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Could non-Saccharomyces yeasts contribute on innovative brewing fermentations?

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... Wine yeasts involved in wine fermentation have been extensively studied. Their use in beer fermentation is becoming more widespread, as they are considered to be of particular value in the search for yeasts that produce outstanding aromas [6][7][8]. ...
... S. pombe has been described as having a high fermentative capacity, the alcohol obtained in the present study being 5% (v/v) [72]. The other strains tested (i.e., H. vineae, H. valbyensis, H. guilliermondii, T. delbrueckii, W. anomalus, C. stellata and M. pulcherrima) showed an ethanol production of around 1% (v/v), which makes them good candidates for low ethanol or mixed-culture brewing [6,8,15,62,[73][74][75][76]. ...
... The use of non-Saccharomyces yeasts opens up new possibilities to improve and create innovations in the sensory profile of beers [6]. This would meet the expectations of the modern consumer, satisfying consumer demand for beers with improved and differentiated flavours, as well as for products without chemical additives. ...
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Non-Saccharomyces yeasts represent a very attractive alternative for the production of beers with superior sensory quality since they are able to enhance the flavour of beer. Furthermore, they can produce beers with low ethanol content due to the weak fermentative capacity of a large percentage of non-Saccharomyces species. The objective of this study was to evaluate the ability of 34 non-Saccharomyces yeast strains isolated from Madrilenian agriculture to produce a novel ale beer. The non-Saccharomyces yeast strains were screened at two scales in the laboratory. In the first screening, those with undesirable aromas were discarded and the selected strains were analysed. Thirty-three volatile compounds were analysed by GC, as well as melatonin production by HPLC, for the selected strains. Thirteen strains were then fermented at a higher scale in the laboratory for sensory evaluation. Only yeast strains of the species Schizosaccharomyces pombe and Lachancea thermotolerans were able to complete fermentation. Species such as Torulaspora delbrueckii, Metschnikowia pulcherrima, Wickerhamomyces anomalus, Hanseniaspora vineae, and Hanseniaspora guilliermondii could be used both for production of low ethanol beers and co-fermentation with a Saccharomyces yeast to improve the organoleptic characteristics of the beer. In addition, for these strains, the levels of melatonin obtained were higher than the concentrations found for Saccharomyces strains subjected to the same study conditions. The selected strains can be used in future trials to further determine their viability under different conditions and for different purposes.
... Despite lower fermentation efficiency and lower resistance to ethanol in the environment, they often exhibit other metabolic activities, which may be decisive to the exceptional character of the product. Mixed non-Saccharomyces cultures or monocultures can be mainly used to lend specific sensory features to products and produce low-calorie beers characterised by lower alcohol content or functional properties (Basso et al. 2016; Callejo et al. 2017). Brewers may modify the sensory properties of their products through the application of specific malts, hops or adjuncts. ...
... In this respect, there are other promising microorganisms such as Wickerhamomyces subpelliculosus and Cyberlindnera saturnus. They are used in the production of low alcohol wine with acceptable sensory characteristics (Basso et al. 2016; Canonico et al. 2017). The prevalence of obesity, and the resulting popularity of low-calorie products, has given rise to a new branch in the brewing sector -reduced calorie beers. ...
... Dekkera/Brettanomyces, capable of hydrolysing and fermenting polysaccharides such as dextrins, which represent up to 80% of the residual extract. As a result, high degree of fermentation is achieved with a significant content of alcohol and decreased caloric value (Yeo & Liu 2014;Basso et al. 2016). The objective of this paper was to evaluate the potential of selected non-Saccharomyces strains for beer production. ...
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The objective of this paper was to test the potential of selected non- Saccharomyces strains for beer production, by using Saccharomyces cerevisiae as a control sample. For some of variants brewing enzymes were added to wort to increase the content of fermentable sugars. The non- Saccharomyces yeasts differed in the fermentation process rate. The basic beer physiochemical parameters were assessed, including: alcohol content, extract, free amino nitrogen, sugars, acidity, colour, and the profile of volatile compounds and metal ions. The use of enzymes caused an increase in alcohol and fusel alcohols concentration in beers obtained. Total acidity, free amine nitrogen content, colour and sugar content indicated that the tested non- Saccharomyces yeast allowed obtaining beers with the proper analytical parameters.
... Sin duda, los compuestos de sabor y aroma deben mantenerse dentro de ciertos límites o pueden predominar y perjudicar el balance organoléptico de la cerveza 75,91 . Además de la amplia gama de productos metabólicos generados por las levaduras, éstas también tienen un rol activo en procesos de biotransformación, ya que son capaces de convertir precursores no volátiles e inodoros (en particular, del lúpulo) en compuestos de flavor, aumentando así el potencial organoléptico del mosto 6,89 . Las cepas de levaduras son tan diversas como los aromas y sabores resultantes; por lo tanto, la elección de aquella deberá apuntar a las características organolépticas deseadas en los estilos de cerveza producidos 98 . ...
... El crecimiento del segmento de cerveza artesanal y el creciente número de consumidores especializados han impulsado la búsqueda de estrategias para la diferenciación productiva, y el papel de las diferentes levaduras como protagonistas en la generación de productos innovadores y con características distintivas ha recibido especial atención 30 . Generalmente, las levaduras no convencionales presentan bajos rendimientos de fermentación y son más sensibles al estrés por etanol, pero abren un abanico de posibilidades al proporcionar aromas y sabores distintivos, así como nuevos enfoques y características que impactan en el perfil organoléptico de la cerveza 6,68 . En el sector de alimentos y bebidas, la producción o el aumento de compuestos de flavor a través de sistemas biológicos se conoce como bioflavoring 94 ; en este contexto, diversas especies de levaduras no convencionales han sido indicadas como agentes factibles para acentuar, mejorar y diversificar las características sensoriales de la cerveza 6 . ...
... Generalmente, las levaduras no convencionales presentan bajos rendimientos de fermentación y son más sensibles al estrés por etanol, pero abren un abanico de posibilidades al proporcionar aromas y sabores distintivos, así como nuevos enfoques y características que impactan en el perfil organoléptico de la cerveza 6,68 . En el sector de alimentos y bebidas, la producción o el aumento de compuestos de flavor a través de sistemas biológicos se conoce como bioflavoring 94 ; en este contexto, diversas especies de levaduras no convencionales han sido indicadas como agentes factibles para acentuar, mejorar y diversificar las características sensoriales de la cerveza 6 . El término bioflavoring será utilizado a lo largo de este trabajo de revisión basado en esta capacidad de mejorar, aumentar o diversificar las propiedades organolépticas de flavor (aroma, sabor y sensación en boca). ...
Article
Resumen En la elaboración de cerveza las levaduras cumplen un rol fundamental. Además de ser responsables de llevar a cabo la fermentación, generando principalmente etanol y dióxido de carbono, también son capaces de metabolizar y producir numerosos compuestos orgánicos que tienen un impacto determinante en el aroma y el sabor final de la cerveza. Las especies Saccharomyces cerevisiae y Saccharomyces pastorianus son utilizadas tradicionalmente para la producción de cervezas ale y lager, respectivamente. No obstante, el continuo crecimiento en el mercado de la cerveza artesanal y el aumento del interés y las exigencias de los consumidores han orientado los esfuerzos hacia la producción de cervezas diferenciales e innovadoras. En este punto, las levaduras no convencionales han cobrado gran protagonismo como herramientas para el desarrollo de nuevos productos. En el presente trabajo se describe y desarrolla la potencial aplicación en el sector cervecero de diferentes especies de levaduras no convencionales pertenecientes a los géneros Brettanomyces, Torulaspora, Lachancea, Wickerhamomyces, Pichia y Mrakia, entre otras, así como también levaduras del género Saccharomyces distintas a las levaduras cerveceras tradicionales. Se detallan las condiciones de fermentación de este tipo de levaduras y su capacidad de asimilar y metabolizar diferentes componentes del mosto y de aportar características particulares al producto final. Este trabajo provee el estado del arte sobre levaduras no convencionales, lo que resulta de gran relevancia para evaluar su aplicación en la producción de cervezas artesanales con características sensoriales diferenciales, cervezas bajas en calorías, cervezas sin alcohol y cervezas funcionales.
... Over time, research concluded that S. cerevisiae was the most abundant and prevalent (the main one to lead the fermentation), as well as being the one that survived the entire fermentation process to the greatest extent. For this reason, most production has been focused on its use and disregarded the importance of other organisms, which were simply ignored (Basso et al. 2016). ...
