Monocarboxylic acid production by lactococci and lactobacilli

Balasubramanian Ganesan, Kimberly Seefeldt, Ramarathna C. Koka, Benjamin Dias, Bart C Weimer

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Branched-chain fatty acids (BCFAs), such as isobutyric and isovaleric acid, contribute positively to cheese flavor at low concentrations and negatively at high concentrations. The source of these compounds in Cheddar cheese is controversial. The objective of this study was to determine the capability of lactococci and lactobacilli to produce BCFAs from amino and α-keto acids. In the assay conditions used in this study, α-keto acids spontaneously degraded to monocarboxylic acids (MCAs) without any organisms added. When lactococci and lactobacilli were assayed with individual α-keto acids, they produced MCAs above the level of spontaneous degradation and above the flavor thresholds associated with positive Cheddar cheese flavor. Similar results were observed using amino acids as the substrate. Assays with equimolar mixtures of amino acids led to lower concentrations of MCAs than from individual amino acids and the flavor thresholds associated with positive Cheddar cheese flavor. Catabolism of amino acids or α-keto acids yielded similar MCAs types, but different total concentrations of MCAs. This study demonstrated that lactococci and lactobacilli were capable of converting amino acids and α-keto acids to MCAs at concentrations associated with positive and negative effects on Cheddar cheese flavor.

Original languageEnglish (US)
Pages (from-to)237-246
Number of pages10
JournalInternational Dairy Journal
Issue number3
StatePublished - Mar 2004
Externally publishedYes


  • α-Keto acids
  • Aminotransferase
  • Branched-chain fatty acids

ASJC Scopus subject areas

  • Food Science


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