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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Estudio integral de los recursos hídricos y las coberturas del suelo de la cuenca media y baja del Río Sauce Grande (Argentina)

Brendel, Andrea Soledad 16 March 2020 (has links)
Las cuencas hidrográficas son sistemas que presentan una estrecha relación entre los factores naturales tales como la geomorfología, el clima, el suelo, el agua, la vegetación y los factores antrópicos como las actividades agrícolas. Los objetivos generales de la presente tesis fueron evaluar el efecto de la variabilidad pluviométrica sobre los principales recursos hídricos de la cuenca del río Sauce Grande (SW de la provincia de Buenos Aires), como así también analizar el comportamiento espacio-temporal de los parámetros limnológicos en su cuenca. Además, se propuso estudiar la dinámica del caudal del río Sauce Grande y la circulación atmosférica local de la laguna homónima, determinar su origen y los efectos del ingreso de la brisa de mar sobre este cuerpo de agua. Inicialmente, se analizaron las anomalías de las principales variables meteorológicas, utilizando una extensa serie de tiempo (1960-2017) de tres estaciones meteorológicas ubicadas en el norte, centro y sur del área de influencia de la cuenca. Los resultados indicaron que la temperatura aumentó (+0,5 °C en el norte y + 0,8 °C, en el sur), mientras que la velocidad del viento disminuyó (-1 km/h en el sur y -3,3 km/h en el norte). La tendencia de la precipitación fue espacialmente heterogénea dado que aumentó en el norte y sur (+42 mm y +16 mm, respectivamente) y disminuyó en el centro (-6 mm). Este parámetro, se estudió en función de la variación espacio-temporal de la cobertura de agua de los dos principales recursos hídricos de la cuenca del río Sauce Grande: el dique Paso de Las Piedras (DPP) y la laguna Sauce Grande (LSG) durante el período 1987-2017. Los resultados arrojaron que el área cubierta por agua y la precipitación poseen una asociación lineal positiva, alta y estadísticamente significativa. La variación areal de la LSG estuvo explicada por la precipitación en un 67 %, mientras que la del DPP en un 55 %. Ambos presentaron los mismos períodos de incremento (2001 a 2005 y 2014 a 2017) y reducción de su área (2007 a 2013) relacionados al monto anual de precipitación. Los parámetros morfométricos que presentaron mayor variación con respecto a la precipitación fueron el área, el perímetro y la longitud máxima total. El caudal del río Sauce Grande, medido en alta frecuencia, fluctuó en función de la variabilidad pluviométrica. Durante el período analizado (noviembre 2016-marzo de 2018) el río presentó tres crecidas. La más importante ocurrió en septiembre de 2017 con un caudal máximo de 34,8 m3 s-1 en el sector más cercano a la descarga del rio en el Océano Atlántico y de 4,1 m3 s-1 antes de su ingreso a la laguna. Este valor fue generado por precipitaciones diarias entre 60 y 80 mm. El tiempo máximo de escurrimiento directo fue 12 días y fue mayor en el sector más cercano a la desembocadura del río en el Océano Atlántico, dado la escasa pendiente del terreno. Las áreas inundables ante un evento de precipitación intenso se ubicaron en la barrera Medanosa Austral y en los sectores cercanos al ingreso del río en la laguna homónima. Esta laguna también fue monitoreada con sensores de alta frecuencia (septiembre de 2016-marzo de 2018). Los resultados permitieron caracterizar la dinámica de las variables medidas en un período de mayor profundidad de la laguna y compararlos con un estudio previo realizado durante un período de sequía (febrero de 2011-enero de 2012). En esta tesis, además de aumentar el nivel del agua en relación con un período húmedo, se registró un aumento de la temperatura del agua y del aire, como así también, una disminución de la conductividad eléctrica y la velocidad del viento. La Trasformada Rápida de Fourier mostró diferentes intensidades de la señal en las distintas variables, principalmente representadas por los ciclos anuales, mensuales y estacionales, diarios y semidiurno. Sin embargo, la temperatura del agua y del aire y la velocidad del viento mostraron ciclos de energía en 4 y 8 h. Estos resultados determinaron la existencia de una circulación atmosférica local sobre la laguna de origen geomorfológico. La misma se caracterizó por un aumento significativo de la velocidad del viento en las horas de mayor radiación solar producto del desigual calentamiento, que fue analizado a partir del procesamiento de imágenes satelitales Landsat, entre la laguna y el médano que la limita al sur. Esta circulación se encontró sólo cuando en la región se localizan centros de alta presión, cielo despejado y viento regional mínimo. Además, se comprobó que los eventos de brisa marina ocurridos en la costa de Monte Hermoso (ubicada a 6 km de la laguna) ingresan a la laguna aproximadamente 2 h más tarde, modifican la velocidad y dirección del viento y disminuye la temperatura del aire producto del viento con componente sur. Teniendo en cuenta los parámetros limnológicos medidos de manera estacional (abril-diciembre de 2016), la cuenca media y baja del río Sauce Grande presenta tres unidades espaciales: i) el río Sauce Grande antes de su ingreso en la laguna homónima, ii) el arroyo Las Cortaderas y iii) el arroyo Las Mostazas, la laguna y el sitio más cercano a la descarga del río en el Océano Atlántico. En general, las variables presentaron una marcada variación espacio-temporal. La CE fue mayor en la laguna y en el sitio más cercano a la descarga del río en el Océano Atlántico, dado que son los sectores de menor altura por lo que se genera la acumulación las sales provenientes de toda la cuenca. El arroyo Las Mostazas presentó valores altos de estas variables producto de su cercanía a la ciudad de Coronel Dorrego. El seston y la MOP también se incrementaron a medida que el río se encuentra más cercano a su desembocadura en la laguna y fue registrado en el otoño, en coincidencia con elevadas precipitaciones. El