... Thus, most of them have been considered as contaminants to be avoided . However, they are currently being studied in greater depth since they could represent an interesting route to produce beers with completely innovative profiles (Basso et al. 2016;Holt et al. 2018;Jolly et al. 2014). These different yeast genera present the handicap of their difficult coexistence and interaction with Saccharomyces, so that research and fine-tuning in this aspect is a key factor to obtain beers that are different from traditional beers and of higher quality from the sensory point of view (Varela, 2016). ...
... In addition to these aforementioned flavors, beers brewed with different species of this yeast genus may also have flavors such as: smoked, plastic, phenolic, cracker, citric, etc. . Not all these flavors are considered as positive and, in fact, when the population of Brettanomyces is too high, undesirable flavors and aromas may appear, such as the one described as "pungent smoky" (an unpleasant pungent and harsh smokiness) or fecal aromas (Basso et al. 2016). In this context, the understanding of the biochemistry, biology and genetics of this yeast is of vital importance, both to select the right strains and to design them so as to avoid the off-flavors that it may cause and thus obtaining beers with recognized value in today's market (Serra Colomer et al. 2019). ...
Article
Beer is a biotechnologically produced beverage that results from the anaerobic fermentation of the sugars contained in cereals such as barley or wheat. Such fermentation is mainly carried out by Saccharomyces cerevisiae yeasts, but other microorganisms — other yeast species or bacteria — may be involved in the process. Depending on such microbiota and the conditions used in the processes involved in beer production, products exhibiting different physicochemical and sensory characteristics are obtained. For this reason, the aim of this review is to examine the current published literature on the microorganisms which are present at the fermentation stage in beer production, some of them contaminants, and their effect of the sensory properties of beer.
... Up until a few years ago, the selection of starter yeasts, used in beer production, was exclusively carried out on strains belonging to the genus Saccharomyces; this is because these yeasts were predominant in spontaneous fermentations [2,12,13]. ...
... Michel et al. [11] and Basso et al. [12] emphasized the great potential of non-Saccharomyces yeasts to develop beers with different alcohol contents and a broad range of flavors. They highlighted the varying abilities of unconventional yeasts to metabolize desirable aroma-active substances, such as fruity esters, monoterpenes, higher alcohols, phenols, and acids. ...
... However, in recent years, the selection and use of non-Saccharomyces yeasts has been a biotechnological resource in brewing [62,63]. In fact, in some cases, the use of these yeasts allows, in addition to some technological advantages, also an improvement and diversification of the sensory profile of the beers [12,64]. For example, the characteristic lambic beer sensory profile is caused by spontaneous fermentations of non-Saccharomyces yeasts, including, in particular, Brettanomyces bruxellensis strains. ...
Article
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Nowadays, in the beer sector, there is a wide range of products, which differ for the technologies adopted, raw materials used, and microorganisms involved in the fermentation processes. The quality of beer is directly related to the fermentation activity of yeasts that, in addition to the production of alcohol, synthesize various compounds that contribute to the definition of the compositional and organoleptic characteristics. The microbrewing phenomenon (craft revolution) and the growing demand for innovative and specialty beers has stimulated researchers and brewers to select new yeast strains possessing particular technological and metabolic characteristics. Up until a few years ago, the selection of starter yeasts used in brewing was exclusively carried out on strains belonging to the genus Saccharomyces. However, some non-Saccharomyces yeasts have a specific enzymatic activity that can help to typify the taste and beer aroma. These yeasts, used as a single or mixed starter with Saccharomyces strains, represent a new biotechnological resource to produce beers with particular properties. This review describes the role of Saccharomyces and non-Saccharomyces yeasts in brewing, and some future biotechnological perspectives.
... The potential to generate pleasant flavors using the microbiological method has been shown to be effective in numerous studies. There is a particular focus on generating different fruity flavor characteristics due to a more diverse and higher ester concentration in beer [2][3][4][5][6][7][8]. ...
... The flavor threshold concentration of 2-phenylethyl acetate in beer is 3.8 mg/L, for isoamyl acetate this is 1.2 mg/L, ethyl hexanoate 0.21 mg/L, ethyl octanoate 0.9 mg/L, and ethyl decanoate 1.5 mg/L. In addition to these five esters, acetaldehyde is also known for its apple flavor, being recognized rather as green apple and grassy when exceeding a flavor threshold concentration of 10 mg/L [6][7][8][9]. Furthermore, the ketone (2E)-1-(2,6,6-trimethylcyclohexa-1,3-dien-1-yl)but-2-en-1-one ((E)-β-damascenone) can also induce an apple or cooked apple-like impression in beer [12][13][14][15][16]. ...
... As there was no significant difference between the six center point samples based on the one-sample t-test, only Run 3 was analyzed as the center point. This was the reason why Runs 7,8,10,19, and 20 were excluded for ANOVA in the context of the RSM. Table 6. ...
Article
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The diversification of beer flavor is becoming increasingly popular, especially in the field of non-alcoholic beers, where sales are growing steadily. While flavor substances of traditional beers can largely be traced back to defined secondary metabolites, the production of non-alcoholic beers with non-Saccharomyces yeasts generates novel fruity flavors, some of which cannot yet be assigned to specific flavor substances. In a recently published study, besides pear, cool mint sweets, and banana-like flavor, distinctive red berry and apple flavors were perceived in a non-alcoholic beer fermented with the yeast strain Cyberlindnera saturnus TUM 247, whose secondary metabolites were to be elucidated in this study. The trials were carried out using response surface methodology to examine the fermentation properties of the yeast strain and to optimize the beer with maximum fruitiness but minimal off-flavors and ethanol content. It turned out that a low pitching rate, a moderate fermentation temperature, and an original gravity of 10.5 °P gave the optimal parameters. Qualitative analysis of the secondary metabolites, in addition to standard analysis for traditional beers, was first performed using headspace-gas chromatography with olfactometry. (E)-β-damascenone emerged as the decisive substance for the red berry and apple flavor and so this substance was then quantitated. Although (E)-β-damascenone is a well-known secondary metabolite in beer and this substance is associated with apple or cooked apple-and berry-like flavors, it has not yet been reported as a main flavor component in non-alcoholic beers.
... Saccharomyces cerevisiae is the common yeast frequently reported in spontaneous fermentation of various raw materials due to which it got rigorously selected over generations in various cultures. Qualities like high ethanol production, tolerance capability and preference for fermentation over respiration under high sugar concentrations of domesticated S. cerevisiae strains, eventually led to extensive use of this yeast for controlled fermentation in breweries all over the world [2]. In addition to Saccharomyces, a wide diversity of yeasts belonging to other genera has also been recorded from many sources like fruits [3][4][5], indigenous fermented foods, and beverages [6,7]. ...
... Recent explorations have brought some of them into the spotlight as they have proved to be quite promising in bringing unique and desirable attributes to various alcoholic products even though they were earlier regarded as 'spoilage yeasts' [10]. Brettanomyces sp. and Torulaspora delbrueckii were reported to produce flavour precursors [11][12][13], and thus they are being used in some breweries to formulate alcoholic beverages with novel and complex aroma [2]. Moreover, the growing demands for specialised products like alcoholic beverages with healthpromoting factors, low calorific value, and low alcohol content, which are the common functional beer attributes, also bring an immense number of possibilities that such nonconventional yeasts can render in brewing. ...
Article
The recent realisation regarding the potentiality of the long-neglected non-Saccharomyces yeasts in improving the flavour profile and functionality of alcoholic beverages has pushed researchers to search for such potent strains in many sources. We studied the fungal diversity and the rice beer production capability of the fungal strains isolated from emao—a traditional rice beer starter culture of the Boro community. Fifty distinct colonies were picked from mixed-culture plates, of which ten representative morphotypes were selected for species identification, and simultaneous saccharification and beer fermentation (SSBF) assay. The representative isolates were identified as Hyphopichia burtonii (Hbur-FI38, Hbur-FI44, Hbur-FI47 & Hbur-FI68), Saccharomyces cerevisiae (Scer-FI51), Wickerhamomyces anomalus (Wano-FI52), Candida carpophila (Ccar-FI53), Mucor circinelloides (Mcir-FI60), and Saccharomycopsis malanga (Smal-FI77 and Smal-FI84). The non-Saccharomyces yeast strains Hbur-FI38, Hbur-FI44, Ccar-FI53, and Smal-FI77 showed SSBF capacity on rice substrate producing beer that contained 7–10% (v/v) ethanol. A scaled-up fermentation assay was performed to assess the strain-wise fermentation behaviour in large-scale production. The nutritional, functional, and sensory qualities of the SSBF strain fermented beer were compared to the beer produced by emao. All the strains produced beer with reduced alcohol and energy value while compared to the traditional starter emao. Beer produced by both the strains of H. burtonii stood out with higher ascorbic acid, phenol, and antioxidant property, and improved sensory profile in addition to reduced alcohol and energy value. Such SSBF strains are advantageous over the non-SSBF S. cerevisiae strains as the former can be used for direct beer production from rice substrates.
