792 research outputs found
Aflatoxinas B1, B2, G1 y G2 en productos destinados a la alimentación de vacuno lechero y presencia de aflatoxina M1 en leche (abstract)
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Estudio in vitro del efecto de los ácidos fenólicos naturales sobre el crecimiento y producción de aflatoxinas por Aspergillus parasiticus: abstract
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Prevención y reducción de toxinas de Fusarium en cereales mediante el uso de ácidos fenólicos naturales: abstract
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Mycoprev: elaboración de un código de buenas prácticas en la zona fronteriza España-Francia-Andorra como herramienta de prevención y control de micotoxinas en cereales: abstract
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Incidencia de aflatoxinas B1, B2, G1 y G2 en raciones alimenticias de ganado ovino, y de aflatoxinas M1 en leche de oveja (abstract)
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Novel Strategies for Upstream and Downstream Processing of Tannin Acyl Hydrolase
Tannin acyl hydrolase also referred as tannase is an enzyme with important applications in several science and technology fields. Due to its hydrolytic and synthetic properties, tannase could be used to reduce the negative effects of tannins in beverages, food, feed, and tannery effluents, for the production of gallic acid from tannin-rich materials, the elucidation of tannin structure, and the synthesis of gallic acid esters in nonaqueous media. However, industrial applications of tannase are still very limited due to its high production cost. Thus, there is a growing interest in the production, recovery, and purification of this enzyme. Recently, there have been published a number of papers on the improvement of upstream and downstream processing of the enzyme. These papers dealt with the search for new tannase producing microorganisms, the application of novel fermentation systems, optimization of culture conditions, the production of the enzyme by recombinant microorganism, and the design of efficient protocols for tannase recovery and purification. The present work reviews the state of the art of basic and biotechnological aspects of tannin acyl hydrolase, focusing on the recent advances in the upstream and downstream processing of the enzyme
Fructo-oligosaccharides (FOS) production by fungal submerged culture using aguamiel as a low-cost by-product
Supplementary data to this article can be found online at https:// doi.org/10.1016/j.lwt.2018.12.020.Fructooligosaccharides (FOS) are important ingredients in the functional food industry because they have different biological properties such as decrease level of triglycerides, cholesterol and phospholipids and stimulate growth of probiotics for enhancement of microflora in large intestine. However, current strategies for the FOS production through simple and economical bioprocess has been necessary. The aim of this work was evaluated the capacity of three fungal strains (Aspergillus niger GH1, Aspergillus niger PSH and Aspergillus oryzae DIA-MF) to produce fructooligosaccharides (FOS) using aguamiel from Agave salmiana as an economical substrate. In addition, Czapek Dox medium supplemented with sucrose as carbon source was used as a control medium for the FOS production. A. oryzae DIA-MF was a fungi producer of FOS using aguamiel or Czapek Dox medium as substrate at 24?h of fermentation. However, the yield of FOS was increased two folds (20.30?g/L), with a productivity of 0.84?g FOS/l.h when aguamiel was used as substrate. On the other hand, A. niger GH1 and A. niger PSH showing only hydrolytic activity on sucrose under the studied conditions. In conclusion, this study shown excellent compatibility of A. oryzae DIA-MF using aguamiel as an economical substrate for the FOS production under a simple bioprocess.Authors thank all technical support and comments made by Dra. Adriana C. Flores-Gallegos and Dra. Abril Flores-Maltos. Authors thank National Council for Science and Technology (CONACYT) of Mexico by the financial support through the project No. CB-2011-C01-167764. Author D. B. Muñiz-Márquez also thank CONACYT for the financial support during her postgraduate program (Doctorate) in Food Science and Technology offered by the University Autonomous of Coahuila, Mexico.info:eu-repo/semantics/publishedVersio
Validating anthropogenic threat maps as a tool for assessing river ecological integrity in Andean-Amazon basins
