RESUMO
The objective of this work was to study lactic fermentation as a biostrategy to enhance the antioxidant activity of oats. The adaptability of 31 strains of lactic bacteria (LB) in an oats/water system (OWS/SAA) was evaluated, measuring growth, acidification and fermentation activity (impedimetric method; detection time [DT], maximum rate of conductance change [MRCC/VMCC] and percentage of conductance change [PCC]). Moreover, the content of phenolic compounds (PC) was determined using the Folin-Ciocalteu method (gallic acid equivalents [GAE]), free peptides and amino acids and free radical scavenging activity (DPPH⢠and ABTSâ¢+ methods) of methanolic and aqueous extracts obtained from fermented OWS/SAAs (fOWS/SAAf) were determined. Six strains have shown the best adaptability to SAA, with high values of VMCC (0.34-0.47 µS/min) and PCC (53.6-66.6%), and low values of DT (≤ 3 h). In these f/OWS/SAAf the chemical composition was also modified (PC concentration, peptides and free amino acids) with strain-dependent behavior. The PC content in f/OWS/SAAf using these six strains (29.1-36.9 µg GAE/ml) was higher than the control content in OWS/SAA control (17.1 ± 1.9 µg GAE/ml). An increase (9-25.5%) in antioxidant activity in f/OWS/SAAf methanolic extracts was detected using both methods. Minor modifications were observed in the peptide and free amino acid content of SAA and their antioxidant activity. Our results show LB ability to adapt to oat as fermentation substrate and increase the content of its antioxidant compounds.
Assuntos
Antioxidantes , Avena , Lactobacillales , Antioxidantes/metabolismo , Avena/metabolismo , Fermentação , Fenóis , Extratos VegetaisRESUMO
The consumption of soybean isoflavones (IS) is associated with several beneficial properties on human health. Some lactic acid bacteria possess ß-glucosidase enzyme, that allows to obtain the active form of IS (aglycone). The solid state fermentation (SSF) has received great attention in the last years in order to obtain several valuable compounds. SSF, using soybean as substrate and Lactobacillus rhamnosus CRL 981 as starter, was studied in the present work. Sucrose was added into soybean paste to study the effect on the behavior of the selected strain. The development of L. rhamnosus CRL 981 through pH and recount measures, sugar intake, organic acid production, ß-glucosidase activity and IS conversion were analyzed. No significant differences in growth and acidity were observed between soybean pastes with and without sucrose added, but the production of lactic acid was higher in the latter paste. The ß-glucosidase activity was detected in both pastes and the complete hydrolysis of IS at 12h of fermentation was observed. Also, this strain was able to increase the free amino acids in soybean paste. SSF, using soybean as substrate and L. rhamnosus CRL 981 as starter culture, is an alternative process to obtain a soybean product bio-enriched in active IS with attractive nutritional characteristics.
Assuntos
Fermentação , Glycine max/metabolismo , Isoflavonas/biossíntese , Lacticaseibacillus rhamnosus/metabolismo , Produtos Vegetais/análise , Aminoácidos/metabolismo , Proteínas de Bactérias/metabolismo , Microbiologia de Alimentos , Hidrólise , Ácido Láctico/biossíntese , Sacarose/farmacologia , beta-Glucosidase/metabolismoRESUMO
At present, consumers are looking for more natural foods so as to improve health through their active compounds. Within this context, soybean is an excellent substrate due to its beneficial effects on consumers' health. Moreover, lactic cultures are widely used in the food industry to improve the technological, nutritional and functional characteristics of fermented foods. It is interesting to find new matrices in which to transport these starter cultures (potentially probiotic microorganisms). The aim of this research was to obtain a solid state fermentation system from soybean to analyze the behavior of selected lactobacilli and bifidobacteria, with the potential to develop a functional vegetarian food to serve as carrier for the microorganisms. A soybean solid substrate system was optimized by selecting the relationship of the main processing parameters. Homogeneous soybean pastes with different moisture content (60-80%) were obtained and used as substrate and support for solid substrate fermentation. Moisture, inoculum size and temperature were optimized: 80%, 4%, 37°C, respectively. L. rhamnosus CRL 981 was chosen as the best starter to use in this kind of fermentation, showing high acidification and cell counts at 24h of fermentation and increased specific growth rate in tested soybean pastes. It was demonstrated that the selected soybean paste could be used as a carrier of these microorganisms having probiotic potential for the production of vegetarian foods. Moreover, these microorganisms are able to modify the substrate to enhance their nutritional and functional characteristics, which would change the soybean into a more attractive product for consumers.
