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1.
Int J Food Microbiol ; 322: 108547, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32097827

RESUMO

The present study aimed to characterize lactic acid bacteria involved in the different processing steps of tchapalo, a traditional Ivoirian beverage, for their potential application as starter cultures in food and beverages. Lactic acid bacteria (LAB) were therefore isolated and enumerated at different steps of the process on MRS and BEA agars. Of the 465 isolates, 27 produced bacteriocins that inhibit Lactobacillus delbrueckii F/31 strain. Of those, two also inhibited Listeria innocua ATCC 33090, while two others displayed inhibitory activity against L.innocua ATCC 33090, E. faecalis CIP 105042, E. faecalis ATCC 29212, Streptococcus sp. clinical LNSP, E. faecalis CIP 105042 and E. faecium ATCC 51558. The dominant species involved in tchapalo LAB fermentation, as determined by 16S rRNA gene sequencing, were Lactobacillus fermentum (64%), followed by Pediococcus acidilactici (14%). Two strains representing the two dominant species, L. fermentum S6 and P. acidilactici S7, and two potential bacteriocin producers, Weissella confusa AB3E41 and Enterococcus faecium AT1E22, were selected for further characterization. First, genome analysis showed that these strains do not display potential harmful genes such as pathogenic factors or transmissible antibiotic resistance genes. Furthermore, phylogenetic analyses were performed to assess evidence of eventual links to groups of strains with particular properties. They revealed that (i) L. fermentum S6 and P. acidilactici S7 are closely related to strains that ferment plants, (ii) E. faecium AT1E22 belongs to the environmental clade B of E. faecium, while W. confusa is quite similar to other strains also isolated from plant fermentations. Further genome analysis showed that E. faecium AT1E22 contains the Enterocin P gene probably carried by a megaplasmid, whereas no evidence of a bacteriocin gene was found in W. confusa AB3E41. The metabolic and the first step of the probiotic potentials of the different strains were analyzed. Lactobacillus fermentum S6 and P. acidilactici S7 are good candidates to develop starter cultures, and E. faecium AT1E22 should be further tested to confirm its potential as a probiotic strain in the production of sorghum wort.


Assuntos
Cerveja/microbiologia , Lactobacillales/isolamento & purificação , Sorghum/microbiologia , Bacteriocinas/genética , Bacteriocinas/metabolismo , Fermentação , Genoma Bacteriano/genética , Lactobacillales/classificação , Lactobacillales/genética , Lactobacillales/metabolismo , Listeria/crescimento & desenvolvimento , Filogenia , Probióticos/classificação , Probióticos/metabolismo , RNA Ribossômico 16S/genética
2.
Int J Food Microbiol ; 322: 108545, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32109681

RESUMO

PVOH-based polymer matrices in the form of films were evaluated as carriers of living Lactococcus lactis subsp. Lactis. These lactic acid bacteria are capable of producing nisin, which is an effective antilisterial peptide. A low percentage (1:0.125 w/w) of yeast extract, gelatin, sodium caseinate, gelatin, or casein hydrolysates was incorporated in PVOH matrices with the aim of increasing the viability of bacteria in the film. The films were obtained by casting after incorporating L. lactis. Then they were evaluated for antilisterial activity in liquid medium at 37 °C for 24 h, and also at 4 °C for 21 days in order to simulate the storage of liquid foods in refrigeration conditions. The survival of the lactic acid bacteria was also evaluated at both temperatures during the experiment. L. lactis remained viable in all the films tested at 37 and 4 °C. The antimicrobial activity of the films was greater at 4 °C than at 37 °C. With regard to the effect of the film composition, the activity of the films was higher when protein hydrolysates and sodium caseinate were incorporated in the formulation. Films supplemented with protein hydrolysates or sodium caseinate inhibited growth of the pathogen during the 21 days of storage at 4 °C. At 37 °C, after 24 h the films had slowed the growth of the inoculated pathogen by between 2 and 4 log CFU/mL. Finally, as the films developed are intended to be used in the design of active packaging of foods, they were tested in pasteurized milk inoculated with 4 log CFU/mL of Listeria monocytogenes and stored at 4 °C for 21 days. The pathogen began to grow after the second day of storage with or without film, but when the films were added to the medium the growth of the pathogen was slowed down, without reaching >6 log CFU, whereas the control reached a maximum growth of 8.5 log CFU. The pH of the milk was monitored throughout the experiment, and it decreased with time. This was due to the generation of organic acids by the lactic bacteria. Buffering the food stabilized the pH without modifying the activity of the films. Thus, the current study shows that PVOH films supplemented with nutrients can act as carriers of L. lactis, and they can help to increase the safety of refrigerated dairy beverages and sauces.