arroyo Las Cortaderas y la laguna presentaron los máximos valores medios de seston y MOP. Su concentración fue mayor durante el verano, probablemente por las altas concentraciones de fitoplancton. El valor medio de seston de la laguna fue ampliamente inferior al registrado en un estudio previo sobre el cuerpo de agua durante un período de extrema sequía (septiembre de 2008-diciembre de 2010), mientras que el encontrado en esta tesis fue durante un período húmedo. Por lo tanto, el seston es altamente fluctuante con respecto al nivel de agua de la laguna. El valor medio de oxígeno disuelto permitió clasificar a todos los ambientes analizados como moderadamente ricos en oxígeno y se correlacionó negativamente con la temperatura del agua. Su valor fue aceptable para la gran mayoría de los organismos acuáticos y especies de peces. El NT y el PT, fueron los más variables temporalmente y el NT se registró en mayor proporción. Ambos presentaron su máximo en invierno y elevadas concentraciones en primavera. Esta situación se relaciona con que, durante estos períodos, se aplican fertilizantes en la siembra (junio-julio) y maduración (septiembre-octubre) del cultivo de trigo, el principal de la cuenca. Estas prácticas, en conjunto con el escurrimiento superficial de la cuenca, generaría el incremento de los nutrientes durante estos dos momentos del año. Se utilizaron diferentes métodos de clasificación de las coberturas del suelo en las tres unidades geomorfológicas de la cuenca. El de mejor precisión en la llanura fue el de Máxima Verosimilitud, mientras que en el médano y en el afloramiento rocoso fue la Distancia de Mahalanobis. En todos los casos, la utilización de seis índices espectrales calculados a partir de imágenes satelitales Landsat mejoró significativamente la discriminación de las coberturas del suelo en comparación con el uso de la reflectividad de las bandas. A partir de la selección del mejor método y conjunto de datos para su determinación, se realizó un análisis multitemporal de las coberturas del suelo durante el período 2000-2016. Las cubiertas de vegetación y particularmente los cultivos, fluctuaron en función de los montos de precipitación. Por ejemplo, durante el año 2014, se encontró la menor área de cultivos de invierno (584 km2) producto del exceso hídrico ocurrido antes de su implantación, mientras que durante ese mismo año los cultivos de verano presentaron su máxima superficie (1144 km2), beneficiados por las óptimas condiciones de humedad de suelo en el momento de siembra. El mapa generado con información in situ no sólo fue útil para conocer la distribución y variación de las coberturas del suelo a lo largo de toda la cuenca, sino que sirvió de base para contrastarlo con el escenario óptimo y definir el nivel de vulnerabilidad eco-ambiental. Se encontró que la cuenca del río Sauce Grande presentó cinco niveles de vulnerabilidad eco-ambiental. El más frecuente fue el bajo (1343,7 km2), seguido del alto (1091,4 km2). La importancia de considerar esta última categoría es que las áreas de pastizales se utilizaron para la implantación de cultivos, por lo que su conservación es fundamental dado la significativa provisión de bienes y servicios ecosistémicos que estos brindan. Los niveles muy alto y medio fueron menos frecuentes, pero las problemáticas que en estos espacios se generan son importantes, dado que los cultivos se realizan sobre áreas inundables, en el primer caso, lo que podría generar graves consecuencias económicas a los productores agropecuarios. En el segundo, el recurso suelo está sobreexplotándose por el incremento de la superficie destina a cultivos. Teniendo en cuenta estos niveles y sus problemáticas asociadas, se diseñaron estrategias que tuvieron como objetivo mejorar la calidad ambiental de la cuenca, considerando la sostenibilidad ambiental, social y económica. / Hydrographic basins are systems related to natural (such as geomorphology, climate, soil, water, vegetation), and anthropic factors (i.e., agricultural activities). The main objectives of this thesis were to evaluate the effect of rainfall variability on the primary water resources of the Sauce Grande river basin (SW of the province of Buenos Aires), as well as to analyze the Spatio-temporal behavior of its limnological parameters. Moreover, the dynamics of the flow of the Sauce Grande river and the local atmospheric circulation were studied. The purpose was to determine its origin and the effects of the sea breeze on this water body. First of all, the meteorological anomalies were analyzed considering the period 1960-2017. This information was obtained from three meteorological stations located in the north, the center, and the south of an influence area of the basin. The results indicated that the temperature increased (+0.5 °C in the north and + 0.8 °C in the south), while the wind speed decreased (-1 km/h in the south and -3,3 km/h in the north). The precipitation trend was spatially heterogeneous since it increased in the north and south (+42 mm and +16 mm, respectively), and decreased in the center (-6 mm). This parameter was studied based on the spatial and temporal variation of the water coverage of the two primary water resources of the Sauce Grande river basin: the Paso de Las Piedras dam and the Sauce Grande shallow lake during the period 1987-2017. The results evidenced that the water coverage and the precipitation have a positive and statistically significant linear agreement. The areal variation of the Sauce Grande shallow lake was explained by precipitation in 67 %, while in the Dique Paso de las Piedras dam in 55 %. The increase and reduction periods presented a relationship with the annual rainfall amount. As a consequence, morphometric parameters ranged widely, observing the most extensive changes in the area, the perimeter, and the maximum length. The discharge of the Sauce Grande River was measured at high-frequency, and it fluctuated according to the rainfall variability. During the period analyzed (November 2016-March 2018), the river