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1.
AIMS: The aim of this study was to identify potential souring agents, isolated from fermented plant material, by API 50 CHL assay and a molecular method based on polymerase chain reaction and colorimetric hybridization (PCR-ELISA). METHODS AND RESULTS: Forty-two strains of lactic acid bacteria derived from plant material were screened by taking advantage of API 50 CHL and PCR-ELISA. Oligonucleotide probes used for hybridization in PCR-ELISA were specific for lactobacilli, the Leuconostoc family, Lactobacillus pentosus/plantarum and Lactobacillus brevis. The hybrides were detected by a colour-developing reaction. Bacteria isolated from fermented cucumbers were identified as Lact. plantarum-related (Lact. plantarum and Lact. pentosus) and Leuconostoc species. Most of the strains isolated from sauerkraut were identified as Lact. pentosus/plantarum. CONCLUSIONS: Complementary results were obtained in the identification of bacterial strains, isolated from fermented cucumbers and sauerkraut, by API 50 CHL and PCR-ELISA. SIGNIFICANCE AND IMPACT OF THE STUDY: PCR-ELISA proved to be suitable for the screening of large numbers of bacterial isolates from fermented vegetables. This will be useful for the identification of strains suitable for the design of starter cultures for the fermentation of plant material.  相似文献   

2.
Sixty-five strains of obligately and facultatively heterofermentative sourdough lactic acid bacteria were screened for their capacity to grow optimally in the presence of arabinose, ribose and xylose as carbon sources. Lactobacillus alimentarius 15F, Lact. brevis 10A, Lact. fermentum 1F and Lact. plantarum 20B showed higher growth rate, cell yield, acidification rate and production of acetic acid when some pentoses instead of maltose were added to the SDB medium. Lactobacillus plantarum 20B used arabinose also in a synthetic medium where complex growth factors such as yeast extract were omitted. Other Lact. plantarum strains did not show the same property. Pentosan extract was treated with alpha-L-arabinofuranosidase from Aspergillus niger or endo-xylanase from Bacillus subtilis to produce hydrolysates containing mainly arabinose and xylose, respectively. In particular, the hydrolysate containing arabinose substantiated the growth and the production of lactic acid and, especially, of acetic acid by Lact. plantarum 20B. Sourdough fermentation by Lact. plantarum 20B with addition of pentosan extract and alpha-L-arabinofuranosidase increased the acidification rate, titratable acidity and acetic acid content compared with traditional sourdough. A facultatively heterofermentative strain, Lact. plantarum 20B, also produced a sourdough with an optimal fermentation quotient.  相似文献   

3.
Prevention of growth in wheat bread for more than 6 d of approximately 106 rope-producing Bacillus subtilis spores per gram of dough was achieved by addition of propionic or acetic acids at levels of 0·10% v/w (based on flour weight), or by addition of 15% sour dough fermented with Lactobacillus plantarum C11, Lact. brevis L62, Lact. plantarum ('vege-start 60'), Lact. plantarum (ch 20), Lact. maltaromicus (ch 15), or the commercial sour dough starter culture, Lact. sanfrancisco L99. These cultures resulted in an amount of total titratable acids above 10 in the sour dough and a pH value below 4·8 in the final bread. Bacteriocin-producing lactic acid bacteria added as starter cultures in wheat dough and nisin (Nisaplin) at levels up to 100 p.p.m. g−1 flour had no effect against B. subtilis and B. licheniformis strains, despite the fact that nisin-producing strains of Lactococcus lactis ssp. lactis among 186 strains of lactic acid bacteria had demonstrated inhibitory activity against B. subtilis and B. licheniformis in an agar spot assay.  相似文献   

