Modeling Plain Vacuum Drying by Considering a Dynamic Capillary Pressure

A coupled drying model for wood is proposed by introducing a dynamic capillary pressure. The pressures of non-wetting phase, the wetting phase, and the capillary pressure at equilibrium has been considered as non-static; this approach includes a two-scale model. According to numerical results, liquid, water vapor and air dynamics in the chamber have strong interactions with re-homogenization in the surface, controlled by capillary forces. The results at 60–100 bar and 70 °C are discussed. The phenomenological one-dimensional drying model is solved by using the COMSOL’s coefficient form and a global equation format. A good description of drying kinetics, moisture redistribution, and mass fluxes is obtained. A comprehensible transition at the fiber saturation point is well simulated

Modeling Plain Vacuum Drying by Considering a Dynamic Capillary Pressure

A coupled drying model for wood is proposed by introducing a dynamic capillary pressure. The pressures of non-wetting phase, the wetting phase, and the capillary pressure at equilibrium has been considered as non-static; this approach includes a two-scale model. According to numerical results, liquid, water vapor and air dynamics in the chamber have strong interactions with re-homogenization in the surface, controlled by capillary forces. The results at 60–100 bar and 70 °C are discussed. The phenomenological one-dimensional drying model is solved by using the COMSOL’s coefficient form and a global equation format. A good description of drying kinetics, moisture redistribution, and mass fluxes is obtained. A comprehensible transition at the fiber saturation point is well simulated

Physicochemical characterization of mesquite flours

[EN] Ethnic foods are healthy products interesting for the new societies. Mesquite flour offers another option for making gluten-free recipes as part of a diet for people with celiac disease. The physicochemical properties of mesquite flours (Prosopis laevigata) were characterized. The mesquite pods were dried at 60°C, 15% RH and 2 m/s airflow; then a grinding and sieving process were applied. The nutritional composition and the sorption isotherms were obtained at 30, 35, 40 and 45°C for water activities of 0.07-0.9. The particle-size distribution, morphology and thermal stability of the flours were determined by different methods.The authors are grateful to Conacyt for the scholarship granted to Larissa Reyes, and to the Instituto Politénico Nacional (Mexico) for SIP funding 20161016 and 20170755. Thanks to Dr. P. F. de Jesús Cano Barrita and M.C. Frank León Martinez for their technical assistance in the use of SEM microscope.Sandoval Torres, S.; Reyes López, L.; Méndez Lagunas, L.; Rodríguez Ramírez, J.; Barriada Bernal, G. (2018). Physicochemical characterization of mesquite flours. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 989-996. https://doi.org/10.4995/IDS2018.2018.7707OCS98999

Análisis cuantitativo de ácidos grasos en harina de Prosopis laevigata

Ripe mesquite pods are widely consumed by humans and animals in arid and semi-arid areas for their protein, carbohydrate, crude fiber and fat contents. The goal of this work is to identify and to quantify the fatty acid profile of flour from mesquite pods. Structural assignments were confirmed by the analysis of fragmentation patterns of mass spectra obtained by GC-MS. The results showed that 75% of the fatty acids were unsaturated, of which linoleic acid was predominant, while palmitic and stearic acids, and saturated fatty acids were found in minor proportions.Las vainas de mezquite maduro son ampliamente consumidas por humanos y animales en las zonas áridas y semiáridas por su contenido de proteínas, carbohidratos, fibra cruda y grasas. El propósito de este trabajo es identificar y cuantificar el perfil de ácidos grasos de harinas de vainas mezquite. La estructura química fue confirmada mediante el análisis de los fragmentos del espectro de masas obtenidos por GC-MS. Los resultados mostraron que el 75% de los ácidos grasos fueron insaturados, de los cuales, el ácido linoleico predomina mientras que el ácido pálmico y esteárico, ambos ácidos grasos saturados, fueron encontrados en menor proporción

Physicochemical Characterization of Mesquite Flour (<em>Prosopis laevigata</em>), Particle Size Distribution, Morphology, Isosteric Heat, and Rheology

Mesquite pods were dried and milled. The physicochemical properties of mesquite flour were characterized. The pods were dried at 60°C, 15% RH, and 2 m/s airflow. After drying, two types of milling were applied: (1) industrial blade mill and (2) Blender, and the nutritional composition was determined. The sorption isotherms were obtained at 30, 35, 40, and 45°C for a range of water activity of 0.07–0.9. The particle size distribution and the average particle size of the flours were characterized by means of diffraction of blue laser light; furthermore, the morphology was analyzed by (SEM). The powders were also analyzed by DSC. Alveography was applied to study the rheology of the flour. Mesquite powders are highly hygroscopic, and the (GAB) model displays a good description of the experimental data. Flours expose different morphologies depending on the milling technique; a more homogeneous powder was obtained from the industrial blade mill. Rheological characterization indicates that mesquite flour decreases the tenacity and extensibility of the flour mixture. According to DSC, the flours are very stable over a wide temperature range from 0 to 120°C, and the thermograms indicate a transition of proteins affected by high-molecular-weight carbohydrates and moisture content

Efecto de las condiciones de secado por aspersión en las propiedades de polvos de micílago de nopal

Instituto Politécnico Nacional CIIDIR Unidad Oaxac

Análisis comparativo del contenido de azucares en fruto de pitaya (stenocereus pruinosus endémicad de Oaxaca y Nayarit

Instituto Politécnico Nacional CIIDIR Unidad Oaxac

Efecto del mérodo de extracción en el secado por aspersión de mucílago de pitahaya (Hylocereus undatus)

Instituto Politécnico Nacional CIIDIR Unidad Oaxac

Evaluación del coeficiente de transferencia de calor de un colector solar con placa absorbedora acanalada

Instituto Politécnico Nacional CIIDIR Unidad Oaxac

Effect of glass transition on density changes of foodstuffs during the drying

Instituto Politécnico Nacional CIIDIR Unidad Oaxac