Las colecciones de cultivo de investigacion permiten resguardar la biodiversidad microbiana en to... more Las colecciones de cultivo de investigacion permiten resguardar la biodiversidad microbiana en todas sus formas. La coleccion del Centro de Referencia para Lactobacilos (CERELA), es altamente especializada y unica en su tipo en Latinoamerica. Alberga 1.270 cepas de bacterias lacticas de las cuales 1.160 son cepas silvestres de diversos origenes: alimentos de elaboracion artesanal como quesos, chacinados, encurtidos, etc; ecosistemas caprinos, bovinos y buvalinos; plantas familiares de elaboracion de subproductos lacteos; suelos y pasturas de altura; vegetales, etc, provenientes de regiones del NOA. La caracterizacion taxonomica y tecnologica de las cepas, asi como los estudios sobre sus potencialidades probioticas y la busqueda de condiciones apropiadas para su conservacion a largo plazo, ha dado lugar a diferentes programas de investigacion. Los resultados obtenidos evidencian la biodiversidad de este grupo de microorganismos y avalan el posible uso de las cepas en industrias de di...
Silage is a method of forage conservation based on lactic fermentation. In order to improve the f... more Silage is a method of forage conservation based on lactic fermentation. In order to improve the fermentative performance in corn silages, the aims of the present work were as follows: (I) to screen lactic acid bacteria with acidifying activity, (II) to study their antifungal activity against filamentous fungi and yeasts and (III) to evaluate their performance as antifungal in mini-silos. The acidifying activity was determined by measuring the pH and total titratable acidity. Those most acidifying bacteria were incubated in plates together with fungal markers strains to observe the presence or absence of inhibition halos, in addition to studying the nature of the antifungal metabolites by means of the treatment with proteases. The strain with the widest spectrum of action was selected to formulate an inoculum used in corn mini-silos. During storage, both silos determined humidity, acidification and microbiological composition, and then aerobic stability. The results showed that Lactoplantibacillus (L.) plantarum cultures had a higher production of lactic acid (7.7-17.5 g/L) than Pediococcus (8.8-10.9 g/L). L. plantarum CRL363 could inhibit the growth of filamentous fungi and some yeasts and consequently it was used in mini-silos. Compared to the control, the inoculated silo presented low pH values (4.02-4.85) and low fungi and yeast count until 20 days of storage, demonstrating the great potential of CRL363 strain for the formulation of inoculants for corn silage.
Ochratoxin A (OTA) is a mycotoxin produced by filamentous fungi with high impact in food safety d... more Ochratoxin A (OTA) is a mycotoxin produced by filamentous fungi with high impact in food safety due to its toxicity. In the last decade, the presence of OTA was widely reported in different foods. In this study, the ability of Lactobacillus (L.) plantarum CRL 778 to control growth and OTA production by Aspergillus (A.) niger 13D strain, at different water activity (a w) values (0.955, 0.964, 0.971, 0.982, and 0.995) was determined in vitro. Both parameters were significantly (p < 0.05) reduced by the lactobacilli and the effect depended on a w. Greatest growth rate inhibition (46.9%) was obtained at a w = 0.995, which is the most suitable value for growth and production of antifungal metabolites (lactic acid, acetic acid, phenyllactic and hydroxyl-phenyllactic acids) by L. plantarum CRL 778. Besides, morphological changes and inhibition of melanin synthesis were observed in colonies of A. niger 13D in presence of L. plantarum CRL 778 at a w ranged between 0.971 and 0.995. In addition, maximum reduction (90%) of OTA production took place at a w = 0.971, while inhibition of fungi growth was more evident at a w = 0.995. These findings suggest that L. plantarum CRL 778 could be used for control of ochratoxigenic fungal growth and OTA contamination in different fermented foods with a w values between 0.971 and 0.995.
La lactancia materna es la mejor forma de iniciar la alimentacion de un nino. Se la recomienda en... more La lactancia materna es la mejor forma de iniciar la alimentacion de un nino. Se la recomienda en forma exclusiva hasta los seis meses y luego, acompanada de alimentacion complementaria, hasta los dos anos o mas. Posibilita disminuir la incidencia de numerosas enfermedades en el nino y fortalecer su vinculo con la madre. Sin embargo los porcentajes de lactancia exclusiva son bajos en relacion a lo deseable. Dado que las actitudes y decisiones del equipo de salud son fundamentales para el establecimiento de la lactancia, fortalecer la capacitacion de estudiantes de medicina constituye un camino para apoyar esta practica. Para ello se plantea un abanico de estrategias didacticas en el marco de un Modulo Optativo en la carrera de medico de la Universidad Nacional de Tucuman. Las mismas se evaluan en funcion de la valoracion otorgada por los estudiantes. Los resultados reflejan la satisfaccion de los alumnos con el Modulo en general y cada una de las actividades planteadas en particula...
