The Experts below are selected from a list of 6246 Experts worldwide ranked by ideXlab platform
Nagendra P Shah - One of the best experts on this subject based on the ideXlab platform.
-
cell growth and proteolytic activity of Lactobacillus acidophilus Lactobacillus helveticus Lactobacillus delbrueckii ssp bulgaricus and streptococcus thermophilus in milk as affected by supplementation with peptide fractions
International Journal of Food Sciences and Nutrition, 2014Co-Authors: Akanksha Gandhi, Nagendra P ShahAbstract:AbstractThe present investigation examined the effects of supplementation of milk peptide fractions produced by enzymatic hydrolysis on the fermentation of reconstituted skim milk (RSM). Changes in pH, cell growth, proteolytic activity, and angiotensin-converting enzyme (ACE)-inhibitory activity were monitored during fermentation of RSM by pure cultures of Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus delbrueckii ssp. bulgaricus, and Streptococcus thermophilus. The study showed that supplementation with peptide fractions of different molecular weights did not significantly affect the bacterial growth in RSM. All bacteria showed an increased proteolytic activity in RSM supplemented with large peptides (>10 kDa), and L. helveticus in general exhibited the highest proteolytic activity among the bacteria studied. The ACE-inhibitory activity was observed to be the maximum in RSM supplemented with larger peptides (>10 kDa) for all bacteria. The results suggest that proteolysis by bacteria l...
-
influence of addition of proteolytic strains of Lactobacillus delbrueckii subsp bulgaricus to commercial abt starter cultures on texture of yoghurt exopolysaccharide production and survival of bacteria
International Dairy Journal, 2002Co-Authors: A Shihata, Nagendra P ShahAbstract:Abstract The effects of addition of proteolytic strains of Lactobacillus delbrueckii subsp. bulgaricus to commercial ABT starter cultures on the texture of yoghurt, exopolysaccharide production and survival of starter bacteria were studied. The firmness of set yoghurts was measured with a cone-penetrometer and the apparent viscosity with a Brookfield viscometer. Exopolysaccharides (EPS) was extracted by precipitation with ethanol. Supplementation of a proteolytic strain of L. delbrueckii subsp. bulgaricus 2501 or 2515 to ABT-1 or ABT-4 starter culture reduced the fermentation time in making yoghurt. Yoghurts made with ABT-1 and ABT-4 with added L. delbrueckii subsp. bulgaricus 2501 fermented in the shortest time of 5 h and 33 min and 5 h and 8 min, respectively. Quantities of EPS extracted from the different yoghurt batches did not show any significant differences (P
-
evaluation of media for selective enumeration of streptococcus thermophilus Lactobacillus delbrueckii ssp bulgaricus Lactobacillus acidophilus and bifidobacteria
Journal of Dairy Science, 1996Co-Authors: Rajiv I Dave, Nagendra P ShahAbstract:Abstract Fifteen media were evaluated to determine their suitability for selective enumeration of Streptococcus thermophilus, Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus acidophilus , and bifidobacteria using 5 to 6 strains of each of the four groups of organisms. Streptococcus thermophilus agar was found to be suitable for selective enumeration of S. thermophilus under aerobic incubation at 37°C for 24h. The MRS agar at pH 5.2 or reinforced clostridial agar at pH 5.3 could be used for the selective enumeration of L. delbrueckii ssp. bulgaricus when the incubation was carried out at 45°C for ≥72h. However, the recovery of this organism was lower on MRS agar at pH 5.2 or reinforced clostridial agar at pH 5.3 than that obtained on MRS agar. The recovery of L. acidophilus and bifidobacteria on MRS agar and MRS-maltose agar was similar; MRS-maltose agar could be used to enumerate total counts of L. acidophilus and bifidobacteria. For selective enumeration of L. acidophilus , MRS-salicin agar or MRS-sorbitol agar could be used. For selective enumeration of bifidobacteria, MRS NNLP (nalidixic acid, neomycin sulfate, lithium chloride, and paromomycin sulfate) agar was suitable; however, determination of bifidobacteria by differential counts between L. acidophilus enumerated on MRS-salicin agar or MRS-sorbitol agar and the total counts of L. acidophilus and bifidobacteria obtained from MRS-maltose agar resulted in higher recovery of some strains of bifidobacteria. Other media that were evaluated in this study were not suitable for selective enumeration.