... These stress factors of temperature and ethanol tolerance generate greater costs of beverages with S. cerevisiae involved in their production. Although the sensorial profile of this yeast is well-known and popular (Basso et al., 2016), there is growing consumer demand for alcoholic beverages (especially beer, wine, and spirits) with new sensorial characteristics. To meet this demand, genetic engineering could be a valuable resource for genetically modifying yeasts with the aim of obtaining an attractive aroma and flavor for the final product as well as good ethanol production and tolerance during production. ...
... Hence, ongoing research is seeking to find new natural yeast strains (whether from Saccharomyces or another genus) that can serve as starter cultures in fermentation (Abe et al., 2019;Basso et al., 2016;Capece et al., 2018;Hu et al., 2018b;Varela, 2016). Yeast strains have been isolated from flowers, fruits, insects, soil, and artisanal beverages, among other sources, and grown on different substrates to evaluate their capability of production and the flavor and aroma of the beverage. ...
Article
Meeting the demand for novel alcoholic beverages implies seeking innocuous yeasts that generate ethanol abundantly and give good taste and fragrance to the final product. For the yeasts isolated to date, there are few reports on the kinetics and thermodynamics of ethanol production, despite the key role this compound plays in accelerating fermentation. The aim of the current contribution was to isolate yeast strains from sugarcane and soil, select the innocuous ones that best produce and tolerate ethanol while growing on malted barley as substrate, and then determine their kinetic/thermodynamic parameters by evaluating cell growth, ethanol production, and substrate consumption over time and at different temperatures (10-40 °C). Saccharomyces cerevisiae 8A and Pichia kudriavzevii 4A exhibited 9.55% v/v and 20% v/v tolerance to ethanol, respectively. P. kudriavzevii 4A was chosen for the kinetic/thermodynamic study, conducted under an oxygen-limited condition (as exists in fermentation). Yeast growth and substrate consumption were best predicted by the Gompertz model, and ethanol production by the Luedeking-Piret model. P. kudriavzevii 4A showed a great tolerance to ethanol and a high level of ethanol production at all temperatures tested. These properties are invaluable economically and technically in industrial fermentation for the elaboration of alcoholic beverages.
... For lager and ale beer styles, Saccharomyces is the traditional genus in the brewing industry focusing on its efficient ethanol production, the use of the fermentation pathway as the crucial metabolic step and a high tolerance to ethanol and adverse environmental factors (Aslankoohi et al., 2016). However, in recent years some non-Saccharomyces yeast species are being evaluated in beer fermentations (Basso et al., 2016;Holt et al., 2018). There is a global interest in innovating, creating new beer flavours and finding greater sensory complexity, mainly when a beer has traditionally been considered a product with reduced sensory diversity. ...
... Pichia anomala (BCMO15_2) and Zygoascus meyerae (T12_135F) showed the best results for non-Saccharomyces yeasts, despite their low fermentation capability and reduced cell growth ( Fig. 1A and B). In this sense, Sannino et al. (2019) reported a small tolerance to ethanol for Pichia anomala, and it has been suggested as a promising yeast for low-alcohol beer production (Basso et al., 2016). ...
Article
Recently, the increase in microbreweries and the consequent production of craft beers have reached exponential growth. The interest in non-conventional yeasts for innovation and a unique selling feature in beer fermentation is increasing. This work studied the autochthonous Saccharomyces and non-Saccharomyces yeasts, isolated from various food sources, with the ability to modify and improve the fermentative and aromatic profiles during alcoholic fermentation. The ability to ferment maltose and produce desirable aroma compounds were considered as the key characters for the screening selection. A synthetic beer wort was developed for this purpose, to simulate beer wort composition. A total of forty-seven yeast strains belonging to different genera were analysed according to their fermentation profile, volatile compounds production and sensory analysis. Three native strains of Saccharomyces cerevisiae, Zygoascus meyerae and Pichia anomala were selected to evaluate their aromatic profile in single and mixed fermentations. The strains produced 4-vinylguaiacol, β-phenylethyl alcohol, and isoamyl alcohol at levels significantly above the sensory threshold, making them interesting for wheat and blond craft beer styles. The native Hanseniaspora vineae was also included in a co-fermentation treatment, resulting in a promising yeast to produce fruity beers.
... Their widespread usage is primarily due to the (i) repression of respiration by glucose (Crabtree-positive) and preference for the fermentative pathway, (ii) efficient production of and tolerance to high amounts of ethanol, (iii) production of desirable aromas, and (iv) absence of toxin production (Steensels and Verstrepen, 2014). Notwithstanding, limiting microbial diversity during the fermentation was found to reduce the sensorial complexity of beer and eliminate subtle aromatic notes (Basso et al., 2016;Gibson et al., 2017;Steensels and Verstrepen, 2014), which justifies brewers' increasing interest in using non-Saccharomyces species for bioflavouring. ...
... In the past, non-Saccharomyces yeasts were considered irrelevant or strictly regarded as spoilage agents (Padilla et al., 2016). Numerous studies now suggest that hitherto poorly explored species may positively contribute to the beer's aroma by producing a wide range of aroma-active compounds, such as higher (or fusel) alcohols, volatile esters, carboxylic acids, sulphur compounds, and volatile phenols (Basso et al., 2016;Canonico et al., 2019;Holt et al., 2018;van Rijswijck et al., 2017). As such, mixed starters, combining the fermentative power of Saccharomyces species and the distinct aroma production of non--Saccharomyces yeasts, represent a promising strategy to obtain a completely fermented beverage with improved organoleptic profile that meets the demands of a growing number of consumers. ...
Article
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.
... Saccharomyces cerevisiae dominates both spontaneous and controlled fermentations and has traditionally been the species of choice for the production of alcoholic beverages [3]. However, non-conventional yeasts (NCY) have gained interest in recent years [4][5][6]. The use of NCY has opened the door for innovation within the brewing application. ...
... These organisms, which were traditionally considered as spoilage, can produce beverages with improved characteristics such as aroma profile [7,8], texture [9], and recently marketable low-alcohol content [9][10][11][12]. The use of NCY in brewing has grown significatively [5]partially, thanks to the expansion of the craft brewing industry, which appears to be more open to innovation than large-scale industrial brewing. Craft brewers are continuously looking for new ingredients, processes and yeast strains for manufacturing distinctive products [13,14]. ...
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Abstract Both Saccharomyces and non‐Saccharomyces yeast strains are of great importance for the fermentation industry, especially with the flourishing of craft breweries, which are driving current innovations. Non‐conventional yeasts can produce novel beverages with attractive characteristics such as flavour, texture, and reduced alcohol content; however, they have been poorly explored. A new method for screening the fitness of conventional and non‐conventional yeast libraries utilising robotic platforms and solidified media representing industrial conditions is proposed. As proof of concept, a library formed of 6 conventional and 17 non‐conventional yeast strains was distributed in 96, 384 and 1536 arrays onto a YPD agar medium. Following this, the library was replicated in different conditions mimicking beer and cider fermentation conditions. The colony size was monitored over time, and fitness values measured in maximum pixels/h and maximum biomass were calculated. Significant differences in growth were observed in between the different strains and conditions. As examples, Candida milleri Y‐7245 displayed good performance in wort conditions, and Kazachstania yakushimaensis Y‐48837 stood out for its performance in apple juice. The method is proposed to be used as a pre‐screening step when studying vast yeast libraries. This would enable interested parties to discover potential hits for further study at a low initial cost. Furthermore, this method can be used in other applications where the desired screening media can be solidified.
... Likewise, over the last few years, the craft beer industry has been growing and with it the interest on the part of consumers for new beers with different properties [6]. This demand has led to pure culture and sequential fermentations with non-conventional yeasts to obtain beers with a low ethanol content, as well as functional and good organoleptic properties [7]. In this context, studies on wine are more abundant than on beer. ...
... The main ketones analysed were diacetyl and acetoin. The species T. delbrueckii stands out as it is characterised by a high production of diacetyl which may not be reduced during bottle conditioning [7]. This fact could be observed in our study, as all beers were analysed after at least one month of maturation and the diacetyl threshold values were only exceeded in beers brewed with T. delbrueckii strains CLI 902 and 7A-3A. ...
Article
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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.