Spontaneous fermented sourdoughs prepared from amaranth flour were investigated for the presence ... more Spontaneous fermented sourdoughs prepared from amaranth flour were investigated for the presence of autochthonous lactic acid bacteria (LAB) predominating microbiota. The doughs were fermented with daily backslopping on a laboratory scale at 30°C for 10 days. LAB counts ranged from 2·60 to 8·54 log CFU g(-1) with a pH declined from 6·2 to 3·8 throughout fermentation. The combined use of randomly amplified polymorphic DNA (RAPD)-PCR analysis and sequence analysis of 16S rRNA was applied for LAB intraspecies differentiation and taxonomic identification, respectively. Enterococcus, Pediococcus and Lactobacillus species were present in amaranth sourdoughs (AS). After the first refreshment step, Lactobacillus plantarum dominated AS until the end of fermentation. In coincidence, when DGGE analysis was performed, the occurrence of a progressive change in bacterial communities allowed the selection of Lact. plantarum as a dominant species. Moreover, technological, functional and safety characteristics of representative RAPD-biotypes were investigated. Lact. plantarum CRL1898 was selected as a potential candidate for gluten-free amaranth sourdough starter. Nowadays, there is an increasing interest in ancient noncereal gluten-free (GF) crops such as amaranth, due to their reported nutritional and health benefits. However, the use of these grains is still limited to traditional foods and bread making processes that are not yet well standardized. Results on the dynamics of autochthonous lactic acid bacteria (LAB) microbiota during laboratory spontaneous amaranth sourdoughs (AS) fermentation will contribute to overcome challenges for GF-fermented products development. In addition, knowledge about LAB diversity involving Enterococcus, Pediococcus and Lactobacillus species, with Lactobacillus plantarum predominating during AS fermentation, and their technological and functional properties provides the basis for the selection of autochthonous strains as starters cultures for novel gluten-free bakery products with enhanced nutritional, sensory and/or safety quality.
ABSTRACT The effect of bile on b-galactosidase,activity,and cell viability was,investigated,using... more ABSTRACT The effect of bile on b-galactosidase,activity,and cell viability was,investigated,using,two,strains,of Lactobacillus,reuteri that,were,subjected,to freeze- drying. In the presence of 0.15% oxgall, b- galactosidase,activity of the whole,cells was,signifi- cantly increased. After lyophilization, the cultures that had,been,treated,with,oxgall showed,a low sur- vival rate without,changes,in b-galactosidase activity. The,poor,resistance,of the,cells to damage,from freeze-drying,might,be,related,to the,presence,of membranous,structures,containing,simple,folds and buds of the cell membrane, as was observed by trans- mission,electron,microscopy. ( Key words: lactic acid bacteria, bile, b- galactosidase, freeze-drying) Abbreviation key: b-GAL = b-galactosidase, MRSL
Fast atom bombardment (FAB) technique was employed to determine the structure of polar lipids fro... more Fast atom bombardment (FAB) technique was employed to determine the structure of polar lipids from the cellular membrane of Lactobacillus delbruekii ssp. bulgaricus and Streptococcus salivarius ssp. thermophilus. Analysis of spectra provided useful information about the molecular species and aminoacids constituents of the samples.
Fil: Correa Deza, Maria Alejandra. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Ce... more Fil: Correa Deza, Maria Alejandra. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Tucuman. Centro de Referencia para Lactobacilos (i); Argentina
SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate,... more SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
La lactancia materna es la mejor forma de iniciar la alimentacion de un nino. Se la recomienda en... more La lactancia materna es la mejor forma de iniciar la alimentacion de un nino. Se la recomienda en forma exclusiva hasta los seis meses y luego, acompanada de alimentacion complementaria, hasta los dos anos o mas. Posibilita disminuir la incidencia de numerosas enfermedades en el nino y fortalecer su vinculo con la madre. Sin embargo los porcentajes de lactancia exclusiva son bajos en relacion a lo deseable. Dado que las actitudes y decisiones del equipo de salud son fundamentales para el establecimiento de la lactancia, fortalecer la capacitacion de estudiantes de medicina constituye un camino para apoyar esta practica. Para ello se plantea un abanico de estrategias didacticas en el marco de un Modulo Optativo en la carrera de medico de la Universidad Nacional de Tucuman. Las mismas se evaluan en funcion de la valoracion otorgada por los estudiantes. Los resultados reflejan la satisfaccion de los alumnos con el Modulo en general y cada una de las actividades planteadas en particula...
