Droplet Size Distribution (DSD) and linear viscoelastic properties of concentrated o/w emulsions stabilized by different proteins (crayfish, gluten and soybean) have been studied. A typical behaviour of highly concentrated emulsions with a high degree of flocculation has been found. An increase in energy input for the emulsification process or in emulsifier concentration leads to an increase in both viscoelastic moduli (G’, G’’) as well as to a decrease in droplet size. Thus, an enhancement of the entanglement network produced by association of protein molecules that are surrounding oil droplets or are present in the continuous phase takes place, leading to a significant improvement of emulsion stability. | Se ha realizado un estudio de la distribución del tamaño de gotas y de las propiedades viscoelásticas lineales de emulsiones concentradas de aceite en agua, estabilizadas con diferentes proteínas (cangrejo, gluten y soja). Los sistemas estudiados siempre presentan un comportamiento típico de emulsiones altamente concentradas con un alto grado de floculación. Se ha observado que un incremento de la velocidad de agitación empleada durante la preparación o de la concentración de emulsionante dan lugar a un aumento de los módulos viscoelásticos (G’ y G’’) y a una disminución del tamaño de gotas. Por tanto se produce un reforzamiento del entramado formado por asociación de las gotas de fase dispersa y como consecuencia, un aumento en la estabilidad de las emulsiones.

A total of 300 Centropomus undecimalis juveniles, with an average initial weight of 3.16 ± 0.28 g and average total length of 7.17 ± 0.22 cm, were reared for eight weeks using a recirculating system to determine the dietary protein requirement for their growth and survival. The e ect of ve experimental diets containing 40, 45, 50, 55 and 60% total protein content and two salinities (brackish water, BW at 5 UPS and marine water, MW at 36 UPS) were assessed. Fish were fed ve times per day at 2.5% of total biomass. All treatments were performed in triplicate, recording the individual weight and total length every 15 d, while weight gain and daily growth rate were recorded at the end of the experiment. Mean weight increased proportionally as protein content increased, with the greatest growth occurring with a 60% protein diet for sh reared in brackish water, and 55% for sh in marine water. We consider that the protein requirement in C. undecimalis juveniles is high; in addition, it differs depending on the salinity, which may be due to the higher energy expenditure derived from the processes of osmoregulation in fish reared in marine water.

A total of 300 Centropomus undecimalis juveniles, with an average initial weight of 3.16 ± 0.28 g and average total length of 7.17 ± 0.22 cm, were reared for eight weeks using a recirculating system to determine the dietary protein requirement for their growth and survival. The e ect of ve experimental diets containing 40, 45, 50, 55 and 60% total protein content and two salinities (brackish water, BW at 5 UPS and marine water, MW at 36 UPS) were assessed. Fish were fed ve times per day at 2.5% of total biomass. All treatments were performed in triplicate, recording the individual weight and total length every 15 d, while weight gain and daily growth rate were recorded at the end of the experiment. Mean weight increased proportionally as protein content increased, with the greatest growth occurring with a 60% protein diet for sh reared in brackish water, and 55% for sh in marine water. We consider that the protein requirement in C. undecimalis juveniles is high; in addition, it differs depending on the salinity, which may be due to the higher energy expenditure derived from the processes of osmoregulation in fish reared in marine water.

