Browsing by Author "Mejia Galarza, William Andres"

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Effect of different drying airflows and harvest periods on the quality of specialty coffee (Coffea arabica L.)
(2023) Ortiz Ulloa, Silvia Johana
Coffee is one of the most consumed commercial beverages worldwide, and coffee growers are constantly seeking innovative processing techniques to improve the quality of the final product. This study evaluated the influence of four drying airflows and three harvest periods on the chemical composition of green and roasted specialty coffee beans. The samples were obtained from the Hacienda La Papaya in Loja, Ecuador. Liquid and gas chromatographic techniques characterized the chemical profile of coffee beans, and sensory analysis was performed using the Specialty Coffee Association of America methodology. In total, 49 compounds were described, 29 in green beans and 20 in roasted beans. A significant (p<0.05) effect of the harvest period was observed in all phenolic compounds except for chlorogenic acid. The drying type significantly affected the levels of rutin and trigonelline. In addition, samples from different harvest periods observed significant differences in the levels of the amino acids serine, arginine, phenylalanine and leucine. Similarly, the drying type significantly influenced glycine, alanine, valine and isoleucine levels. For all drying-harvest combinations, the final cupping score was higher than 85/100, as the different drying processes slightly influenced the cupping attributes. Drying with minimal airflow was characterized by a low balance and intense flavor while drying with medium airflow presented a high ratio and soft body. The harvest period and drying type cannot be used as cupping predictors since no clear trends were observed to classify specialty coffee organoleptic attributes. Therefore, other variables involved in specialty coffee processing should be explored to evaluate higher sensitivity toward flavor prediction and innovation.
Simulation of the Catalytic Gasification of Banana Biomass in the Production of Hydrogen, Using Glucose as a Model Compound
(2023) Bernal Pesantez, Edison Bolivar; Gaona Cumbicos, Jessica; Jara Cobos, Lourdes Elizabeth; Naula Duchi, Kelly Dayanna; Álvarez Lloret, Edgar Paúl; Mejia Galarza, William Andres
Abstract: In the face of the climate change problem caused by fossil fuels, it is essential to seek efficient alternative energies with a lower environmental impact that are derived from renewable resources. Biomass gasification technology continues to generate significant interest in sustainable energy research as an alternative to traditional combustion technology. Gasification involves the thermochemical conversion of raw materials, resulting in a highly valuable gaseous product known as synthesis gas, commonly used as a fuel. Its numerous advantages include the availability of raw materials, the reduction in harmful emission streams, performance, and costs. As this topic gains momentum in the global energy framework, it is imperative to advance the maturity of this technology by addressing its weaknesses, primarily in terms of efficiency. The objective of this project was to investigate the hydrogen production process through the simulation of glucose gasification as a representative compound for biomass. This was achieved by conducting an integrated simulation of glucose gasification, encompassing both the heat transfer in the external system and the conversion of glucose into hydrogen gas, using the results obtained in the external system as initial conditions. Interrelated aspects of this complex process, including heat transfer and the kinetics of the gasification process, were modeled. Glucose was selected as the model compound due to its availability, simplicity, fundamental understanding, reproducibility, comparability, knowledge of reaction pathways, and simplification of mathematical models. The simulation resulted in a H2:CO ratio of 2.2, and molar fluxes were obtained for H2, CO, CO2, CH4, and H2O consistent with those typically observed in the gasification process of organic ma􀀻er. These models were constructed, laying the foundation for the adaptability of subsequent optimization studies.