismos Geneticamente Modificados
9.
Yeast ; 38(6): 339-351, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33978982

RESUMO

Much like other living organisms, yeast cells have a limited life span, in terms of both the maximal length of time a cell can stay alive (chronological life span) and the maximal number of cell divisions it can undergo (replicative life span). Over the past years, intensive research revealed that the life span of yeast depends on both the genetic background of the cells and environmental factors. Specifically, the presence of stress factors, reactive oxygen species, and the availability of nutrients profoundly impact life span, and signaling cascades involved in the response to these factors, including the target of rapamycin (TOR) and cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathways, play a central role. Interestingly, yeast life span also has direct implications for its use in industrial processes. In beer brewing, for example, the inoculation of finished beer with live yeast cells, a process called "bottle conditioning" helps improve the product's shelf life by clearing undesirable carbonyl compounds such as furfural and 2-methylpropanal that cause staling. However, this effect depends on the reductive metabolism of living cells and is thus inherently limited by the cells' chronological life span. Here, we review the mechanisms underlying chronological life span in yeast. We also discuss how this insight connects to industrial observations and ultimately opens new routes towards superior industrial yeasts that can help improve a product's shelf life and thus contribute to a more sustainable industry.


Assuntos
Cerveja/análise , Cerveja/microbiologia , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/fisiologia , Divisão Celular , Regulação Fúngica da Expressão Gênica , Microbiologia Industrial , Proteínas de Saccharomyces cerevisiae/genética , Transdução de Sinais , Fatores de Tempo
10.
Food Microbiol ; 98: 103644, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33875226

RESUMO

The potential of yeasts isolated from traditional chichas as starter cultures, either for controlled production of the native beverage or for industrial beer production, has been investigated. Three S. cerevisiae strains and one T. delbrueckii strain isolated from four different Ecuadorian chichas were compared to ale and lager beer strains with respect to fermentation performance, sugar utilisation, phenolic off-flavour production, flocculation and growth at low temperature. Fermentations were performed in 15 °P all-malt wort and in a model chicha substrate at 12 °C and 20 °C. Tall-tube fermentations (1.5 L) were also performed with both substrates to assess yeast performance and beer quality. Among the strains tested, only one Ecuadorian S. cerevisiae strain was able to ferment the wort sugars maltose and maltotriose. Fermentations with all Ecuadorian strains were poor in wort at 12 °C relative to 20 °C, but were similar in model chicha substrate at both temperatures. The aromatic profile was different between species and strains. These results indicate the potential of yeasts derived from traditional Andean fermented beverages for commercial applications. One of the chicha strains demonstrated traits typical of domesticated brewery strains and could be suitable for ale fermentation, while the other strains may have potential for low-alcohol beer or chicha production.


Assuntos
Bebidas Alcoólicas/microbiologia , Saccharomyces cerevisiae/metabolismo , Trissacarídeos/metabolismo , Zea mays/microbiologia , Cerveja/microbiologia , Equador , Fermentação , Aromatizantes/química , Aromatizantes/metabolismo , Microbiologia de Alimentos , Maltose/metabolismo , Saccharomyces cerevisiae/classificação , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Leveduras/classificação , Leveduras/genética , Leveduras/metabolismo , Zea mays/metabolismo
11.
Int J Food Microbiol ; 347: 109173, 2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-33812163

