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.     

Effect of Fermentation by Pure Cultures of Yeasts and Lactobacilli on Phytic Acid and Polyphenol Content of Pearl Millet

Single and mixed pure culture fermentations of pearl millet flour with yeasts and lactobacilli, namely, Saccharomyces diastaticus, Saccharomyces cerevisiae, Lactobacillus brevis and Lactobacillus fermentum, at 30^oC for 72 hr brought about a significant reduction in phytic acid and polyphenols which were present in considerable amounts in pearl millet flour. Reduction in phytic acid was more pronounced than that in the polyphenols.     

Influence of starter culture combinations of<Emphasis Type="Italic"> Lactobacillus fermentum</Emphasis>,<Emphasis Type="Italic"> Saccharomyces cerevisiae</Emphasis> and<Emphasis Type="Italic"> Candida krusei</Emphasis> on aroma in Ghanaian maize dough fermentation

Various combinations of Lactobacillus fermentum, Saccharomyces cerevisiae and Candida krusei were investigated as starter cultures for the fermentation of the Ghanaian maize dough. The four combinations used were each yeast species with L. fermentum, both yeast species together, and both yeast species together with L. fermentum. Maize dough fermented spontaneously was also used as control. The aroma profile, acidity values and sensory characteristics of all dough samples were compared. Using Principal Component Analysis (PCA), the aroma profiles of the dough samples could be separated into five distinct groups based on the type of fermentation. Fermentations where S. cerevisiae and C. krusei were combined produced the highest concentrations of aroma compounds, particularly esters, but were judged as having the lowest acceptability scores. A more balanced profile that included alcohols, carbonyls, esters and acids was obtained with the combination of L. fermentum and C. krusei, which produced fermented dough with a high sensory score comparable to spontaneous fermentations. Combinations of L. fermentum and S. cerevisiae produced high concentrations of ethanol and fusel alcohols. Lactic and acetic acid concentrations were highest with the combined use of all three starter cultures.     

Adaptability of lactic acid bacteria and yeasts to sourdoughs prepared from cereals, pseudocereals and cassava and use of competitive strains as starters

The adaptability of lactic acid bacteria (LAB) and yeasts to sourdoughs prepared from cereals, pseudocereals and cassava was investigated using PCR-DGGE and bacteriological culture combined with rRNA gene sequence analysis. Sourdoughs were prepared either from flours of the cereals wheat, rye, oat, barley, rice, maize, and millet, or from the pseudocereals amaranth, quinoa, and buckwheat, or from cassava, using a starter consisting of various species of LAB and yeasts. Doughs were propagated until a stable microbiota was established. The dominant LAB and yeast species were Lactobacillus fermentum, Lactobacillus helveticus, Lactobacillus paralimentarius, Lactobacillus plantarum, Lactobacillus pontis, Lactobacillus spicheri, Issatchenkia orientalis and Saccharomyces cerevisiae. The proportion of the species within the microbiota varied. L. paralimentarius dominated in the pseudocereal sourdoughs, L. fermentum, L. plantarum and L. spicheri in the cassava sourdough, and L. fermentum, L. helveticus and L. pontis in the cereal sourdoughs. S. cerevisiae constituted the dominating yeast, except for quinoa sourdough, where I. orientalis also reached similar counts, and buckwheat and oat sourdoughs, where no yeasts could be detected. To assess the usefulness of competitive LAB and yeasts as starters, the fermentations were repeated using flours from rice, maize, millet and the pseudocereals, and by starting the dough fermentation with selected dominant strains. At the end of fermentation, most of starter strains belonged to the dominating microbiota. For the rice, millet and quinoa sourdoughs the species composition was similar to that of the prior fermentation, whereas in the other sourdoughs, the composition differed.     