Assuntos
Conservação de Alimentos/métodos , Lactobacillales/fisiologia , Listeria monocytogenes/crescimento & desenvolvimento , Leite/microbiologia , Álcool de Polivinil , Animais , Antibacterianos/metabolismo , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Conservantes de Alimentos/metabolismo , Lactobacillales/química , Lactobacillales/metabolismo , Lactococcus lactis/química , Lactococcus lactis/metabolismo , Lactococcus lactis/fisiologia , Nisina/metabolismo , Proteínas/química , Refrigeração
3.
Arch Microbiol ; 202(4): 875-885, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31894393

RESUMO

The objective of this study was to assess the effects of some culture conditions [temperature (20, 30, 37 °C), incubation time (48, 72, 120 h), pH (5.0, 6.0, 7.0), NaCl concentration (0, 3, 6%), carbon (glucose, fructose, lactose), nitrogen (sodium nitrate, ammonium sulfate, bacto-peptone), and mineral sources (calcium carbonate, ferric chloride)] on the exopolysaccharide (EPS) production by lactic acid bacteria (LAB) strains (belonging to Lactobacillus (L.) plantarum, L. namurensis, and Pediococcus (P.) ethanolidurans species) isolated from naturally fermented pickles. The maximum EPS production was determined at 30 °C and pH 6.0. The highest amount of EPS was obtained after 120 h of incubation, with glucose as carbon source, bacto-peptone as nitrogen source and calcium carbonate as mineral source for most of the tested strains. The EPS formation was not stimulated by NaCl, indicating that EPS formation of the tested strains was not a stress response. L. plantarum MF460 produced the highest amount of EPS at 30 °C after 48 h of incubation, which was 515.48 mg/L. One of the most pronounced results of this study was that the EPS production of L. plantarum MF556 strain was increased up to 512.81 mg/L with the addition of calcium carbonate to MRS medium. The effect of different culture conditions, particularly of incubation time, carbon, nitrogen, and mineral sources, on the EPS production often vary depending on the strain. Therefore, these apparent strain specific results demonstrated that the optimum culture conditions for the enhanced EPS production should be specifically determined for each LAB strain.


Assuntos
Meios de Cultura/farmacologia , Alimentos e Bebidas Fermentados/microbiologia , Microbiologia de Alimentos , Lactobacillales/efeitos dos fármacos , Lactobacillales/metabolismo , Polissacarídeos Bacterianos/biossíntese , Fermentação , Lactobacillales/isolamento & purificação , Temperatura
4.
J Sci Food Agric ; 100(4): 1448-1457, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31756265

RESUMO

BACKGROUND: Baixi sufu (BS) is a traditional Chinese spicy fermented bean curd manufactured with a natural starter. In this study, the bacterial and fungal communities during BS fermentation were determined by culture and by the culture-independent method of high-throughput sequencing (HTS). Correlation analyses were performed to select the microorganisms potentially contributing to this fermentation. RESULTS: During the fermentation of BS, 162 bacterial and 97 fungal strains were isolated and identified, and a total of 268 314 bacterial and 287 844 fungal high-quality sequences were analyzed. In general, lactic acid bacteria (LAB), especially Enterococcus and Lactococcus, were dominant in the early stage of fermentation, and spore-forming bacteria, especially Bacillus spp., became the predominant bacteria by the end of fermentation. Geotrichum, Mortierella, and unclassified Ascomycota, were the major fungal populations, which could not be detected in the final product. Correlation analyses indicated that Enterococcus, Bacillus, Geotrichum, and unclassified Ascomycota correlated significantly and positively with amino nitrogen. However, due to the sporulation characteristics of Bacillus, they may have little effect on BS ripening. The presence of Bifidobacterium spp. in sufu is reported for the first time, but the excessive counts of the Bacillus cereus group (>105 CFU g-1 ) indicate a potential hazard to consumers. CONCLUSION: The profiles obtained from this study will contribute to the development of autochthonous starter cultures to control BS fermentation, and may lead to the development of novel strategies to shorten the fermentation time of sufu products. © 2019 Society of Chemical Industry.


