Characterization of lactic acid bacteria strains on the basis of neutral volatile compounds produced in whey.
OBJECTIVE
Seventy-eight strains of lactic acid bacteria belonging to five genera and showing six different phenotype combinations of Lac (lactose fermentation), Prt (proteolytic activity) and Cit (citrate degradation) characters were investigated for their main flavouring properties with the aim to detect variability among and within the groups.


RESULTS
High resolution gas chromatography-mass spectrometry analysis of neutral volatile compounds produced in whey showed that, considering both neo-formation compounds and substances quantified in the whey cultures at different concentrations in comparison to the extract from sterile whey, the groups of lactococci, enterococci, thermophilic streptococci and mesophilic lactobacilli produced a higher number of volatiles than thermophilic lactobacilli and leuconostocs. Applying principal component analysis (PCA) to the results, enterococci, mesophilic lactobacilli and thermophilic streptococci showed a broad diversity, while lactococci included rather similar strains as well as strains with special flavouring properties. Applying PCA to thermophilic streptococci and enterococci, to lactococci and enterococci, to lactococci and thermophilic streptococci, or to mesophilic and thermophilic lactobacilli, the strains gathered consistently with their systematic position.


CONCLUSIONS
The study evidenced strains producing some volatile compounds responsible for food flavouring. Flavouring properties were variable among the systematic groups and in some cases different within the same bacterial group.


CONCLUSIONS
The potential of the findings is discussed with reference to the development of flavouring adjuncts for the dairy industry.
Mauriello
G
G
Dipartimento di Scienza degli Alimenti, Università degli Studi di Napoli Federico II, Naples, Italy.
Moio
L
L
Moschetti
G
G
Piombino
P
P
Addeo
F
F
Coppola
S
S
D016000:Cluster Analysis; D003470:Culture Media; D003611:Dairy Products / Q000382:microbiology*; D005421:Flavoring Agents / Q000378:metabolism*; D005516:Food Microbiology; D008401:Gas Chromatography-Mass Spectrometry; D019344:Lactic Acid / Q000378:metabolism*; D007778:Lactobacillus / Q000145:classification* / Q000378:metabolism; D013289:Streptococcaceae / Q000145:classification* / Q000378:metabolism; D014835:Volatilization
D003470:Culture Media; D005421:Flavoring Agents; D019344:Lactic Acid