4.
The concentrations of gamma-aminobutyric acid (GABA) in 22 Italian cheese varieties that differ in several technological traits markedly varied from 0.26 to 391 mg kg(-1). Presumptive lactic acid bacteria were isolated from each cheese variety (total of 440 isolates) and screened for the capacity to synthesize GABA. Only 61 isolates showed this activity and were identified by partial sequencing of the 16S rRNA gene. Twelve species were found. Lactobacillus paracasei PF6, Lactobacillus delbrueckii subsp. bulgaricus PR1, Lactococcus lactis PU1, Lactobacillus plantarum C48, and Lactobacillus brevis PM17 were the best GABA-producing strains during fermentation of reconstituted skimmed milk. Except for L. plantarum C48, all these strains were isolated from cheeses with the highest concentrations of GABA. A core fragment of glutamate decarboxylase (GAD) DNA was isolated from L. paracasei PF6, L. delbrueckii subsp. bulgaricus PR1, L. lactis PU1, and L. plantarum C48 by using primers based on two highly conserved regions of GAD. A PCR product of ca. 540 bp was found for all the strains. The amino acid sequences deduced from nucleotide sequence analysis showed 98, 99, 90, and 85% identity to GadB of L. plantarum WCFS1 for L. paracasei PF6, L. delbrueckii subsp. bulgaricus PR1, L. lactis PU1, and L. plantarum C48, respectively. Except for L. lactis PU1, the three lactobacillus strains survived and synthesized GABA under simulated gastrointestinal conditions. The findings of this study provide a potential basis for exploiting selected cheese-related lactobacilli to develop health-promoting dairy products enriched in GABA.  相似文献   

5.
The use of length-heterogeneity PCR was explored to monitor lactic acid bacteria succession during ensiling of maize. Bacterial diversity was studied during the fermentation of 30-day-old maize in optimal and spoilage-simulating conditions. A length heterogeneity PCR profile database of lactic acid bacteria isolated from the silage and identified by 16S rRNA gene sequencing was established. Although interoperonic 16S rRNA gene length polymorphisms were detected in some isolates, strain analysis showed that most of the lactic acid bacteria species thriving in silage could be discriminated by this method. The length heterogeneity PCR profiles of bacterial communities during maize fermentation were compared with those on a database. Under optimal fermentation conditions all the ecological indices of bacterial diversity, richness and evenness, deduced from community profiles, increased until day thirteen of fermentation and then decreased to the initial values. Pediococcus and Weissella dominated, especially in the first days of fermentation. Lactococcus lactis ssp. lactis and Lactobacillus brevis were mainly found after six days of fermentation. A peak corresponding to Lactobacillus plantarum was present in all the fermentation phases, but was only a minor fraction of the population. Unsuitable fermentation conditions and withered maize leaves in the presence of oxygen and water excess caused an enrichment of Enterococcus sp. and Enterobacter sp.  相似文献   

6.
The development of lactic fermentation processes for the storage of directly brined olives (Aloreña cultivar) was investigated by three procedures: (1) a modification of the traditional method with an initial brine containing 9% (w/v) NaCl and 0.2% (w/v) acetic acid; (2) induced lactic fermentation with 6% NaCl and 0.2% acetic acid; and (3) conservation in acidified brine containing 6% NaCl and 0.6% acetic acid. In all cases, strains of Lactobacillus plantarum and Pediococcus spp. were present in each, indicating the great tolerance of these micro-organisms to high levels of lactic and acetic acids. They also appeared in an altered sequence. Counts of Pediococcus remained moderate (higher than Lact. plantarum ) throughout the last part of the preservation period. A commercial starter improved colonization by Lact. plantarum. Yeasts coexisted with the lactic bacteria throughout the preservation period although their importance in the fermentation process was very limited. The brine characteristics obtained after fermentation were suitable for assured product preservation. There was no spoilage. These results encourage research on the mechanism of lactic acid bacteria inhibition in brines and the development of lactic fermentation processes for directly brined olives from other olive cultivars.  相似文献   