Assuntos
Fabaceae/microbiologia , Fungos/metabolismo , Lactobacillales/metabolismo , Micobioma , Fabaceae/metabolismo , Fermentação , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Sequenciamento de Nucleotídeos em Larga Escala , Lactobacillales/classificação , Lactobacillales/genética , Lactobacillales/isolamento & purificação
5.
J Sci Food Agric ; 100(3): 926-935, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31523827

RESUMO

BACKGROUND: The effects were studied of different inoculation strategies for selected starters -yeasts and lactic acid bacteria (LAB) - used for the fermentation process of two Greek olive cultivars, Conservolea and Kalamàta. The LAB strains applied were Leuconostoc mesenteroides K T5-1 and L. plantarum A 135-5; the selected yeast strains were S. cerevisiae KI 30-16 and Debaryomyces hansenii A 15-44 for Kalamàta and Conservolea olives, respectively. RESULTS: Table olive fermentation processes were monitored by performing microbiological analyses, and by monitoring changes in pH, titratable acidity and salinity, sugar consumption, and the evolution of volatile compounds. Structural modifications occurring in phenolic compounds of brine were investigated during the fermentation using liquid chromatography / diode array detection / electrospray ion trap tandem mass spectrometry (LC/DAD/ESI-MSn ) and quantified by high-performance liquid chromatography (HPLC) using a diode array detector. Phenolic compounds in processed Kalamàta olive brines consisted of phenolic acids, verbascoside, caffeoyl-6-secologanoside, comselogoside, and the dialdehydic form of decarboxymethylelenolic acid linked to hydroxytyrosol, whereas oleoside and oleoside 11-methyl ester were identified only in Conservolea olive brines. CONCLUSION: Volatile profile and sensory evaluation revealed that the 'MIX' (co-inoculum of yeast and LAB strain) inoculation strategy led to the most aromatic and acceptable Kalamàta olives. For the Conservolea table olives, the 'YL' treatment gave the most aromatic and the overall most acceptable product. © 2019 Society of Chemical Industry.


Assuntos
Debaromyces/metabolismo , Microbiologia de Alimentos/métodos , Lactobacillales/metabolismo , Olea/química , Olea/microbiologia , Fenol/metabolismo , Saccharomyces cerevisiae/metabolismo , Fermentação , Frutas/química , Frutas/microbiologia , Humanos , Fenol/análise , Sais/análise , Sais/metabolismo , Paladar
6.
J Agric Food Chem ; 68(1): 301-314, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31820631

RESUMO

Xylooligosaccharides (XOS) from woody biomass were evaluated as a substrate for secondary lactic acid bacteria (LAB) fermentation in sour beer production. XOS were extracted from birch (Betula pubescens) and added to beer to promote the growth of Lactobacillus brevis BSO 464. Growth, pH, XOS degradation, and metabolic products were monitored throughout fermentations, and the final beer was evaluated sensorically. XOS were utilized, metabolic compounds were produced (1800 mg/L lactic acid), and pH was reduced from 4.1 to 3.6. Secondary fermentation changed sensory properties significantly, and the resulting sour beer was assessed as similar to a commercial reference in multiple attributes, including acidic taste. Overall, secondary LAB fermentation induced by wood-derived XOS provided a new approach to successfully produce sour beer with reduced fermentation time (from 1-3 years to 4 weeks). The presented results demonstrate how hemicellulosic biomass can be valorized for beverage production and to obtain sour beer with improved process control.


Assuntos
Cerveja/análise , Microbiologia de Alimentos/métodos , Glucuronatos/metabolismo , Lactobacillales/metabolismo , Oligossacarídeos/metabolismo , Extratos Vegetais/metabolismo , Madeira/química , Cerveja/microbiologia , Betula/química , Betula/metabolismo , Betula/microbiologia , Fermentação , Humanos , Concentração de Íons de Hidrogênio , Lactobacillales/crescimento & desenvolvimento , Paladar , Madeira/metabolismo , Madeira/microbiologia
7.
J Dairy Sci ; 103(1): 141-149, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31629528

RESUMO

The objective of this study was to develop a novel immobilized system using kefir lactic acid bacteria and sugar cane pieces for the production of fermented milk. Lactobacillus kefiranofaciens HL1, Lactobacillus kefiri HL2, Leuconostoc mesenteroides HL3, and Lactococcus lactis HL4 were isolated from Taiwanese kefir grains and immobilized on pieces of sugar cane using adsorption. Scanning electron micrographs of the cell-immobilized sugar cane pieces (CISCP) showed that the microorganisms were embedded within the porous structures of the sugar cane pieces. During 28 cycles of repeated batch fermentation, viable cells on both sugar cane pieces and fermented products were maintained at 10 log cfu/g (cfu/mL). Random amplified polymorphic DNA PCR analysis revealed that Leu. mesenteroides HL3 (29-43%) and Lc. lactis HL4 (31-49%) were predominant on the CISCP, and the fermented samples had 79% Lc. lactis HL4. When tracking fermentation parameters, the data on the microbial, chemical, and physical properties of the fermented milk suggested that the CISCP had stable fermentative ability over the course of successive fermentations. We found an enhancement of the acid-producing ability of CISCP as the number of fermentations increased, with a significant growth in titratable acidity from 0.65 to 0.81% by the end.


