Effects of Germination and Pure Culture Fermentation by Yeasts and Lactobacilli on Phytic Acid and Polyphenol Content of Pearl Millet

Germination of pearl millet at 30°C for 24 hr reduced phytic acid significantly (P<0.05) which, on fermentation with mixed pure cultures of Saccharomyces diastaticus, Saccharomyces cerevisiae, Lactobacillus brevis, and Lactobacillus fermentum at 30°C for 72 hr, was eliminated or reduced to negligible levels in fermented sprouts. Concentration of polyphenols did not change on germination. The fermentation of sprouts by combinations of S. cerevisiae with L. brevis and S. cerevisiae and L. fermentum did not change polyphenol whereas S. diastaticus with L. brevis (SdLb) increased and S. diastaticus with L. fermentum combinations decreased the polyphenol in the sprouts.     

Comparison of the effect of exopolysaccharide-producing lactic acid bacteria from sourdough on dough characteristics and steamed bread quality

The use of exopolysaccharide (EPS)-producing lactic acid bacteria (LAB) is promising in sourdough fermentation. However, the knowledge of the effects of various species of LAB on steamed bread making remains limited. In this study, the effects of two LAB with high EPS-producing capacity, namely Weissella cibaria L32 and Lactobacillus brevis L17 on dough fermentation and steamed bread quality were estimated. The addition of these two LAB strains significantly increased the titratable acidity and protease activity during the dough fermentation, especially L. brevis L17. Although the in situ EPS synthesised by LAB could improve the steamed bread quality, excessive acidification of L. brevis L17 would still increase the protease activity and thus destroy its gluten network structure. As a result, the steamed bread fermented with L. brevis L17 had the lowest specific volume and hardest texture in comparison with the steamed bread fermented with W. cibaria L32 and with added EPS produced by W. cibaria L32 and L. brevis L17. These results indicated that different EPS-producing LAB exhibited distinctive dough fermentation characteristics, and the in situ EPS-producing W. cibaria L32 could improve steamed bread quality, which confirmed its potential application in steamed bread making.     

Antioxidant activity and γ-aminobutyric acid (GABA) content in sea tangle fermented by Lactobacillus brevis BJ20 isolated from traditional fermented foods

GABA-producing lactic acid bacteria were isolated from kimchi and salt-fermented Jot-gal, which are traditional Korean fermented foods. The strain, BJ-20, isolated from salt-fermented Jot-gal (cod gut), possessed the highest GABA-producing ability in MRS broth with 1% monosodium glutamate (MSG), as determined by thin layer chromatography. The BJ-20 strain was identified as Lactobacillus brevis and designated as L. brevis BJ20. A sea tangle solution was fermented over 5 days to produce GABA using L. brevis BJ20. During fermentation, the GABA concentration dramatically increased, while the glutamic acid concentration decreased. This result indicates that the glutamic acid was converted to GABA by L. brevis BJ20 in the fermented sea tangle solution. Furthermore, the fermented solution exhibited strong antioxidant activities, such as DPPH scavenging, superoxide scavenging, and xanthine oxidase inhibition, which were higher than those of BHA as a positive control.     

Influence of Lactobacillus brevis on metabolite changes in bacteria-fermented sufu

Sufu is a form of food derived from traditional Chinese fermented soybean. It has a unique flavor and contains abundant nutrients. With demands for healthy food on the rise, a higher level of sufu functionality is required. In fermentation of soybean-derived products, lactic acid bacteria (LAB) are widely used as an adjunct culture, which provides health benefits and enhances flavor of food. Among LAB, Lactobacillus brevis has the potential to generate γ-aminobutyric acid (GABA), which is well-known for its physiological functions. In this study, L. brevis was added to bacteria-fermented sufu to evaluate its impacts on sufu quality. Sufu was produced via co-inoculation with Bacillus subtilis and L. brevis (group A sufu) or a single inoculation with B. subtilis (group B sufu). Metabolite changes in the two groups during fermentation were investigated and physicochemical changes were observed. The results indicated that the addition of L. brevis increased the concentration of GABA and decreased the concentrations of histamine and serotonin. The concentrations of volatile compounds, such as esters and acids, especially 2-methyl-butanoic acid ethyl ester, as well as the concentrations of phenylethyl alcohol and 3-methyl-butanol were significantly higher in group A. Inoculation of L. brevis changed the metabolite profile of sufu and improved its functionality and safety of edibility. The current study explored the potential of applying L. brevis to the manufacture of bacteria-fermented sufu.     

