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1.
J Appl Microbiol ; 132(3): 2093-2105, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34606147

RESUMO

AIMS: To evaluate the capacity of autochthonous lactic acid bacteria (LAB) (43) from Andean grains to increase the antioxidant activity (AOA) and total phenolic compounds (TPCs) in quinoa sourdough to select best performing strains to be used as starter cultures in the elaboration of biscuits. METHODS AND RESULTS: Microbial growth (CFU per g) and pH were evaluated during quinoa dough fermentation. Counts were increased in a range of 0.61-2.97 log CFU per g and pH values between 3.95 and 4.54 were determined after 24 h at 30°C of fermentation. Methanolic (ME) and aqueous (AE) extracts were obtained at the end of fermentation, and free radical scavenging capacity was performed by the DPPH and ABTS methods. ME was selected for further analysis using other methods and TPC quantification. Principal component analysis showed the highest scores of growth, acidification capacity, AOA and TPC for the strains Lc. mesenteroides subsp. mesenteroides CRL 2131 and L. plantarum CRL 1964 and CRL 1973. AOA and TPC in biscuits made with sourdough from these LAB were higher than the acidified and uninoculated controls. CONCLUSIONS: Autochthonous LAB strains (3) increased the AOA of quinoa-based biscuits. SIGNIFICANCE AND IMPACT OF THE STUDY: Quinoa sourdough obtained with selected LAB is suitable as an ingredient for bakery foods with improved antioxidant status.


Assuntos
Chenopodium quinoa , Lactobacillales , Antioxidantes/análise , Pão/microbiologia , Chenopodium quinoa/química , Chenopodium quinoa/microbiologia , Fermentação , Microbiologia de Alimentos
2.
J Sci Food Agric ; 101(2): 441-448, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32648586

RESUMO

BACKGROUND: Low molecular-weight phenolic fractions (LMPFs) were extracted from Albion (LMPF-A) and Camarosa (LMPF-C) strawberry cultivars. Their antibacterial activity against Listeria monocytogenes and Salmonella Typhimurium cocktails in vitro and in vivo was investigated using strawberry juice as a food model. This study also sought to determine their antibacterial mechanism. RESULTS: Quercetin was identified as a principal compound in both phenolic fractions. The minimum bactericide concentration (MBC) values were 750 and 850 µg mL-1 (LMPF-C) and 800 and 950 µg mL-1 (LMPF-A) against S.Typhimurium and L. monocytogenes, respectively. The possible antibacterial activity of the phenolic extracts could be related to the release of phosphate and potassium ions, the effect of the disruption of membrane integrity on L. monocytogenes, and the effect of the inhibition of dihydronicotinamide adenine dinucleotide (NADH) oxidase activity on S. Typhimurium. Quercetin and kaempferol were the most active compounds in producing bacterial damage. Strawberry juice supplemented with the phenolic fractions and incubated at 37, 20, and 4 °C reduced bacterial viability; moreover, after treatment with the phenolic fraction at the lowest temperature, no viable cells were detected after 7 days' incubation. Salmonella was more sensitive to the supplements than Listeria in strawberry juice. CONCLUSIONS: This study could form the basis for the development of natural antibacterial agents that could be included in natural juice or used by the pharmaceutical industry. © 2020 Society of Chemical Industry.


Assuntos
Antibacterianos/farmacologia , Fragaria/química , Sucos de Frutas e Vegetais/microbiologia , Listeria monocytogenes/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacos , Extratos Vegetais/farmacologia , Polifenóis/farmacologia , Salmonella typhimurium/efeitos dos fármacos , Antibacterianos/química , Frutas/química , Sucos de Frutas e Vegetais/análise , Listeria monocytogenes/crescimento & desenvolvimento , Extratos Vegetais/química , Polifenóis/química , Salmonella typhimurium/crescimento & desenvolvimento
3.
J Basic Microbiol ; 60(9): 787-798, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33448445