presented three events of flood. The most relevant occurred in September of 2017. It was observed a maximum flow of 34.8 m3 s-1 in the sector closest to the Atlantic Ocean and 4.1 m3 s-1 before entering the lake. This value was generated during daily extreme precipitation events, with a total of 60 and 80 mm. The maximum runoff time was 12 days and was longer in the sector closest to the Atlantic Ocean, due to the existence of low slopes. Flood areas were located in the Medanosa Austral barrier and near the entrance of the river in the shallow lake. This lake was also monitored with high-frequency sensors (September 2016-March 2018). The results allowed characterizing the dynamics of the physical and biological variables and comparing them with a previous study carried out during a dry period (February 2011-January 2012). In this thesis, it was observed an increase in water and air temperature, as well as a decrease in electrical conductivity and wind speed. The Fast Fourier Transform showed different signal intensities in the different variables, mainly represented by the annual, monthly, and seasonal, daily, and semidiurnal cycles. However, water and air temperature and wind speed identified cycles in 4 and 8 hours. These results determined the existence of a local atmospheric circulation over the shallow lake with a geomorphological origin. It was characterized by a significant increase in wind speed during maximum solar radiation due to uneven heating. This study was carried out with Landsat satellite image processing. This circulation only appeared with high-pressure, clear skies, and minimum regional wind. Moreover, it was found that sea breeze events that occurred on the coast of Monte Hermoso (located 6 km from the shallow lake) enter into the shallow lake approximately two hours later, modifying the wind speed and direction, decrease the air temperature, and changing the wind direction. On the other hand, the limnological parameters measured seasonally (April-December 2016) in the middle and lower basin of the Sauce Grande River basin. The presented three spatial units: i) the Sauce Grande River before entering the homonymous shallow lake, ii) the Las Cortaderas stream, and iii) Las Mostazas stream, the shallow lake, and the site closest to the river discharge into the Atlantic Ocean. In general, the variables showed a marked spatial and temporal variation. The electrical conductivity was higher in the shallow lake and closed to the Atlantic Ocean discharge due to the lowest heights favor accumulation of salts. Las Mostazas stream presented high values of this variable because of its proximity to Coronel Dorrego city. The seston and the POM increased while the river was closing to its mouth in the shallow lake. Las Cortaderas stream and the lake had the highest average values of seston and POM. Its concentration was higher during the summer, probably due to the high concentrations of phytoplankton. The mean seston value of the shallow lake was widely lower than that recorded in a previous study during a period of extreme drought (September 2008-December 2010), while the one found in this thesis was during a wet period. Therefore, the seston is highly fluctuating concerning the water level of the lake. The mean value of dissolved oxygen allowed all the analyzed environments to be classified as moderately rich in oxygen and was negatively correlated with the water temperature. Its value was acceptable for a vast majority of aquatic organisms and fish species. The NT and the PT were the most temporarily variable, and the NT was recorded in a higher proportion. Both presented their maximum in winter and high concentrations in spring. This situation is related to the fact that, during these periods, fertilizers are applied in the sowing (June-July) and growth (September-October) of the wheat crop, the main one of the basin. These practices would generate an augmentation of the nutrients during these seasons. Different methods of classifying land cover were analyzed in the three geomorphological units of the basin. The one with the best precision in the plain was Maximum Likelihood, while in the dune and the hills were the Mahalanobis Distance. In all cases, the application of six spectral indexes calculated from Landsat satellite images improved the discrimination of the land cover significantly compared to the use of the reflectivity of the bands. From the selection of the best method and data set for its determination, a multitemporal analysis of the land cover during the period 2000-2016 was carried out. The vegetation covers, and particularly crops fluctuated depending on the amounts of precipitation. For example, during 2014, the smallest area of winter crops (584 km2) was found as a result of the excess water that occurred before its implementation, while during that same year the summer crops had their maximum surface area (1144 km2), benefited by the optimal soil moisture conditions at the time of planting. The land cover map generated with information in situ was useful to define the optimal scenario and the level of eco-environmental vulnerability. It was found that the Sauce Grande river basin presented five levels of eco-environmental vulnerability. The most frequent was the low (1343.7 km2), followed by high (1091.4 km2). The importance of considering this last category is that the grassland areas were used for the implantation of crops so that their conservation is crucial due to the significant provision of ecosystem services. Very high and medium levels were less frequent, but the problems generated in these spaces are essential, given that the crops are carried out on flood areas, in the first case, which could generate severe economic consequences for farmers. In the second, the soil is being overexploited due to the increase in the area devoted to crops. Vulnerability levels and their spatial and temporal problems allowed to delimit adaptation strategies aimed at improving the environmental quality, considering a sustainability scenario.
32