RESUMO

Saccharomyces cerevisiae sub-species diastaticus (S. diastaticus) is the main fungal cause of spoilage of carbonated fermented beverages in the brewing industry. Here, prevalence of S. diastaticus in nature and breweries was assessed as well as the spoilage capacity of its vegetative cells and spores. S. diastaticus could only be enriched from 1 out of 136 bark and soil samples from the Netherlands, being the first described natural isolate of this yeast outside South America. On the other hand, it was identified by PCR and selective enrichment in 25 and 21 out of 54 biofilm samples from beer filling halls in Asia, Africa, Europe and North America. ITS sequencing revealed that S. cerevisiae (including S. diastaticus) represented <0.05% of fungal DNA in 17 out of 20 samples, while it represented 0.1, 2 and 32% in samples VH6, VH1 and VH3 respectively. Next, vegetative cells and ascospores of the natural S. diastaticus isolate MB523 were inoculated in a variety of beer products containing 0.0-5.0% alcohol (v/v). Ascospores spoiled all beer products, while vegetative cells did not grow in Radler lemon 0.0, Radler lime mint 0.0 and Radler lemon lime 0.0. Notably, vegetative cells could spoil these Radlers when they first had been grown in alcohol free beer either or not mixed with Radler lemon lime 0.0. Conversely, vegetative cells that had been grown in Radler lemon lime lost their spoilage potential of this beer product when they had grown in YPD medium for more than 24 h. In addition, it was shown that cells grown in alcohol free beer were more heat resistant than cells grown in YPD (D52 40 min and ≤ 10.3 min, respectively). Together, these data show that S. diastaticus is a less prevalent variant of S. cerevisiae in nature, while it accumulates in breweries in mixed biofilms. Data also show that both vegetative cells and spores can spoil all tested beer products, the latter cell type irrespective of its environmental history.


Assuntos
Cerveja/microbiologia , Microbiologia Ambiental , Saccharomyces cerevisiae/isolamento & purificação , Saccharomyces cerevisiae/metabolismo , Cerveja/análise , Biofilmes/crescimento & desenvolvimento , Meios de Cultura/química , DNA Fúngico/análise , Etanol/análise , Alimentos e Bebidas Fermentados/análise , Alimentos e Bebidas Fermentados/microbiologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Esporos Fúngicos/isolamento & purificação , Esporos Fúngicos/metabolismo
12.
Molecules ; 26(5)2021 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-33800512

RESUMO

The consumers' interest towards beer consumption has been on the rise during the past decade: new approaches and ingredients get tested, expanding the traditional recipe for brewing beer. As a consequence, the field of "beeromics" has also been constantly growing, as well as the demand for quick and exhaustive analytical methods. In this study, we propose a combination of nuclear magnetic resonance (NMR) spectroscopy and chemometrics to characterize beer. 1H-NMR spectra were collected and then analyzed using chemometric tools. An interval-based approach was applied to extract chemical features from the spectra to build a dataset of resolved relative concentrations. One aim of this work was to compare the results obtained using the full spectrum and the resolved approach: with a reasonable amount of time needed to obtain the resolved dataset, we show that the resolved information is comparable with the full spectrum information, but interpretability is greatly improved.


Assuntos
Cerveja/análise , Cerveja/microbiologia , Metabolômica/métodos , Espectroscopia de Ressonância Magnética/métodos
13.
World J Microbiol Biotechnol ; 37(5): 75, 2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33779846

RESUMO

In recent years, there had been growing demand for distinctive high quality beer. Fermentation management has a fundamental role in beer quality and the levels of aroma compounds. Use of non-conventional yeast has been proposed to enhance beer flavor. In this study, the bioflavor of traditional sorghum beer from Côte d'Ivoire was investigated. The flavor profile of two beers fermented with wild yeasts and with pure culture of Saccharomyces cerevisiae respectively were studied. The main flavor components of the beer fermented by pure culture of Saccharomyces cerevisiae were different from those of the beer fermented with wild yeasts. The total level of esters and higher alcohols were (173.51 and 128.85 mg/L) respectively in the beer fermented with wild yeasts. These levels were significantly higher than those in the beer fermented with pure culture of Saccharomyces cerevisiae which were 13.08 and 78.26 mg/L for higher alcohols and esters respectively. On the other hand, the beer fermented with pure culture of Saccharomyces cerevisiae had an acid content higher than beer fermented with wild yeasts, i.e. 9.3 mg/L and 7.53 mg/L respectively.