RESUMO

Cereals and pseudocereals are a rich source of nutrients and trace elements, but their dietary bioavailability is low due to the presence of phytate (IP6), an antinutritional compound with the ability to chelate cations and proteins. Phytase is an enzyme that catalyzes the hydrolysis of IP6 and it is used as an additive improving the nutritional quality of grain-based foods. The aim of this study was to select lactic acid bacteria (LAB) isolated from pseudocereals with phytase activity, characterize their production and activity, and purify the enzyme. LAB strains isolated from grains and spontaneous sourdough of quinoa and amaranth were grown in the Man Rogosa and Sharpe medium where the inorganic phosphate (Pi) was replaced by 1% of IP6. Phytase activity was determined by measuring the Pi released from IP6. Phytase of Lactobacillus (L.) plantarum CRL1964 (PhyLP) showed the highest specific activity from 73 LAB evaluated. IP6 induces PhyLP production, which is at its maximum at the end of the exponential phase. PhyLP was thermostable and maintained its activity under acidic conditions. The enzymatic activity is stimulated by ethylenediaminetetraacetic acid, Co2+, and ascorbic acid. PhyLP was partially purified and showed a molecular mass of 55 kDa. L. plantarum CRL1964 and/or PhyLP have the potential to be included in the processing of cereal/pseudocereals based products for animal feed and/or the food industry improving its nutritional value.


Assuntos
6-Fitase/metabolismo , Grão Comestível/microbiologia , Lactobacillus plantarum/enzimologia , 6-Fitase/química , 6-Fitase/isolamento & purificação , Meios de Cultura/química , Concentração de Íons de Hidrogênio , Hidrólise , Lactobacillales/enzimologia , Lactobacillales/crescimento & desenvolvimento , Lactobacillales/isolamento & purificação , Lactobacillus plantarum/crescimento & desenvolvimento , Lactobacillus plantarum/isolamento & purificação , Peso Molecular , Fosfatos/metabolismo , Ácido Fítico/metabolismo , Especificidade por Substrato , Temperatura
4.
Food Res Int ; 127: 108735, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31882084

RESUMO

In recent years, quinoa (Chenopodium quinoa Willd), an ancestral crop of the Andean region of South America, has gained worldwide attention due to its high nutritional value. This grain is a good source of several vitamins and minerals; however, their bioavailability is decreased by the presence of antinutritional factors such as phytic acid. These compounds can be reduced using lactic acid bacteria (LAB), that have a GRAS (Generally Recognized as Safe) status and have traditionally been associated with food fermentation due to their biosynthetic capacity and metabolic versatility. The objective of this study was to evaluate the effectiveness of a pasta made with quinoa sourdough fermented by L. plantarum strains producing vitamins B2 and B9 and phytase to prevent vitamins and minerals deficiency using an in vivo mouse model. The results showed that the pasta fermented with the mixed culture containing L. plantarum CRL 2107 + L. plantarum CRL 1964 present increased B2 and B9 levels in mice blood. Likewise, higher concentrations of P, Ca+2, Fe+2, Mg+2 (18.75, 10.70, 0.37, 4.85 mg/dL, respectively) were determined with respect to the deficient group (DG) (9.85, 9.90, 0.26, 3.34 mg/dL, respectively). Hematological studies showed an increase in hemoglobin (14.4 ±â€¯0.6 g/dL), and hematocrit (Htc, 47.0 ±â€¯0.6%) values, compared to the DG (Hb: 12.6 ±â€¯0.5 g/dL, Hto: 39.9 ±â€¯1.1%). Furthermore, histological evaluations of the intestines showed an increase of the small intestine villi length in this latter group. The results allow us to conclude that bio-enrichment of quinoa pasta using LAB could be a novel strategy to increase vitamin and minerals bioavailability in cereal/pseudocereal - derived foods.


Assuntos
Chenopodium quinoa , Culinária , Alimentos Fermentados , Deficiência de Ácido Fólico/prevenção & controle , Lactobacillus plantarum/metabolismo , Deficiência de Riboflavina/prevenção & controle , 6-Fitase , Animais , Ácido Fólico/administração & dosagem , Camundongos , Minerais , Estado Nutricional , Riboflavina/administração & dosagem
5.
Front Nutr ; 6: 98, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31334241

