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1.
J Food Sci Technol ; 61(11): 2133-2144, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39397834

RESUMO

The aim of this study was to formulate a Selenium (Se)-bioenriched fermented beverage using selenized lactic acid bacteria (LAB) with desirable sensory attributes and shelf-life. The fruit-origin strains Lactiplantibacillus paraplantarum CRL 2051 and Fructobacillus tropaeoli CRL 2034 were grown in MRS-fructose with 5 mg/L Se before inoculation. Then, the selenized strains were inoculated separately or together in a fruit juice and cowmilk beverage and allowed to ferment at 30 °C for 14 h. During microbial growth, the strains accumulated 62.8-93.5 µg/L of total Se, with 32.7-47.8 µg/L composed of the amino acids selenocysteine (SeCys), and 6.1-12.7 µg/L of selenomethionine (SeMet). The beverages fermented by L. paraplantarum CRL 2051 alone and by the mixed culture showed the highest levels of general acceptance and best sensory attributes. The latter fermented beverage exhibited high microbial resistance to cold storage after 52 days and to gastrointestinal tract conditions as well as an acceptable sensory shelf-life of 42 days. For the first time, microbial selenization previous to food fermentation successfully allowed Se fortification and the formulation of a functional Se-enriched beverage with desirable sensory properties and shelf-life. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-024-05984-4.

2.
Appl Microbiol Biotechnol ; 107(4): 1329-1339, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36680586

RESUMO

The fruit-origin strain Fructobacillus tropaeoli CRL 2034 can biotransform selenium into seleno-nanoparticles and selenocysteine. The proteomic analysis of F. tropaeoli CRL 2034 exposed to 5 and 100 ppm of Se showed a dose-dependent response since 19 and 77 proteins were deregulated, respectively. In the presence of 5 ppm of Se, the deregulated proteins mainly belonged to the categories of energy production and conversion or had unknown functions, while when cells were grown with 100 ppm of Se, most of the proteins were grouped into amino acid transport and metabolism, nucleotide transport and metabolism, or into unknown functions. However, under both Se conditions, glutathione reductases were overexpressed (1.8-3.1-fold), while mannitol 2-dehydrogenase was downregulated (0.54-0.19-fold), both enzymes related to oxidative stress functions. Mannitol 2-dehydrogenase was the only enzyme found that contained SeCys, and its activity was 1.27-fold increased after 5 ppm of Se exposure. Our results suggest that F. tropaeoli CRL 2034 counteracts Se stress by overexpressing proteins related to oxidative stress resistance and changing the membrane hydrophobicity, which may improve its survival under (food) storage and positively influence its adhesion to intestinal cells. Selenized cells of F. tropaeoli CRL 2034 could be used for producing Se-enriched fermented foods. KEY POINTS: • Selenized cells of F. tropaeoli showed enhanced resistance to oxidative stress. • SeCys was found in the Fructobacillus mannitol 2-dehydrogenase polypeptide chain. • F. tropaeoli mannitol 2-dehydrogenase activity was highest when exposed to selenium.


Assuntos
Selênio , Selênio/química , Frutas/metabolismo , Manitol Desidrogenases/metabolismo , Proteômica , Estresse Oxidativo
3.
Appl Microbiol Biotechnol ; 104(17): 7409-7426, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32666186

