Identification and assessment of non-conventional yeasts in mixed fermentations for brewing bioflavored beer

• Published in: International journal of food microbiology Vol. 399; p. 110254
• Main Authors: Sampaolesi, Sofía, Pérez-Través, Laura, Pérez, Dolores, Roldán López, David, Briand, Laura E., Pérez-Torrado, Roberto, Querol, Amparo
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 16.08.2023
• Subjects: Aroma profile; Brewing; Fruity volatiles; Non-Saccharomyces yeasts; Novelty beers; Non-Saccharomyces yeasts; ISOL; 2-PEA; 2-PE; HEXAC; Brewing; Aroma profile; EP; ETOL; ISAC; Sc; EHEX; 1-POL; Mg; OCTAC; DECAC; Pk; EOCT; Novelty beers; EA; EDEC; Fruity volatiles; ISBOL
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2023.110254

The increasing demand for more flavored and complex beers encourages the investigation of novel and non-conventional yeasts with the ability to provide a combination of bioflavoring and low ethanol yields. The present study identified 22 yeasts isolated from different brewing sources, including the fermentation by-products known as yeast sludges, and characterized a selection of strains to find the more suitable for the aforementioned aims. HPLC and GC-FID analysis of its brewing products were performed. The most promising results were obtained with the non-conventional yeasts Pichia kudriavzevii MBELGA61 and Meyerozyma guilliermondii MUS122. The former, isolated from a Belgian wheat beer sludge, was capable of growing in wort (17.0°Bx., 20 °C) with very low ethanol yields (1.19 % v/v). Besides, upon mixed fermentations with Saccharomyces cerevisiae, was suitable to produce volatile compounds such as ethyl acetate, 2-phenyl ethanol and isoamyl alcohol, with characteristic fruity notes. M. guilliermondii MUS122, isolated from a golden ale beer sludge, partially attenuated the wort with low production of ethanol and biomass. In addition, provided some fruity and floral nuances to the aroma profile of mixed fermentations with brewer's yeast. The results suggest that these strains favor the development of more fruity-flowery aroma profiles in beers. Furthermore, they are suitable for use in mixed fermentations with Saccharomyces brewer's strains, although the ethanol level did not decrease significantly. •Identification of brewer's strains and the analysis of its aroma profile are reported.•Non-Saccharomyces strains produce the lowest ethanol levels in mono-fermentations.•P. kudriavzevii MBELGA61 yields fruity aromas and adequate amounts of ethyl acetate.•M. guilliermondii MUS122 brings fruity and floral volatiles to co-fermentations.•Co-fermentations of S. cerevisiae and non-conventional yeasts did not reduce ethanol.