RESUMO

One of the greatest challenges is to reduce malnutrition worldwide while promoting sustainable agricultural and food systems. This is a daunting task due to the constant growth of the population and the increasing demands by consumers for functional foods with higher nutritional values. Cereal grains are the most important dietary energy source globally; wheat, rice, and maize currently provide about half of the dietary energy source of humankind. In addition, the increase of celiac patients worldwide has motivated the development of gluten-free foods using alternative flour types to wheat such as rice, corn, cassava, soybean, and pseudocereals (amaranth, quinoa, and buckwheat). Amaranth and quinoa have been cultivated since ancient times and were two of the major crops of the Pre-Colombian cultures in Latin- America. In recent years and due to their well-known high nutritional value and potential health benefits, these pseudocereals have received much attention as ideal candidates for gluten-free products. The importance of exploiting these grains for the elaboration of healthy and nutritious foods has forced food producers to develop novel adequate strategies for their processing. Fermentation is one of the most antique and economical methods of producing and preserving foods and can be easily employed for cereal processing. The nutritional and functional quality of pseudocereals can be improved by fermentation using Lactic Acid Bacteria (LAB). This review provides an overview on pseudocereal fermentation by LAB emphasizing the capacity of these bacteria to decrease antinutritional factors such as phytic acid, increase the functional value of phytochemicals such as phenolic compounds, and produce nutritional ingredients such as B-group vitamins. The numerous beneficial effects of lactic fermentation of pseudocereals can be exploited to design novel and healthier foods or grain ingredients destined to general population and especially to patients with coeliac disease.

6.
J Mol Microbiol Biotechnol ; 27(5): 289-298, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29166640

RESUMO

Amaranth is a rediscovered pseudocereal with high nutritional properties. Lactic acid fermentation can increase the functional and nutritional value of foods. The aims of this study were to isolate and evaluate the functionality of lactic acid bacteria (LAB) from amaranth. LAB strains (n = 29) isolated from amaranth sourdough and grains included Lactobacillus (L.) plantarum (n = 8), L. rhamnosus (n = 6), Enterococcus (E.) mundtii (n = 4), E. hermanniensis (n = 3), E. durans (n = 1), Enterococcus sp. (n = 1), Leuconostoc (Lc.) mesenteroides (n = 3), and Lc. mesenteroides subsp. mesenteroides (n = 3). Only 21% of the strains showed the ability to synthesize capsular exopolysaccharides or display ropiness and only 8 strains showed amylolytic activity. L. plantarum CRL 2106 and E. durans CRL 2122 showed the highest phytase activity, which is of importance for mineral bioavailability. L. plantarum CRL 2106 and CRL 2107 and Lc. mesenteroides subsp. mesenteroides CRL 2131 synthesized the highest concentrations of B2 and B9 vitamin (140-250 ng/mL). This study demonstrates the potential of LAB to improve the nutritional and functional values of pseudocereal-derived foods.


Assuntos
Grão Comestível/microbiologia , Lactobacillales/enzimologia , Lactobacillales/metabolismo , Vitaminas/biossíntese , 6-Fitase/metabolismo , Cápsulas Bacterianas/metabolismo , Disponibilidade Biológica , Enterococcus/classificação , Fermentação , Ácido Fólico , Microbiologia de Alimentos , Genótipo , Lactobacillales/classificação , Lactobacillales/isolamento & purificação , Lactobacillus/classificação , Leuconostoc/classificação , Polissacarídeos Bacterianos/metabolismo , Riboflavina/biossíntese
7.
Food Res Int ; 89(Pt 1): 488-494, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28460943

RESUMO

The lactic acid bacteria (LAB) microbiota of quinoa grains (QG) and spontaneous sourdough (QSS) was evaluated. Different strains of Lactobacillus (L.) plantarum (7), L. rhamnosus (5), L. sakei (1), Pediococcus (Ped.) pentosaceus (9), Leuconostoc (Leuc.) mesenteroides (1), Enterococcus (E.) casseliflavus (2), E. mundtii (3), E. hirae (1), E. gallinarum (12), Enterococcus sp. (1), and E. hermanniensis (2) were isolated, identified and characterized. Only four strains isolated from QSS and eight strains isolated from QG showed amylolytic activity. L. plantarum CRL 1973 and CRL 1970, L. rhamnosus CRL 1972 and L. sakei CRL 1978 produced elevated concentrations of folate with strain CRL 1973 producing the highest concentration (143±6ng/ml). L. rhamnosus, isolated from QSS, was the LAB species that produced the most elevated concentrations of total riboflavin (>270ng/ml) with strain CRL 1963 producing the highest amounts (360±10ng/ml). Phytase activity, evaluated in forty-four LAB strains from quinoa, was predominantly detected in L. rhamnosus and Enterococci strains with the highest activities observed in E. mundtii CRL 2007 (957±25U/ml) followed by E. casseliflavus CRL 1988 (684±38U/ml), Leuc. mesenteroides CRL 2012 (617±38U/ml) and L. rhamnosus CRL 1983 (606±79U/ml). In conclusion, this study shows that a diverse LAB microbiota is present in quinoa with important properties; these microorganisms could be used as potential starter cultures to increase the nutritional and functional properties of Andean grains based foods.