-
evaluation of media for selective enumeration of streptococcus thermophilus Lactobacillus delbrueckii ssp bulgaricus Lactobacillus acidophilus and bifidobacteria
Journal of Dairy Science, 1996Co-Authors: Rajiv I Dave, Nagendra P ShahAbstract:Fifteen media were evaluated to determine their suitability for selective enumeration of Streptococcus thermophilus, Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus acidophilus, and bifidobacteria using 5 to 6 strains of each of the four groups of organisms. Streptococcus thermophilus agar was found to be suitable for selective enumeration of S. thermophilus under aerobic incubation at 37 degrees C for 24 h. The MRS agar at pH 5.2 or reinforced clostridial agar at pH 5.3 could be used for the selective enumeration of L. delbrueckii ssp. bulgaricus when the incubation was carried out at 45 degrees C for > or = 72 h. However, the recovery of this organism was lower on MRS agar at pH 5.2 or reinforced clostridial agar at pH 5.3 than that obtained on MRS agar. The recovery of L. acidophilus and bifidobacteria on MRS agar and MRS-maltose agar was similar; MRS-maltose agar could be used to enumerate total counts of L. acidophilus and bifidobacteria. For selective enumeration of L. acidophilus, MRS-salicin agar or MRS-sorbitol agar could be used. For selective enumeration of bifidobacteria, MRS NNLP (nalidixic acid, neomycin sulfate, lithium chloride, and paromomycin sulfate) agar was suitable; however, determination of bifidobacteria by differential counts between L. acidophilus enumerated on MRS-salicin agar or MRS-sorbitol agar and the total counts of L. acidophilus and bifidobacteria obtained from MRS-maltose agar resulted in higher recovery of some strains of bifidobacteria. Other media that were evaluated in this study were not suitable for selective enumeration.
Emmanuelle Maguin - One of the best experts on this subject based on the ideXlab platform.
-
Combining selected immunomodulatory Propionibacterium freudenreichii and Lactobacillus delbrueckii strains leads to anti-inflammatory functional food development.
2017Co-Authors: Coline Plé, Emmanuelle Maguin, Victoria Chuat, Maarten Van De Guchte, Benoit Foligne, Gwénaël Jan¨Abstract:IBD constitute a growing public health concern in western countries. Inflammation is a key parameter involved in many non-communicable chronic diseases. Bacteria with anti-inflammatory properties are lacking in dysbiosis accompanying IBD. Selected strains of probiotic bacteria with anti-inflammatory properties accordingly alleviate symptoms and enhance treatment of ulcerative colitis in clinical trials. Such properties are also found in selected strains of dairy starters, including Propionibacterium freudenreichii and Lactobacillus delbrueckii, which are widely ingested. We investigated the possibility to develop a fermented dairy product, combining both starter and probiotic abilities of both lactic acid and propionic acid bacteria, designed to extend remissions in IBD patients. Methods & Results We developed a two-strain P. freudenreichii and L. delbrueckii-fermented experimental pressed cheese using strains previously selected for their anti-inflammatory properties. This cheese was made in fully mastered conditions and contained only the two selected strains. It was consumed daily by mice during five days before induction of acute colitis by trinitrobenzenesulfonic acid (TNBS). Outcomes of colitis induction were then monitored in mice consuming this cheese or a placebo dairy matrix. For the first time, consumption of a designer P. freudenreichii and Lactobacillus delbrueckii pressed cheese was shown to protect mice against experimental colitis, alleviating severity of symptoms, modulating local and systemic inflammation, as well as colonic oxidative stress and epithelial cell damages. As a control, the corresponding sterile dairy matrix failed to afford such protection. Conclusion We eat more bacteria through daily consumption of fermented dairy products then through functional food supplements. This offers a tremendous level to modulate the digestive tract through the intake of desired bacteria. This work reveals the probiotic potential of a mixture of lactic and propionic selected starters. A “two-in-one” ability is revealed for bacteria able both to produce a fermented dairy product and to modulate inflammation. Such an innovation opens new avenues for the reverse engineering development of anti-inflammatory fermented foods designed for target populations with IBD, and has provided evidences leading to an ongoing pilot clinical study in ulcerative colitis patients. This work was financed by the French National Agency for Research.