Utilization of Enterococcus casseliflavus and Lactobacillus pentosus as starter cultures for Spanish-style green olive fermentation

Green olive were fermentated with starter cultures of Enterococcus casseliflavus cc45 andLactobacillus pentosus CECT 5138. A total of 32 strains of enterococci isolated from brines at high pH were characterized and identified by phenotypic methods. The strain cc45 was selected after a preliminary screening and applied together with thelactobacillus culture the first day after brining, comparing the results with those obtained when both cultures were used sequentially, enterococci at day 1 and lactobacilli at day 2, and with uninoculated controls. Microbial growth, substrate and product evolution, and flavour of the fermented olives were studied. Inoculation produced a quicker acidification of brines, consumption of carbohydrates and decrease of pH. The best results were attained when both cultures of lactic acid bacteria were applied sequentially with 1day delay. This is the first report dealing with the presence of E. casseliflavus in table olive brines and their utilization as starter culture.     

Effect of Germination and Fermentation on in vitro Starch and Protein Digestibility of Pearl Millet

Germination of pearl millet grain for 24 hr significantly improved its in vitro starch and protein digestibility. Fermentation of pearl millet sprouts by mixed culture combinations of yeasts and bacteria (Saccharomyces diastaticus and Lactobacillus brevis; Saccharomyces diastaticus and Lactobacillus fermentum; Saccharomyces cerevisiae and Lactobacillus brevis; and Saccharomyces cerevisiae and Lactobacillus fermentum) resulted in a significant increase in protein and starch digestibility. The pearl millet sprouts fermented with mixed culture containing S. diastaticus and L. brevis had the highest in vitro starch digestibility, while the sprouts fermented with the culture containing 5. cerevisiae and L. fermentum had the highest in vitro protein digestibility.     

Survival of Escherichia coli O157:H7 in cucumber fermentation brines

Abstract: Bacterial pathogens have been reported on fresh cucumbers and other vegetables used for commercial fermentation. The Food and Drug Administration currently has a 5‐log reduction standard for E. coli O157:H7 and other vegetative pathogens in acidified pickle products. For fermented vegetables, which are acid foods, there is little data documenting the conditions needed to kill acid resistant pathogens. To address this knowledge gap, we obtained 10 different cucumber fermentation brines at different stages of fermentation from 5 domestic commercial plants. Cucumber brines were used to represent vegetable fermentations because cabbage and other vegetables may have inhibitory compounds that may affect survival. The 5‐log reduction times for E. coli O157:H7 strains in the commercial brines were found to be positively correlated with brine pH, and ranged from 3 to 24 d for pH values of 3.2 to 4.6, respectively. In a laboratory cucumber juice medium that had been previously fermented with Lactobacillus plantarum or Leuconostoc mesenteroides (pH 3.9), a 5‐log reduction was achieved within 1 to 16 d depending on pH, acid concentration, and temperature. During competitive growth at 30 °C in the presence of L. plantarum or L. mesenteroides in cucumber juice, E. coli O157:H7 cell numbers were reduced to below the level of detection within 2 to 3 d. These data may be used to aid manufacturers of fermented vegetable products determine safe production practices based on fermentation pH and temperature. Practical Application: Disease causing strains of the bacterium E. coli may be present on fresh vegetables. Our investigation determined the time needed to kill E. coli in cucumber fermentation brines and how E. coli strains are killed in competition with naturally present lactic acid bacteria. Our results showed how brine pH and other brine conditions affected the killing of E. coli strains. These data can be used by producers of fermented vegetable products to help assure consumer safety.     