RESUMO

The enzymes D- and L-lactate dehydrogenase are involved in the reduction of pyruvate to D(+)- and L(-)-lactate, respectively. The fig-origin strain Fructobacillus tropaeoli CRL 2034 produces D- and L-lactic acids in a 9:1 ratio. In this work, two D-ldh (ldh1 and ldh2) and one L-ldh (ldh3) genes were found in the CRL 2034 genome. ldh1 and ldh2 are homologous (79% identity) and organized as contiguous operons, each gene containing 996 base pair (bp) and encoding for a 331-amino acid (aa) protein (74% identity). In contrast, ldh3 is a 927-bp gene coding for a 308-aa protein. The identity between ldh1/ldh2 and ldh3 was lower than 48%. To elucidate the role of these genes in the synthesis of lactic acid by the Fructobacillus strain, plasmid insertion mutants in each gene were generated and characterized. The growth kinetic parameters were affected only in CRL2034 ldh1::pRV300 cells, this mutant showing the lowest total lactic acid production (4.50 ± 0.15 versus 6.36 ± 0.67 g/L of wild-type strain), with a D/L ratio of 7.1:2.9. These results showed that the ldh1 gene is primarily responsible for lactic acid production by the studied strain. A comparative analysis among strains of the five Fructobacillus species revealed that the identity of D-LDH proteins was higher than 70%, while the identity of L-LDH was over 60%. Finally, phylogenetic analysis of D- and L-LDHs revealed that only D-LDH phylogeny was consistent to the phylogenetic evolution among Fructobacillus and evolutionarily related genera. Key Points •F. tropaeoli CRL 2034 harbors three ldh genes in its genome. •ldh1 and ldh2 encode D-lactate dehydrogenase; ldh3 encodes L-lactate dehydrogenase. •Gene ldh1 plays the major role in lactic acid production by strain CRL 2034. •Fructobacillus D-LDH phylogeny was consistent to phylogenetic evolution.


Assuntos
L-Lactato Desidrogenase , Ácido Láctico , Isoenzimas , L-Lactato Desidrogenase/genética , Leuconostocaceae , Filogenia
4.
Curr Microbiol ; 77(9): 2215-2225, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32601836

RESUMO

We report the draft genome sequence of Fructobacillus tropaeoli CRL 2034, a strain isolated from ripe fig in Tucumán province, Argentina. The interest in studying the genome of this fructophilic lactic acid bacterium strain was motivated by its ability to produce high levels of mannitol from fructose. This polyol has multiple industrial applications; however, it is mainly used as low calorie sugar in the food industry. The assembled genome of this strain consists of a 1.66-Mbp circular chromosome with 1465 coding sequences and a G+C content of 44.6%. The analysis of this genome supports the one step reaction of fructose reduction to mannitol by the mannitol 2-dehydrogenase enzyme, which together with a fructose permease, were identified as involved in mannitol synthesis. In addition, a phylogenetic analysis was performed including other Leuconostocaceae members to which the Fructobacillus genus belongs to; according to the 16S rRNA gene sequences, the strain CRL 2034 was located in the Fructobacillus clade. The present genome sequence could be useful to further elucidate regulatory processes of mannitol and other bioactive metabolites and to highlight the biotechnological potential of this fruit-origin Fructobacillus strain.


Assuntos
Ficus , Leuconostocaceae , Argentina , Frutose , Leuconostocaceae/genética , Manitol , Filogenia , RNA Ribossômico 16S/genética
5.
Appl Microbiol Biotechnol ; 101(15): 6165-6177, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28674850

RESUMO

Mannitol is a natural low-calorie sugar alcohol produced by certain (micro)organisms applicable in foods for diabetics due to its zero glycemic index. In this work, we evaluated mannitol production and yield by the fruit origin strain Fructobacillus tropaeoli CRL 2034 using response surface methodology with central composite design (CCD) as optimization strategy. The effect of the total saccharide (glucose + fructose, 1:2) content (TSC) in the medium (75, 100, 150, 200, and 225 g/l) and stirring (S; 50, 100, 200, 300 and 350 rpm) on mannitol production and yield by this strain was evaluated by using a 22 full-factorial CCD with 4 axial points (α = 1.5) and four replications of the center point, leading to 12 random experimental runs. Fermentations were carried out at 30 °C and pH 5.0 for 24 h. Minitab-15 software was used for experimental design and data analyses. The multiple response prediction analysis established 165 g/l of TSC and 200 rpm of S as optimal culture conditions to reach 85.03 g/l [95% CI (78.68, 91.39)] of mannitol and a yield of 82.02% [95% CI (71.98, 92.06)]. Finally, a validation experiment was conducted at the predicted optimum levels. The results obtained were 81.91 g/l of mannitol with a yield of 77.47% in outstanding agreement with the expected values. The mannitol 2-dehydrogenase enzyme activity was determined with 4.6-4.9 U/mg as the highest value found. To conclude, F. tropaeoli CRL 2034 produced high amounts of high-quality mannitol from fructose, being an excellent candidate for this polyol production.