7.
Lactic acid fermentation of starch by Lactobacillus manihotivorans LMG 18010T, a new amylolytic L(+) lactic acid producer, was investigated and compared with starch fermentation by Lact. plantarum A6. At non-controlled pH, growth and lactic acid production from starch by Lact. manihotivorans LMG 18010T lasted 25 h. Specific growth and lactic acid production rates continuously decreased from the onset of the fermentation, unlike Lact. plantarum A6 which was able to grow and convert starch product hydrolysis into lactic acid more rapidly and efficiently at a constant rate up to pH 4.5. In spite of complete and rapid starch hydrolysis by Lact. manihotivorans LMG 18010T during the first 6 h, only 45% of starch hydrolysis products were converted to lactic acid. When pH was maintained at 6.0, lactic acid, amylase and final biomass production by Lact. manihotivorans LMG 18010T increased markedly and the fermentation time was reduced by half. Under the same conditions, an increase only in amylase production was observed with Lact. plantarum A6. When grown on glucose or starch at pH 6.0, Lact. manihotivorans LMG 18010T had an identical maximum specific growth rate (0.35 h(-1)), whereas the maximum rate of specific lactic acid production was three times higher with glucose as substrate. Lactobacillus manihotivorans LMG 18010T did not produce amylase when grown on glucose. Based on the differences in the physiology between the two species and other amylolytic lactic acid bacteria, different applications may be expected.  相似文献   

8.
AIM: To develop in vitro assays for comparing the antagonistic properties and anti-oxidative activity of probiotic Lactobacillus and Bifidobacterium strains against various entero- and urinary pathogens. METHODS AND RESULTS: The antagonistic activity of five probiotic lactobacilli (Lactobacillus rhamnosus GG, Lactobacillus fermentum ME-3, Lactobacillus acidophilus La5, Lactobacillus plantarum 299v and Lactobacillus paracasei 8700:2) and two bifidobacteria (Bifidobacterium lactis Bb12, Bifidobacterium longum 46) against six target pathogens was estimated using different assays (solid and liquid media, anaerobic and microaerobic cultivation) and ranked (low, intermediate and high). Bacterial fermentation products were determined by gas chromatography, and the total anti-oxidative activity of probiotics was measured using linolenic acid test. Pyelonephritic Escherichia coli was highly suppressed by GG and both bifidobacteria strains. Lactobacilli strains 8700:2, 299v and ME-3 were the most effective against Salmonella enterica ssp. enterica in microaerobic while ME-3 and both bifidobacteria expressed high activity against Shigella sonnei in anaerobic milieu. Lact. paracasei, Lact. rhamnosus and Lact. plantarum strains showed intermediate antagonistic activity against Helicobacter pylori under microaerobic conditions on solid media. The highest anti-oxidative activity was characteristic for Lact. fermentum ME-3 (P < 0.05). No efficient antagonist against Clostridium difficile was found. The positive correlations between the pH, lactic acid production and anti-microbial activity for all tested probiotics were assessed. CONCLUSIONS: Developed experimental assays enable to compare the anti-microbial and -oxidative activity of Lactobacillus and/or Bifidobacterium probiotics, which have been claimed to possess the ability of suppressing the growth of various enteric and urinary pathogens. SIGNIFICANCE AND IMPACT OF THE STUDY: Screening Lactobacillus and Bifidobacterium sp. strains according to their activity in various environmental conditions could precede the clinical efficacy studies for adjunct treatment with probiotics in cure of different gastrointestinal and urinary tract infections.  相似文献   

9.
Aims:  To investigate the microbial community in sunki , an indigenous, unsalted, fermented vegetable, made from the leaves of red beet.
Methods and Results:  Fermenting samples were collected at 1- to 2-day intervals from four houses and investigated by culture-dependent and culture-independent techniques. PCR-Denaturing-Gradient-Gel-Electrophoresis profiles indicated that the bacterial community was stable and Lactobacillus delbrueckii , Lact. fermentum and Lact. plantarum were dominant during the fermentation. This result agreed well with that obtained by the culturing technique. Moulds, yeasts or bacteria other than lactic acid bacteria (LAB) were not detected.
Conclusions:  The bacterial community was stable throughout the fermentation, and Lact. delbrueckii , Lact. fermentum and Lact. plantarum were dominant. The acidic pH and lactic acid produced by LAB probably preserve the sunki from spoilage.
Significance and Impact of the Study:  This is the first report on the use of both culture-dependent and culture-independent techniques to study the bacterial community in sunki . A combination of culture-dependent and culture-independent techniques is necessary for the analysis of complex microbial communities.  相似文献   