High γ-aminobutyric acid production from lactic acid bacteria: Emphasis on Lactobacillus brevis as a functional dairy starter

γ-Aminobutyric acid (GABA) and GABA-rich foods have shown anti-hypertensive and anti-depressant activities as the major functions in humans and animals. Hence, high GABA-producing lactic acid bacteria (LAB) could be used as functional starters for manufacturing novel fermented dairy foods. Glutamic acid decarboxylases (GADs) from LAB are highly conserved at the species level based on the phylogenetic tree of GADs from LAB. Moreover, two functionally distinct GADs and one intact gad operon were observed in all the completely sequenced Lactobacillus brevis strains suggesting its common capability to synthesize GABA. Difficulties and strategies for the manufacture of GABA-rich fermented dairy foods have been discussed and proposed, respectively. In addition, a genetic survey on the sequenced LAB strains demonstrated the absence of cell envelope proteinases in the majority of LAB including Lb. brevis, which diminishes their cell viabilities in milk environments due to their non-proteolytic nature. Thus, several strategies have been proposed to overcome the non-proteolytic nature of Lb. brevis in order to produce GABA-rich dairy foods.     

Safety assessment and antimicrobial properties of the lactic acid bacteria strains isolated from polish raw fermented meat products

Twenty-one strains of the genus Lactobacillus and the genus Pediococcus, isolated from Polish raw fermented meat products, were examined for the potential probiotic properties: resistance to simulated gastric and intestine conditions, safety assessment, and antimicrobial properties. Strains were resistant to gastric enzymes and low pH (3–6 log CFU/mL decrease) and intestinal enzymes and bile salts (1–3 log CFU/mL decrease). Most strains were resistant to gentamycin, streptomycin, vancomycin, tetracycline, ciprofloxacin, and kanamycin. Three of them (Lb. brevis BAL1, BAL10, and KL5) produced β-glucuronidase, which excludes them from qualifying as safe. Seven strains had the ability to produce bacteriocins or bacteriocin-like substances. Overall, strains Lb. brevis SCH6, Pd. pentosaceus BAL6, and KL14 revealed selected superior characteristics (resistance to the gastrointestinal conditions, safety assessment, and antimicrobial properties) as compared to the other LAB strains investigated, which made them a viable bioprotective culture that can be inoculated in raw fermented meat products as starter cultures.     

Free D- and L-Amino Acid Evolution During Sourdough Fermentation and Baking

The evolution of free D- and L-amino acids in sourdoughs started with various lactic acid bacteria (LAB) and yeasts was studied. Lactobacillus brevis subsp. lindneri CB1 and Lactobacillus plantrum DC400 had high proteolytic activity. During sourdough fermentation, Saccharomyces cerevisiae 141 and Saccharomyces exiguus M14 sequentially utilized free amino acids produced by bacterial activity. Due to increased cell yeast autolysis, more S. exiguus M14 inocula caused more free amino acids which were partially utilized by LAB without causing hydrolysis of wheat flour protein. D-alanine, D-glutamic acid and traces of other D-isomers were observed in sourdoughs fermented with L. brevis subsp. lindneri CB1 and S. cerevisiae 141. Free total D- and L-amino acid content decreased by more than 44% after baking the sourdoughs. No abiotic generation of new D-amino acid isomers was detected in the baked sourdoughs.     

Preparation of elemental selenium-enriched fermented milk by newly isolated Lactobacillus brevis from kefir grains

A Lactobacillus brevis strain CGMCC No. 6683 that can survive at high selenium concentrations was isolated from kefir grains. Using a scanning electron microscope equipped with an energy dispersive X-ray spectroscope, it was shown that L. brevis CGMCC No. 6683 reduced sodium selenite into elemental selenium. L. brevis CGMCC No. 6683 was then pre-treated with sodium selenite to prepare selenium-enriched L. brevis. To study the selenium-enriched yoghurt, selenium-enriched L. brevis was co-fermented in skimmed milk with traditional yoghurt starter culture (Streptococcus thermophilus and Lactobacillus bulgaricus). Results showed that it enhanced selenium concentration in the selenium-enriched yoghurt, and more importantly, elemental selenium was detected in the selenium-enriched yoghurt. The isolated L. brevis provides a new way of preparing a functional dairy product: elemental selenium-enriched fermented milk.     