Assuntos
Ficus/microbiologia , Leuconostocaceae/metabolismo , Manitol/isolamento & purificação , Manitol/metabolismo , Metabolismo dos Carboidratos , Fermentação , Frutose/metabolismo , Glucose/metabolismo , Concentração de Íons de Hidrogênio , Leuconostocaceae/classificação , Manitol/química , Manitol Desidrogenases/metabolismo , Temperatura
6.
Appl Microbiol Biotechnol ; 100(10): 4573-83, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26910041

RESUMO

The ability of microorganisms to synthesize S-layer, the outermost structure of the microbial cell envelope composed of non-covalently bound proteins, has been ascribed to help microorganisms to exert their probiotic properties in the host. In this work, formation of S-layer by the potentially probiotic strain Lactobacillus acidophilus IBB 801 under different stress culture conditions (high incubation temperatures, presence of bile salts or NaCl, and acidic pH) was assayed. A marked S-layer synthesis by L. acidophilus IBB 801 was detected when the strain was grown at 42 °C and in the presence of 0.05 % bile salts or 2.0 % NaCl. The presence of S-layer proteins was further confirmed by transmission electron microscopy and protein identification by MS/MS. The differential expression of the proteome of this strain at 42 °C, when a marked formation of S-layer was detected, revealed the overexpression of six proteins mainly related to general stress and protein biosynthesis and translation, while four proteins detected in lower amounts were involved in DNA repair and energy metabolism. As L. acidophilus IBB 801 produces both a bacteriocin and S-layer proteins, the strain could be of interest to be used in the formulation of functional food products with specific properties.


Assuntos
Proteínas de Bactérias/biossíntese , Lactobacillus acidophilus/metabolismo , Glicoproteínas de Membrana/biossíntese , Estresse Fisiológico , Bacteriocinas/biossíntese , Ácidos e Sais Biliares/química , Meios de Cultura/química , Concentração de Íons de Hidrogênio , Microbiologia Industrial , Proteômica , Cloreto de Sódio/química , Espectrometria de Massas em Tandem
7.
Appl Microbiol Biotechnol ; 99(20): 8717-29, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26084891

RESUMO

Mannitol is a natural polyol with multiple industrial applications. In this work, mannitol production by Lactobacillus reuteri CRL 1101 was studied at free- and controlled-pH (6.0-4.8) fermentations using a simplified culture medium containing yeast and beef extracts and sugarcane molasses. The activity of mannitol 2-dehydrogenase (MDH), the enzyme responsible for mannitol synthesis, was determined. The effect of the initial biomass concentration was further studied. Mannitol production (41.5 ± 1.1 g/l), volumetric productivity (Q Mtl 1.73 ± 0.05 g/l h), and yield (Y Mtl 105 ± 11 %) were maximum at pH 5.0 after 24 h while the highest MDH activity (1.66 ± 0.09 U/mg protein) was obtained at pH 6.0. No correlation between mannitol production and MDH activity was observed when varying the culture pH. The increase (up to 2000-fold) in the initial biomass concentration did not improve mannitol formation after 24 h although a 2-fold higher amount was produced at 8 h using 1 or 2 g cell dry weight/l comparing to the control (0.001 g cell dry weight/l). Finally, mannitol isolation under optimum fermentation conditions was achieved. The mannitol production obtained in this study is the highest reported so far by a wild-type L. reuteri strain and, more interestingly, using a simplified culture medium.