10.
Fermented buckwheat sprouts (FBS) are used as multifunctional foods. Their production process includes fermentation with lactic acid bacteria. The major strains were found to include Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus pentosus, Lactococcus lactis subsp. lactis, and Pediococcus pentosaceus in an investigation of the lactic acid bacteria. We searched for the functional components, and nicotianamine (NA) and 2″-hydroxynicotianamine (HNA) were identified as angiotensin I-converting enzyme (ACE) inhibitors. NA and HNA increased during fermentation. Indole-3-ethanol was identified as an antioxidant (a SOD active substance), and may have been generated from tryptophan during fermentation because it was not contained in green buckwheat juice. A safety test demonstrated that FBS contained were safe functional food components, showing negative results in buckwheat allergy tests. Any buckwheat allergy substances might have been degraded during the fermentation process.  相似文献   

11.
A survey of lactic acid bacteria in Italian silage   总被引:3,自引:2,他引:1  
G razia , L. & S uzzi , G. 1984. A survey of lactic acid bacteria in Italian silage. Journal of Applied Bacteriology 56 , 373–379.
Lactic acid bacteria, isolated from Italian ensiled products, were represented by strains of the genera Lactobacillus and Leuconostoc . The predominant strains were heterofermentative lactobacilli, with Lactobacillus buchneri being the most frequent. Among homofermentative lactic acid bacteria, strains of Lact. plantarum and Lact. casei were recovered. Almost all strains utilized malic acid and showed good acid-tolerance, but only some of them were able to metabolize malic acid at extremely low pH; these were five homofermentative lactobacilli (4 Lact. plantarum and 1 Lacr. casei var. casei ) and two heterofermentative lactobacilli ( Lact. cellobiosus and Lactobacillus sp.).  相似文献   

12.
The group that includes the lactic acid bacteria is one of the most diverse groups of bacteria known, and these organisms have been characterized extensively by using different techniques. In this study, 180 lactic acid bacterial strains isolated from sorghum powder (44 strains) and from corresponding fermented (93 strains) and cooked fermented (43 strains) porridge samples that were prepared in 15 households were characterized by using biochemical and physiological methods, as well as by analyzing the electrophoretic profiles of total soluble proteins. A total of 58 of the 180 strains were Lactobacillus plantarum strains, 47 were Leuconostoc mesenteroides strains, 25 were Lactobacillus sake-Lactobacillus curvatus strains, 17 were Pediococcus pentosaceus strains, 13 were Pediococcus acidilactici strains, and 7 were Lactococcus lactis strains. L. plantarum and L. mesenteroides strains were the dominant strains during the fermentation process and were recovered from 87 and 73% of the households, respectively. The potential origins of these groups of lactic acid bacteria were assessed by amplified fragment length polymorphism fingerprint analysis.  相似文献   

13.
AIMS: To biochemically characterize the bacteriocin produced by Lactococcus lactis ssp. lactis M30 and demonstrate its effect on lactic acid bacteria (LAB) during sourdough propagation. METHODS AND RESULTS: A two-peptide bacteriocin produced by L. lactis ssp. lactis M30 was purified by ion exchange, hydrophobic interaction and reversed phase chromatography. Mass spectrometry of the two peptides and sequence analysis of the ltnA2 gene showed that the bacteriocin was almost identical to lacticin 3147. During a 20-day period of sourdough propagation the stability of L. lactis M30 was demonstrated, with concomitant inhibition of the indicator strain Lactobacillus plantarum 20, as well as the non-interference with the growth of the starter strain Lact. sanfranciscensis CB1. CONCLUSIONS: In situ active bacteriocins influence the microbial consortium of sourdough LAB and can "support" the dominance of insensitive strains during sourdough fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: The in situ bacteriocinogenic activity of selected lactococci enables the persistence of insensitive Lact. sanfranciscensis strains, useful to confer good characteristics to the dough, at a higher cell concentration with respect to other LAB of the same ecosystem.  相似文献   

