Cereal matrix shapes acidification and volatile compound formation, but not culturable bacterial counts, in boza, a fermented cereal beverage

Fink, Katja (author), Uršnik, Ines (author), Janeš, Damjan (author), Kreft, Marko (author)

Boza is a fermented cereal beverage whose fermentation phenotype depends on cereal composition and starter microbiota. We evaluated a controlled laboratory model comprising three cereal bases and three inoculum sources. Maize flour, millet flour, and purified maize starch were each inoculated with sour cream, a defined mesophilic dairy starter, or a boza-derived inoculum and fermented for 48 h at 22 °C. We measured pH, titratable acidity, culturable aerobic bacterial counts, and 14 targeted volatile compounds. Flour formulations acidified markedly, with pH decreases of up to 3.5 units and final titratable acidity of up to 24.6 mmol NaOH/kg; starch formulations decreased by less than 1 pH unit and remained below 2 mmol NaOH/kg. Maize flour produced the largest pH decrease, whereas millet flour, particularly with sour-cream inoculum, reached the highest titratable acidity and showed the broadest increases in acetoin, two 2,3-butanediol isomers, 1-hexanol, and 1-octen-3-ol. Endpoint aerobic bacterial counts did not differ significantly among formulations despite marked differences in acidification. Thus, flour-based and starch-based formulations exhibited distinct fermentation phenotypes, with matrix-dependent inoculum effects. Across the tested formulations, cereal matrix was strongly associated with the measured phenotype, whereas endpoint culturable aerobic counts alone did not reflect acidification or volatile remodeling.

• Language: English
• Keywords: boza, lactic acid bacteria, acidification kinetics, volatile compounds
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: MF - Faculty of Medicine; BF - Biotechnical Faculty; FFA - Faculty of Pharmacy
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: 10 str.
• Numbering: Vol. 131, art. 104544
• PID: 20.500.12556/RUL-186316
• UDC: 664
• ISSN on article: 0733-5210
• DOI: 10.1016/j.jcs.2026.104544
• COBISS.SI-ID: 290053635
• Publication date in RUL: 07.09.2026

Record is a part of a journal

• Title: Journal of cereal science
• Shortened title: J. cereal sci.
• Publisher: Elsevier
• ISSN: 0733-5210
• COBISS.SI-ID: 6397447

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: boza, mlečnokislinske bakterije, kinetika zakisanja, hlapne spojine

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P3-0310
• Name: Celična fiziologija

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: I0-0034
• Name: Infrastrukturni program Večdimenzijska mikroskopija