Effect of co-inoculation of Saccharomyces cerevisiae and Lactobacillus fermentum on the quality of the distilled sugar cane beverage cachaça

Abstract: The effect of Lactobacillus fermentum in co‐inoculation with Saccharomyces cerevisiae UFLA CA11 on the quality of cachaça (sugar cane spirit) was evaluated. The co‐inoculation was first evaluated in flask fermentation, and subsequently, yeast and bacteria were co‐cultured at approximately 10⁵ CFU/mL and 10⁸ CFU/mL, respectively, in 4 consecutive batches. L. fermentum did not affect the growth or activity (sugar consumption and fermentation rate) of S. cerevisiae UFLA CA11 during fermentation. The physicochemical analysis revealed a higher concentration (Tukey test) of aldehydes (22.07 mg/100 mL anhydrous alcohol) in cachaça produced by co‐inoculation. Analysis of volatile compounds using GC‐FID demonstrated that cachaça produced by co‐inoculation had higher concentrations of acetaldehyde (25.15 mg/L), ethyl acetate (30.17 mg/L), and 2,3‐butanedione (170.39 μ/L), while cachaça produced by UFLA CA11 contained higher concentrations of ethyl lactate (1205.98 μ/L), propionic acid (127.97 μ/L), butyric acid (2335.57 μ/L), and 1‐pentanol (469.23 μ/L). The lowest concentration of acetic acid measured by HPLC was found in cachaça obtained with UFLA CA11. The sensory analysis, performed using the Mann–Whitney test, revealed that cachaça produced by co‐inoculation differed from that produced by UFLA CA11 in taste and aroma. Practical Application: This study reports on the use of a mixed culture of Saccharomyces cerevisae and Lactobacillus fermentum to produce cachaça and shows the influence of co‐inoculation of yeast and bacteria on the quality of this beverage.     

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.     

Die Mikroflora des Sauerteiges

Zusammenfassung Es wurde dem Verhalten heterofermentativer Sauerteigbakterien bei gemeinsamer Kultur mit Hefen nachgegangen. Diese Untersuchungen erstreckten sich aufLactobacillus brevis, L. brevis var. lindneri undL. fermentum einerseits, sowic aus Sauerteigen isolierte Hefen (Candida krusei, Pichia saitoi, Torulopsis holmii, Saccharomyces cerevisiae) andererseits. Das Verhalten der Mischkulturen wurde an Sauerteigen aus Roggenmehl (Type 997, Teigausbeute 180, 27–28 °C, 18 Std) studiert. Je nach den zueinander in Wechselbezichung tretenden Sauerteigbakterien und Hefen ergab sich eine unterschiedliche Beeinflussung der Säurebildung. WährendTorulopsis holmii insbesondere die vonLactobacillus brevis undL. brevis var. lindneri ausgehende Teigsäuerung um bis zu fünf Einheiten erhöhte, bedingteSaccharomyces cerevisiae eine Förderung der vonL. brevis var. lindneri undL. fermentum ausgehenden Säuerung des Sauerteiges.

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The microflora of sourdoughXV. Communication: On the behaviour of heterofermentative sourdough bacteria and yeasts in mixed culture

Summary The behaviour of heterofermentative sourdough bacteria in mixed culture with yeasts was investigated. The investigations includedLactobacillus brevis, L. brevis var. lindneri andL. fermentum as well as several yeasts, isolated from sourdough (Candida krusei, Pichia saitoi, Torulopsis holmii, Saccharomyces cerevisiae). The behaviour of the mixed cultures was studied in ryeflour doughs (Type 997, dough yield 180, 27–28 °C; 18 h). Depending on specific interrelationships between types of sourdough bacteria and yeasts influence on acidification varied.Torulopsis holmii raised the dough acidification produced byLactobacillus brevis andL. brevis var. lindneri by up to five units;Saccharomyces cerevisiae enhanced the acidification byL. brevis var. lindneri andL. fermentum.

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Nr. 4676 der Veröffentlichungen der Bundesforschungsanstalt für Getreide- und Kartoffelverarbeitung, Detmold

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Diese Untersuchungen wurden ermöglicht durch eine finanzielle Förderung seitens des Bundesministeriums für Forschung und Technologie im Rahmen des Programms Biologic and Technologic     

Characterization and Distribution of Lactobacilli during Lactic Fermentation of Okra (Hibiscus esculentus)

The distribution and identification of lactobacilli during fermentation of okra were studied. Fermentation characteristics of lactobacilli isolated on MRS agar at 30°C under anaerobic conditions were presented using the API 50 CHL system. The phenogram constructed by an unweighted, pair group, arithmetic average, linkage method and by use of the Jacquard similarity coefficient (1-Sj) was used to identify nine phena. The studies showed five homolactic species initially (Lactobacillus plantarum, Lactobacillus casei subsp. pseudoplantarum, Lactobacillus acidophilus, Lactobacillus leichmannii, Lac-tobacillus salivarius subsp. salicinius) and two heterolactic species (Lactobacillus cellobiosus and Lactobacillus brevis). After 24 hr fermentation, the majority of the isolated strains were L. cellobiosus. During the final stage of fermentation L. plantarum strains dominated.     