Assuntos
Bifidobacterium , Fermentação , Lactobacillus , Probióticos , Glycine maxRESUMO
Lactobacillus (L.) rhamnosus CRL1505 accumulates inorganic polyphosphate (polyP) in its cytoplasm in response to environmental stress. The aim of this study was to evaluate the potential effects of polyP from the immunobiotic CRL1505 on an acute respiratory inflammation murine animal model induced by lipopolysaccharide (LPS). First, the presence of polyP granules in the cytoplasm of CRL1505 strain was evidenced by specific staining. Then, it was demonstrated in the intracellular extracts (ICE) of CRL1505 that polyP chain length is greater than 45 phosphate residues. In addition, the functionality of the genes involved in the polyP metabolism (ppk, ppx1 and ppx2) was corroborated by RT-PCR. Finally, the possible effect of the ICE of CRL1505 strain containing polyP and a synthetic polyP was evaluated in vivo using a murine model of acute lung inflammation. It was observed that the level of cytokines pro-inflammatory (IL-17, IL-6, IL-2, IL-4, INF-γ) in serum was normalized in mice treated with ICE, which would indicate that polyP prevents the local inflammatory response in the respiratory tract. The potential application of ICE from L. rhamnosus CRL1505 as a novel bioproduct for the treatment of respiratory diseases is one of the projections of this work.
RESUMO
The consumption of soybean isoflavones (IS) is associated with several beneficial properties on human health. Some lactic acid bacteria possess ß-glucosidase enzyme, that allows to obtain the active form of IS (aglycone). The solid state fermentation (SSF) has received great attention in the last years in order to obtain several valuable compounds. SSF, using soybean as substrate and Lactobacillus rhamnosus CRL 981 as starter, was studied in the present work. Sucrose was added into soybean paste to study the effect on the behavior of the selected strain. The development of L. rhamnosus CRL 981 through pH and recount measures, sugar intake, organic acid production, ß-glucosidase activity and IS conversion were analyzed. No significant differences in growth and acidity were observed between soybean pastes with and without sucrose added, but the production of lactic acid was higher in the latter paste. The ß-glucosidase activity was detected in both pastes and the complete hydrolysis of IS at 12 h of fermentation was observed. Also, this strain was able to increase the free amino acids in soybean paste. SSF, using soybean as substrate and L. rhamnosus CRL 981 as starter culture, is an alternative process to obtain a soybean product bio-enriched in active IS with attractive nutritional characteristics.
El consumo de isoflavonas de soja (IS) está asociado a diversos beneficios para la salud humana. Ciertas bacterias lácticas poseen la enzima ß-glucosidasa, que permite obtener la forma bioactiva (agliconas) de las IS. La fermentación en sustrato sólido (FSS) ha recibido gran atención en los últimos anos debido a sus numerosas ventajas, y permite la obtención de productos con valor agregado. En el presente trabajo se estudió la FSS utilizando soja como sustrato y Lactobacillus rhamnosus CRL981 como cultivo iniciador. Con el fin de estudiar el efecto de una fuente de carbono externa sobre el comportamiento de la cepa seleccionada, se adicionó sacarosa a la pasta de soja. Se evaluó el crecimiento de L. rhamnosus CRL 981 a través de medidas de pH y recuento en placa. Además, se analizó el consumo de azúcares, producción de ácidos orgánicos, actividad ß-glucosidasa y conversión de IS. No se observaron diferencias significativas en el crecimiento y acidez entre las pastas de soja sin adición de sacarosa y con ella, sin embargo, la producción de ácido láctico fue mayor en esta última. La actividad de ß-glucosidasa se detectó en ambas pastas y se observó la hidrólisis completa de IS a las 12 h de fermentación. Además, esta cepa fue capaz de aumentar los aminoácidos libres en la pasta de soja. La FSS, utilizando soja como sustrato y L. rhamnosus CRL 981 como cultivo iniciador, es un proceso alternativo para obtener un producto de soja bioenriquecido en IS bioactivas con características nutricionales atractivas.