... In regard to fermentation, the exploitation of different microbial resources has assumed relevance in recent years due to the diversity of final products that could be obtained. This is confirmed by the recent expansion of starter cultures, which, nowadays, comprise of not only Saccharomyces strains but also non-Saccharomyces and lactic acid bacteria [145,146], as is the case with commercial starter cultures for oenological production [147][148][149]. In this regard, a sector of craft beer could be a model sector of regionalisation by means of 'cross-over' microbial innovations [150]. ...
Article
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Selected biological resources used as raw materials in beer production are important drivers of innovation and segmentation in the dynamic market of craft beers. Among these resources, local/regional ingredients have several benefits, such as strengthening the connection with territories, enhancing the added value of the final products, and reducing supply costs and environmental impacts. It is assumed that specific ingredients provide differences in flavours, aromas, and, more generally, sensory attributes of the final products. In particular, of interest are ingredients with features attributable and/or linked to a specific geographical origin. This review encompasses the potential contribution and exploitation of biodiversity in the main classes of beer inputs, such as cereals, hops, microbes, and adjuncts, with a specific emphasis on autochthonous biological resources, detailing the innovative paths already explored and documented in the scientific literature. This dissertation proposes an overview of the impact on beer quality for each raw material category, highlighting the benefits and limitations that influence its concrete applications and scale-up, from the field to the stain. The topics explored promote, in the sector of craft beers, trends already capitalised in the production of other alcoholic beverages, such as the preservation and revalorisation of minor and autochthonous varieties, the exploitation of yeast and bacteria strains isolated from specific sites/plant varieties, and the valorisation of the effects of peculiar terroirs on the quality of agricultural products. Finally, the examined tendencies contribute toward reducing the environmental impacts of craft beer manufacturing, and are in line with sustainable development of food systems, increasing the economic driver of biodiversity preservation.
... In the case of the Belgium lambic beer the participation of non-Saccharomyces (in particular Brettanomyces genus) is key in the maturation phase for the development of some typical notes of this type of beer (Bossaert et al., 2021;De Roos et al. 2020). Other interesting applications are the generation of low-calorie beers, low alcohol beers and even non-alcoholic beers (Basso et al., 2016;Bellut et al., 2018;Capece et al., 2021;Holt et al., 2018;Michel et al., 2016). Most of the published works also use co-inoculation with S. cerevisiae (for an example, see Holt et al., 2018). ...
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There is a recent and growing interest in the study and application of non-Saccharomyces yeasts, mainly in fermented foods. Numerous publications and patents show the importance of these yeasts. However, a fundamental issue in studying and applying them is to ensure an appropriate preservation scheme that allows to the non-Saccharomyces yeasts conserve their characteristics and fermentative capabilities by long periods of time. The main objective of this review is to present and analyze the techniques available to preserve these yeasts (by conventional and non-conventional methods), in small or large quantities for laboratory or industrial applications, respectively. Wine fermentation is one of the few industrial applications of non-Saccharomyces yeasts, but the preservation stage has been a major obstacle to achieve a wider application of these yeasts. This review considers the preservation techniques, and clearly defines parameters such as culturability, viability, vitality and robustness. Several conservation strategies published in research articles as well as patents are analyzed, and the advantages and disadvantages of each technique used are discussed. Another important issue during conservation processes is the stress to which yeasts are subjected at the time of preservation (mainly oxidative stress). There is little published information on the subject for non-Saccharomyces yeast, but it is a fundamental point to consider when designing a preservation strategy.
... Some research has been conducted to characterize the sensory profiles produced by Brettanomyces fermentations; however, B. bruxellensis has been more thoroughly researched than B. claussenii. The flavors commonly associated with Brettanomyces are "rubber", "burnt plastic", "medicinal", "leather", and "barnyard" [34]. These terms neatly match the participants' perceptions of the sample fermented by B. bruxellensis. ...
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Acid whey is a by-product generated in large quantities during dairy processing, and is characterized by its low pH and high chemical oxygen demand. Due to a lack of reliable disposal pathways, acid whey currently presents a major sustainability challenge to the dairy industry. The study presented in this paper proposes a solution to this issue by transforming yogurt acid whey (YAW) into potentially palatable and marketable beverages through yeast fermentation. In this study, five prototypes were developed and fermented by Kluyveromyces marxianus, Brettanomyces bruxellensis, Brettanomyces claussenii, Saccharomyces cerevisiae (strain: Hornindal kveik), and IOC Be Fruits (IOCBF) S. cerevisiae, respectively. Their fermentation profiles were characterized by changes in density, pH, cell count, and concentrations of ethanol and organic acids. The prototypes were also evaluated on 26 sensory attributes, which were generated through a training session with 14 participants. While S. cerevisiae (IOCBF) underwent the fastest fermentation (8 days) and B. claussenii the slowest (21 days), K. marxianus and S. cerevisiae (Hornindal kveik) showed similar fermentation rates, finishing on day 20. The change in pH of the fermentate was similar for all five strains (from around 4.45 to between 4.25 and 4.31). Cell counts remained stable throughout the fermentation for all five strains (at around 6 log colony-forming units (CFU)/mL) except in the case of S. cerevisiae (Hornindal kveik), which ultimately decreased by 1.63 log CFU/mL. B. bruxellensis was the only strain unable to utilize all of the sugars in the substrate, with residual galactose remaining after fermentation. While both S. cerevisiae (IOCBF)- and B. claussenii-fermented samples were characterized by a fruity apple aroma, the former also had an aroma characteristic of lactic acid, dairy products, bakeries and yeast. A chemical odor characteristic of petroleum, gasoline or solvents, was perceived in samples fermented by B. bruxellensis and K. marxianus. An aroma of poorly aged or rancid cheese or milk also resulted from B. bruxellensis fermentation. In terms of appearance and mouthfeel, the S. cerevisiae (IOCBF)-fermented sample was rated the cloudiest, with the heaviest body. This study provides a toolkit for product development in a potential dairy-based category of fermented alcoholic beverages, which can increase revenue for the dairy industry by upcycling the common waste product YAW.
... Species such as Torulaspora delbrueckii, Wickerhamomyces anomalus, Hanseniaspora guilliermondii, Schizosaccharomyces pombe, Metschnikowia pulcherrima, Brettanomyces spp., Lachancea spp., have been widely described and used in beer fermentation, not only for the organoleptic characteristics that many of them provide, but also for their potential for the production of low ethanol beers due to their inability to ferment maltose and maltotriose [7][8][9][10][11]. ...
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The use of wild yeasts, isolated from different environments, is becoming the most interesting option for the production of new beers. The objective of this study is to evaluate the potential of seven non-conventional yeast strains from five different species (Saccharomyces cerevisiae, Hanseniaspora guilliermondii, Metschnikowia pulcherrima, Torulaspora delbrueckii, and Zygosaccharomyces bailii) isolated from Madrid agriculture to produce type ale beer. Wild yeast strains were evaluated at laboratory and pilot plant scales under different fermentation conditions (pure, aerated, and sequential culture). Strain S. cerevisiae SafAle S-04 was used as a reference. Throughout the fermentation of beer, volatile compounds were determined by GC and residual sugars by HPLC, among other parameters. The yeast strains used for the fermentation in pure culture conditions were unable to ferment maltose and maltotriose (0.73–1.18 % v/v of ethanol). The results of the study under aerated conditions showed varying levels of higher alcohol and ester concentrations. It should be noted that the strain CLI 1057 (S. cerevisiae) fermented maltose in the presence of oxygen (Kluyver effect). This strain also showed a high production of 4-vinyl guaiacol, making it suitable for producing beers with a phenolic profile. Finally, three strains (H. guilliermondii, Z. bailii, and T. delbrueckii) were evaluated in sequential culture together with commercial strain and found to improve the organoleptic characteristics of the brewed beer. These approaches offer the opportunity to add new product characteristics to the beers.
... As microcervejarias ocupam essencialmente um mercado local e regional, por isso possuem grande destaque no desenvolvimento da soberania alimentar das diferentes regiões do país. Assim, o setor de cervejas especiais, premium ou artesanais, são de suma importância para o desenvolvimento da economia local e possuem um público de mercado e nichos mais específicos, que buscam primeiro, novas experiências sensoriais (BASSO et al., 2016). ...