Assuntos
Meios de Cultura/química , Limosilactobacillus reuteri/metabolismo , Manitol/metabolismo , Fermentação , Concentração de Íons de Hidrogênio , Manitol Desidrogenases/análise , Fatores de Tempo
8.
Appl Microbiol Biotechnol ; 99(15): 6183-96, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26124070

RESUMO

Whey, the main by-product of the cheese industry, is considered as an important pollutant due to its high chemical and biological oxygen demand. Whey, often considered as waste, has high nutritional value and can be used to obtain value-added products, although some of them need expensive enzymatic synthesis. An economical alternative to transform whey into valuable products is through bacterial or yeast fermentations and by accumulation during algae growth. Fermentative processes can be applied either to produce individual compounds or to formulate new foods and beverages. In the first case, a considerable amount of research has been directed to obtain biofuels able to replace those derived from petrol. In addition, the possibility of replacing petrol-derived plastics by biodegradable polymers synthesized during bacterial fermentation of whey has been sought. Further, the ability of different organisms to produce metabolites commonly used in the food and pharmaceutical industries (i.e., lactic acid, lactobionic acid, polysaccharides, etc.) using whey as growth substrate has been studied. On the other hand, new low-cost functional whey-based foods and beverages leveraging the high nutritional quality of whey have been formulated, highlighting the health-promoting effects of fermented whey-derived products. This review aims to gather the multiple uses of whey as sustainable raw material for the production of individual compounds, foods, and beverages by microbial fermentation. This is the first work to give an overview on the microbial transformation of whey as raw material into a large repertoire of industrially relevant foods and products.


Assuntos
Bactérias/metabolismo , Indústria Alimentícia/métodos , Tecnologia Farmacêutica/métodos , Soro do Leite/metabolismo , Leveduras/metabolismo , Biotransformação , Fermentação
9.
Food Chem ; 463(Pt 4): 141434, 2024 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-39348771

RESUMO

This study investigated the health-functional properties of a lactic fermented pomegranate juice (FPJ) enriched with pomegranate seed oil (FPJO) by using the fruit-origin strain Lactiplantibacillus paraplantarum CRL 2051 (FPJO-CRL2051). For this aim, the in vitro human antiplatelet aggregation effect and antioxidant activities were determined in the fermented juices while in vivo studies using high-fat-diet (HFD) C57BL/6 mice fed with a high-fat diet or pomegranate fermented juices for 8 weeks were performed. A high anti-platelet aggregation activity for FPJO-CRL2051 was determined. The formulated juice was administered to C57BL/6 HFD mice over 8 weeks, which showed a significant decrease in triglycerides, LDL-C, and pro-inflammatory cytokines levels. The FPJO-CRL2051 administration was effective in ameliorating liver damage caused by HFD, reducing fat accumulation and oxidative biomarkers, and improving the liver fatty acid profile by incorporation of conjugated fatty acids. This study shows the significance of lactic fermentation in developing novel fermented plant-based beverages with enhanced functional activities with a circular economy approach for the prevention of metabolic disorders.

10.
Appl Microbiol Biotechnol ; 97(11): 4713-26, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23604535

RESUMO

Polyols such as mannitol, erythritol, sorbitol, and xylitol are naturally found in fruits and vegetables and are produced by certain bacteria, fungi, yeasts, and algae. These sugar alcohols are widely used in food and pharmaceutical industries and in medicine because of their interesting physicochemical properties. In the food industry, polyols are employed as natural sweeteners applicable in light and diabetic food products. In the last decade, biotechnological production of polyols by lactic acid bacteria (LAB) has been investigated as an alternative to their current industrial production. While heterofermentative LAB may naturally produce mannitol and erythritol under certain culture conditions, sorbitol and xylitol have been only synthesized through metabolic engineering processes. This review deals with the spontaneous formation of mannitol and erythritol in fermented foods and their biotechnological production by heterofermentative LAB and briefly presented the metabolic engineering processes applied for polyol formation.