Assuntos
Produtos Fermentados do Leite/microbiologia , Kefir/microbiologia , Lactobacillales/metabolismo , Lactobacillus/isolamento & purificação , Leite/metabolismo , Saccharum , Animais , Células Imobilizadas , Fermentação , Lactobacillales/isolamento & purificação , Lactococcus lactis/isolamento & purificação , Lactococcus lactis/metabolismo , Leuconostoc/isolamento & purificação , Leite/química
8.
Food Chem ; 306: 125620, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31606627

RESUMO

The lactic acid bacteria (LAB) and yeast strains with phytate degrading ability were isolated from Iranian traditional sourdough, and based on the acid and bile tolerance, three LAB and three yeast strains were selected and molecularly identified. In this study, baker's yeast (Saccharomyces cerevisiae) was considered as a positive control strain to investigate the nutritional and technological properties of the isolated strains. All of the identified microorganisms were characterized based on additional probiotic properties and were evaluated for nutritional and technological characteristics. The functional features are associated with degradation of phytate, antioxidant capacity, exopolysaccharides, phenolic compound content and in vitro starch digestion. Among all the tested strains the highest amount of phytase production capacity (1.64 Unit/ml) and lowest phytate content (17.49 mg/5 g) belonged to Kluyveromyces marxianus. According to the results, the bread prepared by using Kluyveromyces aestuarii possessed the highest porosity percentage (70.43%), and the lowest hardness (508.71 g).


Assuntos
Pão/análise , Lactobacillales/metabolismo , Ácido Fítico/metabolismo , Saccharomyces cerevisiae/metabolismo , Triticum/química , 6-Fitase/metabolismo , Pão/microbiologia , Irã (Geográfico) , Lactobacillales/isolamento & purificação , Probióticos , Saccharomyces cerevisiae/isolamento & purificação , Triticum/metabolismo
9.
Int J Food Microbiol ; 313: 108384, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31670259

RESUMO

Aiming at meeting the recommendations of the World Health Organization regarding the total fiber daily intake, an integrate biotechnological approach, combining xylanase treatment and lactic acid bacteria fermentation of milling by-products from pigmented wheat varieties, hull-less barley and emmer was proposed. The effects on the biochemical and nutritional features were investigated. Enhanced radical scavenging activity, increased concentrations of free amino acids (up to three times) and peptides and optimal in vitro protein digestibility (up to ca. 87%) value as well as relevant phytic acid degradation were achieved during bran fermentation. The main nutritional features of each matrix were enhanced and distinguished. Fortified breads were characterized by a concentration in total dietary fibers and protein of ca. 7 and 13% of dry matter, respectively. Compared to wheat bread the addition of pre-fermented brans caused a significant increase in protein digestibility (up to 79%), and a relevant decrease of the predicted glycemic index (ca. 8%) of the fortified bread. According to the results, this study demonstrates the potential of xylanase treatment and lactic acid bacteria fermentation to be used as suitable strategy to include bran in breadmaking, meeting both nutritional and sensory requests of modern consumers.


Assuntos
Pão/análise , Fibras na Dieta/análise , Endo-1,4-beta-Xilanases/química , Hordeum/microbiologia , Lactobacillales/metabolismo , Triticum/microbiologia , Biocatálise , Pão/microbiologia , Fibras na Dieta/metabolismo , Fermentação , Farinha/análise , Farinha/microbiologia , Aditivos Alimentares/análise , Aditivos Alimentares/metabolismo , Humanos , Lactobacillaceae/metabolismo , Valor Nutritivo , Ácido Fítico/análise , Ácido Fítico/metabolismo , Triticum/química , Resíduos/análise
10.
Lett Appl Microbiol ; 70(1): 48-54, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31642537

RESUMO

This study aims to describe the native microbiota of fermented spelt, taking into consideration both lactic acid bacteria (LAB) and yeasts, for which little data are available. Five samples of commercial spelt flour were subjected to spontaneous fermentation to obtain a type I sourdough. A total of 186 LAB and 174 yeast isolates were selected at different refreshment steps and subjected to further analyses. Within LAB, coccal isolates constituted 78·5% of the total LAB, with the dominance of Pediococcus pentosaceus. Although documented before as a component, this is the first report of a spelt sourdough fermentation dominated by this homofermentative LAB, characterized by a high acidification rate, ability to utilize a wide range of carbon sources and to grow in high osmolarity conditions. Yeast communities resulted in four dominant species, Saccharomyces cerevisiae, Wickerhamomyces anomalus, Pichia fermentans and Clavispora lusitaniae. This study highlights for the first time the biodiversity and dynamics of yeast communities involved in sourdough fermentation of spelt. Compared to commercial baker's yeast, autochthonous W. anomalus, P. fermentans and S. cerevisiae isolates show a good performance, and their use could be an advantage for their acquired adaptation to the environment, providing stability to the fermentation process. SIGNIFICANCE AND IMPACT OF THE STUDY: Nowadays, there is a renewed interest in products based on spelt. This 'ancient grain' is a highly nutritional grain; however, its use is limited to bread-making processes, which are not standardized. The low baking and sensory quality of spelt can be overcome through fermentation processes. However, the autochthonous microbiota of spelt sourdough is poorly known. This study highlights the dynamics of microbial communities involved in sourdough fermentation of spelt and provides the basis for the selection of autochthonous cultures, with the aim of improving the nutritional potential of spelt and its rheology and bread-making properties.


