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Search Results: 1 - 10 of 211908 matches for " Diego P. Alonso "
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Unifying Theories of Molecular, Community and Network Evolution
Carlos J. Melian,David Alonso,Diego P. Vazquez,James Regetz
Quantitative Biology , 2008,
Abstract: The origin of diversification and coexistence of genes and species have been traditionally studied in isolated biological levels. Ecological and evolutionary views have focused on the mechanisms that enable or constrain species coexistence, genetic variation and the genetics of speciation, but a unified theory linking those approaches is still missing. Here we introduce evolutionary graphs in the context of neutral theories of molecular evolution and biodiversity to provide a framework that simultaneously addresses speciation rate and joint genetic and species diversities. To illuminate this question we also study two models of evolution on graphs with fitness differences, which provide insights on how genetic and ecological dynamics drive the speed of diversification. Neutral evolution generates the highest speed of speciation, species richness (i.e. five times and twice as many species as compared to genetic and ecological graphs, respectively) and genetic--species diversity (i.e., twice as many as genetic and ecological graphs, respectively). Thus the speed of speciation, the genetic--species diversity and coexistence can differ dramatically depending on whether genetic factors versus ecological factors drive the evolution of the system. By linking molecular, sexual and trophic behavior at ecological and evolutionary scales, interacting graphs can illuminate the origin and evolution of diversity and organismal coexistence.
Frequency-Dependent Selection Predicts Patterns of Radiations and Biodiversity
Carlos J. Melián ,David Alonso,Diego P. Vázquez,James Regetz,Stefano Allesina
PLOS Computational Biology , 2010, DOI: 10.1371/journal.pcbi.1000892
Abstract: Most empirical studies support a decline in speciation rates through time, although evidence for constant speciation rates also exists. Declining rates have been explained by invoking pre-existing niches, whereas constant rates have been attributed to non-adaptive processes such as sexual selection and mutation. Trends in speciation rate and the processes underlying it remain unclear, representing a critical information gap in understanding patterns of global diversity. Here we show that the temporal trend in the speciation rate can also be explained by frequency-dependent selection. We construct a frequency-dependent and DNA sequence-based model of speciation. We compare our model to empirical diversity patterns observed for cichlid fish and Darwin's finches, two classic systems for which speciation rates and richness data exist. Negative frequency-dependent selection predicts well both the declining speciation rate found in cichlid fish and explains their species richness. For groups like the Darwin's finches, in which speciation rates are constant and diversity is lower, speciation rate is better explained by a model without frequency-dependent selection. Our analysis shows that differences in diversity may be driven by incipient species abundance with frequency-dependent selection. Our results demonstrate that genetic-distance-based speciation and frequency-dependent selection are sufficient to explain the high diversity observed in natural systems and, importantly, predict decay through time in speciation rate in the absence of pre-existing niches.
INFLUENCIA DEL ALGINATO DE SODIO SOBRE LA SINERESIS EN JAMóN COCIDO
Montoya Pérez,Luz Amparo; Restrepo Molina,Diego Alonso; Suárez Mahecha,Héctor;
Revista Facultad Nacional de Agronomía, Medellín , 2010,
Abstract: the aim of this study was to evaluate the quality of cooked pork ham using sodium alginate and carrageenan during processing and storage at 8°c for 35 days. two treatments were conducted using sodium alginate 0.3% and 0.5% and carrageenan treatment 0.5%, after preparation the pork cooked ham was vacuum packed at 8 °c for 35 days. the results indicate that the major water losses were presented from the 21 day of the storage period, without significant differences between treatments (p> 0.05). the lowest water loss corresponded to treatment with sodium alginate at 0.5% and the loss was greater for treatment with 0.5% carrageenan (p <0.05). the initial mesophilic count was of 1.03 log cfu / g, by the end of the storage period were obtained values of 5.74 log cfu / g showing no significant differences among treatments. the initial ph values of 6.64 were declining throughout the storage period, reaching values of 6.35. for flavor attribute highest and lowest scores corresponded to ham prepared with carrageenan 0.5% and alginate 0.3% respectively. the appearance attribute shows the highest scores for carrageenan 0.5%, while smaller values correspond to ham formulated with 0.3% alginate. for cutting force, the minor values correspond to ham with carrageenan 0.5 %, whereas the worst qualifications correspond again to ham elaborated with alginate 0.3 %. in this respect, the texture of product, specifically the bite, is negatively affected by the use of alginates.