Construcción de identidades laborales y relaciones de género en el área hortícola regada por el río Sauce Chico (Provincia de Buenos Aires, Argentina)

Nieto, María Belén 24 November 2017 (has links)
En diferentes regiones y culturas del mundo la mujer desempeña un rol fundamental en la agricultura y la provisión de alimentos. El funcionamiento de las explotaciones agropecuarias, donde la unidad de producción es la familia, no puede analizarse sin la participación de la mujer. Más allá de la creciente participación femenina, la condición y situación de la mujer rural es la menos conocida. A su vez este escaso reconocimiento al cual se enfrentan las mujeres en el ámbito rural, les dificulta la construcción de su identidad profesional-laboral. Es por ello que es importante incorporar el enfoque de género en el desarrollo territorial, el cual se basa en la necesidad de lograr mayor equidad y justicia en la participación de las mujeres. De esta manera, la inclusión de la perspectiva de género en el presente trabajo de investigación está orientada a caracterizar la dinámica y lógica de las familias de los pequeños productores hortícolas del espacio periurbano de Bahía Blanca, estudiando el papel que cumplen las mujeres como productoras y reproductoras de esta sociedad rural. El territorio de estudio se encuentra atravesado por el río Sauce Chico, enmarcado administrativamente por tres partidos: Bahía Blanca, Villarino y Tornquist. En el espacio de estudio se encuentran un total de 44 explotaciones hortícolas. El marco metodológico que se plantea en esta investigación es eminentemente cualitativo basado en diez entrevistas en profundidad y la observación participante a través de las cuales se logra llegar a la subjetividad de las mujeres y comprender que más allá de lo que ellas enuncian, su trabajo es altamente significativo y fundamental para la producción y el arraigo de la familia en este espacio, combinando con técnicas cuantitativas en función a las veinte encuestas en el área de estudio. El trabajo tiene un significado y un valor heterogéneo entre las mujeres entrevistadas y juega un rol muy diferencial en la construcción de su identidad y su empoderamiento individual y colectivo. Para la mayoría de ellas, el trabajo tiene básicamente un valor económico, destinado al bienestar familiar, con lo que se convierte en una responsabilidad reproductiva adicional. / In different regions and cultures of the world, women play a vital role in agriculture and food supply. The operation of farms where the production unit is the family, can not be analyzed without the participation of women. Beyond the increasing participation of women, the condition and status of rural women is the least known. In turn, this lack of recognition which women face in rural areas, have difficulty building their professional identity and labor. That is why it is important to incorporate a gender perspective in regional development, which is based on the need to achieve greater equity and justice in the participation of women. Thus, the inclusion of a gender perspective in the present research is aimed at characterizing the dynamics and logic families horticultural smallholder periurban space of Bahia Blanca, studying the role of women as producers and breeding of this rural society. The study area is crossed by the Sauce Chico, framed administratively by three political parties: Bahía Blanca Villarino and Tornquist . In the space of study include a total of 44 vegetable farms. The methodological framework is proposed in this research is eminently qualitative based on ten in-depth interviews and participant observation through which it is possible to reach the subjectivity of women and understand that beyond what they enunciate, their work is highly significant and fundamental for the production and the rooting of the family in this space, combining with quantitative techniques according to the twenty surveys in the study area. Job has a meaning and a value heterogeneous among the women interviewed and plays a very differential in the construction of their identity and individual and collective empowerment. For most of them, job is basically an economic value, for family welfare, which becomes an additional reproductive responsability.
33

Human impacts and fluvial metamorphosis : the effects of flow regulation on the hydrology, morphology and water temperature of the Sauce Grande River, Argentina. / Impact anthropique et métamorphose fluviale : effets de la régulation du débit sur l'hydrologie, la morphologie et la température de l'eau de la Sauce Grande, Argentine.

Casado, Ana 18 June 2013 (has links)
Cette recherche évalue le degré de régulation hydrologique induite par le barrage-réservoir Paso de las Piedras sur la Sauce Grande et quantifie les effets de cette régulation sur la hydrologie, la morphologie et la température de l'eau de la rivière en aval. Le travail de thèse consiste en une évaluation exhaustive et systématique des impacts du barrage-réservoir sur le système fluvial basée sur la compréhension des processus naturels qui se produisent en amont. En plus de fournir des informations sur les impacts hydrologiques, morphologiques et thermiques de la construction du barrage Paso de las Piedras et de l'exploitation de son réservoir, cette étude génère des séries de données climatiques et hydrologiques qui fournissent une base significative sur laquelle fonder des recherches futures. Par ailleurs, cette étude met en place un cadre méthodologique appliqué à l'analyse hydrogéomorphologique des bassins versants non jaugés qui a un grand potentiel d'application dans d'autres bassins de la région similaires ainsi que dans d'autres régions semi-arides du monde. / Despite the regional importance of the Sauce Grande River as main source for water supply and the large capacity of the Paso de las Piedras Reservoir, both the hydrology of the river basin and the effects of the impoundment on the river environment remain poorly evaluated. This study provides the very first assessment of the degree of flow regulation induced by the Paso de las Piedras Dam on the middle section of the Sauce Grande River, and quantifies its impacts on the hydrology, morphology and patterns of water temperature of the river downstream from the impoundment. In addition to providing new information on the response of regulated rivers to upstream impoundment and on the effects of impoundment on the Sauce Grande River specifically, this study generates spatial, climatic and hydrologic data and implements a methodological framework to hydrological assessment of ungauged basins.
34

