Comparison of Batch and Continuous Wet-Processing of Coffee: Changes in the Main Compounds in Beans, By-Products and Wastewater.

Many technical challenges still need to be overcome to improve the quality of the green coffee beans. In this work, the wet Arabica coffee processing in batch and continuous modus were investigated. Coffee beans samples as well as by-products and wastewaters collected at different production steps were analyzed in terms of their content in total phenols, antioxidant capacity, caffeine content, organic acids, reducing sugars, free amino group and protein content. The results showed that 40% of caffeine was removed with pulp. Green coffee beans showed highest concentration of organic acids and sucrose (4.96 ± 0.25 and 5.07 ± 0.39 g/100 g DW for the batch and continuous processing). Batch green coffee beans contained higher amount of phenols. 5-caffeoylquinic Acid (5-CQA) was the main constituent (67.1 and 66.0% for the batch and continuous processing, respectively). Protein content was 15 and 13% in the green coffee bean in batch and continuous processing, respectively. A decrease of 50 to 64% for free amino groups during processing was observed resulting in final amounts of 0.8 to 1.4% in the processed beans. Finally, the batch processing still revealed by-products and wastewater with high nutrient content encouraging a better concept for valorization.

Carga contaminante de los residuos sólidos municipales en la cabecera departamental de Jalapa, Guatemala / Pollution load of municipal solid waste in the City of Jalapa, Guatemala

Se expone la carga contaminante de los residuos sólidos municipales, en la cabecera departamental de Jalapa, Guatemala. Cada residuo, sin importar su origen o forma, tiene una composición química específica, la cual indicará su grado de contaminación o carga contaminante. El estudio se enfocó en el análisis de los residuos sólidos de tipo domiciliar, institucional, comercial, mercados y barrido y limpieza de calles por un periodo de cinco días. La muestra se analizó mediante la determinación de las fracciones de composición de los residuos, clasificándolos en: papel, cartón, plástico, pet, restos de comida, duroport, textiles, hule, vidrio, papel higiénico, pañales y madera. Para el cálculo de la carga contaminante se multiplicó los porcentajes que aporta el carbono, hidrógeno, oxígeno, nitrógeno y azufre a cada fracción de los residuos por el peso total de cada componente para luego dividirlo por el peso atómico. Para minimizar la carga contaminante de los residuos sólidos, la recolección debe darse con una frecuencia mínima de dos veces por semana, para evitar proceso de descomposición, pudiendo generar vectores y enfermedades en los sitios temporales de disposición que afecten a la población. El volumen de los desechos generados por el barrido de calles presenta la mayor carga contaminante, dando como resultado porcentajes altos en los componentes de carbono, hidrogeno, oxígeno y nitrógeno, sin embargo, la misma puede reducirse implementando prácticas de valorización como el compostaje. Uno de los grandes problemas es el aporte de nitrógeno que en cantidades excesivas puede causar contaminación al suelo y a cuerpos de agua superficial.

The pollution load of municipal solid waste in the departmental capital of Jalapa is discussed. Each waste, regardless of their origin or form, has a specific chemical composition, which shall indicate the degree of pollution or pollution load. The study focused on the analysis of solid waste type household, institutional, comercial and street sweeping for a period of five days. The sample was analyzed by determining the fractions of waste composition, classifying them into paper, cardboard, plastic, pet, food scraps, styrofoam, textiles, rubber, glass, toilet paper, diapers and wood. To calculate the pollution load percentages provided by the carbon, hydrogen, oxygen, nitrogen and sulfur to each fraction multiplied by the total weight of each component and then divided by the atomic weight. To minimize the pollution load of solid waste, collection must occur with a frequency of twice a week, in order to avoid decomposition process, potentially leading to disease vectors and temporary disposal sites affecting the population. The volume of waste generated by street sweeping has the highest pollution load, resulting in high percentages of the carbon, hydrogen, oxygen and nitrogen components, but this can be reduced by implementing recovery practices such as composting. One of the big problems is the contribution of nitrogen that in excessive amounts can cause contamination to the soil and bodies of superficial water.