A soja apresenta elevada demanda por nitrogênio devido ao alto teor protéico dos grãos, de cerca de 40%, o que a torna de grande importância econômica. Este trabalho teve como objetivo determinar o efeito da disponibilidade hídrica e arranjo de plantas sobre a qualidade dos grãos de duas cultivares de soja, no ano agrícola 1998/99, na Estação Experimental Agronômica da Universidade Federal do Rio Grande do Sul (EEA/UFRGS), em Eldorado do Sul, RS. O delineamento experimental foi de blocos ao acaso, em parcelas sub-subdivididas, com quatro repetições. Foram testados dois regimes hídricos (irrigado e não irrigado), duas cultivares (BRS 137 e BRS 138) e três espaçamentos entre linhas (20cm, 40cm e 20-40cm em linhas pareadas). Avaliou-se o teor de N nas folhas durante a ontogenia, os teores de proteína e óleo, bem como o tamanho e peso dos grãos. O rendimento médio de grãos foi de 3360kg ha-1. A irrigação proporcionou aumento de 1101kg ha-1 (39%), decorrente do aumento no teor de N nas folhas, tamanho e peso dos grãos. A cultivar BRS 137 rendeu 535kg ha-1 (17%) a mais do que a BRS 138; os grãos eram de maior tamanho, peso e teor de proteína. No final do período reprodutivo, o teor de N nas folhas foi mais elevado em 20cm e 40cm, resultando em teor de proteína e rendimento de grãos 18 e 13% mais elevado do que 20-40cm em linhas pareadas, respectivamente. O teor de óleo nos grãos não foi alterado em função dos tratamentos. | The soybean is a crop with high demand for nitrogen (N) due to the grain protein content of about 40%. Because of the high protein, soybean is of great economic importance. The present study had its objectives to determine the effect of water availability and soybean plant arrangement on grain quality of two cultivars. With this objective, an experiment was performed during the 1998/99 growing season, in the Agronomic Experimental Station of the Federal University of Rio Grande do Sul (EEA/UFRGS), Eldorado do Sul, RS. The treatments were arranged in a randomized complete-block in a split split-plot design, with four replications. Two water availability (irrigated and not irrigated), two cultivars (BRS 137 and BRS 138) and three row spacings (20cm, 40cm and 20-40cm in skip row) were tested. The leaf N content was evaluated during crop growth, and the protein and oil content, as well as the size and weight of the grains, at the harvest. The average grain yield was of 3360kg ha-1. The irrigation increased grain yield by 1101kg ha-1 (39%), due to the increase in leaf N, size and weight of the grain. The yield of the cultivar BRS 137 was 535kg ha-1 (17%) greater, as well as it produced grains with larger size, weight and protein content than BRS 138. In the late reproductive stage, leaf N was higer in 20cm and 40cm, what resulted in larger protein content and grain yield 18 and 13% higher, compared to 20-40 cm in skip row, respectively. The grain oil content was not altered by the treatments

Heat-induced interfacial aggregation of a whey protein isolate (WPI) with a high content of β-lactoglobulin, previously adsorbed at the oil-water interface, was studied by interfacial dynamic characteristics (interfacial tension and surface dilational properties) performed in a automatic drop tensiometer coupled with microscopic observation and image analysis of the drop after heat-treatment. The temperature, ranging between 20 and 80 ºC, and protein concentration in aqueous bulk phase, ranging between 1.10-1 and 1.10-5% wt/wt, were studied as variables. The pH, and ionic strength were maintained constant at 5 and 0.05 M, respectively. During the heat-treatment, WPI films behave typically as viscoelastic with non-zero phase angle, but with increasing elastic characteristics as the heat-treatment progresses. During isothermal treatment the surface dilational modulus, E, increases and the interfacial tension, σ, and phase angle, φ, decrease with time to a plateau value. The time dependence of E can be quantified by a first-order equation according to two kinetic mechanisms. The rate of thermal changes in WPI adsorbed films increases with protein concentration in solution. Heat-treatment produces irreversible changes in WPI adsorbed films because the interfacial characteristics do not return to original values after cooling back to the initial temperature. Significant changes in interfacial characteristics and drop image associated with interfacial WPI gelation were observed at protein concentration as low as 1.10-5% wt/wt, even for heat-treatment at 40 ºC. | En este trabajo se ha estudiado la agregación interfacial inducida por el calor en un aislado proteico del suero bovino (WPI), previamente adsorbido sobre la interfase aceite-agua. Se ha seguido la evolución, durante el tratamiento térmico, de las características dinámicas interfaciales (tensión interfacial y propiedades dilatacionales superficiales), determinadas en un tensiómetro dinámico de gota, en unión de la observación microscópica y posterior análisis de la imagen de una gota que tiene adsorbida a la proteína sobre su superficie. Las variables estudiadas fueron la temperatura (en el intervalo comprendido entre 20 y 80 ºC) y la concentración de proteína en el seno de la fase acuosa (en el intervalo comprendido entre 1.10-1 y 1.10-5% en peso). Durante el tratamiento térmico, (a) la película de WPI presenta un comportamiento viscoelástico, con un ángulo de fase distinto de cero, (b) se incrementa el carácter elástico de la interfase, (c) se produce un incremento del módulo dilatacional superficial (E) y (d) una disminución de la tensión interfacial. La variación de E con el tiempo puede cuantificarse mediante ecuaciones de primer orden que pueden relacionarse con dos mecanismos cinéticos, asociados con la gelificación de WPI sobre la interfase aceite-agua. El tratamiento térmico produce cambios irreversibles en la película de WPI adsorbida sobre la interfase. Se han observado cambios significativos en las características interfaciales y en la imagen de la gota a concentraciones de proteína tan bajas como 1.10-5% en peso.