Revisión: Uso de Ingredientes no Cárnicos como Reemplazantes de Grasa en Derivados Cárnicos
Pacheco Pérez,Waldir Augusto; Restrepo Molina,Diego Alonso; Sepúlveda Valencia,José Uriel;
Revista Facultad Nacional de Agronomía, Medellín , 2011,
Abstract: a literature review, where the different alternatives in terms of non-meat ingredients and additives that have been evaluated as fat replacers in the development of low fat meat derivatives, was carried out. these possibilities aim at looking for response to the necessity that have been generated within the meat sector, in the formulation and manufacturing of healthy meat derivatives, that comply with the requirements and current eating habits, associated to the new trends of the food industry. in this review, studies of the use of certain ingredients based on carbohydrates, proteins and lipids are reported; as other comments on the results and conclusions established by the authors. the review showed that among the different ingredients evaluated, fat replacers based on carbohydrates, specifically hydrocolloids, showed the main applications, since many researches could keep very similar functional and sensorial characteristics to the products formulated with animal fat. on the other hand, fat replacers based on chemically modified lipids, showed to be a promising alternative; since the modification of their physical and chemical properties help to minimize some unfavorable aspects, that can appear in the finished product during the processing, like the production of trans fatty acids.
CARACTERíSTICAS DE LAS BEBIDAS CON PROTEíNA DE SOYA
Vanegas Pérez,Luz Stella; Restrepo Molina,Diego Alonso; López Vargas,Jairo Humberto;
Revista Facultad Nacional de Agronomía, Medellín , 2009,
Abstract: soy is described since its bromatologic, nutritional and functional aspects, as well as, developed associated matters to nutritional benefits carried by means of clinical studies from different authors, for the identification of the responsible components. subsequently, physical and chemical soy protein functionality characteristics, and their impact on soy beverages sensorial are evaluated; soy protein deficiencies, are also discussed. finally, aspects that get mitigate the soy limitations, are pointed out with a through analysis of complementary ingredients use.
Evaluación de un Extensor Graso sobre las Propiedades de Calidad del Chorizo Tipo Antioque?o
Pacheco Pérez,Waldir Augusto; Restrepo Molina,Diego Alonso; López Vargas,Jairo Humberto;
Revista Facultad Nacional de Agronomía, Medellín , 2011,
Abstract: the effect of a fat extender elaborated with pork backfat and a mixture of sodium alginate and calcium carbonate on the quality properties of a chorizo antioque?o type was studied, with the purpose of developing a product reduced in fat. the chorizos elaborated with the fat extender was compared against a chorizo elaborated with pork backfat. the proximal composition, content of cholesterol, profile of fatty acids, energy value, cooking loss, purge losses, texture, color and sensorial attributes were analyzed in the obtained products. the data reported in each of the measurements were analyzed by one way analysis of variance. significant differences (p<0,05) were found in the content of fat and in the profile of fatty acids, in the texture properties, so much at instrumental level as sensory. also in the sensory attributes such as appearance, odour, taste and fatty sensation, as well as a reduction in the energy value, while an increase in the cooking loss was observed.