Heredabilidades para características de crecimiento a través de los años en la raza Blanco Orejinegro
The aim of this study was to estimate the values of direct and maternal heritability and the variances due to the permanent environment from 1990 to 2012 in the Colombian Creole Blanco Orejinegro breed. In total, 10 698 data on growth variables were analyzed for birth weight (BW), adjusted weight at 240 days (PAJ240) and adjusted weight at 480 days (PAJ480). The derivative-free restricted maximum likelihood methodology (DFREML) was used, adjusting an animal model that included direct genetic effects, maternal and variations due to the permanent environment, assuming as fixed effects the year, time of birth, the sex of the calf and as covariate the mother's age at delivery. The heritability for BW were h²d = 0.31, h²m = 0.03 and σ²c = 0.07. the heritability values for PAJ240 were moderate and low (h²d = 0.18, h²m = 0.05, σ²c = 0.04) while for PAJ480 they were h²d = 0.17, h²m = 0.04, σ²c = 0.06, without presenting significant values and the proportion of the variances presented negative and decreasing values on the line. The genetic trends were increasing and decreasing, indicating that the environmental variance negatively affects the maternal component and the permanent environment for the weight at 240 and 480 days, respectively.El objetivo del estudio fue estimar los valores de heredabilidad directa, materna y las varianzas debidas al ambiente permanente desde año 1990 hasta 2012 en la raza criolla colombiana Blanco Orejinegro. Se analizaron 10 698 datos sobre las variables de crecimiento para peso al nacimiento (PN), peso ajustado a los 240 días (PAJ240) y peso ajustado a los 480 días (PAJ480). Se utilizó la metodología de máxima verosimilitud restringida libre de derivadas (DFREML), ajustando un modelo animal que incluyó efectos genéticos directos, maternos y variaciones debidas al ambiente permanente, asumiendo como efectos fijos el año, época de nacimiento, el sexo del ternero y como covariable la edad de la madre al parto. Las heredabilidades para PN fueron de h²d = 0.31, h²m = 0.03 y σ²c = 0.07. los valores de heredabilidad para PAJ240 fueron moderados y bajos (h²d = 0.18, h²m = 0.05, σ²c = 0.04) en tanto que para PAJ480 fueron de h²d = 0.17, h²m = 0.04, σ²c = 0.06, sin presentar valores significativos, y la proporción de las varianzas presentaron valores negativos y decreciente en la recta. Las tendencias genéticas fueron creciente y decreciente, indicando que la varianza ambiental afecta negativamente el componente materno y del ambiente permanente para el peso a los 240 y 480 días respectivamente
Effect of SiC on the oxidation behavior of a Carbon-Carbon composite
Se prepararon dos materiales compuestos, CC y CC-SiC, mediante ciclos de infiltración líquida de brea-carbonización, el porcentaje en peso de SiC requerido fue determinado a través de TGA. Las estructuras morfológicas de los compuestos CC y CC-SiC se evaluaron mediante PLM y SEM. Las pérdidas de masa en llama de oxiacetileno se observaron en ambos compuestos durante 5, 10 y 15 minutos, respectivamente. Los valores de peso de los materiales CC y CC-SiC decrecieron con un mayor tiempo de exposición a la llama; se indujeron cambios morfológicos durante la exposición a la llama. El exceso de carbono en la matriz se oxidó formando CO, y se emitieron sustancias volátiles, generando una estructura porosa en los compuestos. Sin embargo, para el compuesto CCSiC, se conservó la integridad del refuerzo, verificando el efecto del SiC en el comportamiento de los compuestos a altas temperaturas.Abstract: Two composite materials, CC and CC-SiC, were prepared by liquid pitch infiltration-carbonization cycles; required SiC weight percentage was determined by TGA. Morphological structures of CC and CC-SiC composites
were evaluated using PLM and SEM. Weight loss at oxy-acetylene flame was observed on both composites during 5, 10 and 15 minutes, respectively. CC and CC-SiC weight values decreased with the increasing of flame exposure time; morphological changes were induced during flame exposure. Excessive carbon on the matrix was oxidized forming CO, and volatile substances were released, generating a porous structure on the composites. However, for CC-SiC composite, the reinforcement integrity was remained, verifying the effect of SiC on the composites behavior at high temperatures
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