Microbial characterization of Iranian traditional Lighvan cheese over manufacturing and ripening via culturing and PCR-DGGE analysis: identification and typing of dominant lactobacilli

This paper reports on the diversity and dynamics of the dominant microbial populations during manufacturing and ripening of Lighvan, a traditional, starter-free Iranian cheese made from raw ewe and goat’s milk as determined by culturing and PCR-DGGE. Similar dominant populations, composed of Lactococcus lactis and Lactobacillus spp. strains, were found by both techniques. However, discrepancies regarding the identity of the Lactobacillus species were encountered. Lactobacillus curvatus and Lactobacillus sakei proved to be dominant by PCR-DGGE; in contrast, Lactobacillus paraplantarum, Lactobacillus paracasei, Lactobacillus brevis and Lactobacillus plantarum were the majority cultivable organisms. RAPD typing of lactobacilli isolates showed wide genetic diversity among the species. Moreover, strain compositions change over time; L. brevis and L. paraplantarum were dominant in milk and were replaced by L. plantarum and L. paracasei strains as ripening progressed.     

Biochemical evolution of nitrogen compounds during fermentation of wheat bread doughs containing pure cultures of lactic acid bacteria

Summary The metabolic activities of three species of lactic acid bacteria (Lactobacillus brevis, L. plantarum andStreptococcus faecium) during wheat bread dough fermentation have been investigated by evaluating the biochemical changes which occur in 0.85 mol/L NaCl-soluble nitrogen components in unfermented, 4-h and 24-h fermented straight doughs. Non-protein nitrogen compounds increase during a 24-h-fermentation period in all doughs. Exoproteolytic activity is denoted mainly inL. plantarum fermented doughs by an important rise in the free amino acids. Doughs containingL. brevis show a larger production of peptides over a 24-h fermentation period and strong nutritional requirements on low-molecular-weight peptides are evidenced byStreptococcus faecium over short fermentation periods. Progressive depletion in the polypeptides and protein contents as well as a decrease in the estimated protein chain length over the fermentation period forL. plantarum andSt. faecium containing doughs are evidence of endoproteolytic activities in the high-molecular-weight soluble components. An increase in the size of the protein fragments released in the 4-h fermented doughs containingL. brevis denotes enzymatic hydrolysis on non-soluble protein chains.

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Biochemische Veränderungen an Stickstoffverbindungen während der Gärung von Weizenteigen mit reinen Kulturen von Milchsäurebakterien

Zusammenfassung Es wurde die Stoffwechselaktivität von 3 Milchsäurebakterien,L. brems, L. plantarum undSt. faecium, während der Gärung von Weizenteigen durch Bestimmung der biochemischen Veränderungen in 0,85 mol/L NaCl-löslichen Stickstoffverbindungen von nicht fermentierten, 4 h und 24 h fermentierten direkt geführten Teigen untersucht. Der Gehalt an Nicht-Protein-Stickstoffverbindungen stieg in allen Teigen während der 24-h-Gärung an. Es wurde exoproteolytische Aktivität festgestellt, besonders in den mitL. plantarum fermentierten Teigen, durch einen erheblichen Anstieg der freien Aminosäuren. Teige, dieL. brevis enthielten, wiesen die größere Peptonbildung bei der 24-h-Gärung auf; es wurden stärkere Nahrungsansprüche an Peptiden mit niedrigem Molekulargewicht beiSt. faecium in kurzen Gärungszeiten beobachtet. Progressiver Abfall des Polypeptid-und Proteingehaltes sowie Abnahme der Protein-Kettenlänge während der Gärung bei den Teigen, dieL. plantarum undSt. faecium enthielten, weisen auf endoproteolytische Aktivität auf lösliche Verbindungen mit hohem Molekulargewicht hin. Eine Zunahme der Größe der Proteinfragmente bei den 4-h-fermentierten Teigen mitL. brevis zeigt eine enzymatische Hydrolyse der nicht löslichen Proteinkette an.