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Por estar relacionado com as maiores Taxas de Mortalidade (TM) em todo mundo, o câncer representa um dos maiores problemas de saúde pública da atualidade. O presente estudo propõe-se a analisar a distribuição dos cânceres com as maiores TM feminina nas regiões brasileiras e o comportamento do câncer de maior impacto. Para tanto, foi realizada uma pesquisa documental no Atlas de Mortalidade Online do Instituto Nacional de Câncer (INCA), considerando os 5 tipos de cânceres com as maiores TM em mulheres no período de 2001-2015. Conhecendo-se o câncer de maior magnitude, foi analisada sua distribuição segundo as regiões de ocorrência e por faixa etária. Assim, os cânceres de mama, brônquios e pulmões, colo do útero, estômago e cólon demostraram as maiores TM no Brasil, sendo o câncer de mama o de maior magnitude. Em algumas regiões, surgiram situações distantes do padrão nacional, como a permanência do câncer de colo de útero na posição de segunda maior TM e o aparecimento dos cânceres de encéfalo e fígado e vias biliares intra-hepáticas entre os 5 de maior mortalidade. O câncer de mama, que possui a maior TM, aumenta seus índices medida que as faixas etárias aumentam. Conclui-se que os cânceres de mama, brônquios e pulmões, colo do útero, estômago e cólon descrevem o cenário de morbimortalidade brasileiro caracterizando um país em desenvolvimento.
... As microcervejarias ocupam essencialmente um mercado local e regional, por isso possuem grande destaque no desenvolvimento da soberania alimentar das diferentes regiões do país. Assim, o setor de cervejas especiais, premium ou artesanais, são de suma importância para o desenvolvimento da economia local e possuem um público de mercado e nichos mais específicos, que buscam primeiro, novas experiências sensoriais (BASSO et al., 2016). ...
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A taxa de mortalidade é um índice demográfico que expressa o número de mortes registradas de uma determinada região em um período de tempo. Pode ser considerada como um forte indicador social, uma vez que, quanto pior as condições de vida, maior será a taxa de mortalidade. O objetivo desta pesquisa é traçar o perfil dos óbitos infantis que ocorreram na última década (2006-2016), com enfoque no estado da Paraíba. Trata-se de uma pesquisa exploratória do tipo documental com abordagem qualitativa. Os dados foram obtidos durante setembro e outubro de 2018, através da plataforma eletrônica do Departamento de Informática do SUS (DATASUS). Apesar da redução importante da taxa de mortalidade infantil (TMI) no Brasil, um número expressivo de mortes infantis ainda faz parte da realidade social do País. Tais mortes, em sua maioria, ocorrem por causas evitáveis, principalmente no que diz respeito às ações dos serviços de saúde. Ao longo de 10 anos a Paraíba permaneceu relativamente estável no que diz respeito a redução da TMI, o que chama atenção para a efetividade das políticas públicas de promoção à saúde materno-infantil. Com relação ao perfil dos óbitos infantis da Paraíba, a prematuridade, via de parto vaginal, sexo masculino e baixo peso ao nascer caracterizam as maiores TMI. Esses fatores compilam para a iminente necessidade de revisão e aprimoramento das políticas públicas voltadas à qualidade da assistência à saúde materno-infantil na Paraíba.
... Increasing fruity and floral aroma has repeatedly been stated to be an objective of applying non-conventional yeasts in alcoholic fermentation [36,37]. In this study, floral and fruity notes are also considered desirable since they are associated with superior honey quality [15] and may enhance the honey aroma of the mead beverage. ...
Article
In recent years, ample research has focused on applying wild (especially non-Saccharomyces) yeasts in producing alcoholic beverages. Common characteristics of wild yeast strains include simultaneous high production of fruity and floral aroma compounds and low ethanol production. In this study, mead starter cultures were selected based on preliminary screening of wild yeast strains from a Brazilian culture collection (n = 63) for their ability to produce aroma-active compounds. The selected strains included one strain of Saccharomyces cerevisiae and three non-Saccharomyces strains (Pichia jadinii, Torulaspora delbrueckii, and Kluyveromyces lactis). These strains were used to ferment honey must prepared with Aroeira honey, adjusted to 24°Brix, which took 36 days to complete. Single culture fermentations and co-fermentations with S. cerevisiae and non-Saccharomyces strains were carried out. The quality of the produced beverages was evaluated by sugar consumption and production of alcohols and organic acids, analyzed with high-performance liquid chromatography. The volatile organic compound composition was analyzed with gas chromatography-mass spectrometry. Meads with various ethanol amounts (4.7–11.0% v/v) and residual sugar contents (70.81–160.25 g l−1) were produced. In addition, in both single-strain fermentation and co-fermentation with S. cerevisiae, meads produced with either Torulaspora delbrueckii or Kluyveromyces lactis had a roughly three-fold higher content of honey-aroma compound phenethyl acetate and a higher hedonic impression score than meads produced with only S. cerevisiae. These results demonstrated non-Saccharomyces yeasts’ ability to increase aroma complexity and improve the sensory quality of low-alcoholic meads.
... To find new beers with more complex sensory profiles that meet the new market trends, in recent years, various studies have focused on the use of non-Saccharomyces yeasts as starters, their objectives ranging from the production of low-alcohol beers to functional beers and the use of bioflavourings in pure, sequential or co-inoculated fermentation [3]. ...
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The non-Saccharomyces yeasts represent a great richness for the production of new and different types of beers. In this study, the role of eight yeast strains (Saccharomycodes ludwigii, Metchnikowia pulcherrima, Hanseniaspora uvarum, Hanseniaspora osmophila and Brettanomyces bruxellensis) isolated from Asturian cider and belonging to five unconventional species was evaluated. None of the strains could ferment the main wort sugars (maltose and maltotriose). Beers produced by S. ludwigii strains showed the highest ethanol content (21.6 g/L) and interestingly high levels of fusel alcohols, fatty esters and isoamyl acetate. Strains of B. bruxellensis were the only ones that produced ethyl phenols and they also generated the highest concentration of fatty acids and their ethyl esters. Sucrose was not utilised by Metschnikowia and Hanseniaspora strains, resulting in low ethanol formation (4.7 g/L), although these yeasts differed in terms of their synthesis of volatile compounds. Larger amounts of fatty acid esters were detected in beers fermented by H. osmophyla 10, while H. uvarum 62 produced more 2-phenylethyl acetate and ethyl acetate. M. pulcherrima 301 stands out for its low fermentative capacity and production of volatile compounds. These results show the interest of non-Saccharomyces strains in the production of beers with low alcohol content and their potential use in developing new beer styles in sequential or mixed inoculations with S. cerevisiae strains.
... Hence, a potential alternative to overcome this barrier is to carry out single-fermentation using nonconventional yeasts (NCY) specifically selected for such performance and harboring original fruity characters. The Brettanomyces genus (e.g., B. anomalus or B. bruxellensis) have been the most popular NCY involved in beer fermentation especially for the production of some lambic-style beers in which they bring smoky, barnyard, spicy and fruity flavours (Basso, Alcarde, & Portugal, 2016;Bokulich & Bamforth, 2013;Daenen, Sterckx, Delvaux, Verachtert, & Derdelinckx, 2008;Gibson et al., 2017;Serra Colomer, Funch, & Forster, 2019). More recently other yeast species such as Lachancea thermotolerans, Pichia kluyveri, Saccharomycodes ludwigii, Scheffersomyces shehatae, Torulaspora delbrueckii, Wickerhamomyces anomalus, Williopsis saturnus, Lachancea thermotolerans and Zygosshacaromycodes rouxii have been investigated in singlefermentation (Bellut & Arendt, 2019;Michel et al., 2016;Petruzzi et al., 2016;Steensels & Verstrepen, 2014;Varela, 2016). ...
Article
Fruity beers can be promoted through production of flavoring compounds during fermentation by partial replacement of brewing yeast by non-conventional-yeasts with high aroma production abilities. We evaluated here the use of a wild Saprochaete suaveolens strain, producing atypical aroma compounds, to produce new natural fruity beer, while keeping classical production conditions used in brewing industry. S. suaveolens was inoculated as starter of culture during beer fermentation and the fermentation performance was evaluated through measurement of several physicochemical parameters. The aroma profile of the engineered beers was monitored using HS-SPME GC/MS. The results showed that high fruity aroma and low-ethanol content beers were obtained through single-fermentation using S. suaveolens. We also demonstrated that during mixed-fermentation, S. suaveolens maintained high metabolic activity and allowed production of beer enriched with fruity aroma. Production of high or low ethanol content fruity beer could be achieved by varying the composition of the starter of culture.
... But, if brewing is not correctly managed, Dekkera/Brettanomyces strains could be responsible for off-flavors, such as "acrid smoke," "bandaid," and "fecal." Dekkera/Brettanomyces strains also show the ability to metabolize carbon sources not assimilated by Saccharomyces species, including cellobiose and dextrins, due to the β-glucosidase enzyme (Basso, Alcarde, & Barbosa Portugal, 2016). To expand the number of strains usable in craft beer production, the interests of several laboratories and breweries have been focused on wild yeasts for the characterization of their beer fermentation abilities and the selection of strains with desirable brewing characteristics. ...