Las colecciones de cultivo de investigacion permiten resguardar la biodiversidad microbiana en to... more Las colecciones de cultivo de investigacion permiten resguardar la biodiversidad microbiana en todas sus formas. La coleccion del Centro de Referencia para Lactobacilos (CERELA), es altamente especializada y unica en su tipo en Latinoamerica. Alberga 1.270 cepas de bacterias lacticas de las cuales 1.160 son cepas silvestres de diversos origenes: alimentos de elaboracion artesanal como quesos, chacinados, encurtidos, etc; ecosistemas caprinos, bovinos y buvalinos; plantas familiares de elaboracion de subproductos lacteos; suelos y pasturas de altura; vegetales, etc, provenientes de regiones del NOA. La caracterizacion taxonomica y tecnologica de las cepas, asi como los estudios sobre sus potencialidades probioticas y la busqueda de condiciones apropiadas para su conservacion a largo plazo, ha dado lugar a diferentes programas de investigacion. Los resultados obtenidos evidencian la biodiversidad de este grupo de microorganismos y avalan el posible uso de las cepas en industrias de di...
Silage is a method of forage conservation based on lactic fermentation. In order to improve the f... more Silage is a method of forage conservation based on lactic fermentation. In order to improve the fermentative performance in corn silages, the aims of the present work were as follows: (I) to screen lactic acid bacteria with acidifying activity, (II) to study their antifungal activity against filamentous fungi and yeasts and (III) to evaluate their performance as antifungal in mini-silos. The acidifying activity was determined by measuring the pH and total titratable acidity. Those most acidifying bacteria were incubated in plates together with fungal markers strains to observe the presence or absence of inhibition halos, in addition to studying the nature of the antifungal metabolites by means of the treatment with proteases. The strain with the widest spectrum of action was selected to formulate an inoculum used in corn mini-silos. During storage, both silos determined humidity, acidification and microbiological composition, and then aerobic stability. The results showed that Lactoplantibacillus (L.) plantarum cultures had a higher production of lactic acid (7.7-17.5 g/L) than Pediococcus (8.8-10.9 g/L). L. plantarum CRL363 could inhibit the growth of filamentous fungi and some yeasts and consequently it was used in mini-silos. Compared to the control, the inoculated silo presented low pH values (4.02-4.85) and low fungi and yeast count until 20 days of storage, demonstrating the great potential of CRL363 strain for the formulation of inoculants for corn silage.
Ochratoxin A (OTA) is a mycotoxin produced by filamentous fungi with high impact in food safety d... more Ochratoxin A (OTA) is a mycotoxin produced by filamentous fungi with high impact in food safety due to its toxicity. In the last decade, the presence of OTA was widely reported in different foods. In this study, the ability of Lactobacillus (L.) plantarum CRL 778 to control growth and OTA production by Aspergillus (A.) niger 13D strain, at different water activity (a w) values (0.955, 0.964, 0.971, 0.982, and 0.995) was determined in vitro. Both parameters were significantly (p < 0.05) reduced by the lactobacilli and the effect depended on a w. Greatest growth rate inhibition (46.9%) was obtained at a w = 0.995, which is the most suitable value for growth and production of antifungal metabolites (lactic acid, acetic acid, phenyllactic and hydroxyl-phenyllactic acids) by L. plantarum CRL 778. Besides, morphological changes and inhibition of melanin synthesis were observed in colonies of A. niger 13D in presence of L. plantarum CRL 778 at a w ranged between 0.971 and 0.995. In addition, maximum reduction (90%) of OTA production took place at a w = 0.971, while inhibition of fungi growth was more evident at a w = 0.995. These findings suggest that L. plantarum CRL 778 could be used for control of ochratoxigenic fungal growth and OTA contamination in different fermented foods with a w values between 0.971 and 0.995.
La lactancia materna es la mejor forma de iniciar la alimentacion de un nino. Se la recomienda en... more La lactancia materna es la mejor forma de iniciar la alimentacion de un nino. Se la recomienda en forma exclusiva hasta los seis meses y luego, acompanada de alimentacion complementaria, hasta los dos anos o mas. Posibilita disminuir la incidencia de numerosas enfermedades en el nino y fortalecer su vinculo con la madre. Sin embargo los porcentajes de lactancia exclusiva son bajos en relacion a lo deseable. Dado que las actitudes y decisiones del equipo de salud son fundamentales para el establecimiento de la lactancia, fortalecer la capacitacion de estudiantes de medicina constituye un camino para apoyar esta practica. Para ello se plantea un abanico de estrategias didacticas en el marco de un Modulo Optativo en la carrera de medico de la Universidad Nacional de Tucuman. Las mismas se evaluan en funcion de la valoracion otorgada por los estudiantes. Los resultados reflejan la satisfaccion de los alumnos con el Modulo en general y cada una de las actividades planteadas en particula...