The maralfalfa is a soft forage very palatable and sweet that can replace the molasses. In the Bolivian highland region there are seasons of scarcity of forage, which is why new alternatives for cattle feeding must be evaluated, for this reason the objective of the research is to evaluate the efficiency of water use and the bromatological characteristics of maralfalfa under the application of biol and irrigation. The methodology consisted of the evaluation in the hot bed, greenhouse, field and open field environments, with the application of 9 treatments consisting of the incorporation of bovine biol at 20, 40 and 60% and application of irrigation sheets at 25, 50 and 75%, the design was of random blocks with arrangement of divided plots, resulting in three blocks with three repetitions, soil moisture was evaluated, bromatological analysis of the amount of protein, crude fiber, energy value, yield in dry matter and the efficiency of water use. The main results show that the bromatological quality parameters based on crude protein, crude fiber and energy value in the hot bed and in the open field were as expected, the production in greenhouse and field obtained lower than expected values; however, they are found above other fodder crops of the region, which is why maralfalfa is a good alternative for its use in feeding ruminants in the different farms of the region. The irrigation water use efficiency was better in the warm bed to an irrigation sheet of 25% registering 4.54 kg m-3 of water which means that to produce 1 kg of dry matter of the forage maralfalfa 220.47 L of water is required, during the five cuts | La maralfalfa es un forraje suave muy palatable y dulce que puede sustituir a la melaza. En la región del Altiplano boliviano existen temporadas de escasez de forraje, razón por la que se deben evaluar nuevas alternativas para la alimentación del ganado, es por esta razón que el objetivo de la investigación es evaluar la eficiencia del uso de agua y las características bromatológicas de la maralfalfa bajo la aplicación de biol y riego. La metodología consistió en la evaluación en los ambientes de cama caliente, carpa, canchón y campo abierto, con la aplicación de 9 tratamientos consistentes en la incorporación de biol bovino al 20, 40 y 60% y aplicación de láminas de riego al 25, 50 y 75%, el diseño fue de bloques al azar con arreglo de parcelas divididas, resultando en tres bloques con tres repeticiones, se evaluó la humedad del suelo, análisis bromatológico de la cantidad de proteína, fibra cruda, valor energético, rendimiento en materia seca y la eficiencia del uso del agua. Los principales resultados muestran que los parámetros de la calidad bromatológica en base en la proteína cruda, fibra cruda y valor energético en la cama caliente y a campo abierto fueron los esperados, la producción en carpa y canchón obtuvo valores inferiores a los esperados; sin embargo se encuentran por encima de otros forrajes de corte de la región razón por lo cual maralfalfa es una buena alternativa para su uso en la alimentación de los rumiantes en las diferentes explotaciones de la región. La eficiencia de uso del agua de riego fue mejor en la cama caliente a una lámina de riego de 25% registrando 4.54 kg m-3 de agua lo que significa que para producir 1 kg de materia seca del forraje maralfalfa se requiere 220.47 L de agua, durante los cinco cortes.

"Se realizó un estudio para evaluar el efecto de los niveles de proteína y energía sobre el crecimiento, supervivencia y la respuesta antioxidante de la enzima superóxido dismutasa (SOD) en juveniles de Cherax quadricarinatus. El experimento incluyó seis dietas prácticas con tres niveles de proteína cruda (28, 35 y 40%) y dos niveles de energía (~18 y 20 kJ·g–1). El grupo control fue alimentado con alimento comercial para camarón. La actividad SOD más alta (34.8 U·mg–1 prot.) se presentó en juveniles alimentados con 35% de proteína cruda (PC) y 18 kJ·g–1. La proteína soluble en tejido de langosta de agua dulce alimentada con 28 y 35% de PC fue superior con respecto a los acociles del grupo control. El mejor peso final promedio (9.23 g), la mejor ganancia en peso (788%) y el factor de conversión alimenticia mas bajo (1.3) se presentó en acociles alimentados con 35% de PC. Se concluye que una dieta conteniendo 35% de PC y 18 kJ·g–1 de energía es recomendada para la producción y además incrementa la respuesta inmune de los acociles en su fase de juvenil." | "This study determined the influence of dietary crude protein and energy levels on growth, survival, and antioxidant response of superoxide dismutase (SOD) in juvenile redclaw Cherax quadricarinatus. Six practical diets containing three crude protein (CP) levels (28, 35, and 40%) and two energy levels (~18 and 20 kJ·g–1) were tested. The control group was fed a commercial shrimp diet. The highest SOD activity (34.8 U·mg–1 protein) occurred in the diet with 35% CP and 18 kJ · g–1. Soluble protein in tissue of redclaw fed 28 and 35% CP increased, compared to the control. The best mean final weight (9.23 g), weight gain (788%), and the lowest feed conversion ratio (1.3) occurred with the 35% CP diet. We conclude that a dietary CP content of 35% and 18 kJ · g–1 is recommended for production and best immune responses in redclaw."