Assuntos
Pão/microbiologia , Lactobacillales/metabolismo , Consórcios Microbianos , Triticum/microbiologia , Leveduras/metabolismo , Biodiversidade , Pão/análise , Fermentação , Farinha/microbiologia , Microbiologia de Alimentos , Lactobacillales/classificação , Lactobacillales/genética , Lactobacillales/isolamento & purificação , Triticum/metabolismo , Leveduras/classificação , Leveduras/genética , Leveduras/isolamento & purificação
11.
Gen Physiol Biophys ; 38(5): 455-460, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31595883

RESUMO

Lactic acid bacteria (LAB) are exceptionally important strains in food industry. It is a heterogeneous group sharing same metabolic and physiological properties. They are usually catalase-negative strains, which represents a big disadvantage in food production in comparison with pathogenic bacteria as staphylococci and listeria existing in the same environment, because of the use of hydrogen peroxide as a disinfection agent which is utilized by catalases. We focused on increase in LAB surviving through the disinfection without any positive effect on growth of pathogenic bacteria. In our functional test hydrogen peroxide was used for disinfection. Ten mM thermostable catalase-peroxidase AfKatG was added to solid media to cultivate bacteria afterwards. As predicted there was no difference in the growth of pathogenic bacteria with or without catalase-peroxidase addition to media. However, we showed a huge positive effect on surviving LAB. With addition of AfKatG to solid media we gained 2-38 times higher CFU/ml than in control samples without it. We can assume AfKatG as an excellent supplement for growth media of food strains.


Assuntos
Catalase/metabolismo , Meios de Cultura/farmacologia , Meios de Cultura/toxicidade , Peróxido de Hidrogênio/metabolismo , Peróxido de Hidrogênio/toxicidade , Lactobacillales/efeitos dos fármacos , Lactobacillales/crescimento & desenvolvimento , Peroxidase/metabolismo , Meios de Cultura/química , Estabilidade Enzimática , Lactobacillales/metabolismo
12.
Int J Mol Sci ; 20(20)2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31600952

RESUMO

Biotransformation via solid state fermentation (SSF) mediated by microorganisms is a promising approach to produce useful products from agricultural biomass. Lactic acid bacteria (LAB) that are commonly found in fermented foods have been shown to exhibit extracellular proteolytic, ß-glucosidase, ß-mannosidase, and ß-mannanase activities. Therefore, extracellular proteolytic, cellulolytic, and hemicellulolytic enzyme activities of seven Lactobacillus plantarum strains (a prominent species of LAB) isolated from Malaysian foods were compared in this study. The biotransformation of palm kernel cake (PKC) biomass mediated by selected L. plantarum strains was subsequently conducted. The results obtained in this study exhibited the studied L. plantarum strains produced versatile multi extracellular hydrolytic enzyme activities that were active from acidic to alkaline pH conditions. The highest total score of extracellular hydrolytic enzyme activities were recorded by L. plantarum RI11, L. plantarum RG11, and L. plantarum RG14. Therefore, they were selected for the subsequent biotransformation of PKC biomass via SSF. The hydrolytic enzyme activities of treated PKC extract were compared for each sampling interval. The scanning electron microscopy analyses revealed the formation of extracellular matrices around L. plantarum strains attached to the surface of PKC biomass during SSF, inferring that the investigated L. plantarum strains have the capability to grow on PKC biomass and perform synergistic secretions of various extracellular proteolytic, cellulolytic, and hemicellulolytic enzymes that were essential for the effective biodegradation of PKC. The substantial growth of selected L. plamtraum strains on PKC during SSF revealed the promising application of selected L. plantarum strains as a biotransformation agent for cellulosic biomass.