Effect of the bread-making process on zearalenone levels

The effects of the bread-making process including fermentation with Saccharomyces cerevisiae and lactic acid bacteria (Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus acidophilus and Lactobacillus fermentum) and baking at 200°C on zearalenone (ZEA) levels were investigated. Standard solutions of ZEA were added to flour and then loaves of bread were prepared. Sourdough and three types of yeast including active dry yeast, instant dry yeast and compressed yeast were used for the fermentation of dough. ZEA levels in flour, dough and bread were determined by HPLC with fluorescence detection after extraction and clean-up on an immunoaffinity column. The highest reduction in levels of ZEA was found in the first fermentation (first proof), while the lowest reduction was observed in the baking stage. In addition, the results showed that compressed yeast had the maximum reduction potential on ZEA levels even at the baking stage.     

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.     

Determination of the relationship between oxalate degradation and exopolysaccharide production by different Lactobacillus probiotic strains

The aim of this study was to evaluate the protective effects of exopolysaccharide (EPS) production on resistance to gastrointestinal digestive conditions and oxalate by probiotic strains of the species Lactobacillus rhamnosus, Lactobacillus fermentum and Lactobacillus brevis. The oxalate‐degrading ability of the strains was determined using an enzymatic assay. The correlation between oxalate degradation rate and EPS production was not significant (P > 0.05); however, the high‐EPS‐producing L. fermentumIP5 and L. brevisYG7 strains showed high oxalate‐degrading activity, whereas the low‐EPS‐producing strain L. fermentumBP5 demonstrated low oxalate‐degrading activity. The present findings suggest that dietary supplementation with the probiotic strain L. fermentumIP5 could be a promising strategy for the prevention of oxalate stone disease.     

Improvement of the quality and abatement of the biogenic amines of grass carp muscles by fermentation using mixed cultures

BACKGROUND: To improve the quality of processed grass carp (Ctenopharyngodon idellus) products and control the accumulation of hazardous substances therein, minced grass carp slices were salted for 6 h at room temperature and then inoculated with mixed starter cultures of Lactobacillus casei, Streptococcus lactis, Saccharomyces cerevisiae Hansen and Monascus anka and fermented for 12 h at 30 °C. The changes in some characteristics and biogenic amine contents of the fermented muscles were investigated. RESULTS: During the 12 h fermentation at 30 °C, muscles inoculated with mixed starter cultures showed a rapid decrease in pH from 6.0 to 5.1 and suppression of the growth of enterobacteria and pseudomonads. The fermented muscles exhibited better colour, appearance, flavour and overall acceptability than the control (P < 0.05). The changes in non‐protein nitrogen and free amino acid contents of the fermented muscles and in their sodium dodecyl sulfate polyacrylamide gel electrophoresis profiles indicated that severe hydrolysis of muscle proteins occurred during fermentation. The accumulation of biogenic amines in the muscles was efficiently reduced by fermentation with mixed starter cultures. CONCLUSION: Fermentation with mixed starter cultures of L. casei, S. lactis, S. cerevisiae Hansen and M. anka significantly improved the characteristics of grass carp muscles and controlled the accumulation of biogenic amines. Copyright © 2009 Society of Chemical Industry     

Citrulline production by lactic acid bacteria in Chinese rice wine

Ethyl carbamate (EC) is a carcinogenic compound derived from the spontaneous reaction of ethanol with urea or citrulline in Chinese rice wine. Polymerase chain reaction–denaturing gradient gel electrophoresis showed that five species, Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus brevis, Lactococcus lactis and Lactobacillus coryniformis were the most abundant bacteria in the Chinese rice wine production process. Five strains belonging to these species can degrade arginine primarily in the exponential growth phase and accumulate citrulline in MRS‐Arg medium. In addition, an L. brevis strain was shown to be capable of assimilating citrulline, indicating the potential of this strain suggesting a potential route to reduce citrulline content and ethyl carbamate formation in Chinese rice wine fermentation. Copyright © 2018 The Institute of Brewing & Distilling     