Utilização da metodologia de superfície de resposta no desenvolvimento de um molho tipo Pesto visando a atividade antioxidante / Utilization of response surface methodology in the development of a Pesto sauce to maximize its antioxidant activity

Afonso, Guilherme 06 September 2006 (has links)
Evidências recentes têm demonstrado que dietas com elevado conteúdo de vegetais, frutas e grãos podem reduzir o risco de diversas doenças não transmissíveis. As propriedades benéficas desses alimentos têm sido atribuídas, em grande parte, à presença de substâncias antioxidantes, que são capazes de diminuir os efeitos prejudiciais dos radicais livres. O objetivo deste trabalho foi desenvolver uma formulação de molho tipo Pesto, com base nas propriedades antioxidantes dos seus ingredientes principais: manjericão, castanha do Brasil e azeite de oliva extra virgem. A metodologia foi divida em duas fases: a primeira consistiu na avaliação da interação entre os componentes com atividade antioxidante (AA) presentes nos ingredientes principais do molho, realizada através da metodologia de superfície de resposta por modelagem de misturas. Foi utilizado um planejamento centróide simplex, no qual a resposta medida foi a atividade antioxidante dos extratos de diferentes polaridades obtidos das diferentes formulações. Utilizando-se o método DPPH (1,1-difenil-2-picrilhidrazil) e o sistema ß-caroteno/ácido linoléico, não foi encontrada interação entre os componentes com AA presentes nos ingredientes. Apesar dos modelos obtidos não descreverem adequadamente a variação dos resultados, o manjericão foi identificado como o ingrediente de maior contribuição para a AA total do molho. Foi realizada análise sensorial para determinar a formulação melhor aceita dentre as possibilidades obtidas. A segunda fase consistiu em submeter a formulação determinada na fase 1 às análises de composição centesimal, quantificação dos compostos fenólicos totais e quatro métodos in vitro de avaliação da AA: método do poder redutor, sistema ß-caroteno/ácido linoléico, DPPH e ensaio em meio lipídico pelo aparelho Rancimat®. A formulação final pode ser considerada como uma boa fonte de antioxidantes naturais e portanto fazer parte de uma dieta saudável. / Recent evidences have shown that high consumption of vegetables, fruits and grains can reduce the risk of non-communicable diseases. The healthy properties of these foods have been related mostly to the presence of antioxidants, substances which are known as capable of decreasing the harmful effects of free radicals. The objective of this work was to develop a Pesto sauce formulation, based on the antioxidant properties of its main ingredients: sweet basil, Brazil nut and extra-virgin olive oil. The methodology was divided in two phases: The first one consisted in the evaluation of the interaction between the components with antioxidant activity (AA) present in the sauce\'s main ingredients, applying the response surface methodology with a mixture model. A centroid simplex plan was used, in which the response measured was the AA of the extracts of different polarities from the different formulations. By using the DPPH (1,1-diphenyl-2-picryhydrazyl) method and the ß-carotene/linoleic acid system, no interaction between the components with AA was detected. Although the models could not describe properly the response variation, sweet basil was identified as the main responsible for the total AA of the sauce. Sensory analysis was conducted to determine the most accepted formulation among the possibilities. The second phase consisted in submitting the formulation obtained in phase 1 to centesimal composition analysis, quantification of total phenolics and four in vitro AA methods: reducing power, DPPH method, ß-carotene/linoleic acid system and the Rancimat® method. The final formulation may be considered a good source of natural antioxidants and therefore be part of a healthy diet.
35

A study of Vietnamese soy sauce fermentation

Bui, The Truong, University of Western Sydney, College of Science, Technology and Environment, Centre for Advanced Food Research January 2003 (has links)
Vietnamese soy sauce has been made for centuries using traditional methods, in villages in Northern Vietnam. This sauce differs from other Asian products not only in its raw materials but also in its flavour characteristics. Presently small scale Vietnamese soy sauce is produced mostly with a standardised inoculum of Aspergillus oryzae under natural conditions. This usually gives rise to a product of variable and inconsistent quality. The aim of this study was to standardise the fermentation condition for the production of Vietnamese soy sauce, so as to obtain a product of more consistently good quality. Aspergillus flavus var columnaris was used as the inoculum. The inoculum was prepared by growing the organism on sticky rice at 20 and 37 degrees centigrade under aerobic conditions. At 20C, a high protease activity was recorded in the inoculum while at 37C, a high amylase activity was observed. The two different inocula prepared at 20C and 37C were then used in the preparation of soy sauce in the normal manner. The inocula were mixed with cooked roasted soy beans and salt water, left to age for 1 month at 30C, followed by ageing at 20C for 2 months. The products obtained were subjected to sensory evaluation and analysed for glucose, fructose, amino acids, nitrogen, ethanol and NaCI. Both inocula produced products of acceptable quality. The inoculum produced at 20C had a higher sensory evaluation score. It also contained a higher level of protein (14.5% compared to 11%), and a higher sensory evaluation score (6.9 compared to 3.2) when compared to a commercial Vietnamese sauce, Hanoi soy sauce. This valuable information will now enable small scale producers to produce this product throughout the year by controlling the temperature, and not be limited to the summer season, as has been the case with the traditional method of production. / Master of Science (Hons)
36

