Bacterial community dynamics, lactic acid bacteria species diversity and metabolite kinetics of traditional Romanian vegetable fermentations.
BACKGROUND
Artisanal vegetable fermentations are very popular in Eastern European countries. Fresh vegetables undergo a spontaneous fermentation in the presence of salt, which is mainly carried out by lactic acid bacteria (LAB).


RESULTS
Culture-dependent and culture-independent analyses of end-samples of various spontaneous vegetable fermentations carried out in houses of the Chiodju region (central Romania) revealed Lactobacillus plantarum and Lactobacillus brevis as the most frequently isolated LAB species. Leuconostoc mesenteroides and Leuconostoc citreum were also found. Furthermore, the community dynamics of spontaneous cauliflower and mixed-vegetable (green tomatoes, carrots and cauliflower) fermentations revealed three steps: an initial phase characterised by the presence of Enterobacteriaceae and a wide LAB species diversity, encompassing Weissella species; a second phase from day 3 onwards wherein L. citreum and Lb. brevis occurred; and a final phase characterised by the prevalence of Lb. brevis and Lb. plantarum. Metabolite target analysis revealed that glucose and fructose were mostly depleted at the end of fermentation. The main products of carbohydrate metabolism were lactic acid, acetic acid, ethanol and small amounts of mannitol, indicating heterolactate fermentation.


CONCLUSIONS
Given their prevalence at the end of vegetable fermentations, Lb. brevis and Lb. plantarum appear to be good candidate starter cultures for controlled vegetable fermentation processes.
Research Group of Industrial Microbiology and Food Biotechnology (IMDO), Department of Bioengineering Sciences, Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium.
Dorrit
D
Wouters
Silvia
S
Grosu-Tudor
Medana
M
Zamfir
Luc
L
De Vuyst
D019342:Acetic Acid / Q000378:metabolism; D044822:Biodiversity; D001937:Brassica / Q000378:metabolism / Q000382:microbiology*; D018552:Daucus carota / Q000378:metabolism / Q000382:microbiology*; D004032:Diet; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D005511:Food Handling / Q000379:methods*; D005632:Fructose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006601:Hexoses / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D019344:Lactic Acid / Q000378:metabolism; D007778:Lactobacillus / Q000145:classification; D007934:Leuconostoc; D018551:Solanum lycopersicum / Q000378:metabolism / Q000382:microbiology*; D008353:Mannitol / Q000378:metabolism; D012383:Romania; D012965:Sodium Chloride; D013045:Species Specificity
D006601:Hexoses; D005632:Fructose; D019344:Lactic Acid; D000431:Ethanol; D008353:Mannitol; D012965:Sodium Chloride; D005947:Glucose; D019342:Acetic Acid