Assuntos
Cerveja/análise , Saccharomyces cerevisiae/metabolismo , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/metabolismo , Leveduras/metabolismo , Ácidos/análise , Ácidos/metabolismo , Álcoois/análise , Álcoois/metabolismo , Cerveja/microbiologia , Costa do Marfim , Ésteres/análise , Ésteres/metabolismo , Fermentação , Aromatizantes/análise , Aromatizantes/química , Aromatizantes/metabolismo , Sorghum/metabolismo , Sorghum/microbiologia , Paladar , Compostos Orgânicos Voláteis/química
14.
Molecules ; 26(3)2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33525580

RESUMO

During the production of beer, and especially beer wort, the main wastes are spent grain and hot trub, i.e., the so-called "hot break." Combined with yeast after fermentation, they represent the most valuable wastes. Hot trub is also one of the most valuable by-products. Studies on the chemical composition of these sediments and their rheological properties as waste products will contribute to their effective disposal and even further use as valuable pharmaceutical and cosmetic raw materials. So far, hot trub has been studied for morphology and particle distribution depending on the raw material composition and beer wort extract. However, there are no preliminary studies on the rheological properties of hot trub and hops. In particular, no attention has yet been paid to the dependence of these properties on the hop variety or different protein sources used. The aim of this study was to examine the effect of different hopping methods on hot trub viscosity and beer wort physicochemical parameters. Additionally, the hop solutions were measured at different temperatures. A microbiological analysis of hop sediments was also performed to determine the post-process survival of selected microorganisms in these wastes. For manufacturers of pumps used in the brewing industry, the most convenient material is that of the lowest viscosity. Low viscosity hot trub can be removed at lower velocities, which reduces costs and simplifies washing and transport. The sediments also had similar equilibrium viscosity values at high shear rates.


Assuntos
Cerveja/microbiologia , Fermentação/fisiologia , Humulus/metabolismo , Humulus/microbiologia , Grão Comestível/microbiologia , Viscosidade , Leveduras/fisiologia
15.
World J Microbiol Biotechnol ; 37(2): 24, 2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-33427964

RESUMO

In order to phenotypically characterized Saccharomyces cerevisiae strains isolated from sorghum beer and palm wines for a possible selection of a starter culture, 30 strains were tested for killer activity, temperature resistance, ethanol tolerance, carbohydrate fermentation, enzyme profile and sorghum wort fermentation. Of the tested strains, three showed a killer profile, while four showed a neutral profile and 23 were found to be sensitive to K2 toxin. Temperatures of 40 °C and 44 °C allowed to distinguish strains into four thermal groups with only three strains may grow at 44 °C. Almost tested strains were tolerant to 5% ethanol with viability rates up to 73%. But at 10% and 15% ethanol, respectively 18 and 7 strains were tolerant. Carbohydrate fermentation revealed 13 fermentation profiles, including one typical and 12 atypical profiles. The typical profile strains (16.13% of the strains) fermented glucose, galactose, fructose, sucrose, maltose, trehalose and raffinose. Most of the strains secreted lipases (mainly esterase and esterase-lipase), proteases (mainly valine and cysteine arylamidase, chrymotrypsin) and phosphatases (mainly acid phosphatase and naphthol phosphohydrolase). On contrary, only five strains isolated from sorghum beer exhibited glucosidase activity, mainly α-glucosidase. The analyse of fermented sorghum wort revealed that fermentative performance is strain dependent. Furthermore, the Hierarchical Cluster Analysis showed that the strains were separated in three distinct clusters with the strains from sorghum beer clustered separately.


Assuntos
Cerveja/microbiologia , Saccharomyces cerevisiae/isolamento & purificação , Saccharomyces cerevisiae/fisiologia , Sorghum/microbiologia , Vinho/microbiologia , Tolerância a Medicamentos , Etanol/farmacologia , Fermentação , Maltose , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/enzimologia , Temperatura
16.
Food Microbiol ; 95: 103678, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33397613