Assuntos
Biotecnologia/métodos , Eritritol/metabolismo , Microbiologia de Alimentos/métodos , Lactobacillales/metabolismo , Manitol/metabolismo , Edulcorantes/metabolismo
11.
Appl Microbiol Biotechnol ; 97(17): 7831-44, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23832109

RESUMO

Ability of industrially relevant species of thermophilic lactobacilli strains to hydrolyze proteins from animal (caseins and ß-lactoglobulin) and vegetable (soybean and wheat) sources, as well as influence of peptide content of growth medium on cell envelope-associated proteinase (CEP) activity, was evaluated. Lactobacillus delbrueckii subsp. lactis (CRL 581 and 654), L. delbrueckii subsp. bulgaricus (CRL 454 and 656), Lactobacillus acidophilus (CRL 636 and 1063), and Lactobacillus helveticus (CRL 1062 and 1177) were grown in a chemically defined medium supplemented or not with 1 % Casitone. All strains hydrolyzed mainly ß-casein, while degradation of αs-caseins was strain dependent. Contrariwise, κ-Casein was poorly degraded by the studied lactobacilli. ß-Lactoglobulin was mainly hydrolyzed by CRL 656, CRL 636, and CRL 1062 strains. The L. delbrueckii subsp. lactis strains, L. delbrueckii subsp. bulgaricus CRL 656, and L. helveticus CRL 1177 degraded gliadins in high extent, while the L. acidophilus and L. helveticus strains highly hydrolyzed soy proteins. Proteinase production was inhibited by Casitone, the most affected being the L. delbrueckii subsp. lactis species. This study highlights the importance of proteolytic diversity of lactobacilli for rational strain selection when formulating hydrolyzed dairy or vegetable food products.


Assuntos
Proteínas de Bactérias/química , Caseínas/química , Lactobacillus/enzimologia , Lactoglobulinas/química , Peptídeo Hidrolases/química , Proteínas de Plantas/química , Verduras/química , Animais , Biocatálise , Bovinos , Laticínios/análise , Hidrólise , Lactobacillus/química , Lactobacillus/classificação , Glycine max/química , Triticum/química
12.
PLoS One ; 18(2): e0281839, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36795789

RESUMO

The Fructobacillus genus is a group of obligately fructophilic lactic acid bacteria (FLAB) that requires the use of fructose or another electron acceptor for their growth. In this work, we performed a comparative genomic analysis within the genus Fructobacillus by using 24 available genomes to evaluate genomic and metabolic differences among these organisms. In the genome of these strains, which varies between 1.15- and 1.75-Mbp, nineteen intact prophage regions, and seven complete CRISPR-Cas type II systems were found. Phylogenetic analyses located the studied genomes in two different clades. A pangenome analysis and a functional classification of their genes revealed that genomes of the first clade presented fewer genes involved in the synthesis of amino acids and other nitrogen compounds. Moreover, the presence of genes strictly related to the use of fructose and electron acceptors was variable within the genus, although these variations were not always related to the phylogeny.


Assuntos
Lactobacillales , Leuconostocaceae , Frutose/metabolismo , Filogenia , Leuconostocaceae/genética , Leuconostocaceae/metabolismo , Lactobacillales/genética , Genômica
13.
J Bacteriol ; 194(2): 538-9, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22207745

RESUMO

Lactobacillus curvatus is one of the most prevalent lactic acid bacteria found in fermented meat products. Here, we present the draft genome sequence of Lactobacillus curvatus CRL705, a bacteriocin producer strain isolated from an Argentinean artisanal fermented sausage, which consists of 1,833,251 bp (GC content, 41.9%) and two circular plasmids of 12,342 bp (pRC12; GC, 43.9%) and 18,664 bp (pRC18; GC, 34.4%).