Assuntos
Biomassa , Biotransformação , Celulose/metabolismo , Microbiologia de Alimentos , Lactobacillales/metabolismo , Phoeniceae/química , Biodegradação Ambiental , Celulose/química , Espaço Extracelular/metabolismo , Fermentação , Hidrólise , Lactobacillales/isolamento & purificação , Proteólise
13.
Food Chem Toxicol ; 134: 110833, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31574266

RESUMO

Flavor deterioration is a serious problem in dried carrots during storage and is frequently accompanied by water absorption and bacterial growth. To explore the underlying mechanism of flavor deterioration, relationship among water status, exogenous bacterial composition and flavor changes in dried carrots were analyzed at different water activities (aw, 0.43, 0.67, 0.76 and 0.84). Results suggested that the water molecules mobility significantly increased in the dried carrots at higher aw levels (0.67, 0.76 and 0.84), this was attributed to the raised content of bound water, rather than immobilized or free water. Consequently, this accelerated microbial growth and flavor deterioration. At aw = 0.84, the characteristic flavor compounds including 2,3-butanediol, pentanoic acid, hexanoic acid, heptanoic acid and nonanoic acid were lost. The disagreeable flavor compounds including terpenes were produced during the storage period. These were the main contributors of flavor deterioration in the dried carrots. Lactic acid bacteria, as the dominant bacteria in dried carrots during storage, were proved to be closely related to the production of o-cymene, ß-pinene and ß-myrcene. Moreover, the emergence of Pediococcus spp. was the major factor leading to the increase of γ-terpinene in dried carrots.


Assuntos
Daucus carota/microbiologia , Conservação de Alimentos , Paladar , /metabolismo , Alcenos/metabolismo , /metabolismo , Lactobacillales/metabolismo , Água/química
14.
Appl Microbiol Biotechnol ; 103(21-22): 8937-8945, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31520133

RESUMO

Inflammatory bowel diseases are chronic and relapsing-remitting disorders that affect the gastrointestinal tract. Previously, the administration of folate and riboflavin-producing lactic acid bacteria (LAB) or an immune-modulating strain showed beneficial effects as they were able to reduce the acute inflammation in mouse models. The aim of this work was to evaluate a mixture of vitamin-producing and immune-modulating LAB administering together with an anti-inflammatory drug during the remission period of a mouse model of recurrent colitis. BALB/c mice were intrarectally instilled with trinitrobenzene sulfonic acid (TNBS) and those who recovered from this acute challenge were given the LAB mixture, mesalazine, or the combination of both (mesalazine + LAB) during 21 days, followed by a second challenge with TNBS. Control mice instilled with ethanol (vehicle of TNBS) and receiving the different treatments were also evaluated in order to study the effect of chronic anti-inflammatory therapy. The combination of mesalazine and LAB mixture was the most effective to decrease the intestinal damage at macroscopic and histological levels and to reduce pro-inflammatory cytokines (IL-6 and TNF-α) in intestinal fluids. In animals instilled with ethanol, mesalazine produced a loss of body weight and intestinal damages with increased IL-6. These side effects were prevented by the co-administration of mesalazine and the LAB mixture. The LAB blend did not affect the primary anti-inflammatory treatment, was able to improve it, and also prevented the side effects of this therapy.


Assuntos
Adjuvantes Imunológicos/administração & dosagem , Colite/tratamento farmacológico , Lactobacillales/metabolismo , Probióticos/administração & dosagem , Vitaminas/metabolismo , Animais , Colite/genética , Colite/imunologia , Modelos Animais de Doenças , Humanos , Interleucina-6/genética , Interleucina-6/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologia
15.
J Dairy Sci ; 102(12): 10724-10736, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31521367

RESUMO

This study was aimed at developing a new functional fermented beverage manufactured with semi-skimmed sheep milk and strawberry pulp (Fragaria × ananassa Duch.) and commercial prebiotic ingredients. We also compared the performance of the yogurt starter cultures and a Lactobacillus plantarum strain (CECT_8328) with potential probiotic properties. We assessed the nutritional profile, bioactivity compounds, viability of lactic acid bacteria during storage, and survival of L. plantarum after in vitro simulated digestion during the storage period. The lactic acid bacteria were viable throughout the storage period, but only L. plantarum maintained good viability after simulated digestion. Nevertheless, neither inulin nor potato starch increased bacterial viability. The fermented semi-skimmed sheep milk strawberry beverages we developed are good sources of minerals and proteins.