-
Postgenomic analysis of streptococcus thermophilus cocultivated in milk with Lactobacillus delbrueckii subsp. bulgaricus: involvement of nitrogen, purine, and iron metabolism
Applied and Environmental Microbiology, 2009Co-Authors: Luciana Herve Jimenez, Emmanuelle Maguin, Isabelle Guillouard, Eric Guédon, Samira Boudebbouze, Pascal Hols, Veronique Monnet, Francoise RulAbstract:Streptococcus thermophilus is one of the most widely used lactic acid bacteria in the dairy industry, in particular in yoghurt manufacture, where it is associated with Lactobacillus delbrueckii subsp. bulgaricus. This bacterial association, known as a proto-cooperation, is poorly documented at the molecular and regulatory levels. We thus investigate the kinetics of the transcriptomic and proteomic modifications of S. thermophilus LMG 18311 in response to the presence of L. delbrueckii subsp. bulgaricus ATCC 11842 during growth in milk at two growth stages. Seventy-seven different genes or proteins (4.1% of total coding sequences), implicated mainly in the metabolism of nitrogen (24%), nucleotide base (21%), and iron (20%), varied specifically in coculture. One of the most unpredicted results was a significant decrease of most of the transcripts and enzymes involved in purine biosynthesis. Interestingly, the expression of nearly all genes potentially encoding iron transporters of S. thermophilus decreased, whereas that of iron-chelating dpr as well as that of the fur (perR) regulator genes increased, suggesting a reduction in the intracellular iron concentration, probably in response to H(2)O(2) production by L. bulgaricus. The present study reveals undocumented nutritional exchanges and regulatory relationships between the two yoghurt bacteria, which provide new molecular clues for the understanding of their associative behavior.
-
csp-like genes of Lactobacillus delbrueckii ssp. bulgaricus and their response to cold shock
FEMS Microbiology Letters, 2003Co-Authors: Pascale Serror, Rozenn Dervyn, S. Dusko Ehrlich, Emmanuelle MaguinAbstract:The two csp-like genes from the lactic acid bacterium Lactobacillus delbrueckii ssp. bulgaricus were characterized and designated cspA and cspB. The gene cspA has been identified using a polymerase chain reaction (PCR)-based approach with degenerated primers and further characterized using an inverse PCR strategy. cspA encodes a protein of 65 amino acid residues which displays between 81 and 77% identity with proteins CspL and CspP of Lactobacillus plantarum. cspB has been identified as a cspA ortholog using the partial sequence of the L. bulgaricus ATCC11842. cspB encodes a protein of 69 amino acids which has 42% identity with CspA. Northern blot analyses showed that cspA is transcribed as a single gene and that its transcription increased after a temperature downshift from 42 to 25 degrees C. In contrast, cspB is part of an operon transcribed at constant level irrespective of the temperature. These results indicate that cspA encodes the only Csp-like protein of L. bulgaricus induced by a downshift of temperature.
-
electrotransformation of Lactobacillus delbrueckii subsp bulgaricus and l delbrueckii subsp lactis with various plasmids
Applied and Environmental Microbiology, 2002Co-Authors: Pascale Serror, Takashi Sasaki, Dusko S Ehrlich, Emmanuelle MaguinAbstract:We describe, for the first time, a detailed electroporation procedure for Lactobacillus delbrueckii. Three L. delbrueckii strains were successfully transformed. Under optimal conditions, the transformation efficiency was 104 transformants per μg of DNA. Using this procedure, we identified several plasmids able to replicate in L. delbrueckii and integrated an integrative vector based on phage integrative elements into the L. delbrueckii subsp. bulgaricus chromosome. These vectors provide a good basis for developing molecular tools for L. delbrueckii and open the field of genetic studies in L. delbrueckii.