     

Improvement in antioxidant activity,angiotensin‐converting enzyme inhibitory activity and in vitro cellular properties of fermented pepino milk by Lactobacillus strains containing the glutamate decarboxylase gene

BACKGROUND: The purpose of this study was to evaluate the functional potential of fermented pepino extract (PE) milk by Lactobacillus strains containing the glutamate decarboxylase (GAD) gene. Three Lactobacillus strains were selected, including L. brevis BCRC 12310, L. casei BCRC 14082 and L. salivarius subsp. salivarius BCRC 14759. The contents of free amino acids, total phenolics content, total carotenoids and the associated functional and antioxidant abilities were analyzed, including angiotensin‐converting enzyme (ACE) inhibition activity, 1,1‐diphenyl‐2‐picylhydrazyl (DPPH) radical‐scavenging ability and oxygen radical absorbance capacity (ORAC). Cell proliferation of fermented PE milk was also evaluated by MTT (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) assay. RESULTS: Compared to the unfermented PE, fermented PE milk from Lactobacillus strains with the GAD gene showed higher levels of total phenolics, γ‐aminobutyric acid, ACE inhibitory activity, DPPH, and ORAC. The viability of human promyelocytic leukemia cells (HL‐60) determined by the MTT method decreased significantly when the cells were incubated with the PE and the fermented PE milk extracts. CONCLUSION: The consumption of fermented PE milk from Lactobacillus strains with the GAD gene is expected to benefit health. Further application as a health food is worthy of investigation. © 2012 Society of Chemical Industry     

Optimal production of fermented whey presenting bifidogenic growth stimulator activity

Various culture conditions for the production of fermented whey presenting bifidogenic growth stimulator (BGS) activity were evaluated using Leuconostoc mesenteroides CJNU 0147 and Lactobacillus casei CJNU 0588. The BGS activity of fermented whey produced with mixed culture of Leu. mesenteroides CJNU 0147 and L. Casei CJNU 0588 was higher than those of single cultures. The optimal temperature for the production of the fermented whey was 20°C. The anaerobic culture conditions via nitrogen gas supply had no influence on the BGS activity of fermented whey. The BGS activity of the heat-treated fermented whey samples was slightly decreased by 7.63, 11.66, and 15.12% at 80, 100, and 121°C, respectively for 15 min. Pilot-scale (75 L) fermented whey was produced using the 2 freeze-dried cell powders of CJNU 0147 and CJNU 0588 and spray-dried. The spray-dried fermented whey presented BGS activity, indicating it can be used as a functional food material.     

Associative Growth of Lactic Acid Bacteria in Cabbage Juice

Combinations of Leuconostoc mesenteroides, Lactobacillus brevis, Pediococcus cerevisiae, and Lactobacillus plantarum were grown in sterile cabbage juice broth. The effects of culture interactions were determined by lag times, generation times, pH change, and total acidity measurements. Fresh filter-sterilized cabbage juice was a better medium than autoclaved cabbage juice, or refrigerated filter-sterilized cabbage juice. The addition of NaCl (2.25%) had a minimal effect on the cultures, except for L. mesenteroides, which was inhibited. In paired association studies, L. mesenteroides was inhibited by all the other cultures, conversely, L. plantarum and L. brevis benefited from most of the culture interactions.     

Preparation and characteristics of lactic acid fermented cowpea milk

 Four Lactobacilli were isolated from both commercial cowmilk yoghurt ("Fan" yoghurt) and "wara", a West African soft cheese. They were identified as Lactobacillus acidophilus ("Fan" yoghurt), L. plantarum, L. brevis and unidentified Lactobacillus spp. ("wara"). L. acidophilus and L. plantarum were chosen as starter organisms for the production of a yoghurt-like product from cowpea milk. There was a decrease in the final pH and an increase in the titratable acidity of the cowpea milk samples at the end of the fermentation period. The crude protein, total ash, calcium, potassium and phosphorus values increased in the fermented cowpea milk, while a decrease was obtained for the lipid, moisture and crude fibre contents. A decreasing trend was noted in the phytic acid and trypsin inhibitor of the cowpea flour when processed into milk, followed by a further reduction at the end of fermentation. Consumer acceptability of the cowpea yoghurt varied, with preference being given to the banana and strawberry flavoured samples. Received: 10 June 1996 / Revised version: 17 September 1997     