Article
The purpose of the work was to provide an overview on craft beer. Details and issues concerning history and legal definition market, fiscal policy, innovation, safety, healthiness, consumer profile, and sustainability are supplied. The term “craft brewery” generally refers to a brewery able to produce low volumes of beer, often made with traditional ingredients—for emulating historic styles—but also with the addition of nontraditional ingredients as a distinctiveness sign of the master brewer. In many countries, the importance of the company size is related to the opportunity to take advantage of reduced excise rates for low production volumes. In several countries, another important requisite of a craft brewery is represented by its independence from other alcohol industry members. Even in the presence of a great heterogeneity of the size of craft breweries in the various countries, their number in the world is around 17,000. Craft beer is mainly consumed in restaurants and bars. Innovation of craft beer concerns aspects, such as ingredients, alcohol content, aging, and packaging, and the profile of the typical craft beer drinker is that of a young man, with a higher education and a medium‐high income. Craft beers are often not filtered/not pasteurized and, for these reasons, they are beverages rich in health compounds but with a reduced shelf life. As in the case of larger breweries, the environmental impact of craft breweries is mainly represented by water consumption and production of liquid and solid wastes.
... Stage 3 enzymatically decarboxylates pyruvate to acetaldehyde and CO2 that leaves the cell, before the alcohol Interest in brewing beer with novel yeast strains and applying Saccharomyces cerevisiae in new methods outside of traditional beer fermentation [33,34] has increased in recent years, due to the growing consumer tastes of sour and wild mixed-fermentation beers, as well as using some of these novel species for low or no alcohol beer production [35,36]. A great deal of research in the brewing industry was done on non-Saccharomyces yeast strains, such as Brettanomyces, Pichia, Hanseniaspora, Metschnikowia, and Torulaspora [37][38][39]. Furthermore, the search for unique flavors and aromas, and a desire to invoke new technologies and techniques for making alcoholic beverages led to the use of non-cerevisiae Saccharomyces spp. in the alcoholic fermentation process [40,41]. ...
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A great deal of research in the alcoholic beverage industry was done on non-Saccharomyces yeast strains in recent years. The increase in research interest could be attributed to the changing of consumer tastes and the search for new beer sensory experiences, as well as the rise in popularity of mixed-fermentation beers. The search for unique flavors and aromas, such as the higher alcohols and esters, polyfunctional thiols, lactones and furanones, and terpenoids that produce fruity and floral notes led to the use of non-cerevisiae Saccharomyces species in the fermentation process. Additionally, a desire to invoke new technologies and techniques for making alcoholic beverages also led to the use of new and novel yeast species. Among them, one of the most widely used non-cerevisiae strains is S. pastorianus, which was used in the production of lager beer for centuries. The goal of this review is to focus on some of the more distinct species, such as those species of Saccharomyces sensu stricto yeasts: S. kudriavzevii, S. paradoxus, S. mikatae, S. uvarum, and S. bayanus. In addition, this review discusses other Saccharomyces spp. that were used in alcoholic fermentation. Most importantly, the factors professional brewers might consider when selecting a strain of yeast for fermentation, are reviewed herein. The factors include the metabolism and fermentation potential of carbon sources, attenuation, flavor profile of fermented beverage, flocculation, optimal temperature range of fermentation, and commercial availability of each species. While there is a great deal of research regarding the use of some of these species on a laboratory scale wine fermentation, much work remains for their commercial use and efficacy for the production of beer.
... Increasingly, changing demands by beer drinkers in search of new sensory experiences are driving research into novel fermentations [1][2][3][4]. Much of this research has utilized non-Saccharomyces yeast strains [5][6][7][8][9][10][11][12], which can be attributed to the rise in popularity of mixed-fermentation beers [13][14][15]. This pursuit of distinctive aromas and flavors has similarly driven the increased use of non-cerevisiae Saccharomyces species in the alcoholic fermentation of all beverages [16][17][18][19][20][21][22]. ...
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Consumer demands for new sensory experiences have driven the research of unconven-tional yeasts in beer. While much research exists on the use of various common Saccharomyces cere-visiae strains as well as non-Saccharomyces yeasts, there exists a gap in knowledge regarding other non-cerevisiae Saccharomyces species in the fermentation of beer, in addition to S. pastorianus. Here, five distinct species of Saccharomyces from the UC Davis Phaff Yeast Culture Collection, as well as one interspecies hybrid from Fermentis, were chosen to ferment 40 L pilot-scale beers. S. kudriavzevii, S. mikatae, S. paradoxus, S. bayanus, and S. uvarum yeasts were used to ferment wort in duplicate pairs, with one fermenter in each pair receiving 10 g/L dry-hop during fermentation. Analytical measurements were made each day of fermentation and compared to controls of SafAle™ US-05 and SafLager™ W 34/70 for commercial brewing parameters of interest. Finished beers were also analyzed for aroma, taste, and mouthfeel to determine the flavor of each yeast as it pertains to brewing potential. All beers exhibited spicy characteristics, likely from the presence of phenols; dry-hopping increased fruit notes while also increasing perceived bitterness and astringency. All of the species in this study displayed great brewing potential, and might be an ideal addition to beer depending on a brewery's desire to experiment with flavor and willingness to bring a new yeast into their production environment.
... There are many genera of yeasts that can offer a diversified enzyme apparatus and bioconversion ability with different adaptations depending on the different substrates or conditions [67]. A total of 80% of the yeasts showed protease activity (Fig. 5c) ...
Article
Yeast isolates from flowers and fruits from a Brazilian forest were studied. The yeasts were identified at species and strain level by PCR–RFLP and PCR-RAPD, respectively. The 46 isolated yeasts were classified into 11 different species belonging to the genera Candida, Diutina, Hanseniaspora, Meyerozyma, Pichia, Rhodotorula, and Torulaspora. A total of 20 different strains were found. In order to ascertain the probiotic potential, the resistance to gastrointestinal conditions, autoaggregation, and hydrophobicity assays were studied, along with the capacity to form biofilm. The results indicate that, although most of the strains presented better results than Saccharomyces boulardii (the only strain recognized as a probiotic yeast), four strains were the most promising, namely, Rhodotorula mucilaginosa 32, Meyerozyma caribbica 35, and Diutina rugosa 12 and 45, according to the Duncan test. Several biotechnological properties were evaluated. D. rugosa inhibited Dekkera bruxellensis. The assimilation or fermentation of seven sugars was tested, and only five of the yeasts did not show a capacity to assimilate any of the sugars under aerobic conditions. However, all strains were able to ferment at least one of the sugars under anaerobic conditions. As far as enzyme production is concerned, positive results were only found for the enzymes’ amylase, pectinase, and protease. D. rugosa 42 and Hanseniaspora opuntiae 18, followed of Pichia kluyveri 26, showed high values for the production of melatonin. In conclusion, the results of this study show that several non-Saccharomyces present probiotic characteristics, and these have good potential for industrial applications in the food or biotechnology industries.
... It might be assumed that the fermentation was carried out in a spontaneous manner-i.e., by adding water to wort and allowing the fermentation process to take place by the wild air-borne yeasts or the constitutional microbiota of the used cereals. 70 We do not see, however, indications for other yeasts species, such as Brettanomyces bruxellensis, that co-occur in spontaneously fermented beers. 71 In addition, we see clear indications of domestication and continuous supply of new admixture components to this yeast, which might suggest that fermentation vessels were repeatedly used for this purpose or the inoculation of the fermentation batches has been done by back-slopping (i.e., inoculation of new fermentation batches with portions of previous batches). ...
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We subjected human paleofeces dating from the Bronze Age to the Baroque period (18th century AD) to in-depth microscopic, metagenomic, and proteomic analyses. The paleofeces were preserved in the underground salt mines of the UNESCO World Heritage site of Hallstatt in Austria. This allowed us to reconstruct the diet of the former population and gain insights into their ancient gut microbiome composition. Our dietary survey identified bran and glumes of different cereals as some of the most prevalent plant fragments. This highly fibrous, carbohydrate-rich diet was supplemented with proteins from broad beans and occasionally with fruits, nuts, or animal food products. Due to these traditional dietary habits, all ancient miners up to the Baroque period have gut microbiome structures akin to modern non-Westernized individuals whose diets are also mainly composed of unprocessed foods and fresh fruits and vegetables. This may indicate a shift in the gut community composition of modern Westernized populations due to quite recent dietary and lifestyle changes. When we extended our microbial survey to fungi present in the paleofeces, in one of the Iron Age samples, we observed a high abundance of Penicillium roqueforti and Saccharomyces cerevisiae DNA. Genome-wide analysis indicates that both fungi were involved in food fermentation and provides the first molecular evidence for blue cheese and beer consumption in Iron Age Europe.