-
physiological study of Lactobacillus delbrueckii subsp bulgaricus strains in a novel chemically defined medium
Applied and Environmental Microbiology, 2000Co-Authors: Christian Chervaux, Dusko S Ehrlich, Emmanuelle MaguinAbstract:We developed a chemically defined medium called milieu proche du lait (MPL), in which 22 Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) strains exhibited growth rates ranging from 0.55 to 1 h−1. MPL can also be used for cultivation of other lactobacilli and Streptococcus thermophilus. The growth characteristics of L. bulgaricus in MPL containing different carbon sources were determined, including an initial characterization of the phosphotransferase system transporters involved. For the 22 tested strains, growth on lactose was faster than on glucose, mannose, and fructose. Lactose concentrations below 0.4% were limiting for growth. We isolated 2-deoxyglucose-resistant mutants from strains CNRZ397 and ATCC 11842. CNRZ397-derived mutants were all deficient for glucose, fructose, and mannose utilization, indicating that these three sugars are probably transported via a unique mannose-specific-enzyme-II-like transporter. In contrast, mutants of ATCC 11842 exhibited diverse phenotypes, suggesting that multiple transporters may exist in that strain. We also developed a protein labeling method and verified that exopolysaccharide production and phage infection can occur in MPL. The MPL medium should thus be useful in conducting physiological studies of L. bulgaricus and other lactic acid bacteria under well controlled nutritional conditions.
Stavros Plessas - One of the best experts on this subject based on the ideXlab platform.
-
lactic acid production by mixed cultures of kluyveromyces marxianus Lactobacillus delbrueckii ssp bulgaricus and Lactobacillus helveticus
Bioresource Technology, 2008Co-Authors: Stavros Plessas, A A Koutinas, C Psarianos, Loulouda Bosnea, Roger Marchant, Ibrahim M BanatAbstract:Lactic acid production using Kluyveromyces marxianus (IFO 288), Lactobacillus delbrueckii ssp. bulgaricus (ATCC 11842) and Lactobacillus helveticus (ATCC 15009) individually or as mixed culture on cheese whey in stirred or static fermentation conditions was evaluated. Lactic acid production, residual sugar and cell biomass were the main features examined. Increased lactic acid production was observed, when mixed cultures were used in comparison to individual ones. The highest lactic acid concentrations were achieved when K. marxianus yeast was combined with L. delbrueckii ssp. bulgaricus, and when all the strains were used revealing possible synergistic effects between the yeast and the two lactic acid bacteria. The same synergistic effects were further observed and verified when the mixed cultures were applied in sourdough fermentations, proving that the above microbiological system could be applied in the food fermentations where high lactic acid production is sought.
-
evolution of aroma volatiles during storage of sourdough breads made by mixed cultures of kluyveromyces marxianus and Lactobacillus delbrueckii ssp bulgaricus or Lactobacillus helveticus
Food Chemistry, 2008Co-Authors: Stavros Plessas, A A Koutinas, Argyro Bekatorou, Poonam Singh Nee Nigam, J Gallanagh, C PsarianosAbstract:Abstract Two mixed starter cultures were used for sourdough bread making to evaluate their ability to improve quality and increase bread shelf-life: Lactobacillus delbrueckii ssp. bulgaricus or Lactobacillus helveticus mixed with the lactose fermenting yeast Kluyveromyces marxianus as alternative baker’s yeast. Control sourdough breads ( K. marxianus ) without the addition of bacteria, were also prepared. The changes on the headspace aroma volatiles during storage were assessed using solid-phase microextraction (SPME) GC–MS analysis. The effect of these changes on bread flavour was evaluated by consumer preference evaluations and the results were co-evaluated with those from the GC–MS analysis. The obtained results showed differences in the volatile composition of the different types of breads examined, as well as dramatic decreases of the number and the amount of volatiles after five days of storage. The sourdough breads made with K. marxianus and L. bulgaricus , had a more complex aroma profile, longer shelf-life and achieved the highest scores in the sensory tests.