Effect of Select Parameters of the Sourdough Rye Fermentation on the Activity of Some Mixed Starter Cultures

The effect of select parameters (i.e., rye flour ash content, temperature, and dough yield) of the sourdough fermentation on the fermentation activity of different starter cultures (lactic acid bacteria Lactococcus lactis ssp. Lactis, Weissella confusa, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus helveticus, and yeast Kluyveromyces marxianus subsp. Marxianus) was determined. The major metabolic end products of fermentation (D, L-lactic acid, acetic acid, ethanol and glycerol) and the evolution of total phenolic content and folic acid during bread making were measured. Lactobacillus helveticus and Kluyveromyces marxianus allowed obtaining sourdoughs with the highest lactic acid/acetic acid ratios. The mixed starter culture with Lactococcus lactis and Saccharomyces cerevisiae generated the most important quantities of D/L lactic acid. The maximum values of ethanol concentration were obtained in case of the sourdoughs from whole rye flour fermented at lower temperature (30°C) with mixed starter cultures containing Sacchomyces cerevisiae. The fermentation process and type of starter culture are also tools to increase the bioactive compounds, enabling the increase of the phenolic content of the sourdough.     

Isolation and characterization of lactic acid bacteria from jiang‐sun (fermented bamboo shoots), a traditional fermented food in Taiwan

BACKGROUND: In this study, lactic acid bacteria (LAB) were isolated, characterized and identified from jiang‐sun (fermented bamboo shoots; a traditional fermented food in Taiwan). Samples were collected at seven time intervals from a fixed fermenting bucket during the fermentation process of jiang‐sun and its initial ingredients, dochi (fermented soybeans) and bamboo shoots. RESULTS: A total of 57 LAB cultures were isolated; 42 cultures were isolated from jiang‐sun samples and 15 cultures were isolated from dochi and bamboo shoots. These isolates were characterized phenotypically and then divided into three groups (A–C) by restriction fragment length polymorphism analysis and sequencing of 16S ribosomal DNA. Alteration of microbial populations during the fermentation process was observed. While various LAB were found in the dochi and bamboo shoots, it was mostly replaced by Lactobacillus plantarum after 1 day of fermentation. Furthermore, the antibacterial activities of the isolates were determined, and one Enterococcus faecium strain showed inhibitory activity against all the indicator strains. CONCLUSION: Results suggest that L. plantarum is the main LAB present during the fermentation of jiang‐sun. To our knowledge, this is the first report describing the distribution and varieties of LAB that exist in the jiang‐sun fermentation process. Copyright © 2010 Society of Chemical Industry     

Evaluation of the composition and quality of watermelon and mango juices fermented by Levilactobacillus brevis,Lacticaseibacillus casei and Pediococcus pentosaceus and subsequent simulated digestion and storage

This study evaluated the composition of watermelon and mango juices fermented by Levilactobacillus (L.) brevis, Lacticaseibacillus (La.) casei and Pediococcus (P.) pentosaceus and subsequently simulated in vitro digestion and storage (4°C for 35 days). After fermentation (24 h), the microorganisms grew (~9 log CFU mL⁻¹) and fermented watermelon (FWJ) and mango juice (FMJ) became more red and yellow, respectively. DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) free radical scavenging capacities significantly increased in L. brevis and La. casei FMJ. After in vitro digestion, all the strains except La. casei in FMJ significantly decreased (P < 0.05), and P. pentosaceus survival was 2.4 and 4.5 times higher in FWJ and FMJ, respectively, than as pure culture. After storage, cell counts remained above 7 log CFU mL⁻¹, and no changes in quality attributes, total phenolic content and antioxidant capacity were recorded in P. pentosaceus FMJ. Thus, watermelon and mango are suitable matrices for lactic acid bacteria.