... However, these yeasts in their wild state often lack adequate fermentation characteristics to be implemented directly in the industry. Generally, these yeasts have low fermentation yields and are more sensitive to ethanol stress, but they open a range of possibilities by providing distinctive aromas and flavours, as well as new approaches and characteristics that impact the organoleptic profile of beer [42,43]. ...
... The dominance of Dekkera in the yeast community is, however, a common trait of the mature fungal microbiomes of sour beer, indicating that a process of souring is occurring during the maturation [29,31]. Because of their capacity to produce esters and ferment the cellobiose of wood, their activity is particularly relevant during the maturation phase, contributing to the fruity flavors and to a more complex sensorial profile of the final product [30,32]. Pichia are highly tolerant to ethanol and can degrade xylose and cellulose, traits that underlie their abundance in the microbiome of wooden-aged beer [11,28]. ...
... T. delbrueckii was found once in the fruit beer in which it was used as co-starter together with S. cerevisiae. T. delbrueckii is well studied today in wine-controlled fermentation processes because of its good production of fruity flavours (Basso et al., 2016). W. anomalus was retrieved in Ale69, Ale72, Ale73, and Ale74 (Table 2). ...
Article
In the last several years, the popularity of homebrewed beers has skyrocketed. However, this type of product is extremely vulnerable to microbial deterioration. Twelve homemade beers, some characterized by defects or stuck fermentation, were analysed by using a polyphasic approach encompassing culturomics and culture-independent techniques to better understand mechanisms that drive microbiota evolution throughout production and to highlight determinants responsible for crowning with success. Two sour beers, one apple-flavoured ale, two Italian grape ales, and seven standard ales were sampled. Microbiological characterization was obtained by plating on nine different media coupled with High-throughput sequencing analysis of fungal and bacterial communities by targeting ITS1–2 and the V3–V4 regions of the 16S rRNA, respectively. Total microflora on PCA largely varied among samples, ranging from <10² CFU/mL up to around 10⁷ CFU/mL often reflecting yeast counts on WL and LM. LAB population's levels on MRS and SDBm did not overlap, with the counts on the latter being even 5 Log CFU/mL greater. Acetic Acid bacteria were retrieved in Sour beers, as well as in one IGA, even though acetic acid was not detectable by HPLC in this last sample. Brettanomyces spp. were only found in sour beers, as expected, whereas Enterobacteriaceae were never counted. A total of 63 yeasts were randomly isolated from countable plates. Saccharomyces cerevisiae and Wickerhamomyces anomalus were the most frequently isolated species. In many cases, Interdelta analysis biotyping of S. cerevisiae isolates consistently allowed the detection of the starter strain. By HST S. cerevisiae dominated the mycobiota in four samples, even if in one of them residual maltose and ethanol contents suggested a stuck fermentation. W. anomalus was found to be the dominant species in two beers. Fifty-five LAB cultures were isolated and identified. Pediococcus damnosus was the only species retrieved in sour beers and two Ales, while Levilactobacillus brevis was found in two Ale samples. HTS did not confirm this result in one Ale sample since the genus Panotea spp. accounted for over 90 % of the microbiota. Enterobacteriaceae which were never counted dominated the microbiome of two Ale beers. Biogenic amines content largely varied with three Ale samples greatly contaminated. Based on chemical and microbiological outcomes only one beer ASAle out of 12 could be considered acceptable. Furthermore, the widespread presence of LAB by culturomics and Enterobacteriaceae by HTS raises concerns about the final products' safety.
... Therefore, strain selection is a crucial step in the bakery industry. Unconventional yeasts (i.e., non-Saccharomyces) have received considerable attention in the wine and brewing industry compared to the bakery leavened industry [8,9]. Some authors [10,11], however, have suggested that some species can be successfully used as alternative cultures to address the new and more demanding challenges of the ...
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Background: Non-conventional yeasts (NCY) (i.e., non-Saccharomyces) may be used as alternative starters to promote biodiversity and quality of fermented foods and beverages (e.g., wine, beer, bakery products). Methods: A total of 32 wine-associated yeasts (Campania region, Italy) were genetically identified and screened for decarboxylase activity and leavening ability. The best selected strains were used to study the leavening kinetics in model doughs (MDs). A commercial strain of Saccharomyces cerevisiae was used as the control. The volatile organic profiles of the inoculated MDs were analyzed by solid phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS). Results: Most of strains belonged to the NCY species Hanseniaspora uvarum, Metschnikowia pulcherrima, Pichia kudriavzevii, Torulaspora delbruekii, and Zygotorulaspora florentina, while a few strains were S. cerevisiae. Most strains of H. uvarum lacked decarboxylase activity and showed a high leaving activity after 24 h of incubation that was comparable to the S. cerevisiae strains. The selected H. uvarum strains generated a different flavor profile of the doughs compared to the S. cerevisiae strains. In particular, NCY reduced the fraction of aldehydes that were potentially involved in oxidative phenomena. Conclusions: The use of NCY could be advantageous in the bakery industry, as they can provide greater diversity than S. cerevisiae-based products, and may be useful in reducing and avoiding yeast intolerance.
... Functional beers are products obtained by adding beneficial health value, intended either as functional ingredients or functional fermenting yeasts [9]. An absolute novelty is represented by probiotic beer among the functional beers, obtained by incorporating probiotic microorganisms. ...
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During the last few years, consumer demand has been increasingly oriented to fermented foods with functional properties. This work proposed to use selected non-conventional yeasts (NCY) Lachanceathermotolerans and Kazachstaniaunispora in pure and mixed fermentation to produce craft beer fortified with hydrolyzed red lentils (HRL). For this, fermentation trials using pils wort (PW) and pils wort added with HRL (PWL) were carried out. HRL in pils wort improved the fermentation kinetics both in mixed and pure fermentations without negatively affecting the main analytical characters. The addition of HRL determined a generalized increase in amino acids concentration in PW. L. thermotolerans and K. unispora affected the amino acid profile of beers (with and without adding HRL). The analysis of by-products and volatile compounds in PW trials revealed a significant increase of some higher alcohols with L. thermotolerans and ethyl butyrate with K. unispora. In PWL, the two NCY showed a different behavior: an increment of ethyl acetate (K. unispora) and β-phenyl ethanol (L. thermotolerans). Sensory analysis showed that the presence of HRL characterized all beers, increasing the perception of the fruity aroma in both pure and mixed fermentation.
... Meanwhile, the use of non-Saccharomyces yeasts has traditionally been linked to spontaneous fermentations. 7 The exclusive use of Saccharomyces spp. for decades is based on three fundamental characteristics such as their efficiency to produce ethanol, the use of fermentation as the main metabolic pathway, favored by the Crabtree effect, and finally, their tolerance to environmental stress caused by ethanol (cell-toxic compound) or other metabolites. ...
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... It was also reported that the diacetyl content in the sample beers was well below the detection threshold. Diacetyl is commonly found in unconventional yeast beers, and some cases may not be reduced to the derivatives of diacetyl, which are flavourless (such as 2,3-butanediol and acetoin) [111,118]. According to the sensory analysis results of the De Francesco, et al. [36] studies, the M. gelida-fermented sample was described as clear, yellow in colour, fine-headed, and persistently foamy. ...
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... For instance, several oenology studies focused on aroma profile contribution by Torulaspora delbrueckii [19][20][21] and Metschnikowia pulcherrima [22,23] yeast strains. T. delbrueckii has been successfully selected to increase fruity aroma compounds such as β-phenylethanol ('rose' flavor), 1-propanol, isobutanol, amyl alcohol ('solvent brandy' aroma) and ethyl acetate [24][25][26]. M. pulcherrima was found to alter the aromatic bouquet in wine by producing enhanced levels of ethyl propanoate, 2-methylpropyl acetate, 2-methylbutyl acetate, ethyl decanoate and 2-phenylethyl acetate [18,23,27]. The ability of both non-Saccharomyces yeasts to significantly change the perceived flavor in wines makes them an interesting target in the context of craft beer production. ...
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... Saccharomyces (CAPECE et al., 2018;OSBURN et al., 2016;BASSO et al., 2016), como Zygosaccharomyces bailii (BELLUT et al., 2018), Lachancea fermentati (BELLUT et al., 2020), Wickerhamomyces anomalus (CAPECE et al., 2018), Kloeckera apiculata (ESTELA-ESCALANTE et al., 2018) e Brettanomyces anomalus (MICHEL et al., 2016). Seu uso como iniciadores de fermentação ainda é raro, sendo usualmente utilizadas de modo conjunto com outras espécies de Saccharomyces, em processos de cofermentação ou fermentação sequencial (CHEN, 2011;HOLT et al., 2018). ...