-
application of kluyveromyces marxianus Lactobacillus delbrueckii ssp bulgaricus and l helveticus for sourdough bread making
Food Chemistry, 2008Co-Authors: Stavros Plessas, Ann Fisher, Katerina Koureta, C Psarianos, Poonam Singh Nee Nigam, A A KoutinasAbstract:Abstract The application of Kluyveromyces marxianus (IFO 288), Lactobacillus delbrueckii ssp. bulgaricus (ATCC 11842) and Lactobacillus helveticus (ATCC 15009) as starter cultures for sourdough bread making was examined. Production of lactic and acetic acids, bread rising, volatile composition, shelf-life and organoleptic quality of the sourdough breads were evaluated. The amount of starter culture added to the flour, the dough fermentation temperature and the amount of sourdough used were examined in order to optimise the bread making process. The use of mixed cultures led to higher total titratable acidities and lactic acid concentrations compared to traditionally made breads. Highest acidity (3.41 g lactic acid/kg of bread) and highest resistance to mould spoilage were observed when bread was made using 50% sourdough containing 1% K. marxianus and 4% L. delbrueckii ssp. bulgaricus. The use of these cultures also improved the aroma of sourdough breads, as shown by sensory evaluations and as revealed by GC–MS analysis.
C Psarianos - One of the best experts on this subject based on the ideXlab platform.
-
lactic acid production by mixed cultures of kluyveromyces marxianus Lactobacillus delbrueckii ssp bulgaricus and Lactobacillus helveticus
Bioresource Technology, 2008Co-Authors: Stavros Plessas, A A Koutinas, C Psarianos, Loulouda Bosnea, Roger Marchant, Ibrahim M BanatAbstract:Lactic acid production using Kluyveromyces marxianus (IFO 288), Lactobacillus delbrueckii ssp. bulgaricus (ATCC 11842) and Lactobacillus helveticus (ATCC 15009) individually or as mixed culture on cheese whey in stirred or static fermentation conditions was evaluated. Lactic acid production, residual sugar and cell biomass were the main features examined. Increased lactic acid production was observed, when mixed cultures were used in comparison to individual ones. The highest lactic acid concentrations were achieved when K. marxianus yeast was combined with L. delbrueckii ssp. bulgaricus, and when all the strains were used revealing possible synergistic effects between the yeast and the two lactic acid bacteria. The same synergistic effects were further observed and verified when the mixed cultures were applied in sourdough fermentations, proving that the above microbiological system could be applied in the food fermentations where high lactic acid production is sought.
-
evolution of aroma volatiles during storage of sourdough breads made by mixed cultures of kluyveromyces marxianus and Lactobacillus delbrueckii ssp bulgaricus or Lactobacillus helveticus
Food Chemistry, 2008Co-Authors: Stavros Plessas, A A Koutinas, Argyro Bekatorou, Poonam Singh Nee Nigam, J Gallanagh, C PsarianosAbstract:Abstract Two mixed starter cultures were used for sourdough bread making to evaluate their ability to improve quality and increase bread shelf-life: Lactobacillus delbrueckii ssp. bulgaricus or Lactobacillus helveticus mixed with the lactose fermenting yeast Kluyveromyces marxianus as alternative baker’s yeast. Control sourdough breads ( K. marxianus ) without the addition of bacteria, were also prepared. The changes on the headspace aroma volatiles during storage were assessed using solid-phase microextraction (SPME) GC–MS analysis. The effect of these changes on bread flavour was evaluated by consumer preference evaluations and the results were co-evaluated with those from the GC–MS analysis. The obtained results showed differences in the volatile composition of the different types of breads examined, as well as dramatic decreases of the number and the amount of volatiles after five days of storage. The sourdough breads made with K. marxianus and L. bulgaricus , had a more complex aroma profile, longer shelf-life and achieved the highest scores in the sensory tests.
-
application of kluyveromyces marxianus Lactobacillus delbrueckii ssp bulgaricus and l helveticus for sourdough bread making
Food Chemistry, 2008Co-Authors: Stavros Plessas, Ann Fisher, Katerina Koureta, C Psarianos, Poonam Singh Nee Nigam, A A KoutinasAbstract:Abstract The application of Kluyveromyces marxianus (IFO 288), Lactobacillus delbrueckii ssp. bulgaricus (ATCC 11842) and Lactobacillus helveticus (ATCC 15009) as starter cultures for sourdough bread making was examined. Production of lactic and acetic acids, bread rising, volatile composition, shelf-life and organoleptic quality of the sourdough breads were evaluated. The amount of starter culture added to the flour, the dough fermentation temperature and the amount of sourdough used were examined in order to optimise the bread making process. The use of mixed cultures led to higher total titratable acidities and lactic acid concentrations compared to traditionally made breads. Highest acidity (3.41 g lactic acid/kg of bread) and highest resistance to mould spoilage were observed when bread was made using 50% sourdough containing 1% K. marxianus and 4% L. delbrueckii ssp. bulgaricus. The use of these cultures also improved the aroma of sourdough breads, as shown by sensory evaluations and as revealed by GC–MS analysis.