14.
This study aims to isolate and identify lactic acid bacteria from fermented flour of selected finger millet varieties grown in Sri Lanka and to evaluate their probiotic attributes and bioactive properties in vitro. Fifteen lactic acid bacteria were isolated from three varieties of fermented finger millet flour namely ravi, raavana and oshadha. These isolates were screened for phenotypical and biochemical characteristics. The selected isolates were identified by 16 S rRNA sequencing as Bacillus cereus (five strains), Streptococcus lutetiensis, Lactobacillus plantarum, Lactobacillus fermentum (two strains), Brevibacillus borstelensis, Paenibacillus species, Lactococcus lactis subspecies lactis, Enterococcus faecium, Pediococcus acidilactici, and Enterococcus lactis, and their partial sequences were deposited in GenBank. Among them, five isolates including two isolates, L. plantarum MF405176.1 and L. fermentum MF033346.1 isolated from ravi; two isolates, L. lactis MF480428.1 and E. faecium MF480431.1 isolated from raavana; and P. acidilactici MF480434.1 isolated from oshadha varieties respectively, exhibited in vitro safety attributes and could tolerate acid, gastric juice, bile, salt, phenol, and temperature under simulated gastric conditions, and also were susceptible to antibiotics tested. Further, they demonstrated bactericidal activity against both drug-sensitive and multidrug-resistant pathogens. Among the selected isolates, L. plantarum MF405176.1 demonstrated highest hydrophobicity and adhesion to both colon colorectal adenocarcinoma and colon colorectal carcinoma cell lines. L. lactis subspecies lactis MF480428.1 exhibited the highest auto-aggregation and 2, 2, diphenyl-1-pricrylhydrazyl free radical scavenging activity. P. acidilactici MF480434.1 demonstrated the lowest IC50 values against HCT-116 and HT-29 cells. None of the LAB isolates could assimilate > 10% cholesterol in vitro.  相似文献   

15.
A total of 241 lactic acid bacteria belonging to Lactobacillus plantarum, Pediococcus pentosaceus, Lactobacillus fermentum/reuteri and Lactobacillus brevis from various processing stages of maize dough fermentation were investigated. Results indicated that each processing stage has its own microenvironment with strong antimicrobial activity. About half of the Lact. plantarum and practically all of the Lact. fermentum/reuteri investigated were shown to inhibit other Gram-positive and Gram-negative bacteria, explaining the elimination of these organisms during the initial processing stages. Further, widespread microbial interactions amounting to 85% to 18% of all combinations tested were demonstrated amongst lactic acid bacteria within the various processing stages, i.e. raw material, steeping, 0 h and 48 h of fermentation, explaining the microbial succession taking place amongst lactic acid bacteria during fermentation. The antimicrobial effect was explained by the combined effect of acids, compounds sensitive to proteolytic enzymes and other compounds with antimicrobial activity with the acid production being the most important factor.
The pattern of antimicrobial factors was not species-specific and the safety and storage stability of fermented maize seem to depend on a mixed population of lactic acid bacteria with different types of antimicrobial characteristics. This means that introduction of pure cultures as starters may impose a risk to the product.  相似文献   

16.
The development of the microbial community involved in the production process of Italian dry sausage was investigated using physiological analysis and molecular techniques for strain typing and taxonomical identification. A cycle of sausage production was followed collecting samples during the 2 months of ripening process. Microbiological analysis allowed the identification of the main bacterial groups responsible for the fermentation process as lactobacilli and coagulase-negative staphylococci. The use of a polymerase chain reaction-based technique of strain typing, RAPD fingerprinting, demonstrated that the environmental parameters interact to select a limited number of strains that dominate the fermentation process. The staphylococcal populations were characterized for their physiological properties and the two dominant strains were identified as Staphylococcus xylosus and Staph. sciuri. The use of 16S rDNA sequencing allowed the definition of the taxonomical position of the two dominant strains of lactic acid bacteria, as belonging to Lactobacillus sake and Lact. plantarum.  相似文献   