Utilização da metodologia de superfície de resposta no desenvolvimento de um molho tipo Pesto visando a atividade antioxidante / Utilization of response surface methodology in the development of a Pesto sauce to maximize its antioxidant activity

Guilherme Afonso 06 September 2006 (has links)
Evidências recentes têm demonstrado que dietas com elevado conteúdo de vegetais, frutas e grãos podem reduzir o risco de diversas doenças não transmissíveis. As propriedades benéficas desses alimentos têm sido atribuídas, em grande parte, à presença de substâncias antioxidantes, que são capazes de diminuir os efeitos prejudiciais dos radicais livres. O objetivo deste trabalho foi desenvolver uma formulação de molho tipo Pesto, com base nas propriedades antioxidantes dos seus ingredientes principais: manjericão, castanha do Brasil e azeite de oliva extra virgem. A metodologia foi divida em duas fases: a primeira consistiu na avaliação da interação entre os componentes com atividade antioxidante (AA) presentes nos ingredientes principais do molho, realizada através da metodologia de superfície de resposta por modelagem de misturas. Foi utilizado um planejamento centróide simplex, no qual a resposta medida foi a atividade antioxidante dos extratos de diferentes polaridades obtidos das diferentes formulações. Utilizando-se o método DPPH (1,1-difenil-2-picrilhidrazil) e o sistema ß-caroteno/ácido linoléico, não foi encontrada interação entre os componentes com AA presentes nos ingredientes. Apesar dos modelos obtidos não descreverem adequadamente a variação dos resultados, o manjericão foi identificado como o ingrediente de maior contribuição para a AA total do molho. Foi realizada análise sensorial para determinar a formulação melhor aceita dentre as possibilidades obtidas. A segunda fase consistiu em submeter a formulação determinada na fase 1 às análises de composição centesimal, quantificação dos compostos fenólicos totais e quatro métodos in vitro de avaliação da AA: método do poder redutor, sistema ß-caroteno/ácido linoléico, DPPH e ensaio em meio lipídico pelo aparelho Rancimat®. A formulação final pode ser considerada como uma boa fonte de antioxidantes naturais e portanto fazer parte de uma dieta saudável. / Recent evidences have shown that high consumption of vegetables, fruits and grains can reduce the risk of non-communicable diseases. The healthy properties of these foods have been related mostly to the presence of antioxidants, substances which are known as capable of decreasing the harmful effects of free radicals. The objective of this work was to develop a Pesto sauce formulation, based on the antioxidant properties of its main ingredients: sweet basil, Brazil nut and extra-virgin olive oil. The methodology was divided in two phases: The first one consisted in the evaluation of the interaction between the components with antioxidant activity (AA) present in the sauce\'s main ingredients, applying the response surface methodology with a mixture model. A centroid simplex plan was used, in which the response measured was the AA of the extracts of different polarities from the different formulations. By using the DPPH (1,1-diphenyl-2-picryhydrazyl) method and the ß-carotene/linoleic acid system, no interaction between the components with AA was detected. Although the models could not describe properly the response variation, sweet basil was identified as the main responsible for the total AA of the sauce. Sensory analysis was conducted to determine the most accepted formulation among the possibilities. The second phase consisted in submitting the formulation obtained in phase 1 to centesimal composition analysis, quantification of total phenolics and four in vitro AA methods: reducing power, DPPH method, ß-carotene/linoleic acid system and the Rancimat® method. The final formulation may be considered a good source of natural antioxidants and therefore be part of a healthy diet.
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Produção de pós alimentícios enriquecidos com quercetina encapsulada em lipossomas liofilizados / Production of food powders enriched with quercetin-loaded lyophilized liposomes

