Flavour formation by lactic acid bacteria and biochemical flavour profiling of cheese products

• Published in: FEMS microbiology reviews Vol. 29; no. 3; pp. 591 - 610
• Main Authors: Smit, Gerrit, Smit, Bart A., Engels, Wim J.M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier B.V 01.08.2005; Blackwell
• Subjects: alpha-k; Amino acid converting enzymes; Amino Acids - metabolism; Animals; Bacterial Proteins - biosynthesis; Bacteriology; Biological and medical sciences; chain fatty-acids; Cheese - analysis; Cheese - microbiology; complete genome sequence; cystathionine gamma-lyase; Dairy products; delbrueckii subsp bulgaricus; extract dilution analysis; Fermentative flavour formation; Flavoring Agents - metabolism; Food Microbiology; Fundamental and applied biological sciences. Psychology; Lactic acid bacteria; Lactobacillus; lactococcal aromatic aminotransferase; Lactococcus lactis; Lactococcus lactis - metabolism; Microbiology; Miscellaneous; oligopeptide transport-system; Propionibacterium; Streptococcus; swiss gruyere cheese; volatile sulfur-compounds; Fermentative flavour formation; Lactic acid bacteria; Dairy products; Amino acid converting enzymes; Lactococcus lactis; Propionibacterium; Peptides; Casein; Streptococcal infection; Bacteria; Lactobacillaceae; Micrococcales; Lactobacillus; Volatile compound; Enzyme; Methionine; Fermentation; Protein; Infection; Streptococcaceae; Streptococcus; Antiseptic; Bacteriosis; Propionibacteriaceae; Actinomycetes
• ISSN: 0168-6445; 1574-6976
• DOI: 10.1016/j.femsre.2005.04.002

Flavour development in dairy fermentations, most notably cheeses, results from a series of (bio)chemical processes in which the starter cultures provide the enzymes. Particularly the enzymatic degradation of proteins (caseins) leads to the formation of key-flavour components, which contribute to the sensory perception of dairy products. More specifically, caseins are degraded into peptides and amino acids and the latter are major precursors for volatile aroma compounds. In particular, the conversion of methionine, the aromatic and the branched-chain amino acids are crucial. A lot of research has focused on the degradation of caseins into peptides and free amino acids, and more recently, enzymes involved in the conversion of amino acids were identified. Most data are generated on Lactococcus lactis, which is the predominant organism in starter cultures used for cheese-making, but also Lactobacillus, Streptococcus, Propionibacterium and species used for surface ripening of cheeses are characterised in their flavour-forming capacity. In this paper, various enzymes and pathways involved in flavour formation will be highlighted and the impact of these findings for the development of industrial starter cultures will be discussed.