17.
Fermentation of fructans by epiphytic lactic acid bacteria   总被引:6,自引:2,他引:4  
A total of 712 strains of lactic acid bacteria isolated from forage grasses were studied for their ability to ferment fructans of phlein- as well as inulin-type. Only 16 strains utilized phlein and eight of these also fermented inulin. They were identified as Lactobacillus paracasei subsp. paracasei, Lact. plantarum, Lact. brevis and Pediococcus pentosaceus . In the species Lact. paracasei subsp. paracasei , all strains gave positive results, whereas the other positive strains possessed unique properties within their own species. In all but two cases (strains of the species Lact. plantarum ), the phlein was more intensively fermented than the inulin, as indicated by a lower pH and a higher lactic acid concentration. On the basis of the outcome of this study it seems worthwhile to inoculate grasses of low sugar content before ensiling with an active strain that can ferment fructans.  相似文献   

18.
The normal Lactobacillus flora of healthy human rectal and oral mucosa   总被引:9,自引:1,他引:8  
The Lactobacillus flora of the rectal and oral mucosa was sampled from 42 healthy volunteers. Species identification was carried out by numerically comparing API 50CH fermentation patterns with type strains, using an SJ-similarity cut-off level of 79%. For the largest groups, identity was further confirmed by DNA-DNA hybridizations against the type strain of the species. Seventeen lactobacilli clusters were defined, of which most were found both on rectal and oral mucosa. The largest taxa were Lactobacillus plantarum , Lact. rhamnosus and Lact. paracasei ssp. paracasei , which were isolated from 52%, 26% and 17% of the individuals, respectively. Most isolates were tested for their capacity to adhere to the human colonic cell line HT-29 in the absence and presence of methyl-α- D -mannoside. Mannose-sensitive adherence to HT-29 cells was encountered in two-thirds of the Lact. plantarum isolates, but infrequently among isolates of other taxa. The results suggest that Lact. plantarum is a major colonizer of the human gastrointestinal mucosa, and that its capacity to adhere to mannose-containing receptors may be of some ecological importance.  相似文献   

19.
Ethnic people of the Himalayan regions of India, Nepal, Bhutan and China consume a variety of indigenous fermented milk products made from cows milk as well as yaks milk. These lesser-known ethnic fermented foods are dahi, mohi, chhurpi, somar, philu and shyow. The population of lactic acid bacteria (LAB) ranged from 10(7) to 10(8) cfu/g in these Himalayan milk products. A total of 128 isolates of LAB were isolated from 58 samples of ethnic fermented milk products collected from different places of India, Nepal and Bhutan. Based on phenotypic characterization including API sugar test, the dominant lactic acid bacteria were identified as Lactobacillus bifermentans, Lactobacillus paracasei subsp. pseudoplantarum, Lactobacillus kefir, Lactobacillus hilgardii, Lactobacillus alimentarius, Lactobacillus paracasei subsp. paracasei, Lactobacillus plantarum, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris and Enterococcus faecium. LAB produced a wide spectrum of enzymes and showed high galactosidase, leucine-arylamidase and phosphatase activities. They showed antagonistic properties against selected Gram-negative bacteria. None of the strains produced bacteriocin and biogenic amines under the test conditions used. Most strains of LAB coagulated skim milk with a moderate drop in pH. Some strains of LAB showed a high degree of hydrophobicity, suggesting these strains may have useful adhesive potential. This paper is the first report on functional lactic acid bacterial composition in some lesser-known ethnic fermented milk products of the Himalayas.  相似文献   

20.
Lactic acid fermentation of leguminous plant juices was modeled to provide a comparative efficiency assessment of the previously selected strains of lactic acid bacteria as potential components of starter cultures. Juices of the legumes fodder galega, red clover, and alfalfa were subjected to lactic acid fermentation in 27 variants of experiment. Local strains (Lactobacillus sp. RS 2, Lactobacillus sp. RS 3, and Lactobacillus sp. RS 4) and the collection strain Lactobacillus plantarum BS 933 appeared the most efficient (with reference to the rate and degree of acidogenesis, ratio of lactic and acetic acids, and dynamics of microflora) in fermenting fodder galega juice; Lactobacillus sp. RS 1, Lactobacillus sp. RS 2, Lactobacillus sp. RS 3, Lactobacillus sp. RS 4, and L. plantarum BS 933 were the most efficient for red clover juice. Correction of alfalfa juice fermentation using the tested lactic acid bacterial strains appeared inefficient, which is explainable by its increased protein content and a low level of the acids produced during fermentation.  相似文献   

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