Toniazzo, Taíse 30 May 2017 (has links)
Os compostos antioxidantes naturais têm sido cada vez mais investigados devido à necessidade das indústrias alimentícias suprirem as exigências dos consumidores em relação à saudabilidade dos produtos. A quercetina é um flavonoide cujos benefícios estão relacionados principalmente à sua ação antioxidante. Entretando, tal molécula apresenta, geralmente, baixa absorção no trato gastrointenstinal, o que pode ser um obstáculo para sua efetiva ação biológica. Por este motivo, uma alternativa para melhorar a sua bioacessibilidade é a encapsulação em sistemas coloidais baseados em matrizes lipídicas, como os lipossomas. Os lipossomas possuem a capacidade de incorporar tanto bioativos hidrofílicos quanto hidrofóbicos em sua estrutura, bem como proporcionar liberação controlada e aumentar a bioacessibilidade dos ingredientes encapsulados. No entanto, há necessidade do desenvolvimento de processos de produção de lipossomas em maior escala, e dentre os processos possíveis a serem empregados com este objetivo encontra-se o método de produção de injeção de etanol. O objetivo principal da presente Tese foi a microencapsulação de quercetina em lipossomas através do método de injeção de etanol. A dispersão de lipossomas encapsulando quercetina escolhida foi liofilizada, com a intenção de aumentar a estabilidade dos lipossomas e enriquecer o amido de milho. O enriquecimento do amido de milho foi realizado por aglomeração, especificamente pelo método de alto cisalhamento, sendo que o pó alimentício aglomerado resultante foi caracterizado fisicamente e teve suas propriedades físicas melhoradas. Foi possível realizar a aplicação do amido de milho enriquecido com quercetina no antepasto de berinjela, sendo que tal incorporação não alterou significativamente as características do produto. Além disso, o antepasto de berinjela foi processado a alta pressão hidrostática e teve sua estabilidade avaliada, sendo que a utilização do processamento não-térmico apresentou vantagens em relação ao método de processamento convencional. / The natural antioxidant compounds have been increasingly investigated due to the need of the food industry to provide healthier products. Quercetin is a flavonoid, whose benefits are linked mainly with its antioxidant activity. However, this bioactive generally has a low absorption rate in the gastrointestinal tract, which it can be an obstacle for its biological action effective. For this reason, an alternative to improve such bioavailability is to encapsulate quercetina in lipid-based matrices, e.g, liposomes. The liposomes have the capacity to encapsulate both hydrophilic and hydrophobic bioactive, as well as to control the release of the encapsulated bioactives, and enhance their bioavailability. However, there is a need to develop liposome production methods in larger scale, and one of the processes feasible to be scaled up is the ethanol injection method. One of the main objectives of this Thesis was to microencapsulate quercetin in liposomes by ethanol injection method. The dispersion of quercetin-loaded liposomes was lyophilized aiming to increase the stability of liposomes and enrich cornstarch. The enrichment of cornstarch was performed by agglomeration, specifically by high shear method, and the agglomerated food powders were characterized and their physical properties was improved. It was possible to incorporate the enriched cornstarch with quercetin in eggplant sauce, and such application did not change the product characteristics. Also, the eggplant sauce was processed by high hydrostatic pressure and had its stability evaluated, indicating the use of nonthermal technology showed advantages if compared to the conventional thermal processing.
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Produção de pós alimentícios enriquecidos com quercetina encapsulada em lipossomas liofilizados / Production of food powders enriched with quercetin-loaded lyophilized liposomes

Taíse Toniazzo 30 May 2017 (has links)
Os compostos antioxidantes naturais têm sido cada vez mais investigados devido à necessidade das indústrias alimentícias suprirem as exigências dos consumidores em relação à saudabilidade dos produtos. A quercetina é um flavonoide cujos benefícios estão relacionados principalmente à sua ação antioxidante. Entretando, tal molécula apresenta, geralmente, baixa absorção no trato gastrointenstinal, o que pode ser um obstáculo para sua efetiva ação biológica. Por este motivo, uma alternativa para melhorar a sua bioacessibilidade é a encapsulação em sistemas coloidais baseados em matrizes lipídicas, como os lipossomas. Os lipossomas possuem a capacidade de incorporar tanto bioativos hidrofílicos quanto hidrofóbicos em sua estrutura, bem como proporcionar liberação controlada e aumentar a bioacessibilidade dos ingredientes encapsulados. No entanto, há necessidade do desenvolvimento de processos de produção de lipossomas em maior escala, e dentre os processos possíveis a serem empregados com este objetivo encontra-se o método de produção de injeção de etanol. O objetivo principal da presente Tese foi a microencapsulação de quercetina em lipossomas através do método de injeção de etanol. A dispersão de lipossomas encapsulando quercetina escolhida foi liofilizada, com a intenção de aumentar a estabilidade dos lipossomas e enriquecer o amido de milho. O enriquecimento do amido de milho foi realizado por aglomeração, especificamente pelo método de alto cisalhamento, sendo que o pó alimentício aglomerado resultante foi caracterizado fisicamente e teve suas propriedades físicas melhoradas. Foi possível realizar a aplicação do amido de milho enriquecido com quercetina no antepasto de berinjela, sendo que tal incorporação não alterou significativamente as características do produto. Além disso, o antepasto de berinjela foi processado a alta pressão hidrostática e teve sua estabilidade avaliada, sendo que a utilização do processamento não-térmico apresentou vantagens em relação ao método de processamento convencional. / The natural antioxidant compounds have been increasingly investigated due to the need of the food industry to provide healthier products. Quercetin is a flavonoid, whose benefits are linked mainly with its antioxidant activity. However, this bioactive generally has a low absorption rate in the gastrointestinal tract, which it can be an obstacle for its biological action effective. For this reason, an alternative to improve such bioavailability is to encapsulate quercetina in lipid-based matrices, e.g, liposomes. The liposomes have the capacity to encapsulate both hydrophilic and hydrophobic bioactive, as well as to control the release of the encapsulated bioactives, and enhance their bioavailability. However, there is a need to develop liposome production methods in larger scale, and one of the processes feasible to be scaled up is the ethanol injection method. One of the main objectives of this Thesis was to microencapsulate quercetin in liposomes by ethanol injection method. The dispersion of quercetin-loaded liposomes was lyophilized aiming to increase the stability of liposomes and enrich cornstarch. The enrichment of cornstarch was performed by agglomeration, specifically by high shear method, and the agglomerated food powders were characterized and their physical properties was improved. It was possible to incorporate the enriched cornstarch with quercetin in eggplant sauce, and such application did not change the product characteristics. Also, the eggplant sauce was processed by high hydrostatic pressure and had its stability evaluated, indicating the use of nonthermal technology showed advantages if compared to the conventional thermal processing.
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Estudo de processo para elabora??o de ?creme de soja? e sua aplica??o em chantili e ?molho de espinafre? / Study of process for preparing "soy-cream"and its application in whipped cream and "spinach sauce"