EFECTO DE LA REDUCCIóN DE CLORURO DE SODIO SOBRE LAS CARACTERíSTICAS DE CALIDAD DE UNA SALCHICHA TIPO SELECCIONADA EFFECT OF REDUCTION OF SODIUM CHLORIDE ON THE QUALITY CHARACTERISTICS OF A SAUSAGE TYPE SELECTED
Waldir Augusto Pacheco Pérez,Claudia Elena Arias Mu?oz,Diego Alonso Restrepo Molina
Revista Facultad Nacional de Agronomía, Medellín , 2012,
Abstract: Resumen. Una propuesta para reducir los niveles de sodio en productos cárnicos, y desarrollar productos más saludables, es disminuir la cantidad de cloruro de sodio (NaCl) en las formulaciones. En este estudio fue evaluado el efecto de disminuir y sustituir NaCl por KCl modificado, sobre los niveles de sodio y las características sensoriales y microbiológicas en una salchicha tipo Seleccionada. El porcentaje de reducción y sustitución de NaCl por KCl modificado con relación a un control fue de 50 y 75%, respectivamente. La reducción de NaCl en estos niveles, causó efectos significativos (P≤0,05) sobre el contenido de sodio en el producto final en relación al control, lo que implicaría beneficios nutricionales. De otro lado, diferencias significativas (P≤0,05) en las propiedades de textura, tanto a nivel instrumental como sensorial, fueron detectadas en la formulación con reducción del 75% de NaCl. En cuanto a la estabilidad microbiológica, y demás atributos sensoriales, no se detectaron diferencias entre los tratamientos y el control. Este estudio sugiere que es posible reducir la concentración de NaCl en un 50% en salchichas tipo Seleccionada mediante el uso de KCl modificado, sin cambios desfavorables en las características sensoriales y microbiológicas. Esta reducción permitiría una disminución en los niveles de sodio del 24% en el producto final. Abstract. A proposal to reduce the sodium levels in meat products to develop healthier products is to reduce the amount of sodium chloride (NaCl) in the formulations. In this study, the effect of reducing NaCl and its substituting by modified KCl on sodium levels, sensory and microbiological characteristics in a selected type sausage was evaluated. The percentage of reduction and substitution of NaCl by modified KCl compared to control was 50 and 75%, respectively. The reduction of NaCl caused significant effects (P≤0.05) on the sodium content in the end product relative to the control, which would imply nutritional benefits. On the other hand, significant differences (P ≤0.05) in the instrumental and sensory texture properties were detected in the formulation with reduced 75% of NaCl. On the other microbiological stability and sensory attributes, it was not found significant differences between treatments and the control. This study suggests that is possible to reduce the NaCl concentration by 50% in a selected type sausage using modified KCl without adverse changes in the sensory and microbiological characteristic. Besides, this reduction would allow a decrease in sodium levels of 24% in the end product.
Selección de un Estabilizante y Comportamiento durante Almacenamiento en Refrigeración de un Complemento Nutricional Líquido Selection of a Stabilizer and Behavior during Cold Storage of a Liquid Nutritional Supplement
Luz Stella Vanegas Pérez,Diego Alonso Restrepo Molina,Jairo Humberto López Vargas
Revista Facultad Nacional de Agronomía, Medellín , 2012,
Abstract: Resumen. Con el propósito de estabilizar un complemento nutricional líquido para ni os, se ensayaron desde el punto de vista reológico; en una primera etapa, tres mezclas de hidrocoloides (T1: 100% goma xántica, T2: 50% goma xántica, 50% goma algarrobo y T3: 33, 3% goma xántica, 33,3% goma algarrobo, 33,3% carragenina kappa), dosificados en un nivel del 0,2% a las que se les determinó el efecto sobre las características sensoriales de importancia para la población a la que estaba dirigida. En una segunda etapa se evaluó la estabilidad reológica, sensorial y microbiológica de una bebida mantenida durante 20 días en refrigeración y estabilizada con 0,1% (T1'), 0,2% (T2') y 0,3% (T3') del hidrocoloide seleccionado en la etapa uno. Se concluye que la mezcla en partes iguales de los tres hidrocoloides (T3), fue la preferida por los ni os y que los niveles de uso T1' , T2' y T3' no mostraron diferencias significativas para las variables analizadas, pero la mejor opción y la menor varianza fueron para la bebida estabilizada con 0,2% (T2') del hidrocoloide; no obstante, el tratamiento de menor costo fue para la bebida estabilizada con 0,1% (T1') del hidrocoloide. Abstract. With the purpose of stabilizing a liquid nutritional supplement for children, were assayed from the rheological point of view, in a first stage, three mixtures of hydrocolloids (T1:100% xanthan gum, T2: 50% xanthan gum, 50% locust bean gum and T3: 33, 3% xanthan gum, 33% locust bean gum, 33.3% kappa carrageenan), dosed at a level of 0.2%. It was determined the effect on the sensory characteristics of importance to the people which was directed. In a second step we evaluated the rheological, sensory and microbiological stability in a drink maintained for 20 days under refrigeration and stabilized with 0.1% (T1'), 0.2% (T2') and 0.3% (T3') of hydrocolloid selected in step one. We conclude that the mixture of equal parts of three hidrocololids (T3), was preferred by children and that levels of use T1' , T2' and T3' showed no significant differences for the variables analyzed, but the best option and lower variance were for drink stabilized with 0.2% (T2' ) of the hydrocolloid; however, treatment of lower cost was for the beverage stabilized with 0.1% (T1') of hydrocolloid.
