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Evaluation of non-Saccharomyces yeasts in the fermentation of wine, beer and cider for thedevelopment of new beveragesGutirrez, A.; Boekhout, T.; Gojkovic, Z.; Katz, M.
Published in:Journal of the Institute of Brewing
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Citation for published version (APA):Gutirrez, A., Boekhout, T., Gojkovic, Z., & Katz, M. (2018). Evaluation of non-Saccharomyces yeasts in thefermentation of wine, beer and cider for the development of new beverages. Journal of the Institute of Brewing,124(4), 389-402. https://doi.org/10.1002/jib.512
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Download date: 29 May 2019
Evaluation of non-Saccharomyces yeasts in thefermentation of wine, beer and cider for thedevelopment of new beveragesAlicia Gutirrez,1 Teun Boekhout,2,3 Zoran Gojkovic1 and Michael Katz1*
Non-Saccharomyces yeasts were evaluated for their fermentation properties and the production of pleasant fruity aromas inthree industrial media (beer, wine and cider). A total of 99 yeasts were screened for aroma production using a simple olfactoryplate assay. Of these, 21 yeasts were further evaluated for their aroma profile and fermentation capacity using wort, grapeand apple juice. The most promising yeasts were Galactomyces geotrichum (three strains), Kazachstania zonata, Kluyveromyceslactis, Lindnera meyerae, Pichia kluyveri, Starmera caribae, Yarrowia lipolytica and Saccharomycodes ludwigii. This study confirmsthe potential of non-conventional yeasts to produce pleasant aroma compounds under relevant fermentation conditions. Ingeneral, differences in the medium composition had less impact on the overall aroma profile than the choice of yeast. This studyis the first to simultaneously evaluate multiple non-conventional yeasts in three different industrial media. The results reportedhere are a good starting point for the development of novel fermented beverages. 2018 Carlsberg. Journal of the Institute ofBrewing published byJohn Wiley & Sons Ltd on behalf of The Institute of Brewing & Distilling
Keywords: aroma; Galactomyces; fermentation; non-conventional; ethyl butanoate
IntroductionSaccharomyces cerevisiae is the primarymicroorganism responsiblefor alcoholic fermentation. Through fermentation it transformssugar into ethanol and carbon dioxide together with the produc-tion of metabolites that contribute to the sensorial properties ofthe product (14). In the past, spontaneous fermentation waspractised and characterised by non-Saccharomyces yeasts duringthe early stages of the fermentation, while Saccharomyces speciesdominated the later stages of the fermentation owing to theincreased ethanol concentration (5,6). Today, the inoculation ofpure yeast cultures provides better control of the process, ensuresa rapid and complete fermentation and, as a result, improves thereproducibility of the final product and gives a consistent quality(5,7). However, this practice limits flavour complexity and doesnot produce the unique aromas and character generated fromdiverse strains and species. Accordingly, brewers are returning tospontaneous fermentation by local microflora in an attempt tointroduce more character and complexity in their products (8).
Non-conventional yeasts represent a large untapped reservoir,accounting for more than 1500 known species (9), with a hugepotential for industrial application. Recently, there has beenincreasing interest in the use of non-conventional yeasts in thebeverage sector owing to their unusual properties and contribu-tions of specific metabolites. For instance, they are exploited fortheir ability to produce lower ethanol yields (10,11) and to divertcarbon metabolism away from ethanol production (12,13). Theincrease in glycerol levels during fermentation, which contributesto the smoothness and complexity in wines, is also shown in sev-eral non-Saccharomyces strains (1416). Another well documentedattribute is the range of aromatic compounds produced by thesenon-conventional yeasts (1723). The metabolic products resultingfrom their growth include higher alcohols, esters, acids, aldehydes,
ketones, terpenoids and phenols. Such non-conventional yeastsare notable for the production of new aroma compounds, highconcentration and novel combinations of flavours that add aunique character (2224). Owing to these traits, non-conventionalyeasts may be applicable in new food products.Many variables are known to affect aroma synthesis, including
the yeast strain, the composition of the medium and the cultureconditions (25,26). Although the yeast strain is one of the most im-portant factors, the sugar and nitrogen content of the mediumalso impact on the final aroma profile (25,27). The total sugar con-centration and the relative content of different fermentable sugarsources have an influence on the ester production. For instance, inbrewing, fermentation of high-gravity worts can lead to an unbal-anced flavour profile because of the overproduction of acetateesters (25,28). Likewise, higher nitrogen concentrations in grapemust are positively correlated with a higher concentration of ace-tate and ethyl esters (29,30). Furthermore, the composition and
* Correspondence to: Michael Katz, Applied Yeast Group, Carlsberg ResearchCenter, Gamle Carlsberg Vej 4-6, 1799, Copenhagen V, Denmark. E-mail:firstname.lastname@example.org
1 Applied Yeast Group, Carlsberg Research Center, Gamle Carlsberg Vej 4-6,1799, Copenhagen V, Denmark
2 Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584CTUtrecht, TheNetherlands
3 Institute of Biodiversity and Ecosystem Dynamics (IBED), University ofAmsterdam, Amsterdam, The Netherlands
This is an open access article under the terms of the Creative Commons At-tribution-NonCommercial-NoDerivs License, which permits use and distri-bution in any medium, provided the original work is properly cited, theuse is non-commercial and no modifications or adaptations are made.
J. Inst. Brew. 2018; 124: 389402 2018 Carlsberg. Journal of the Institute of Brewing published byJohn Wiley & Sons Ltd on behalf of The Institute of Brewing & Distilling
Received: 24 January 2018 Revised: 4 June 2018 Accepted: 6 June 2018 Published online in Wiley Online Library: 14 September 2018
(wileyonlinelibrary.com) DOI 10.1002/jib.512
combination of nitrogen sources available in the medium shouldbe considered (3133).
Many studies with non-Saccharomyces yeast strains have beenperformed to determine the aroma profile after fermentation.Most use one medium, evaluate a few strains at the same timeand focus on co-fermentation approaches with selected combina-tions of yeasts from the wine industry (3436). Recent screeningprojects (23) have characterised the formation of volatile com-pounds by a large number of non-conventional yeast strains. How-ever, the traditional laboratory media used in these screenings arevery different in composition from wort and fruit juices used in theproduction of beers and wines and do not reflect the productionreality of different media compositions. To simulate real fermenta-tionmedia and to study the impact ofmedium variation, this studypresents for the first time a screening of non-conventional yeastswith the comparison of aroma production and fermentation prop-erties between three different industrial media used for produc-tion of wine, beer and cider. The aims of the present study were(a) to identify yeast strains with interesting fruity or pleasant aromafeatures, (b) to determine the effect of the industrial medium onthe aroma production and the fermentation performance by eachyeast and (c) to compare the physiological behaviours and rela-tionships between carbon/nitrogen assimilation of different yeaststrains during alcoholic fermentations in the three different fer-mentation processes.
Materials and methods
The strains used in this study are reported in Table 1. Thesenon-Saccharomyces strains were obtained from CBS(Centraalbureau voor Schimmelcultures, Utrecht, TheNetherlands), Department of Cell and Organism Biology (LundUniversity, Sweden) and Carlsberg Research Laboratory (CRL;Copenhagen, Denmark). The yeast strains, belonging to differentgenera and isolated from different origins, were selected to repre-sent yeast biodiversity. However, food origin was the primaryconsideration to ensure an appropriate biosafety level for con-sumption and food production (8). Three reference strains, LalvinEC1118 (L