Sourdough cultures as reservoirs of maltose-negative yeasts for low-alcohol beer brewing

Linnea Johansson, Jarkko Nikulin, Riikka Juvonen, Kristoffer Krogerus, Frederico Magalhaes, Atte Mikkelson, Maija Nuppunen-Puputti, Elina Sohlberg, Giovanni de Francesco, Giuseppe Perretti, Brian Gibson (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

Abstract

De novo sourdough cultures were here assessed for their potential as sources of yeast strains for low-alcohol beer brewing. NGS analysis revealed an abundance of ascomycete yeasts, with some influence of grain type on fungal community composition. Ten different ascomycete yeast species were isolated from different sourdough types (including wheat, rye, and barley) and seven of these were screened for a number of brewing-relevant pheno-types. All seven were maltose-negative and produced less than 1% (v/v) alcohol from a 12 ◦Plato wort in initial fermentation trials. Strains were further screened for their bioflavouring potential (production of volatile aromas and phenolic notes, reduction of wort aldehydes), stress tolerance (temperature extremes, osmotic stress and ethanol tolerance) and flocculence. Based on these criteria, two species (Kazachstania servazzii and Pichia fer-mentans) were selected for 10 L-scale fermentation trials and sensory analysis of beers. The latter species was considered particularly suitable for production of low-alcohol wheat beers due to its production of the spice/ clove aroma 4-vinylguaiacol, while the former showed potential for lager-style beers due to its clean flavour profile and tolerance to low temperature conditions.
Original languageEnglish
Article number103629
JournalFood Microbiology
Volume94
DOIs
Publication statusPublished - Apr 2021
MoE publication typeA1 Journal article-refereed

Keywords

  • sourdough
  • low-alcohol beer
  • next-generation sequencing
  • flavour
  • Kazachstania servazzi
  • Pichia fermentans

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