Modelo de simulación de cultivo de palma aceitera (Elaeis guineensis) en Honduras

El cultivo de la palma africana (Elaeis guineensis Jacq.) en el mundo y, concretamente, en Honduras es el principal motivo que ha impulsado la realización de este trabajo. En él se estudia la relación existente entre factores climáticos y edafológicos con los rendimientos en plantaciones de palma en Honduras. La producción mundial de aceite de palma en 2006 fue de 37 millones de toneladas, obtenidas en una superficie de 8,2 Mha. Actualmente se considera que es una posible fuente de energía renovable y de carburante líquido. Se trata de un cultivo en expansión en las zonas tropicales y subtropicales, particularmente en Honduras. Su cultivo es susceptible a cambios climáticos y a las condiciones edafológicas, los cuales son determinantes de su rendimiento. En este trabajo se desarrolla un modelo de simulación dinámico, utilizando el software Vensim ® DSS en la versión 5.6 a, para estudiar el potencial de crecimiento y desarrollo de la palma aceitera en Honduras en relación con factores climáticos y edafológicos. El modelo construido en el presente trabajo se divide en dos niveles: nivel biótico (palma y pasto herbáceo) y nivel abiótico (clima y suelo). El nivel biótico se ha calibrado a partir de datos bibliográficos. Dentro del nivel abiótico, el sistema clima aporta datos diarios de temperatura, precipitación y radiación, generados a partir de datos reales mensuales y el sistema edáfico, datos reales de suelo. A pesar de la importancia de este cultivo en Honduras, las investigaciones y publicaciones sobre este tema son limitadas, lo que ha afectado a los procesos de calibración y validación del modelo descrito en este trabajo . La simulación del rendimiento de la palma, en kilogramos de materia seca por hectárea y por año, es un poco más elevada que los rendimientos medios observados en Honduras. Asimismo, el Índice de Área Foliar simulado es mayor que los observados en campo. Esto es debido a que se ha considerado un modelo ideal, sin poda de hojas, con la nutrición de suelo adecuada y sin incidencia de plagas ni enfermedades. A pesar de esto, parece que los resultados obtenidos se ajustan relativamente bien a la realidad

Non-Destructive Global and Localized 2D T1/T2 NMR Relaxometry to Resolve Microstructure in Apples Affected by Watercore

Apples can be considered as having a complex system formed by several structures at different organization levels: macroscale (>100 μm) and microscale (>100 μm) and microscale (<100 μm). This work implements 2D T1/T2 global and localized relaxometry sequences on whole apples to be able to perform an intensive non-destructive and non-invasive microstructure study. The 2D T1/T2 cross-correlation spectroscopy allows the extraction of quantitative information about the water compartmentation in different subcellular organelles. A clear difference is found as sound apples show neat peaks for water in different subcellular compartments, such as vacuolar, cytoplasmatic and extracellular water, while in watercore-affected tissues such compartments appear merged. Localized relaxometry allows for the predefinition of slices in order to understand the microstructure of a particular region of the fruit, providing information that cannot be derived from global 2D T1/T2 relaxometry

Modelo de simulación del cultivo de la palma aceitera

El cultivo de la palma aceitera (Elaeis guineensis Jacq) en el mundo y, concretamente, en Honduras es el principal motivo que ha impulsado la realización de este trabajo. En él, se estudia la relación existente entre factores climáticos y edafológicos con los rendimientos en plantaciones de palma en Honduras. La producción mundial de aceite de palma en 2006 fue de 37 millones de toneladas, obtenidas en una superficie de 8,2 Mha. Actualmente se considera que es una posible fuente de energía renovable y de carburante líquido. Es un cultivo en expansión en las zonas tropicales y subtropicales, particularmente en Honduras. Su cultivo es susceptible a cambios climáticos y a las condiciones edafológicas, los cuales son determinantes de su rendimiento. En este trabajo se desarrolla un modelo de simulación dinámico, utilizando el software VENSIM ® DSS versión 4.0, para estudiar el potencial de crecimiento y desarrollo de la palma en Honduras en relación con factores climáticos y edafológico

MRI texture analysis as means for addressing rehydration and milk diffusion in cereals

Cereals microstructure is one of the primary quality attributes of cereals. Cereals rehydration and milk diffusion depends on such microstructure and thus, the crispiness and the texture, which will make it more palatable for the final consumer. Magnetic Resonance Imaging (MRI) is a very powerful tomographic tool since acquisition parameter leads to a wide possibility for identifying textures, structures and liquids mobility. It is suited for noninvasive imaging of water and fats. Rehydration and diffusion cereals processes were measured by MRI at different times and using two different kinds of milk, varying their fat level. Several images were obtained. A combination of textural analysis (based on the analysis of histograms) and segmentation methods (in order to understand the rehydration level of each variety of cereals) were performed. According to the rehydration level, no advisable clustering behaviour was found. Nevertheless, some differences were noticeable between the coating, the type of milk and the variety of cereals

1H HR MAS NMR metabolomic and non-destructive 2D NMR relaxometry to assess internal quality in apples.