Viability and Resistance of Lactobacilli Isolated from Cocoa Fermentation to Simulated Gastrointestinal Digestive Steps in Soy Yogurt

To study the potential probiotic characteristics such as decrease of pH, microbial viability, and tolerance to simulated digestive steps of fermented soy beverage (“soy yogurt”) produced with lactobacilli isolated from cocoa fermentation (Lactobacillus fermentum TcUESC01 and Lactobacillus plantarum TcUESC02) during fermentation and refrigerated storage. The sensory acceptance of the yogurts was also tested. Samples of soy yogurt produced with L. fermentum TcUESC01 or L. plantarum TcUESC02 were collected during fermentation (0, 4, 8, and 12 h) and refrigerated storage (1, 9, 18, and 27 d), and submitted to pH and bacterial viability determinations. Tolerance to simulated digestion steps was done with refrigerated storage samples at 9 °C. Simulated digestion was performed in 3 successive steps: exposure to pepsin‐HCl solution, bile shock, and simulated small intestinal juice. During storage, a decrease in pH and lactobacillus viability was observed. L. fermentum TcUESC01 showed to be more resistant than L. plantarum TcUESC02 to simulated gastrointestinal digestion. All soy yogurts showed acceptable hedonic scores (greater than 5 in a 9‐point hedonic scale ranging from “like extremely” to “dislike extremely”) in sensory evaluation for flavor, aroma, color, consistency, and overall impression. L. plantarum TcUESC02 and, especially, L. fermentum TcUESC01 showed potential probiotic characteristics when considering pH, cell viability, and tolerance to simulated digestive steps and did not affect the sensory characteristics when supplemented to soy yogurt during storage.     

Mixed Culture Fermentation of Cucumber Juice with Lactobacillus plantarum and Yeasts

Saccharomyces cerevisiae and Saccharomyces rosei were tested for use in mixed culture fermentation of cucumber juice with Lactobacillus plantarum. Extent of sugar utilization and the ratio of products formed (lactic acid:ethanol) were influenced by time of inoculation and cell numbers of each microorganism. Sugar fermentation was complete within 6 days at 28°C when similar numbers of bacteria and yeasts were added simultaneously, or when yeasts were added before the bacteria. Sugar remained when only L. plantarum was added, or when yeasts were added in low numbers. Glycerol was produced when yeasts were present, the concentration being directly related to NaCl concentration. Results suggest advantageous uses of yeasts to complete fermentation and to modify acidity.     

Effects of Lactobacillus fermentum HY01 on the quality characteristics and storage stability of yak yogurt

Lactobacillus fermentum HY01 is a probiotic strain screened from traditional yak yogurt, which can effectively relieve enteritis and constipation. This study aimed to evaluate the effects of HY01 as an adjunct starter on the quality and storage of yak yogurt. A total of 36 main volatile flavor substances were detected in all samples. In particular, more aldehydes, esters, and alcohols were detected in yak yogurt prepared by mixed fermentation of L. fermentum HY01 and starter MY105 (including Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus). The rheological results showed that the yak yogurt prepared by mixed fermentation of L. fermentum HY01 and starter MY105 had higher apparent viscosity and lower tan δ value compared with compared with traditional yak yogurt, yak yogurt with only L. fermentum HY01, and cow yogurt with L. fermentum HY01 and starter MY105. Meanwhile, the conjugated linoleic acid in the yak yogurt prepared by mixed fermentation of L. fermentum HY01 and starter was significantly higher than those in the HY01 group or the yogurt starter group alone. After 28 d of storage at 4°C, the number of HY01 in the yak yogurt prepared by mixed fermentation of L. fermentum HY01 and starter was still higher than 10⁷ cfu/mL, its acidity was lower than 110°T, and its syneresis was the lowest. The results indicated that L. fermentum HY01 could improve the flavor, texture, and storage properties of yak yogurt.     