Assuntos
Genoma Bacteriano , Lactobacillus/classificação , Lactobacillus/genética , Fermentação , Microbiologia de Alimentos , Produtos da Carne/microbiologia , Dados de Sequência Molecular
14.
J Bacteriol ; 194(2): 550, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22207752

RESUMO

We report the draft genome sequence of Enterococcus mundtii CRL1656, which was isolated from the stripping milk of a clinically healthy adult Holstein dairy cow from a dairy farm of the northwestern region of Tucumán (Argentina). The 3.10-Mb genome sequence consists of 450 large contigs and contains 2,741 predicted protein-coding genes.


Assuntos
Enterococcus/classificação , Enterococcus/genética , Genoma Bacteriano , Animais , Argentina/epidemiologia , Bovinos , Feminino , Mastite Bovina/epidemiologia , Mastite Bovina/microbiologia , Leite/microbiologia , Dados de Sequência Molecular
15.
Appl Microbiol Biotechnol ; 95(4): 991-9, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22350320

RESUMO

Mannitol is a natural polyol extensively used in the food industry as low-calorie sugar being applicable for diabetic food products. We aimed to evaluate mannitol production by Lactobacillus reuteri CRL 1101 using sugarcane molasses as low-cost energy source. Mannitol formation was studied in free-pH batch cultures using 3-10% (w/v) molasses concentrations at 37 °C and 30 °C under static and agitated conditions during 48 h. L. reuteri CRL 1101 grew well in all assayed media and heterofermentatively converted glucose into lactic and acetic acids and ethanol. Fructose was used as an alternative electron acceptor and reduced it to mannitol in all media assayed. Maximum mannitol concentrations of 177.7 ± 26.6 and 184.5 ± 22.5 mM were found using 7.5% and 10% molasses, respectively, at 37 °C after 24-h incubation. Increasing the molasses concentration from 7.5% up to 10% (w/v) and the fermentation period up to 48 h did not significantly improve mannitol production. In agitated cultures, high mannitol values (144.8 ± 39.7 mM) were attained at 8 h of fermentation as compared to static ones (5.6 ± 2.9 mM), the highest mannitol concentration value (211.3 ± 15.5 mM) being found after 24 h. Mannitol 2-dehydrogenase (MDH) activity was measured during growth in all fermentations assayed; the highest MDH values were obtained during the log growth phase, and no correlation between MDH activities and mannitol production was observed in the fermentations performed. L. reuteri CRL 1101 successfully produced mannitol from sugarcane molasses being a promising candidate for microbial mannitol synthesis using low-cost substrate.


Assuntos
Carbono/metabolismo , Limosilactobacillus reuteri/metabolismo , Manitol/metabolismo , Melaço , Saccharum , Sistema Livre de Células , Cromatografia Líquida de Alta Pressão , Fermentação , Limosilactobacillus reuteri/enzimologia , Limosilactobacillus reuteri/crescimento & desenvolvimento , Manitol Desidrogenases/metabolismo , Temperatura
16.
Appl Microbiol Biotechnol ; 93(6): 2519-27, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21993480

RESUMO

Certain lactic acid bacteria, especially heterofermentative strains, are capable to produce mannitol under adequate culture conditions. In this study, mannitol production by Lactobacillus reuteri CRL 1101 and Lactobacillus fermentum CRL 573 in modified MRS medium containing a mixture of fructose and glucose in a 6.5:1.0 ratio was investigated during batch fermentations with free pH and constant pH 6.0 and 5.0. Mannitol production and yields were higher under constant pH conditions compared with fermentations with free pH, the increase being more pronounced in the case of the L. fermentum strain. Maximum mannitol production and yields from fructose for L. reuteri CRL 1101 (122 mM and 75.7 mol%, respectively) and L. fermentum CRL 573 (312 mM and 93.5 mol%, respectively) were found at pH 5.0. Interestingly, depending on the pH conditions, fructose was used only as an alternative external electron acceptor or as both electron acceptor and energy source in the case of the L. reuteri strain. In contrast, L. fermentum CRL 573 used fructose both as electron acceptor and carbon source simultaneously, independently of the pH value, which strongly affected mannitol production by this strain. Studies on the metabolism of these relevant mannitol-producing lactobacilli provide important knowledge to either produce mannitol to be used as food additive or to produce it in situ during fermented food production.