RESUMO

Beer production is predominantly carried out by Saccharomyces species, such as S. cerevisiae and S. pastorianus. However, the introduction of non-Saccharomyces yeasts in the brewing process is now seen as a promising strategy to improve and differentiate the organoleptic profile of beer. In this study, 17 non-Saccharomyces strains of 12 distinct species were isolated and submitted to a preliminary sensory evaluation to determine their potential for beer bioflavouring. Hanseniaspora guilliermondii IST315 and H. opuntiae IST408 aroma profiles presented the highest acceptability and were described as having 'fruity' and 'toffee' notes, respectively. Their presence in mixed-culture fermentations with S. cerevisiae US-05 did not influence attenuation and ethanol concentration of beer but had a significant impact in its volatile composition. Notably, while both strains reduced the total amount of ethyl esters, H. guilliermondii IST315 greatly increased the concentration of acetate esters, especially when sequentially inoculated, leading to an 8.2-fold increase in phenylethyl acetate ('rose', 'honey' aroma) in the final beverage. These findings highlight the importance of non-Saccharomyces yeasts in shaping the aroma profile of beer and suggest a role for Hanseniaspora spp. in improving it.


Assuntos
Cerveja/análise , Hanseniaspora/metabolismo , Saccharomyces cerevisiae/metabolismo , Cerveja/microbiologia , Técnicas de Cocultura , Etanol/metabolismo , Fermentação , Aromatizantes/análise , Aromatizantes/metabolismo , Humanos , Odorantes/análise , Paladar , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/metabolismo
17.
Int J Food Microbiol ; 339: 109030, 2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33387813

RESUMO

Currently, there is a strong interest in barrel ageing of finished, conventionally fermented beers, as a novel way to produce sour beers with a rich and complex flavour profile. The production process, however, remains largely a process of trial and error, often resulting in profit losses and inconsistency in quality. To improve product quality and consistency, a better understanding of the interactions between microorganisms, wood and maturing beer is needed. The aim of this study was to describe the temporal dynamics in microbial community composition, beer chemistry and sensory characteristics during barrel ageing of three conventionally fermented beers that differed in parameters like alcohol content and bitterness. Beers were matured for 38 weeks in new (two types of wood) and used (one type of wood) oak barrels. Beer samples were taken at the start of the maturation and after 2, 12 and 38 weeks. Microbial community composition, determined using amplicon sequencing of the V4 region of the bacterial 16S rRNA gene and the fungal ITS1 region, beer chemistry and sensory characteristics substantially changed throughout the maturation process. Likewise, total bacterial and fungal population densities generally increased during maturation. PerMANOVA revealed significant differences in the bacterial and fungal community composition of the three beers and across time points, but not between the different wood types. By contrast, significant differences in beer chemistry were found across the different beers, wood types and sampling points. Results also indicated that the outcome of the maturation process likely depends on the initial beer properties. Specifically, results suggested that beer bitterness may restrain the bacterial community composition, thereby having an impact on beer souring. While the bacterial community composition of moderately-hopped beers shifted to a dominance of lactic acid bacteria, the bacterial community of the high-bitterness beer remained fairly constant, with low population densities. Bacterial community composition of the moderate-bitterness beers also resembled those of traditional sours like lambic beers, hosting typical lambic brewing species like Pediococcus damnosus, Lactobacillus brevis and Acetobacter sp. Furthermore, results suggested that alcohol level may have affected the fungal community composition and extraction of wood compounds. More specifically, the concentration of wood compounds like cis-3-methyl-4-octanolide, trans-3-methyl-4-octanolide, eugenol and total polyphenols was higher in beers with a high alcohol content. Altogether, our results provide novel insights into the barrel ageing process of beer, and may pave the way for a new generation of sour beers.


Assuntos
Bactérias/classificação , Bactérias/genética , Cerveja/microbiologia , Microbiologia de Alimentos , Microbiota , Biodiversidade , Fermentação , Aromatizantes , Pediococcus , Polifenóis/análise , RNA Ribossômico 16S/genética , Paladar , Fatores de Tempo
18.
J Biosci Bioeng ; 131(1): 61-67, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33190800

