Abstract
Saccharomyces cerevisiae is routinely used yeast in food fermentations because it combines several key traits, including fermentation efficiency and production of desirable flavors. However, the dominance of S. cerevisiae in industrial fermentations limits the diversity in the aroma profiles of the end products. Hence, there is a growing interest in non-conventional yeast strains that can help generate the diversity and complexity desired in today’s diversified and consumer-driven markets. Here, we selected a set of non-conventional yeast strains to examine their potential for bread fermentation. Here, we tested ten non-conventional yeasts for bread fermentation, including two Saccharomyces species that are not currently used in bread making and 8 non-Saccharomyces strains. The results show that Torulaspora delbrueckii and Saccharomyces bayanus combine satisfactory dough fermentation with an interesting flavor profile. Sensory analysis and HS-SPME-GC-MS analysis confirmed that these strains produce aroma profiles that are very different from that produced by a commercial bakery strain. Moreover, bread produced with these yeasts was preferred by a majority of a trained sensory panel. These results demonstrate the potential of T. delbrueckii and S. bayanus as alternative yeasts for bread dough leavening, and provide a general experimental framework for the evaluation of more yeasts and bacteria.
Highlights
Yeasts have been used for centuries for the production of fermented foods and beverages such as bread, wine and beer [1,2,3]
To select suitable non-conventional yeast strains for bread making, we first tested whether the 10 shortlisted strains (Table 1) were safe to use according to literature and legislation: did not produce any biogenic amines (BAs) and had satisfactory fermentation characteristics
We tested the bread dough fermentation capacity of the six remaining strains by measuring CO2 production as a proxy for fermentation capacity using a Risograph. These tests demonstrated that S. bayanus (Y156), T. delbrueckii (Y273), B. anomalus (Y719) and P. anomala (Y494) ferment dough with a fermentation capacity similar to that of the commercial control strain (Fig 1C), whereas two other strains tested (Saccharomyces pastorianus (Y17) and Brettanomyces anomalus (Y719)) were unable to produce CO2 and leaven dough (Fig 1C)
Summary
Yeasts have been used for centuries for the production of fermented foods and beverages such as bread, wine and beer [1,2,3]. In the late 19th century, spontaneous fermentations were gradually replaced by controlled processes where pure cultures were used as starter cultures, which yielded increased fermentation speed, quality and consistency. The predominant yeast used for such controlled fermentations is Saccharomyces cerevisiae because this species combines several desirable characteristics, including efficient and complete fermentation of high-sugar media, production of desirable flavors, absence of toxin production, and high ethanol production and PLOS ONE | DOI:10.1371/journal.pone.0165126. The predominant yeast used for such controlled fermentations is Saccharomyces cerevisiae because this species combines several desirable characteristics, including efficient and complete fermentation of high-sugar media, production of desirable flavors, absence of toxin production, and high ethanol production and PLOS ONE | DOI:10.1371/journal.pone.0165126 October 24, 2016
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