8.
Appl Microbiol Biotechnol ; 99(9): 3839-49, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25758954

RESUMO

The consumers' demand for food with high nutritional quality and free of chemical additives increases the need to look for new products and preservation strategies. Quinoa (Chenopodium quinoa) is an Andean pseudocereal highly appreciated because of its nutritional properties. Moreover, it is an optimal substrate for growing and production of improved amounts of antifungal compounds by Lactobacillus plantarum CRL 778. The aim of this work was to optimize a lactic ferment for packaged breads with improved nutritional value and prolonged shelf life by applying a statistical experimental design model. The addition of 30 % quinoa to the wheat semiliquid ferment (QWF) could highly improve the amino acids release (4.3 g/L) during fermentation. Moreover, this quinoa proportion was sufficient to obtain the same concentration of the antifungal compounds, phenyllactic and hydroxiphenyllactic acids (PLA and OH-PLA) as with 100 % quinoa (ca. 36 and 51 mg/L, respectively). Statistical model analysis showed that citrate and skimmed milk enhanced significantly all evaluated parameters specially PLA (ca. 71 mg/L), HO-PLA (ca. 75 mg/L), and lactate (27 g/L) with a p value <0.005. The synergic effects of higher antifungal compounds production, acid release, and pH decrease allowed lowering the amount (about 50 %) of the chemical preservative calcium propionate commonly added to bread. Moreover, these breads show increased shelf life.


Assuntos
Antifúngicos/metabolismo , Pão/microbiologia , Chenopodium quinoa/metabolismo , Conservação de Alimentos/métodos , Lactatos/metabolismo , Lactobacillus plantarum/crescimento & desenvolvimento , Lactobacillus plantarum/metabolismo , Farinha , Conservantes de Alimentos/metabolismo , Concentração de Íons de Hidrogênio , Propionatos/metabolismo , Triticum/metabolismo
9.
Actual. nutr ; 14(4): 264-271, Dic. 2013. tab, ilus
Artigo em Espanhol | LILACS | ID: lil-771551

RESUMO

El seitán es el gluten de trigo y se lo denomina carne vegetal por su aspecto similar a ésta. Se lo elabora mediante amasado de harina de trigo y posterior lavado, para eliminar el almidón. Luego se hierve con alga Kombu y tamari (salsa de soja) para enriquecerlo en vitaminas y minerales y tome color. Posee un alto contenido proteico, bajo en carbohidratos y grasas y, al ser un alimento de origen vegetal, no contiene colesterol. Es originario de China. Los japoneses de orientación macrobiótica lo introdujeron en Estados Unidos, principalmente a través de los Mormones y los Adventistas del Séptimo Día, alrededor de 1940. Luego se propagó entre quienes practican el vegetarianismo. La investigación se realizó en base a un tipo de estudio exploratorio-descriptivo. El estudio exploratorio se l levó a cabo a través de la elaboración artesanal de seitán y su inclusión en diferentes preparaciones alimenticias. Los productos que se elaboraron exitosamente fueron: milanesas, sfijas y kipe. Se realizó la cuantificación de macro-nutrientes y antioxidantes y finalmente, con los resultados obtenidos, se calculó el valor calórico por porción ypor 100 g de cada producto elaborado. La cuantificación de macronutrientes indica que tanto el seitán como los productos elaborados poseen un ele-vado contenido proteico y, en cuanto a la valoración nutricional, las tres preparaciones presentan un alto valor calórico, siendo el kipe el de mayor calorías por cada 100 g de alimento...


Seitan is made from wheat gluten, and it is called vegetable meat due to its similarity to meat. It is made by washing wheat flour dough until all the starch has been removed. Then it is simmered in a broth of kombu seaweed and tamari (soy sauce), so as to enrich it with vitamins and minerals, and to give it color. Seitan is a low-fat, low carbohydrate and high-protein food. Being also a vegetable-based food, it doesn’t contain cholesterol. Originally from China, it was introduced in the United States by the Japanese people with a macrobiotic lifestyle, mainly by the Mormons and the Seventh-day Adventists, in around 1940. Then it gained popularity among vegetarians. This research was based in an exploratory-descriptive study. To carry out the exploratory study, seitan was prepared manually and used in different food preparations. The products successfully made were breaded cutlets, sfijas and kibbeh. The macronutrients and antioxidants were quantified, and these results were used to calculate the caloric value per portion and per 100 g for each food product. The macronutrient quantification reveals that both the seitan and the prepared products have high-protein content. As regards the nutritional value, the three food products have a high caloric value, being the kibbeh the one with the highest caloric value per 100 g, followed by the sfijas and the breaded cutlet...