Production of ethanol from liquefied cassava starch using co-immobilized cells of Zymomonas mobilis and Saccharomyces diastaticus

Co-immobilized cells of Saccharomyces diastaticus and Zymomonas mobilis produced a high ethanol concentration compared to immobilized cells of S. diastaticus during batch fermentation of liquefied cassava starch. The co-immobilized cells produced 46.7 g/l ethanol from 150 g/l liquefied cassava starch, while immobilized cells of yeast S. diastaticus produced 37.5 g/l ethanol. The concentration of ethanol produced by immobilized cells was higher than that by free cells of S. diastaticus and Z. mobilis in mixed-culture fermentation. In repeated-batch fermentation using co-immobilized cells, the ethanol concentration increased to 53.5 g/l. The co-immobilized gel beads were stable up to seven successive batches. Continuous fermentation using co-immobilized cells in a packed bed column reactor operated at a flow rate of 15 ml/h (residence time, 4 h) exhibited a maximum ethanol productivity of 8.9 g/l/h.     

CINNAMIC ACID AS THE BASIS OF A MEDIUM FOR THE DETECTION OF WILD YEASTS

Cinnamic acid (100 μg ml^?1) incorporated in a solid medium was found to inhibit the growth of brewing strains (Pof^?) of yeast while permitting the growth of Pof+ wild yeast contaminants. Typically, colonies of Saccharomyces cerevisiae var. diastaticus (Pof+) mixed with brewing yeast (S. cerevisiae NCYC 240) were visible after 5d incubation at 25°C. The incubation time required to detect a selection of brewery wild yeast isolates was found to vary from 3–12 d.     

Multi‐Cereal Beverage Fermented by Lactobacillus Helveticus and Saccharomyces Cerevisiae

A novel multi‐cereal‐based fermented beverage with suitable aroma, flavor, and pH fermented by lactic acid bacteria and Saccharomyces cerevisiae was developed. Twenty‐seven lactobacilli strains were screened for acid production (pH and titratable acidity) in a mixture of malt, rice, and maize substrates. It was found that Lactobacillus helveticus KLDS1.9204 had the greatest acid production among 27 lactobacilli tested. The fermentation performance of L. helveticus KLDS1.9204 was also assayed and the fermentation parameters were optimized using Plackett–Burman design and steepest ascent method. L. helveticus KLDS1.9204 showed good proteolytic capability, however, the strain could not utilize starch. The optimum substrate consisted of 50% malt (25 g/100 mL), 25% rice (20 g/100 mL), and 25% maize (30 g/100 mL). The inoculum was 5% with a ratio of S. cerevisiae to L. helveticus KLDS1.9204 of 2.5:1. The optimum temperature was 37 °C and the time was 22 h. Lastly, the quality of the multi‐cereal‐based fermented beverage was evaluated. This beverage was light yellow, transparent, and it tasted well with a pleasant acid and a unique flavor of cereals. The beverage was rich in free amino acids and organic acids. The pH and titratable acidity of the beverage were 3.5 and 29.86 °T, respectively. The soluble solids content of the beverage was 6.5 °Brix, and the alcohol content was 0.67%.     

Optimisation of bambara groundnut water extract and skim milk composition as cryoprotectant for increasing cell viability of Lactobacillus spp. using response surface methodology

Four legume water extracts, that is bambara groundnut, soya bean, red kidney bean and black bean as well as skim milk, were examined for their effectiveness in protecting Lactobacillus rhamnosus GG and Lactobacillus fermentum SK5 during the freeze‐drying and storage. Bambara groundnut water extract (BGWE) showed promising cryoprotective activity that was comparable to skim milk. BGWE and skim milk at 2–10% w/v and 5–20% w/v individually produced survival rates for both strains of 87–88%. To further optimise the synergistic cryoprotective medium, response surface methodology was employed. The optimal combination was 4.93% w/v BGWE and 11.68% w/v skim milk for L. rhamnosus GG and 5.17% w/v BGWE and 11.36% w/v skim milk for L. fermentum SK5 with survival rates of 95.17% and 94.36%, respectively. The storage life of freeze‐dried cells of both probiotics at 4 °C and 30 °C for 6 months was markedly improved when they were produced with these optimal combinations.