CAMILO, Simone Alves do Nascimento 21 March 2013 (has links)
Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-11-09T17:20:37Z No. of bitstreams: 1 2013 - Simone Alves do Nascimento Camilo.pdf: 363101 bytes, checksum: 552ddec128420b872fba894157546afe (MD5) / Made available in DSpace on 2018-11-09T17:20:39Z (GMT). No. of bitstreams: 1 2013 - Simone Alves do Nascimento Camilo.pdf: 363101 bytes, checksum: 552ddec128420b872fba894157546afe (MD5) Previous issue date: 2013-03-21 / CAPES / The soybean, besides containing protein of high biological value, presents oil with high content of polyunsaturated fatty acids, also having good emulsifying properties. Thus, soybean may be used for preparing creamy products. In spite of these advantages, its use is limited in Brazil due to its beany flavor. With the objective of developing a process to produce "soy-cream" with good sensory characteristics, dehulled soybean grains were boiled in water, as well as in NaHCO3 solution at three concentrations (0.25; 0.75 and 1.25%) at three cooking times (10, 25 and 40min), totaling 12 treatments. Then, the soybean grains were disintegrated with a paste of gelatinized starch, and subsequently, formulated to obtain the "soy-creams". These were submitted to a series of sensory evaluations (overall impression, sensory quality, quantitative descriptive analysis and preference), using a commercial milkcream for comparison. It was also carried out the analysis of proximate centesimal composition, as well as the determination of fatty acid profile. The results showed that a better boiling condition for dehulled soybean grains, used for preparing "soy-cream" with better sensory characteristics, was NaHCO3 at 0.75% for 25min using 40% of oil, although this was less preferred by the untrained panelists than the commercial milkcream. These two creams were submitted once more to consumer-type preference test, showing no significant difference between them. This "soy-cream" presented 84.85% of unsaturated fatty acids. Using this "soy-cream" and the commercial milkcream, two whipped cream (chantily) were prepared and submitted to consumer-type preference test. The results showed that the "soy-chantily? was more preferred than the one prepared with the commercial milkcream. Similarly, two ?spinach sauces? were prepared and submitted to consumer-type preference test. The results show that the "spinach sauce" prepared with the "soy-cream" was more preferred than that prepared with the commercial milkcream. / A soja, al?m de conter prote?na de alto valor biol?gico, apresenta ?leo com alto teor de ?cidos graxos poliinsaturados, tendo tamb?m boas propriedades emulsificantes. Desta forma, a soja pode ser usada para elabora??o do creme. Apesar destas vantagens, a sua utiliza??o no Brasil ? limitada devido ao sabor de feij?o cru (?beany-flavor?). Com objetivo de desenvolver um processo que permita obter um ?creme de soja? com boas caracter?sticas sensoriais, os gr?os de soja decorticados foram fervidos em ?gua e em solu??o de NaHCO3 a tr?s n?veis de concentra??o (0,25; 0,75 e 1,25%), durante tr?s intervalos de tempo (10, 25 e 40min), totalizando 12 tratamentos. Em seguida, os gr?os foram desintegrados com a pasta de amido gelatinoso, e formulados posteriormente, para obter os ?cremes de soja?. Estes foram submetidos a uma s?rie de avalia??es sensoriais (impress?o global, qualidade sensorial, an?lise descritiva quantitativa e prefer?ncia), usando-se o creme de leite comercial para a compara??o. Foi feita tamb?m a an?lise de composi??o centesimal aproximada, bem como a an?lise de perfil de ?cidos graxos. Os resultados indicam que, a melhor condi??o de fervura dos gr?os de soja decorticados para o uso em ?creme de soja? com melhores caracter?sticas sensoriais foi o emprego de NaHCO3 a 0,75% por 25min, usando-se 40% de ?leo, embora este tenha sido menos preferido por provadores n?o treinados do que o creme de leite comercial. Estes dois cremes foram submetidos novamente a teste massal de prefer?ncia com consumidores, mostrando que n?o houve diferen?a significativa entre essas duas amostras. O ?creme de soja? selecionado teve 84,85% de ?cidos graxos insaturados. Usando-se este ?creme de soja? e o creme de leite comercial, foram preparados dois chantilis, sendo submetidos a teste massal de prefer?ncia com consumidores. Os resultados mostram que o ?chantili de soja? foi mais preferido do que aquele preparado com o creme de leite comercial. Da mesma forma, foram preparados os dois ?molhos de espinafre? e submetidos a teste de consumidores. Os resultados indicam que o ?molho de espinafre? preparado com o ?creme de soja? foi mais preferido do que aquele preparado com o creme de leite comercial.
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Nine Venezuelan Composers and a Catalogue of their Choral Works

Grases, Cristian 28 April 2009 (has links)
This document represents an initial endeavor in a long-lasting aspiration to pursue the study and collection of Latin American choral literature. This essay compiles the most complete and current catalogue possible of choral works written by nine Venezuelan composers born in the twentieth century and presents it in a simple and accessible format so it can be used by a variety of school teachers, choral conductors, church musicians, college directors, and professional musicians. Each composer entry presents a brief biographical note and a list of works organized in alphabetical order. The annotation for each composition includes information in eighteen categories. It also includes an extensive list of biographical resources. In addition, a list of terms and definitions of folkloric and traditional genres will help the reader understand the diversity of Venezuelan musical styles and dances; there is some additional information with regard to performance practice.

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