Search results for "Lactobacillaceae"
showing 10 items of 30 documents
Molecular characterization of the phenolic acid metabolism in the lactic acid bacteria Lactobacillus plantarum
2001
The lactic acid bacteria Lactobacillus plantarumdisplays substrate-inducible decar- boxylase activities on p-coumaric, caffeic and ferulic acids. Purification of the p-coumaric acid decarboxylase (PDC) was performed. Sequence of the N-terminal part of the PDC led to the cloning of the corresponding pdc gene. Expression of this gene in Escherichia colirevealed that PDC displayed a weak activity on ferulic acid, detectable in vitro in the presence of ammonium sulfate. Transcrip- tional studies of this gene in L. plantarum demonstrated that the pdc transcription is phenolic acid- dependent. A mutant deficient in the PDC activity, designated LPD1, was constructed to study phe- nolic acid altern…
Biogenic amines in fermented foods
2010
Food-fermenting lactic acid bacteria (LAB) are generally considered to be non-toxic and non-pathogenic. Some species of LAB, however, can produce biogenic amines (BAs). BAs are organic, basic, nitrogenous compounds, mainly formed through decarboxylation of amino acids. BAs are present in a wide range of foods, including dairy products, and can occasionally accumulate in high concentrations. The consumption of food containing large amounts of these amines can have toxicological consequences. Although there is no specific legislation regarding BA content in many fermented products, it is generally assumed that they should not be allowed to accumulate. The ability of microorganisms to decarbox…
Intraspecific diversity of Lactobacillus curvatus, Lactobacillus plantarum, Lactobacillus sakei, and Leuconostoc mesenteroides associated with vacuum…
2006
The intraspecific diversity of Leuconostoc mesenteroides, Lactobacillus curvatus, Lactobacillus sakei, and Lactobacillus plantarum was analyzed by randomly amplified polymorphic DNA (RAPD) PCR with universal primers M13 and T3. The study included 100 reference strains and 210 isolates recovered from two vacuum-packed Spanish meat products, fiambre de magro adobado and morcilla, previously identified by rDNA-restriction fragment length polymorphism profiles. The RAPD-M13 profiles identified isolates at species level in L. plantarum and L. mesenteroides, while RAPD-T3 provided profiles in L. sakei. The combination of RAPD-M13 and RAPD-T3 fingerprints revealed a total of 17 profiles in L. mese…
Biogenic amines in wines from three Spanish regions.
2005
One hundred and sixty-three wines from La Rioja, Utiel-Requena, and Tarragona were analyzed to determine if there were any differences in the concentrations of six biogenic amines that are found in these three regions. The influence of grape variety, type of vinification, wine pH, malolactic fermentation, and storage in bottle on biogenic amine concentrations was studied. Results show important differences in putrescine and histamine concentrations among regions, varieties of grape, and type of wine; differences were less appreciable for the remaining biogenic amines studied. Low pH prevented biogenic amine formation. Malolactic fermentation and short storage periods in bottle (3-6 months) …
Screening of lactic acid bacteria for reducing power using a tetrazolium salt reduction method on milk agar.
2013
WOS:000315703100020 ; www.elsevier.com/locate/jbiosc; International audience; Reducing activity is a physiological property of lactic acid bacteria (LAB) of technological importance. We developed a solid medium with tetrazolium dyes enabling weakly and strongly reducing LAB to be discriminated. It was used to quantify populations in a mixed culture (spreading method) and screen strains (spot method).
Antibacterial effects of enniatins J1 and J3 on pathogenic and lactic acid bacteria
2011
Abstract Enniatins (ENs) are N -methylated cyclohexadepsipeptides, secondary metabolites produced by various species of the genus Fusarium . They are known to act as antifungal, antiyeast and antibacterial and to possess antiinsecticidal and phytotoxic properties. In this study we evaluated for the first time the antibiotic effect of pure fractions of EN J 1 and J 3 on several pathogenic strains and lactic acid bacteria. The ENs J 1 and J 3 were purified from the fermentation extract of Fusarium solani growth on solid medium of wheat kamut, using the technique of the low pressure liquid chromatography (LPLC) followed by a semipreparative liquid chromatography (LC). The purity and the struct…
Selenium bio-enrichment of Mediterranean fruit juices through lactic acid fermentation.
2021
Abstract This work was carried out to elaborate selenium (Se) bio-enriched fermented Mediterranean fruit juices. To this purpose, pomegranate and table red grape juices were added with sodium selenite (Na2SeO3) and fermented by Levilactobacillus brevis CRL 2051 and Fructobacillus tropaeoli CRL 2034 individually or combined. To better evaluate the effect of selenite addition and starter strain inoculums on the total bacterial community of the fruit juices, fermentation trials were performed with raw and pasteurized fruit juices. No statistical significant differences were observed for total mesophilic microorganisms (TMM) and rod-shaped lactic acid bacteria (LAB) levels among raw and pasteur…
Evolutionary history of the OmpR/IIIA family of signal transduction two component systems in Lactobacillaceae and Leuconostocaceae
2011
15 pages, 3 tables, 7 figures.
Evaluation of microbial diversity during the manufacture of Fior di Latte di Agerola, a traditional raw milk pasta-filata cheese of the Naples area
2006
Microbial diversity of the raw milk for the production of Fior di Latte di Agerola and its changes during cheesemaking were studied. Viable counts showed that at the end of curd ripening, loads of lactic acid bacteria, both mesophilic and thermophilic rods and cocci, higher than those commonly evidenced in similar cheeses produced by using natural or commercial starters, were detected. Identification of 272 isolates, supported by molecular diagnostic aids, evidenced representative cultures of a high number of bacterial taxa of interest as participating in the process, although most of the isolates belonged to Lactococcus lactis and Lactobacillus helveticus species. RAPD-PCR and REA-PFGE bio…
Impact of oxidoreduction potential and of gas bubbling on rheological properties of non-fat yoghurt
2010
International audience; The aim of this work was to study the effect of different gaseous conditions on the physico-chemical properties of yoghurt. Four conditions of oxidoreduction potential (Eh7), +433 mV (milk gassed with air), +405 mV (ungassed milk), +283 mV (milk gassed with N2) and −349 mV (milk gassed with N2–H2) were applied to milk. The rheological properties and microstructure of these yoghurts were determined by measuring apparent viscosity, whey separation (WS) and using confocal laser scanning microscopy. Exopolysaccharide (EPS) production by lactic acid bacteria (LAB) was also studied, and production was increased for extreme Eh7 values: the highest values were obtained for a…