O Seitán é o glúten de trigo e é denominado carne vegetal por seu aspecto similar à mesma. É elaborado mediante o amassamento da farinha de trigo e posterior lavagem, para eliminar o amido. Depois é fervido com alga Kombue tamari (molho de soja) para enriquecê-lo em vitaminas e minarias e para adquirir cor. Possui um alto conteúdo proteico, baixo em carboidratos e gordura, por ser um alimento de origem vegetal, não contém colesterol. É originário da China. Os japoneses de orientação macrobiótica introduziram-no nos Estados Unidos, principalmente através dos Mórmons e Adventistas do Sétimo Dia, ao redor de 1940. Depois foi difundido entre aqueles que praticam o vegetarianismo. A pesquisa foi realizada baseada em um tipo de estudo exploratório-descritivo. O estudo exploratório foi realizado através da elaboração artesanal de seitán e sua inclusão em diferentes preparações alimentícias. Os produtos que foram elaborados com sucesso foram: milanesas, sfijas e kipe. Foi realizada a quantificação de macronutrientes e antioxidantes e finalmente, com os resultados obtidos, calculou-se o valor calórico por porção e por 100 g de cada produto elaborado...


Assuntos
Humanos , Antioxidantes , Alimentos , Nutrientes , Valor Nutritivo
10.
Int J Food Microbiol ; 163(2-3): 166-70, 2013 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-23558200

RESUMO

Cells from an exponential Oenococcus oeni m1 culture in a grape juice medium were inoculated into a synthetic wine medium (SW) supplemented with a protein and polypeptide fraction (PPF) of high molecular weight (higher than 12,400 Da) obtained from four varietals of Cafayate Argentinean wines. O. oeni maintains viability after 48 h incubation time and enables the increase in extracellular proteolytic activity and the release of low molecular weight peptides by 1.067, 0.397, 0.915 and 0.705 mg N/L in the respective SW supplemented with PPF from Cabernet Sauvignon, Malbec, Tannat and Torrontés wine varietals. After 48 h incubation time, concomitantly with peptide release, an increase in antioxidant and antihypertensive activities was detected in all studied media. The highest increase was detected in the presence of PPF from Cabernet and Tannat wine varietals. Maximum increase in antioxidant activity (366.1 µmol FeSO4/L in the case of ferric reducing antioxidant power and 8.9% in 2,2-diphenyl-1-picrylhydrazyl radical scavenging) was produced by the peptides released from PPF of Cabernet Sauvignon wine. The peptides released from PPF Tannat wine varietal caused the highest increase in antihypertensive activity (56.2% in angiotensin I-converting enzyme inhibitory activity). Oenococcus oeni m1 would provide additional benefits to wine such as an increase in bioactive peptides with multifunctional beneficial activities.


Assuntos
Antioxidantes/metabolismo , Oenococcus/metabolismo , Biossíntese Peptídica/fisiologia , Vinho/microbiologia , Viabilidade Microbiana , Proteólise
11.
Appl Microbiol Biotechnol ; 97(7): 3129-40, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23129182

RESUMO

Quinoa fermentation by lactic acid bacteria (LAB) is an interesting alternative to produce new bakery products with high nutritional value; furthermore, they are suitable for celiac patients because this pseudo-cereal contains no gluten. Growth and lactic acid production during slurry fermentations by Lactobacillus plantarum CRL 778 were greater in quinoa (9.8 log cfu/mL, 23.1 g/L) than in wheat (8.9 log cfu/mL, 13.9 g/L). Lactic fermentation indirectly stimulated flour protein hydrolysis by endogenous proteases of both slurries. However, quinoa protein hydrolysis was faster, reaching 40-100% at 8 h of incubation, while wheat protein hydrolysis was only 0-20%. In addition, higher amounts of peptides (24) and free amino acids (5 g/L) were determined in quinoa compared to wheat. Consequently, greater concentrations (approx. 2.6-fold) of the antifungal compounds (phenyllactic and hydroxyphenyllactic acids) were synthesized from Phe and Tyr in quinoa by L. plantarum CRL 778, an antifungal strain. These promising results suggest that this LAB strain could be used in the formulation of quinoa sourdough to obtain baked goods with improved nutritional quality and shelf life, suitable for celiac patients.