RESUMO

The genetic diversity of bottom-fermenting yeast classified as Saccharomyces pastorianus is poor because strains are restricted to a few genetically distinct groups. Crossbreeding is an effective approach to construct novel yeast strains, but it is difficult because of inefficiency to obtain mating-competent cells (MCCs) of bottom-fermenting yeast. By using mating pheromone-supersensitive mutants, we previously isolated several mating-competent meiotic segregants from two bottom-fermenting yeast strains: high isoamyl acetate-producing KY1247, and low diacetyl-producing KY2645. Here, we constructed novel non-GM hybrids carrying preferable characteristics from both parents by crossbreeding these bottom-fermenting strains for the first time. Sixteen a/a-type meiotic segregants from KY2645 and 12 α/α-type meiotic segregants from KY1247 were mixed, and cells resembling zygotes were isolated via micromanipulation. In total, 149 hybrids were obtained and verified by examining known single-nucleotide polymorphisms (SNPs) between the parental strains. A sporulation test showed that some of the hybrids were able to sporulate. Moreover, fermentation tests on a test-tube and pilot-plant scale identified two hybrids with production levels of isoamyl acetate and diacetyl that were almost the same as KY1247 and KY2645, respectively. Both of these hybrids produced satisfactory beer in terms of taste, flavor, and overall quality, comparable to that produced by the parental strains. Collectively, our results suggest that crossbreeding between bottom-fermenting yeast strains has the potential to increase the diversity of yeast strains available for brewing, and our method of isolating MCCs provides a huge advance for crossbreeding of bottom-fermenting yeast without using DNA recombination techniques.


Assuntos
Fermentação , Hibridização Genética , Saccharomyces/genética , Saccharomyces/metabolismo , Cerveja/microbiologia
19.
J Sci Food Agric ; 101(7): 2828-2835, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33135178

RESUMO

BACKGROUND: Nowadays, the craft beer market is booming and the consumer trend for trying something new is increasing. Here, nine different treatments of a craft beer were realized in a pilot plant, studying fermentation and dry-hopping types. Quality parameters of the beer such as polyphenols, antioxidants, bitterness, colour and alcohol were analysed. In addition, an electronic nose was used to distinguish beer types. RESULTS: Results showed that dry hopping in maturation with warm temperature increased the bitterness from 33 to 40 IBUs. The treatment using two yeasts and two fermentation temperatures resulted in the highest antioxidant capacity of the beer (around 92%). Antioxidant activity was increased by late dry hopping using ale yeasts for fermenting. Principal component analysis performed with electronic nose data explained up to 97% of the total variability of the compounds in the study. CONCLUSIONS: Combined use of ale and lager yeasts seems to increase the antioxidant capacity and total polyphenol content of beer. Antioxidant activity is increased by late dry hopping. An electronic nose is a suitable device for discriminating the volatile profile complexity in beer. © 2020 Society of Chemical Industry.


Assuntos
Cerveja/análise , Microbiologia de Alimentos/métodos , Humulus/microbiologia , Antioxidantes/análise , Antioxidantes/metabolismo , Cerveja/microbiologia , Etanol/análise , Etanol/metabolismo , Fermentação , Humanos , Humulus/química , Humulus/classificação , Humulus/metabolismo , Valor Nutritivo , Polifenóis/análise , Polifenóis/metabolismo , Paladar , Leveduras/metabolismo
20.
Probiotics Antimicrob Proteins ; 13(1): 187-194, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32613533

RESUMO

Saccharomyces yeasts are able to ferment simple sugars to generate levels of ethanol that are toxic to other yeasts and bacteria. The tolerance to ethanol of different yeasts depends also on the incubation temperature. In this study, the ethanol stress responses of S. cerevisiae and the probiotic yeast S. boulardii CNCM I-745 were evaluated at two temperatures. The growth kinetics parameters were obtained by fitting the Baranyi and Roberts model to the experimental data. The four-parameter logistic Hill equation was used to describe the ethanol tolerance of the yeasts at the temperatures of 28 and 37 °C. Adequate determination coefficients were obtained (R2 > 0.91) in all cases. S. boulardii grown at 28 °C was selected as the yeast with the best ethanol tolerance (6-8%) for use in the elaboration of functional craft beers.


Assuntos
Cerveja/microbiologia , Etanol/metabolismo , Modelos Biológicos , Probióticos , Saccharomyces cerevisiae/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...