Assuntos
Limosilactobacillus fermentum/metabolismo , Limosilactobacillus reuteri/metabolismo , Manitol/metabolismo , Meios de Cultura/metabolismo , Fermentação , Frutose/metabolismo , Concentração de Íons de Hidrogênio
17.
J Dairy Res ; 79(2): 201-8, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22559062

RESUMO

The high nutritional value of whey makes it an interesting substrate for the development of fermented foods. The aim of this work was to evaluate the growth and proteolytic activity of sixty-four strains of lactic acid bacteria in whey to further formulate a starter culture for the development of fermented whey-based beverages. Fermentations were performed at 37 °C for 24 h in 10 and 16% (w/v) reconstituted whey powder. Cultivable populations, pH, and proteolytic activity (o-phthaldialdehyde test) were determined at 6 and 24 h incubation. Hydrolysis of whey proteins was analysed by Tricine SDS-PAGE. A principal component analysis (PCA) was applied to evaluate the behaviour of strains. Forty-six percent of the strains grew between 1 and 2 Δlog CFU/ml while 19% grew less than 0·9 Δlog CFU/ml in both reconstituted whey solutions. Regarding the proteolytic activity, most of the lactobacilli released amino acids and small peptides during the first 6 h incubation while streptococci consumed the amino acids initially present in whey to sustain growth. Whey proteins were degraded by the studied strains although to different extents. Special attention was paid to the main allergenic whey protein, ß-lactoglobulin, which was degraded the most by Lactobacillus acidophilus CRL 636 and Lb. delbrueckii subsp. bulgaricus CRL 656. The strain variability observed and the PCA applied in this study allowed selecting appropriate strains able to improve the nutritional characteristics (through amino group release and protein degradation) and storage (decrease in pH) of whey.


Assuntos
Lactobacillus/crescimento & desenvolvimento , Lactobacillus/metabolismo , Proteínas do Leite/metabolismo , Leite/microbiologia , Animais , Fermentação , Concentração de Íons de Hidrogênio , Lactobacillus acidophilus/metabolismo , Lacticaseibacillus casei/crescimento & desenvolvimento , Lacticaseibacillus casei/metabolismo , Lactobacillus delbrueckii/metabolismo , Lactoglobulinas/metabolismo , Leite/química , Proteólise , Streptococcus thermophilus/crescimento & desenvolvimento , Streptococcus thermophilus/metabolismo , Proteínas do Soro do Leite
18.
Front Microbiol ; 13: 872281, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35898900

RESUMO

The fiber, vitamin, and antioxidant contents of fruits contribute to a balanced human diet. In countries such as Argentina, several tropical fruits are witnessing a high yield in the harvest season, with a resulting surplus. Fruit fermentation using autochthonous starter cultures can provide a solution for food waste. However, limited knowledge exists about the microbiota present on the surfaces of fruits and the preceding flowers. In the present exploratory study, the microbiomes associated with the surfaces of tropical fruits from Northern Argentina, such as white guava, passion fruit and papaya were investigated using a shotgun metagenomic sequencing approach. Hereto, one sample composed of 14 white guava fruits, two samples of passion fruits with each two to three fruits representing the almost ripe and ripe stage of maturity, four samples of papaya with each two to three fruits representing the unripe, almost ripe, and ripe stage of maturity were processed, as well as a sample of closed and a sample of open Japanese medlar flowers. A considerable heterogeneity was found in the composition of the fruits' surface microbiota at the genus and species level. While bacteria dominated the microbiota of the fruits and flowers, a small number of the metagenomic sequence reads corresponded with yeasts and filamentous fungi. A minimal abundance of bacterial species critical in lactic acid and acetic acid fermentations was found. A considerable fraction of the metagenomic sequence reads from the fruits' surface microbiomes remained unidentified, which suggested that intrinsic species are to be sequenced or discovered.

