The objective of this research was to develop a mathematical model for batch photoautotrophic cultivation of Arthrospira platensis and to validate it against data obtained in experiments. All trials were carried at 30°C, under a light intensity of 60 or 120 µmol m -2 s -1 . The purpose of the model was to determine the optimal concentration of carbon dioxide, as well as to investigate the formation of phycocyanin. For the experimental conditions in this study, the optimal concentration carbon dioxide (0.8% CO2, v/v) was predicted using the model according to the initial bicarbonate level, the carbon uptake by the microalga, the pH, and the mass transfer process. The use of this optimal value in the gas inlet seems to be a suitable option for maintaining the optimal pH (9.5), thereby eliminating the need for a pH controller in the bioreactor system. According to the simulations, the mass fraction of the phycocyanin formation rate seems to depend on the internal light level. The percentage of adjustment obtained (R 2 ) was ≥75%. The velocity of phycocyanin formation was enhanced at intensities up to 120 µmol m -2 s -1 . However, the actual internal irradiance values were lower than the light compensation point (4.5 µmol m -2 s -1 ), so phycocyanin formation ceased. The mathematical model may facilitate the examination of optimal carbon delivery, as well as the light input, in several A. platensis culture conditions aimed at phycocyanin production.
Con este estudio se obtuvieron modelos matemáticos semi-empíricos que representan la cinética de secado convectivo del epicarpio de zapallo a diferentes temperaturas (55, 65 y 75 ° C / 10% HR / velocidad de secado 1ms-1). Se seleccionó la mejor condición de secado con la que se obtuvo la harina, la cual se caracterizó y utilizó para la elaboración de la torta libre gluten. Posteriormente, se evaluó el efecto de incorporar harina de epicarpio de calabaza en 4 niveles (control 0, 15, 20 y 25g / 100 g de harina) sobre la aceptación sensorial de la torta. Como resultados se obtuvo que el modelo de dos términos describe mejor la curva obtenida a 55 ° C, y el modelo logarítmico describe mejor las curvas obtenidas a 65 ° C y 75 ° C. Se seleccionó la temperatura de 65 ° C como la mejor condición de secado. Finalmente, la mayor aceptación e intención de compra se obtuvo en el pan formulado con 15 g / 100 g de harina de epicarpio de calabaza.
Tray dryers are usually designed with simplistic scaling rules that do not account for all the transport phenomena associated with drying. The use of computational fluid dynamics coupled with response surface methodology can be a powerful tool to evaluate how different tray dryer design parameters affect the drying process. In this work, two tray dryers, one with a lateral air inlet and another with a bottom air inlet, were parameterized for the position of the air inlet, the dryer length, and the distance between the trays. A central composite design was chosen to determine the sample points, and the average turbulence viscosity and effective thermal conductivity as well as the homogeneity index were calculated. With these values, a response surface curve was constructed. The effective thermal conductivity and its homogeneity index were improved (80 % and 11 %, respectively) with an increased distance between trays and an air inlet located in the middle of the inlet face in the best scenario. In addition, the reductions in effective thermal conductivity outcomes were minimal due to the scale-up process in terms of the dryer length.
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