Assuntos
Glycine max/metabolismo , Lacticaseibacillus rhamnosus/metabolismo , Fermentação , Produtos Vegetais/análise , Isoflavonas/biossíntese , Sacarose/farmacologia , Proteínas de Bactérias/metabolismo , beta-Glucosidase/metabolismo , Ácido Láctico/biossíntese , Microbiologia de Alimentos , Aminoácidos/metabolismo , HidróliseRESUMO
At present, consumers are looking for more natural foods so as to improve health through their active compounds. Within this context, soybean is an excellent substrate due to its beneficial effects on consumers' health. Moreover, lactic cultures are widely used in the food industry to improve the technological, nutritional and functional characteristics of fermented foods. It is interesting to find new matrices in which to transport these starter cultures (potentially probiotic microorganisms). The aim of this research was to obtain a solid state fermentation system from soybean to analyze the behavior of selected lactobacilli and bifidobacteria, with the potential to develop a functional vegetarian food to serve as carrier for the microorganisms. A soybean solid substrate system was optimized by selecting the relationship of the main processing parameters. Homogeneous soybean pastes with different moisture content (60-80%) were obtained and used as substrate and support for solid substrate fermentation. Moisture, inoculum size and temperature were optimized: 80%, 4%, 37 °C, respectively. L. rhamnosus CRL 981 was chosen as the best starter to use in this kind of fermentation, showing high acidification and cell counts at 24 h of fermentation and increased specific growth rate in tested soybean pastes. It was demonstrated that the selected soybean paste could be used as a carrier of these microorganisms having probiotic potential for the production of vegetarian foods. Moreover, these microorganisms are able to modify the substrate to enhance their nutritional and functional characteristics, which would change the soybean into a more attractive product for consumers.
Actualmente los consumidores están en la búsqueda de alimentos naturales, a fin de mejorar la salud a través de sus compuestos activos. En este contexto, la soja es un excelente sustrato debido a sus efectos beneficiosos sobre la salud del consumidor. En la industria alimentaria se emplean cultivos lácticos para mejorar las características tecnológicas, nutricionales y funcionales de los alimentos fermentados. Es interesante encontrar nuevas matrices para transportar estos cultivos iniciadores, que potencialmente son microorganismos probióticos. El objetivo de este estudio fue obtener un sistema de fermentación en estado sólido a partir de soja para analizar el comportamiento de lactobacilos y bifidobacterias seleccionadas, con potencial para desarrollar un alimento vegetariano funcional que sirva de portador de los microorganismos. El sistema de sustrato sólido de soja se optimizó mediante la selección de la relación de parámetros principales de procesamiento. Se obtuvieron pastas de soja homogéneas con diferente contenido humedad (60-80%) y se utilizaron como sustrato y soporte para la fermentación en sustrato sólido. Las variables humedad, tamaño del inóculo y temperatura fueron optimizadas en 80%, 4% y 37°C, respectivamente. Lactobacillus rhamnosus CRL 981 fue elegido como el mejor cultivo iniciador para utilizar en este tipo de fermentación; este mostró acidificación y recuentos celulares altos en 24 horas de fermentación, y mayor velocidad específica de crecimiento en las condiciones evaluadas. Se demostró que la pasta de soja seleccionada podría ser utilizada como portadora de estos microorganismos con potencial probiótico para la elaboración de alimentos vegetarianos. Además, estos microorganismos son capaces de modificar el sustrato y mejorar sus características nutritivas y funcionales, lo que convertiría a la soja en un producto más atractivo para los consumidores.