19.
Int J Food Microbiol ; 354: 109248, 2021 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-34059319

RESUMO

This work was carried out to elaborate selenium (Se) bio-enriched fermented Mediterranean fruit juices. To this purpose, pomegranate and table red grape juices were added with sodium selenite (Na2SeO3) and fermented by Levilactobacillus brevis CRL 2051 and Fructobacillus tropaeoli CRL 2034 individually or combined. To better evaluate the effect of selenite addition and starter strain inoculums on the total bacterial community of the fruit juices, fermentation trials were performed with raw and pasteurized fruit juices. No statistical significant differences were observed for total mesophilic microorganisms (TMM) and rod-shaped lactic acid bacteria (LAB) levels among raw and pasteurized juices inoculated with the starter strains, while significant differences between those juices with and without selenite were registered. LAB cocci, Pseudomonadaceae and yeasts were detected only for the raw juice preparations. The dominance of L. brevis CRL 2051 and F. tropaeoli CRL 2034 was confirmed by randomly amplified polymorphic DNA (RAPD)-PCR analysis. After fermentation, pH dropped for all inoculated trials and control raw juices. The soluble solid content (SSC) levels of the raw juices were higher than the corresponding pasteurized trials. The thermal treatment affected consistently yellowness of grape juice trials and redness of pomegranate juices. No microbial Se accumulation was registered for pomegranate juices, while F. tropaeoli CRL 2034 accumulated the highest amount of Se (65.5 µg/L) in the grape juice. For this reason, only trials carried out with raw grape juices were investigated by metagenomics analysis by Illumina MiSeq technology. Non-inoculated grape juices were massively fermented by acetic acid bacteria while Fructobacillus and Lactobacillus (previous genus name of Levilactobacillus) represented the highest operational taxonomy units (OTUs) relative abundance % of the trials inoculated with the starter strains as confirmed by this technique.


Assuntos
Fermentação , Alimentos Fermentados , Microbiologia de Alimentos , Sucos de Frutas e Vegetais , Ácido Láctico , Selênio , Alimentos Fermentados/microbiologia , Sucos de Frutas e Vegetais/microbiologia , Ácido Láctico/metabolismo , Lactobacillaceae/genética , Lactobacillaceae/metabolismo , Leuconostocaceae/genética , Leuconostocaceae/metabolismo , Região do Mediterrâneo , Técnica de Amplificação ao Acaso de DNA Polimórfico , Selênio/metabolismo
20.
Food Res Int ; 140: 109854, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33648172

RESUMO

Current awareness about the benefits of a balanced diet supports ongoing trends in humans towards a healthier diet. This review provides an overview of fruits and fruit-by products as sources of bioactive compounds and their extraction techniques, and the use of lactic acid fermentation of fruit juices to increase their functionality. Fruit matrices emerge as a technological alternative to be fermented by autochthonous or allochthonous lactic acid bacteria (LAB such as Lactiplantibacillus plantarum, Lacticaseibacillus rhamnosus, and other Lactobacillus species), and also as probiotic vehicles. During fermentation, microbial enzymes act on several fruit phytochemicals producing new derived compounds with impact on the aroma and the functionality of the fermented drinks. Moreover, fermentation significantly reduces the sugar content improving their nutritional value and extending the shelf-life of fruit-based beverages. The generation of new probiotic beverages as alternatives to consumers with intolerance to lactose or with vegan or vegetarian diets is promising for the worldwide functional food market. An updated overview on the current knowledge of the use of fruit matrices to be fermented by LAB and the interaction between strains and the fruit phytochemical compounds to generate new functional foods as well as their future perspectives in association with the application of nanotechnology techniques are presented in this review.


Assuntos
Frutas , Lactobacillales , Bebidas , Fermentação , Humanos , Ácido Láctico
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