A A Koutinas - One of the best experts on this subject based on the ideXlab platform.
-
lactic acid production by mixed cultures of kluyveromyces marxianus Lactobacillus delbrueckii ssp bulgaricus and Lactobacillus helveticus
Bioresource Technology, 2008Co-Authors: Stavros Plessas, A A Koutinas, C Psarianos, Loulouda Bosnea, Roger Marchant, Ibrahim M BanatAbstract:Lactic acid production using Kluyveromyces marxianus (IFO 288), Lactobacillus delbrueckii ssp. bulgaricus (ATCC 11842) and Lactobacillus helveticus (ATCC 15009) individually or as mixed culture on cheese whey in stirred or static fermentation conditions was evaluated. Lactic acid production, residual sugar and cell biomass were the main features examined. Increased lactic acid production was observed, when mixed cultures were used in comparison to individual ones. The highest lactic acid concentrations were achieved when K. marxianus yeast was combined with L. delbrueckii ssp. bulgaricus, and when all the strains were used revealing possible synergistic effects between the yeast and the two lactic acid bacteria. The same synergistic effects were further observed and verified when the mixed cultures were applied in sourdough fermentations, proving that the above microbiological system could be applied in the food fermentations where high lactic acid production is sought.
-
evolution of aroma volatiles during storage of sourdough breads made by mixed cultures of kluyveromyces marxianus and Lactobacillus delbrueckii ssp bulgaricus or Lactobacillus helveticus
Food Chemistry, 2008Co-Authors: Stavros Plessas, A A Koutinas, Argyro Bekatorou, Poonam Singh Nee Nigam, J Gallanagh, C PsarianosAbstract:Abstract Two mixed starter cultures were used for sourdough bread making to evaluate their ability to improve quality and increase bread shelf-life: Lactobacillus delbrueckii ssp. bulgaricus or Lactobacillus helveticus mixed with the lactose fermenting yeast Kluyveromyces marxianus as alternative baker’s yeast. Control sourdough breads ( K. marxianus ) without the addition of bacteria, were also prepared. The changes on the headspace aroma volatiles during storage were assessed using solid-phase microextraction (SPME) GC–MS analysis. The effect of these changes on bread flavour was evaluated by consumer preference evaluations and the results were co-evaluated with those from the GC–MS analysis. The obtained results showed differences in the volatile composition of the different types of breads examined, as well as dramatic decreases of the number and the amount of volatiles after five days of storage. The sourdough breads made with K. marxianus and L. bulgaricus , had a more complex aroma profile, longer shelf-life and achieved the highest scores in the sensory tests.
-
application of kluyveromyces marxianus Lactobacillus delbrueckii ssp bulgaricus and l helveticus for sourdough bread making
Food Chemistry, 2008Co-Authors: Stavros Plessas, Ann Fisher, Katerina Koureta, C Psarianos, Poonam Singh Nee Nigam, A A KoutinasAbstract:Abstract The application of Kluyveromyces marxianus (IFO 288), Lactobacillus delbrueckii ssp. bulgaricus (ATCC 11842) and Lactobacillus helveticus (ATCC 15009) as starter cultures for sourdough bread making was examined. Production of lactic and acetic acids, bread rising, volatile composition, shelf-life and organoleptic quality of the sourdough breads were evaluated. The amount of starter culture added to the flour, the dough fermentation temperature and the amount of sourdough used were examined in order to optimise the bread making process. The use of mixed cultures led to higher total titratable acidities and lactic acid concentrations compared to traditionally made breads. Highest acidity (3.41 g lactic acid/kg of bread) and highest resistance to mould spoilage were observed when bread was made using 50% sourdough containing 1% K. marxianus and 4% L. delbrueckii ssp. bulgaricus. The use of these cultures also improved the aroma of sourdough breads, as shown by sensory evaluations and as revealed by GC–MS analysis.
