In the present study, the optimum parameters for producing biodiesel by transesterification of used oil with methanol, using NaOH as a catalyst, were determined. The used oil was collected from poultry farms in the Pichari district. A three-level, four-factor Box-Benhken design with four replicates in the center and the response surface method were used to optimize the conditions of the trans-esterification process. The selected factors were the methanol-oil molar ratio (6, 9, and 12), NaOH concentration (0.5, 1.25, and 2.0), temperature (35, 45, and 55), and reaction time (30, 60, and 90). The selected response was the biodiesel yield. The optimum production conditions were: methanol-oil molar ratio; 9, NaOH concentration; 1.21%; temperature, 57 °C; and time, 62 min at a stirring frequency of 700 rpm. The estimated yield under these conditions was 94%. Three verification tests under th...

In the present study, the optimum parameters for producing biodiesel by transesterification of used oil with methanol, using NaOH as a catalyst, were determined. The used oil was collected from poultry farms in the Pichari district. A three-level, four-factor Box-Benhken design with four replicates in the center and the response surface method were used to optimize the conditions of the trans-esterification process. The selected factors were the methanol-oil molar ratio (6, 9, and 12), NaOH concentration (0.5, 1.25, and 2.0), temperature (35, 45, and 55), and reaction time (30, 60, and 90). The selected response was the biodiesel yield. The optimum production conditions were: methanol-oil molar ratio; 9, NaOH concentration; 1.21%; temperature, 57 °C; and time, 62 min at a stirring frequency of 700 rpm. The estimated yield under these conditions was 94%. Three verification tests under th...

Adsorption isotherms provide insight into the thermodynamic properties governed by food storage conditions. Adsorption isotherms of purple corn of the Canteño variety were evaluated at 18, 25, and 30 C, for the equilibrium relative humidity (ERH) range between 0.065 and 0.95. The equilibrium moisture (Xe) was determined by the continuous weight-change method. Seven mathematical models of isotherms were modeled, using the coefficient of determination R2, mean absolute error (MAE), and estimated standard error (ESE) as the convergence criterion. Thermodynamic parameters such as isosteric heat (qst), Gibbs Free Energy (DG), differential entropy (DS), activation energy (Ea), and compliance with the isokinetic law were evaluated. It was observed that the adsorption isotherms presented cross-linking around 75% ERH and 17% Xe, suggesting adequate storage conditions at these values. The GAB and...