Assuntos
Bebidas , Fragaria , Leite , Animais , Bebidas/microbiologia , Proteínas na Dieta , Fermentação , Inulina/metabolismo , Lactobacillales/metabolismo , Lactobacillus plantarum , Leite/metabolismo , Valor Nutritivo , Prebióticos , Probióticos , Ovinos , Iogurte/microbiologia
16.
Appl Microbiol Biotechnol ; 103(18): 7687-7702, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31388732

RESUMO

In recent years, there is an increasing interest from the winemaking industry for the use of mixed fermentations with Starmerella bacillaris (synonym Candida zemplinina) and Saccharomyces cerevisiae, due to their ability to modulate metabolites of oenological interest. The current study was carried out to elucidate the effect of this fermentation protocol on the growth and malolactic activity of lactic acid bacteria (LAB) used for malolactic fermentation (MLF) and on the chemical and volatile profile of Nebbiolo wines and their chromatic characteristics. To this end, two LAB species, namely Lactobacillus plantarum and Oenococcus oeni, were inoculated at the beginning and at the end of the alcoholic fermentation (AF) performed by pure and mixed yeast using the abovementioned yeasts. The different yeast inoculation protocols and the combination of species tested influenced greatly the interactions and behavior of the inoculated yeasts and LAB during AF and MLF. For both LAB species, inoculation timing was critical to how rapidly MLF started and finished. Fermentation inoculated with L. plantarum, at the beginning of the AF, completed MLF faster than those inoculated with O. oeni. The presence of Starm. bacillaris in mixed fermentation promoted LAB growth and activity, in particular, O. oeni. Furthermore, LAB species choice had a greater impact on the volatile and chromatic profile of the wines than inoculation time. These findings reveal new knowledge about the importance of LAB species choice and inoculation time to ensure fast MLF completion and to improve wine characteristics in mixed fermentation with Starm. bacillaris and S. cerevisiae.


Assuntos
Fermentação , Ácido Láctico/metabolismo , Lactobacillus plantarum/metabolismo , Malatos/metabolismo , Interações Microbianas , Oenococcus/metabolismo , Lactobacillales/crescimento & desenvolvimento , Lactobacillales/metabolismo , Vinho/análise , Vinho/microbiologia
17.
Int J Mol Sci ; 20(16)2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31443334

RESUMO

This study reports the first application of a next generation sequencing (NGS) analysis. The analysis was designed to monitor the effect of the management of microbial resources associated with alcoholic fermentation on spontaneous malolactic consortium. Together with the analysis of 16S rRNA genes from the metagenome, we monitored the principal parameters linked to MLF (e.g., malic and lactic acid concentration, pH). We encompass seven dissimilar concrete practices to manage microorganisms associated with alcoholic fermentation: Un-inoculated must (UM), pied-de-cuve (PdC), Saccharomyces cerevisiae (SC), S. cerevisiae and Torulaspora delbrueckii co-inoculated and sequentially inoculated, as well as S. cerevisiae and Metschnikowia pulcherrima co-inoculated and sequentially inoculated. Surprisingly, each experimental modes led to different taxonomic composition of the bacterial communities of the malolactic consortia, in terms of prokaryotic phyla and genera. Our findings indicated that, uncontrolled AF (UM, PdC) led to heterogeneous consortia associated with MLF (with a relevant presence of the genera Acetobacter and Gluconobacter), when compared with controlled AF (SC) (showing a clear dominance of the genus Oenococcus). Effectively, the SC trial malic acid was completely degraded in about two weeks after the end of AF, while, on the contrary, malic acid decarboxylation remained uncomplete after 7 weeks in the case of UM and PdC. In addition, for the first time, we demonstrated that both (i) the inoculation of different non-Saccharomyces (T. delbrueckii and M. pulcherrima) and, (ii) the inoculation time of the non-Saccharomyces with respect to S. cerevisiae resources (co-inoculated and sequentially inoculated) influence the composition of the connected MLF consortia, modulating MLF performance. Finally, we demonstrated the first findings of delayed and inhibited MLF when M. pulcherrima, and T. delbrueckii were inoculated, respectively. In addition, as a further control test, we also assessed the effect of the inoculation with Oenococcus oeni and Lactobacillus plantarum at the end of alcoholic fermentation, as MLF starter cultures. Our study suggests the potential interest in the application of NGS analysis, to monitor the effect of alcoholic fermentation on the spontaneous malolactic consortium, in relation to wine.


Assuntos
Metagenoma/genética , Vinho/microbiologia , Fermentação/genética , Fermentação/fisiologia , Lactobacillales/genética , Lactobacillales/metabolismo , Lactobacillus plantarum/genética , Lactobacillus plantarum/metabolismo , RNA Ribossômico 16S , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Torulaspora/genética , Torulaspora/metabolismo
18.
Tuberculosis (Edinb) ; 117: 24-30, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31378264

RESUMO

The aim of this study was to determine the reliability of lactic acid bacteria (LAB) as heterologous hosts for the expression of MPB70 and MPB83, two Mycobacterium bovis antigens that possess diagnostics and immunogenic properties, respectively. We therefore generated recombinant cells of Lactococcus lactis and Lactobacillus plantarum that carried hybrid genes encoding MPB70 and MPB83 fused to signal peptides that are specifically recognized by LAB. Only L. lactis was able to secrete MPB70 using the L. lactis signal peptide Usp45, and to produce MPB83 as an immunogenic membrane protein following its expression with the signal peptide of the L. plantarum lipoprotein prsA. Inactivated cells of MPB83-expressing L. lactis cultures enhanced NF-κB activation in macrophages. Our results show that L. lactis is a reliable host for the secretion and functional expression of antigens that are naturally produced by M. bovis, the causative agent of bovine tuberculosis (bTB). This represents the first step on a long process to establishing whether recombinant LAB could serve as a food-grade platform for potential diagnostic tools and/or vaccine interventions for use against bTB, a chronic disease that primarily affects cattle but also humans and a wide range of domestic and wild animals.