Assuntos
Chenopodium quinoa/metabolismo , Lactobacillus plantarum/metabolismo , Triticum/metabolismo , Biotecnologia/métodos , Fermentação , Microbiologia de Alimentos/métodos , Cinética , Lactobacillus plantarum/crescimento & desenvolvimento , Peptídeo Hidrolases/metabolismo , Proteínas de Plantas/metabolismo , Proteólise
12.
Food Microbiol ; 32(2): 427-30, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22986210

RESUMO

The evaluation of gliadin hydrolysis during dough fermentation by using two lactic acid bacteria, Lactobacillus plantarum CRL 775 and Pediococcus pentosaceus CRL 792, as pooled cell suspension (LAB) or cell free extract (CFE) was undertaken. The CFE pool produced a greater (121%) increase in amino acid concentration than the LAB pool (70-80%). These results were correlated with the decrease (76,100 and 64,300 ppm) in the gliadin concentration of doughs supplemented with CFE and LAB, respectively, compared to control doughs. The use of LAB peptidases seemed to be a viable technologic alternative to reduce the gliadin concentration in wheat dough without using living bacteria as starter.


Assuntos
Gliadina/metabolismo , Lactobacillaceae/metabolismo , Pediococcus/metabolismo , Triticum/metabolismo , Pão/microbiologia , Fermentação , Gliadina/química , Hidrólise , Ácido Láctico/metabolismo , Triticum/microbiologia
13.
Appl Environ Microbiol ; 68(12): 6193-201, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12450844

RESUMO

The cytoplasmic extracts of 70 strains of the most frequently isolated sourdough lactic acid bacteria were screened initially for arginine deiminase (ADI), ornithine transcarbamoylase (OTC), and carbamate kinase (CK) activities, which comprise the ADI (or arginine dihydrolase) pathway. Only obligately heterofermentative strains such as Lactobacillus sanfranciscensis CB1; Lactobacillus brevis AM1, AM8, and 10A; Lactobacillus hilgardii 51B; and Lactobacillus fructivorans DD3 and DA106 showed all three enzyme activities. Lactobacillus plantarum B14 did not show CK activity. L. sanfranciscensis CB1 showed the highest activities, and the three enzymes were purified from this microorganism to homogeneity by several chromatographic steps. ADI, OTC, and CK had apparent molecular masses of ca. 46, 39, and 37 kDa, respectively, and the pIs were in the range of 5.07 to 5.2. The OTCs, CKs, and especially ADIs were well adapted to pH (acidic, pH 3.5 to 4.5) and temperature (30 to 37 degrees C) conditions which are usually found during sourdough fermentation. Internal peptide sequences of the three enzymes had the highest level of homology with ADI, OTC, and CK of Lactobacillus sakei. L. sanfranciscensis CB1 expressed the ADI pathway either on MAM broth containing 17 mM arginine or during sourdough fermentation with 1 to 43 mM added arginine. Two-dimensional electrophoresis showed that ADI, OTC, and CK were induced by factors of ca. 10, 4, and 2 in the whole-cell extract of cells grown in MAM broth containing 17 mM arginine compared to cells cultivated without arginine. Arginine catabolism in L. sanfranciscensis CB1 depended on the presence of a carbon source and arginine; glucose at up to ca. 54 mM did not exert an inhibitory effect, and the pH was not relevant for induction. The pH of sourdoughs fermented by L. sanfranciscensis CB1 was dependent on the amount of arginine added to the dough. A low supply of arginine (6 mM) during sourdough fermentation by L. sanfranciscensis CB1 enhanced cell growth, cell survival during storage at 7 degrees C, and tolerance to acid environmental stress and favored the production of ornithine, which is an important precursor of crust aroma compounds.


Assuntos
Arginina/metabolismo , Pão/microbiologia , Hidrolases/isolamento & purificação , Lactobacillus/enzimologia , Trifosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Biodegradação Ambiental , Fermentação , Concentração de Íons de Hidrogênio , Hidrolases/química , Hidrolases/metabolismo , Peso Molecular
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