Adriana Pulido Diaz

Thermomechanical characterization of an amylose-free starch extracted from cassava (Manihot esculenta, Crantz)

The aim of this study was to determine and compare the melting (Tm), glass transition (Tg) and mechanical relaxation (Tα) temperatures of a new waxy cassava starch. Thermal transitions measurements were obtained by Differential Scanning Calorimetry (DSC) and Dynamical Mechanical Thermal Analysis (DMTA). The experimental data showed a high correlation between water volume fraction and melting temperature (Tm) indicating that the Flory-Huggins theory can be used to describe the thermal behavior of this starch. The Tm of waxy cassava starch-water mixes were lower than a waxy corn starch-water reference system, but differences were not statistically significant. The mechanical relaxation temperatures taken at tan δ peaks were found 29-38°C larger than Tg. The Tα and Tg measured for waxy cassava starch exhibited similar properties to the ones of waxy corn starch, implying that waxy cassava starch can be used in food and materials industry.

Indirect measurement and control of moisture content during dehydration performed by frying

Frying is one of the way for performing drying of food material that permits to obtain very short duration. However the control of such operation is difficult because of the immersion of product into hot oil bath that imply difficult or impossible sensors implementation. Such problems are encoutered for Dehydration Soaking Process (DISP). In the case of Batch drying using frying of food stuffs, an original approach is presented. An indirect measurement of moisture content is performed as a combination of easy to do oil bath temperature mesasurement and an estimator. Validation is provided and performance is well established. Because of the ability of moisture content real time measurements, a control strategy is studied and put into practice. An optimal predictive controller is proprosed, able to put into practice several kind of control objectives. Results are discussed and extension of the strategy is introduced

Evaporación osmótica: fundamentos y aplicaciones en la concentración de jugos de fruta

Osmotic evaporation is a modification of traditional processes using membranes; where the effect of a vapor pressure differential, produced by a highly concentrated solution of extraction, water is transferred as vapor through a membrane that acts as a hydrophobic body. This membrane technology is presented as a great alternative for processing exotic fruits, producing concentrates that can be used in the daily diet, being more comfortable to use, reducing transportation costs and increasing the shelf life. This process has many advantages compared to traditional operations, allowing operated at atmospheric pressure and low temperature, ideal for heat-sensitive products.^les^aLa alta demanda de recursos naturales (Suelo y agua) esta dada por el incremento de la poblacion mundial, que requiere areas de expansion urbana, produccion de alimentos y combustibles fosiles que soporten estas y otras actividades del hombre; que contribuyen con la acumulacion de gases de efecto de invernadero en la atmosfera y el cambio climatico. Bajo esta premisa, se vienen investigando en alternativas agropecuarias sostenibles que mantengan la productividad de los sistemas ganaderos, que sean resilientes ante las variaciones ambientales y contribuyan con la mitigacion del calentamiento global. El presente escrito, documenta las principales estrategias de la ganaderia eco-coeficiente; asi como los efectos sobre el cambio climatico.^len^aThe high demand for natural resources (soil and water) is given by the increase in world population, which requires urban expansion areas, food production and supporting these fossil fuels and other human activities; that contribute to the accumulation of greenhouse gases in the atmosphere and climate change. Under this premise, they have been researching alternatives to maintain sustainable agricultural productivity of livestock systems, but they are resilient to environmental changes and contribute to the mitigation of global warming. This written documents the main strategies of eco-coefficient livestock; and the effects on climate change.^lpt^aA alta demanda por recursos naturais (solo e agua) e dado pelo aumento da populacao mundial, que requer areas de expansao urbana, producao de alimentos e apoio a estes combustiveis fosseis e outras atividades humanas; que contribuem para o acumulo de gases de efeito estufa na atmosfera e as mudancas climaticas. Sob esta premissa, foram pesquisando alternativas para manter a produtividade agricola sustentavel dos sistemas de producao animal, mas eles sao resistentes as mudancas ambientais e contribuir para a mitigacao do aquecimento global. Este documentos escritos as principais estrategias de eco-coeficiente de gado; e os efeitos sobre as mudancas climaticas.The high demand for natural resources (soil and water) is given by the increase in world population, which requires urban expansion areas, food production and supporting these fossil fuels and other human activities; that contribute to the accumulation of greenhouse gases in the atmosphere and climate change. Under this premise, they have been researching alternatives to maintain sustainable agricultural productivity of livestock systems, but they are resilient to environmental changes and contribute to the mitigation of global warming. This written documents the main strategies of eco-coefficient livestock; and the effects on climate change.