Assuntos
Antígenos de Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Lactobacillales/metabolismo , Proteínas de Membrana/metabolismo , Mycobacterium bovis/imunologia , Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , Células Cultivadas , DNA Bacteriano/biossíntese , Expressão Gênica , Vetores Genéticos/imunologia , Humanos , Lactobacillales/genética , Lactobacillus plantarum/genética , Lactobacillus plantarum/metabolismo , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , Macrófagos/metabolismo , Macrófagos/microbiologia , Proteínas de Membrana/genética , NF-kappa B/metabolismo , Recombinação Genética
19.
Curr Microbiol ; 76(10): 1095-1104, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31270565

RESUMO

Fermented cereals are part of the main traditional diets of many people in Africa, usually obtained from artisanal production. The intensification of their manufacturing, responding to the consumers demand, requires a better control to ensure their sanitary, nutritional, and taste qualities, hence, the need of selecting accurate and safe starter cultures. In the present study, 48 lactic acid bacteria (LAB) strains, previously isolated from Algerian fermented wheat lemzeiet, were analyzed for different technological properties. 14 LAB strains, belonging to Pediococcus pentosaceus, Enterococcus faecium, Lactobacillus curvatus, Lactobacillus brevis, and Leuconostoc mesenteroides species, decreased rapidly the pH of the flour extract broth close to 4 or below. 91% of strains showed extracellular protease activity, but only 12% were amylolytics. 18 LAB strains inhibited or postponed the growth of three fungal targets Rhodotorula mucilaginosa UBOCC-A-216004, Penicillium verrucosum UBOCC-A-109221, and Aspergillus flavus UBOCC-A-106028. The strains belonging to Lactobacillus spp., Leuconostoc fallax, L. mesenteroides, and Weissella paramesenteroides were the most antifungal ones. Multiplex PCR for biogenic amines' production did not reveal any of the genes involved in the production of putrescine, histamine, and tyramine for 17 of the 48 strains. The obtained results provided several candidates for use as starter culture in the future production of lemzeiet.


Assuntos
/microbiologia , Microbiologia de Alimentos , Lactobacillales/isolamento & purificação , Lactobacillales/metabolismo , Triticum/microbiologia , Amilases/metabolismo , Antifúngicos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Aminas Biogênicas/biossíntese , DNA Bacteriano/genética , Fermentação , Concentração de Íons de Hidrogênio , Lactobacillales/enzimologia , Lactobacillales/genética , Peptídeo Hidrolases/metabolismo
20.
Appl Microbiol Biotechnol ; 103(17): 6867-6883, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31300854

RESUMO

Production of lactic acid bacteria starters for manufacturing food, probiotic, and chemical products requires the application of successive steps: fermentation, concentration, stabilization, and storage. Despite process optimization, losses of bacterial viability and functional activities are observed after stabilization and storage steps due to cell exposure to environmental stresses (thermal, osmotic, mechanical, and oxidative). Bacterial membrane is the primary target for injury and its damage is highly dependent on its physical properties and lipid organization. Membrane fluidity is a key property for maintaining cell functionality, and depends on lipid composition and cell environment. Extensive evidence has been reported on changes in membrane fatty acyl chains when modifying fermentation conditions. However, a deep characterization of membrane physical properties and their evolution following production processes is scarcely reported. Therefore, the aims of this mini-review are (i) to define the membrane fluidity and the methods used to assess it and (ii) to summarize the effect of environmental conditions on membrane fluidity and the resulting impact on the resistance of lactic acid bacteria to the stabilization processes. This will make it possible to highlight existing gaps of knowledge and opens up novel approaches for future investigations.


Assuntos
Lactobacillales/fisiologia , Fluidez de Membrana/fisiologia , Lipídeos de Membrana/química , Estresse Fisiológico , Membrana Celular/química , Membrana Celular/fisiologia , Fermentação , Polarização de Fluorescência , Lactobacillales/química , Lactobacillales/crescimento & desenvolvimento , Lactobacillales/metabolismo , Lipídeos de Membrana/metabolismo , Transição de Fase , Preservação Biológica
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