NMR can be considered a multi-scale multidimensional technology in the sense that it provides both spatial insight at macroscopic (MRI) or microscopic level (relaxometry), together with chemical characterization (HR-MAS). In this study 296 apples (from 4 cultivars) were MRI screened (20 slices per fruit) among which 7 fruits were used for metabolomic study by 1H HR MAS in order to assess various chemical shifts: malic acid, sucrose, glucose, fructose and ethanol. On the first season, tissue samples were taken from the sound and affected apples (near the core, centre and outer part of the mesocarp) belonging to sound and affected locations, while on the second season, tissue samples were focused on the comparison between sound and affected tissue. Beside, MRI and 2D non-destructive relaxometry (on whole fruits, and localized tissue) where performed on 72 and 12 apples respectively in order to compare features at macroscopic (tissue) and microscopic (subcellular) level. HR MAS shows higher content of ?-glucose, ?-glucose, malic acid and aromatic compounds in watercore affected tissues from both seasons, while sound tissue reflects higher sucrose. Microscopic (subcellular) degradation of tissue varies according to disorder development and is in good accordance with macroscopic characterization with MRI

Cuéntame: análisis de imagen aplicado al crecimiento de colonias de levadura

Algunas levaduras son capaces de producir deterioro en alimentos desarrollándose en su superficie como colonias. La medida del crecimiento de éstas evaluando el aumento de células viables es una técnica laboriosa y tediosa, mientras que la medida del aumento de su radio proporciona un resultado inmediato. En este trabajo, como alternativa a la medición manual del radio de la colonia, se plantea el empleo de técnicas de análisis de imagen que permiten automatizar el proceso de medición. A partir de las imágenes escaladas digitales, adquiridas en escala de gris de las colonias en crecimiento se ha desarrollado un algoritmo de análisis de imagen con el software MATLAB®. Esta herramienta se ha utilizado para procesar diariamente las imágenes de colonias de cuatro especies de levaduras deteriorantes: Zygosaccharomyces rouxii, Debaryomyces hansenii, Saccharomyces cerevisiae y Rhodotorula glutinis. El error de predicción del tamaño de la colonia al aplicar el algoritmo es comparable con el cometido en la medición manual, no superando en ambos casos el 3-4% y obteniéndose un ajuste medio (R2) entre ambas mediciones de 0.99, ajuste consistente e independiente de la especie de levadura estudiada. La observación de que el crecimiento bifásico del radio está correlacionado con las fases de aumento de células viables hace de este algoritmo una excelente herramienta

Effect of fibers and whole grain content on quality attributes of extruded cereals

Incorporation of fiber in cereals may lead to quality issues, thus decreasing consumer acceptance. This is partially due to deterioration of the microstructure, one of the primary quality attributes of cereals. The objective of this study was to better understand the mechanisms by which dietary fibers affect the quality of cereal products during extrusion-cooking. The study quantified the effect of amount and type of fiber and whole grain on (i) texture, (ii) structure, and (iii) rehydration properties of extruded cereals. New innovative methods were applied and combined with traditional techniques to characterize both the structure and the rehydration properties. Extruded cereals were produced using a starch-based recipe (whole and wheat flours) and two sources of fibers (oat bran concentrate and wheat bran). The oat and wheat bran levels used in this study were 0, 10, and 20%. The different mixtures were extruded in a pilot twin-screw extruder BC21 (Clextral) and then sugar coated after drying. Mechanical properties of extruded cereals were investigated by compression test. The cellular structure was observed by X-ray tomography. The quality of coating (thickness, homogeneity) was analyzed by optical coherence tomography. The rehydration properties of such cereals in milk were evaluated by magnetic resonance imaging and optical coherence tomography. This work revealed that structure assessment of extruded cereals may lead to a better understanding of the effect of fiber addition on texture and rehydration properties. The application of innovative methods, such as optical coherence tomography and magnetic resonance imaging, was found to be useful to quantify the structural properties

Relationship between solar radiation on watercore on apple fruit assessed with MRI

This work is a preliminary studio of the possibility of assess a relationship between solar radiation and watercore development on apple fruit, during maturation, using a non destructive method such as Magnetic Resonance Imaging (MRI). For such purpose, several low cost solar radiation sensors were designed for the trial and placed at 2 different heights (1.5 and 2.5 m) on 6 adult ?Esperiega? apple trees, in a commercial orchard in Ademuz (Valencia). Sensors were connected along 27 days, during the end of the growth period and start of the fruit maturation process, and radiation measurements of the a-Si sensors were recorded every 1 minute. At the end of this period, fruits from the upper and the lower part of the canopy of each tree were harvested. In all, 152 apples were collected and images with MRI. A Principal Component Analysis, perfomed over the histograms of the images, as well as segmentation methods were performed on the MR images in order to find a pattern involving solar radiation and watercore incidence