Spontaneous fermented sourdoughs prepared from amaranth flour were investigated for the presence ... more Spontaneous fermented sourdoughs prepared from amaranth flour were investigated for the presence of autochthonous lactic acid bacteria (LAB) predominating microbiota. The doughs were fermented with daily backslopping on a laboratory scale at 30°C for 10 days. LAB counts ranged from 2·60 to 8·54 log CFU g(-1) with a pH declined from 6·2 to 3·8 throughout fermentation. The combined use of randomly amplified polymorphic DNA (RAPD)-PCR analysis and sequence analysis of 16S rRNA was applied for LAB intraspecies differentiation and taxonomic identification, respectively. Enterococcus, Pediococcus and Lactobacillus species were present in amaranth sourdoughs (AS). After the first refreshment step, Lactobacillus plantarum dominated AS until the end of fermentation. In coincidence, when DGGE analysis was performed, the occurrence of a progressive change in bacterial communities allowed the selection of Lact. plantarum as a dominant species. Moreover, technological, functional and safety characteristics of representative RAPD-biotypes were investigated. Lact. plantarum CRL1898 was selected as a potential candidate for gluten-free amaranth sourdough starter. Nowadays, there is an increasing interest in ancient noncereal gluten-free (GF) crops such as amaranth, due to their reported nutritional and health benefits. However, the use of these grains is still limited to traditional foods and bread making processes that are not yet well standardized. Results on the dynamics of autochthonous lactic acid bacteria (LAB) microbiota during laboratory spontaneous amaranth sourdoughs (AS) fermentation will contribute to overcome challenges for GF-fermented products development. In addition, knowledge about LAB diversity involving Enterococcus, Pediococcus and Lactobacillus species, with Lactobacillus plantarum predominating during AS fermentation, and their technological and functional properties provides the basis for the selection of autochthonous strains as starters cultures for novel gluten-free bakery products with enhanced nutritional, sensory and/or safety quality.
ABSTRACT The effect of bile on b-galactosidase,activity,and cell viability was,investigated,using... more ABSTRACT The effect of bile on b-galactosidase,activity,and cell viability was,investigated,using,two,strains,of Lactobacillus,reuteri that,were,subjected,to freeze- drying. In the presence of 0.15% oxgall, b- galactosidase,activity of the whole,cells was,signifi- cantly increased. After lyophilization, the cultures that had,been,treated,with,oxgall showed,a low sur- vival rate without,changes,in b-galactosidase activity. The,poor,resistance,of the,cells to damage,from freeze-drying,might,be,related,to the,presence,of membranous,structures,containing,simple,folds and buds of the cell membrane, as was observed by trans- mission,electron,microscopy. ( Key words: lactic acid bacteria, bile, b- galactosidase, freeze-drying) Abbreviation key: b-GAL = b-galactosidase, MRSL
Fast atom bombardment (FAB) technique was employed to determine the structure of polar lipids fro... more Fast atom bombardment (FAB) technique was employed to determine the structure of polar lipids from the cellular membrane of Lactobacillus delbruekii ssp. bulgaricus and Streptococcus salivarius ssp. thermophilus. Analysis of spectra provided useful information about the molecular species and aminoacids constituents of the samples.
Fil: Correa Deza, Maria Alejandra. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Ce... more Fil: Correa Deza, Maria Alejandra. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Tucuman. Centro de Referencia para Lactobacilos (i); Argentina
SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate,... more SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
La lactancia materna es la mejor forma de iniciar la alimentacion de un nino. Se la recomienda en... more La lactancia materna es la mejor forma de iniciar la alimentacion de un nino. Se la recomienda en forma exclusiva hasta los seis meses y luego, acompanada de alimentacion complementaria, hasta los dos anos o mas. Posibilita disminuir la incidencia de numerosas enfermedades en el nino y fortalecer su vinculo con la madre. Sin embargo los porcentajes de lactancia exclusiva son bajos en relacion a lo deseable. Dado que las actitudes y decisiones del equipo de salud son fundamentales para el establecimiento de la lactancia, fortalecer la capacitacion de estudiantes de medicina constituye un camino para apoyar esta practica. Para ello se plantea un abanico de estrategias didacticas en el marco de un Modulo Optativo en la carrera de medico de la Universidad Nacional de Tucuman. Las mismas se evaluan en funcion de la valoracion otorgada por los estudiantes. Los resultados reflejan la satisfaccion de los alumnos con el Modulo en general y cada una de las actividades planteadas en particula...
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