... Saccharomyces (CAPECE et al., 2018;OSBURN et al., 2016;BASSO et al., 2016), como Zygosaccharomyces bailii (BELLUT et al., 2018), Lachancea fermentati (BELLUT et al., 2020), Wickerhamomyces anomalus (CAPECE et al., 2018), Kloeckera apiculata (ESTELA-ESCALANTE et al., 2018) e Brettanomyces anomalus (MICHEL et al., 2016). Seu uso como iniciadores de fermentação ainda é raro, sendo usualmente utilizadas de modo conjunto com outras espécies de Saccharomyces, em processos de cofermentação ou fermentação sequencial (CHEN, 2011;HOLT et al., 2018). ...
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The movement of craft beers has brought a profusion of raw materials, yeasts and processes that make this drink have a multitude of types, flavors and aromas, which awaken the creativity in its production and the pairing with different foods. In addition to the relaxed bar tables, it incorporates the exchange of information, recipes, products generated and fraternization, even at the time of its elaboration. If before the predominance of a certain type of beer limited its appreciation, after this movement, it becomes the most diversified drink, incorporating ingredients, culture and local patterns into the desired product. This chapter aims to provide a general overview of craft beer making. Some of the ingredients that can be used, and alternatives to traditional ones, as well as an explanation of homemade and artisanal processes, hopping methods, unconventional yeasts and beers will be cited. In the end, a small view of sensory analysis techniques and beer pairing. A good read and beer to all!!!
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Recently, the non-conventional, wild yeast Brettanomyces, with B. bruxellensis (teleomorph Dekkera bruxel-lensis) as the most commonly encountered species, has gained more and more attention in academic research as well as the food and beverage industry. Brettanomyces is a distant relative of the classic brewing yeast Saccharomyces cerevisiae and is especially known for its ambiguous role in food and beverage fermentations. Whilst still mainly considered a spoilage organism responsible for off-flavor production in wine, cider and dairy products, Brettanomyces yeasts can also add desirable flavors to fermented beverages such as lambic and gueuze beers, accounting for many of the typical organoleptic characteristics of the beer. Today, the unique aromatic properties of Brettanomyces and its opportunities for beer brewing are increasingly recognized, with more and more (artisan) brewers adding it deliberately to their fermentations. In this review, we give a comprehensive overview of the currently available information on Brettanomyces yeasts with relevance for the brewing sector, emphasizing B. bruxellensis. First, the history and taxonomy of Brettanomyces is discussed. Secondly, we discuss the dual role of the yeast in fermented beverages by contrasting its role in beer and wine: in certain beer styles it plays a crucial role, in wine it is considered one of the most important spoilage microbes. In this regard we also discuss some of its most important phenotypic characteristics for the food and beverage industry, including flavor and off-flavor production, and focus on its capability to thrive in industrial fermentations. Finally, we review the most important detection and identification methods and address some opportunities for the brewing industry exploiting Brettanomyces yeasts.
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Selected Saccharomyces yeast strains have been used for more than 150 years in brewing and for several decades in winemaking. They are necessary in brewing because of the boiling of the wort, which results in the death of all yeast cells, with the exception of some Belgian style beers (ex. Lambic), where the wort is left to be colonized by indigenous yeast and bacteria from the environment and ferment naturally. In winemaking their use is also pertinent because they provide regular and timely fermentations, inhibit the growth of indigenous spoilage microorganisms and contribute to the desired sensory characters. Even though the use of selected Saccharomyces strains provides better quality assurance in winemaking in comparison to the unknown microbial consortia in the must, it has been debated for a long time now whether the use of selected industrial Saccharomyces strains results in wines with less sensory complexity and “terroir” character. In previous decades, non-Saccharomyces yeasts were mainly considered as spoilage/problematic yeast, since they exhibited low fermentation ability and other negative traits. In the last decades experiments have shown that there are some non-Saccharomyces strains (Candida, Pichia, Kluyveromyces, Torulaspora, etc) which, even though they are not able to complete the fermentation they can still be used in sequential inoculation-fermentation with Saccharomyces to increase sensory complexity of the wines. Through fermentation in a laboratory scale, we have observed that the overall effects of selected Torulaspora delbrueckii yeast strains, is highly positive, leading to products with pronounced sensory complexity and floral/fruity aroma in winemaking and brewing.
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: Brettanomyces bruxellensis is a spoiling yeast responsible for developing off-odours in wine described as "Brett-character". The objective of this study was to evaluate the antimicrobial activity of four enological compounds against Brettanomyces: potassium metabisulphite (PMB), chitosan, enological tannins and dimethyl dicarbonate. Minimal inhibitory concentrations and minimal biocidal concentrations of the antimicrobial agents were determined and a comparative study between B. bruxellensis and Saccharomyces cerevisiae was performed under in vitro controlled conditions. All tested compounds showed inhibitory effect on the growth of Brettanomyces. Chitosan and the enological tannins showed selectivity against Brettanomyces, and PMB showed the highest efficacy in concentrations under the currently permitted limits for enological use, consequently PMB was further evaluated in red wines naturally contaminated by Brettanomyces. Volatile phenol concentrations were determined after long-term storage of the wines treated with PMB. A direct correlation was demonstrated between the concentrations of 4-ethylphenol, 4-ethylguaiacol, 4-propylguaiacol and Brettanomyces populations in the studied wines, and these parameters correlated inversely with the concentrations of PMB employed. This is the first time that 4-propylguaiacol is shown to correlate with Brettanomyces population in wine. It is of enological significance that a concentration of 100 mg/L of total PMB efficiently prevented Brettanomyces growth in the ageing red wines of our study, and that volatile phenol concentrations were significantly (p < 0.05) higher in those poorly protected wines. Keywords: Brettanomyces; potassium metabisulphite; volatile phenols; chitosan; enological tannins; dimethyldicarbonate.
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Yeasts are the main driving force behind several industrial food fermentation processes, including the production of beer, wine, sake, bread, and chocolate. Historically, these processes developed from uncontrolled, spontaneous fermentation reactions that rely on a complex mixture of microbes present in the environment. Because such spontaneous processes are generally inconsistent and inefficient and often lead to the formation of off-flavors, most of today's industrial production utilizes defined starter cultures, often consisting of a specific domesticated strain of Saccharomyces cerevisiae, S. bayanus, or S. pastorianus. Although this practice greatly improved process consistency, efficiency, and overall quality, it also limited the sensorial complexity of the end product. In this review, we discuss how Saccharomyces yeasts were domesticated to become the main workhorse of food fermentations, and we investigate the potential and selection of nonconventional yeasts that are often found in spontaneous fermentations, such as Brettanomyces, Hanseniaspora, and Pichia spp. Expected final online publication date for the Annual Review of Microbiology Volume 68 is September 08, 2014. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.
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The yeast Torulaspora delbrueckii is associated with several human activities including oenology, bakery, distillery, dairy industry, etc. In addition to its biotechnological applications, T. delbrueckii is frequently isolated in natural environments (plant, soil, insect). T. delbrueckii is thus a remarkable ubiquitous yeast species with both wild and anthropic habitats, and appears to be a perfect yeast model to search for evidence of human domestication. For that purpose, we developed eight microsatellite markers that were used for the genotyping of 110 strains from various substrates and geographical origins. Microsatellite analysis showed four genetic clusters: two groups contained most nature strains from Old World and Americas respectively, and two clusters were associated with winemaking and other bioprocesses. Analysis of molecular variance (AMOVA) confirmed that human activities significantly shaped the genetic variability of T. delbrueckii species. Natural isolates are differentiated on the basis of geographical localisation, as expected for wild population. The domestication of T. delbrueckii probably dates back to the Roman Empire for winemaking (∼1900 years ago), and to the Neolithic era for bioprocesses (∼4000 years ago). Microsatellite analysis also provided valuable data regarding the life-cycle of the species, suggesting a mostly diploid homothallic life. In addition to population genetics and ecological studies, the microsatellite tool will be particularly useful for further biotechnological development of T. delbrueckii strains for winemaking and other bioprocesses.
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SUMMARY Brewing beer involves microbial activity at every stage, from raw material production and malting to stability in the package. Most of these activities are desirable, as beer is the result of a traditional food fermentation, but others represent threats to the quality of the final product and must be controlled actively through careful management, the daily task of maltsters and brewers globally. This review collates current knowledge relevant to the biology of brewing yeast, fermentation management, and the microbial ecology of beer and brewing.