Evaluación de un Extensor Graso sobre las Propiedades de Calidad del Chorizo Tipo Antioque o Evaluation of a Fat Extender on the Quality Properties of Chorizo Antioque o Type
Waldir Augusto Pacheco Pérez,Diego Alonso Restrepo Molina,Jairo Humberto López Vargas
Revista Facultad Nacional de Agronomía, Medellín , 2011,
Abstract: Se estudió el efecto de un extensor de grasa elaborado con tocino dorsal de cerdo y una mezcla de alginato de sodio y carbonato de calcio, sobre las propiedades de calidad de un chorizo tipo Antioque o, con el fin de desarrollar un producto reducido en grasa. Los chorizos elaborados con el extensor graso fueron comparados contra un chorizo formulado con tocino de cerdo. La composición proximal, contenido de colesterol, perfil de ácidos grasos, valor energético, pérdidas por cocción, pérdidas por purga, textura, color y atributos sensoriales fueron analizados en los productos obtenidos. Los datos reportados en cada una de las mediciones fueron analizados a través de análisis de varianza de una vía. Diferencias significativas (P<0,05) fueron encontradas en el contenido de grasa y en el perfil de ácidos grasos, en las propiedades de textura, tanto a nivel instrumental como sensorial, igualmente en los atributos sensoriales como apariencia, olor, sabor y sensación grasa, al igual que una reducción en el valor energético; mientras que un aumento fue observado, en las pérdidas por cocción. The effect of a fat extender elaborated with pork backfat and a mixture of sodium alginate and calcium carbonate on the quality properties of a chorizo Antioque o type was studied, with the purpose of developing a product reduced in fat. The chorizos elaborated with the fat extender was compared against a chorizo elaborated with pork backfat. The proximal composition, content of cholesterol, profile of fatty acids, energy value, cooking loss, purge losses, texture, color and sensorial attributes were analyzed in the obtained products. The data reported in each of the measurements were analyzed by one way analysis of variance. Significant differences (P<0,05) were found in the content of fat and in the profile of fatty acids, in the texture properties, so much at instrumental level as sensory. Also in the sensory attributes such as appearance, odour, taste and fatty sensation, as well as a reduction in the energy value, while an increase in the cooking loss was observed.
CARACTERíSTICAS DE LAS BEBIDAS CON PROTEíNA DE SOYA CHARACTERISTICS OF THE DRINKS WITH SOYBEAN PROTEIN
Luz Stella Vanegas Pérez,Diego Alonso Restrepo Molina,Jairo Humberto López Vargas
Revista Facultad Nacional de Agronomía, Medellín , 2009,
Abstract: Se describe la soya desde el punto de vista bromatológico, nutricional y funcional, igualmente se desarrollan los aspectos asociados a los beneficios para la salud que han obtenido diversos autores mediante estudios clínicos, identificando los componentes responsables de esta acción. Posteriormente se desarrollan las características de funcionalidad fisicoquímica de la proteína de soya y su incidencia en los atributos sensoriales de las bebidas con soya, incluyendo las deficiencias que ésta presenta, para finalmente se alar los aspectos que logran mitigar este tipo de defectos mediante el uso de ingredientes complementarios. Soy is described since its bromatologic, nutritional and functional aspects, as well as, developed associated matters to nutritional benefits carried by means of clinical studies from different authors, for the identification of the responsible components. Subsequently, physical and chemical soy protein functionality characteristics, and their impact on soy beverages sensorial are evaluated; soy protein deficiencies, are also discussed. Finally, aspects that get mitigate the soy limitations, are pointed out with a through analysis of complementary ingredients use.
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