Determinación de humedad en la pulpa de café
Fecha
2004
Tipo
artículo original
Autores
Vargas Elías, Guillermo Asdrúbal
Mazón Villegas, Beatriz
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Resumen
El propósito de este trabajo fue adaptar el método del honor de convención forzada para la determinación del contenido de humendad de la pulpa de café. Se realizó una prueba preliminar para establecer el tiempo necesario para estabilizar el peso de una muestra de alta humedad, utilizando una temperatura de 103°C y muestras de 5,00 g; el tiempo establecido fue de 2 h. Se estudiaron 3 lotes de pulpa de café cada uno con un contenido de humedad diferente (bajo, intermedio y alto). De cada lote se pesaron 36 muestras de 5,00 g, se colocaron en el horno a 103°C y cada 10 min por 2 h se sacaron 3 muestras al azar para determinar el porcentaje de humedad. Las muestras se analizaron por duplicado en diferentes ocasiones, y simultáneamente por le método de Bidwell-Sterling (destilación con tolueno) utilizado como método de referencia. Se desarrollaron curvas del % de humedad con los resultados obtenidos utilizando el método del horno. y además se estableció la correlación entre los resultados de ambos métodos. Las humedades en base húmeda (bh) de los 3 lotes se establecieron en 17,6%, 33,6% y 64,6% respectivamente por el método del horno, y en 17,5%, 34,2% y 64,5% por el método de Bidwell-Sterling. Ambos resultados se correlacionaron y mostraron una correspondencia lineal que se ajustó con un coeficiente de determinación alto (R2=0,9991). Las curvas % de humedad mostraron que la broza de humedad baja se estabiliza en menos tiempo pero en todos los casos el tiempo mínimo fue de 1,5 h. Un análisis de los datos demostró que utilizar 3 repeticiones por muestra garantiza una desviación estándar <0,5% entre ellos. Se concluye que los porcentajes de humedad de pulpa de café obtenidos con la adaptación propuesta tienen una alta correlación con los obtenidos por el método Bidwell-Sterling y presenta ventajas, respecto a este, en cuanto a la cantidad de repeticiones y la simultaneidad del análisis, además de ser menos laborioso, no requerir personal especializado, ser más barato y representar menor contaminación ambiental.
The aim of this study was to adapt the forced convection oven method to determine % humidity of coffe pulp. A preliminary study was done to establish time necessary to stabilize the weight of 5,00g samples of a high humidity coffee pulp using 103°C in the oven. Time was established in 2 h. Three coffee pulp lots with different humidites (low, intermediate, high) were studied. From each lot 36 5,00g samples were introduced in a pre-heated oven at 103°C, and every 10 min up to 2 h 3 samples were taken at random to determine humidity percent. Samples were analysed in duplicate, and simultaneously by the Bidwell-Sterling method used as reference. With data obtained humidity % curves were plotted, and correlation between results by both methods was studied. Humidity %, on wet basis, for the 3 coffee pulp lots were 17,6%, 33,6%, 64,6% for the oven method, and 17,5%, 34,2%, 64,55% for the Bidwell-Sterling method. Results correlated and showed a linear correpondence which adjusted to a high determination coefficient (R2=0,9991). Humidity percent curves shiwed that low humidity coffee pulp stabilizes in less time, but in all three cases minimum time was 1,5 h. When % standard deviation of data obtained at each 10 min interval was studied, it was found that using 3 repetions per sample guarantees <0,05% standard deviation between the 3 samples after 1 h. The method proposed has a strong correlation to the Bidwell-Sterling method and presents advantages to it in the amount of repetitions that can be done simultaneously, it is less laborious, it doesn´t require specialized personnel, it is cheaper, and represents less environmental contamination.
The aim of this study was to adapt the forced convection oven method to determine % humidity of coffe pulp. A preliminary study was done to establish time necessary to stabilize the weight of 5,00g samples of a high humidity coffee pulp using 103°C in the oven. Time was established in 2 h. Three coffee pulp lots with different humidites (low, intermediate, high) were studied. From each lot 36 5,00g samples were introduced in a pre-heated oven at 103°C, and every 10 min up to 2 h 3 samples were taken at random to determine humidity percent. Samples were analysed in duplicate, and simultaneously by the Bidwell-Sterling method used as reference. With data obtained humidity % curves were plotted, and correlation between results by both methods was studied. Humidity %, on wet basis, for the 3 coffee pulp lots were 17,6%, 33,6%, 64,6% for the oven method, and 17,5%, 34,2%, 64,55% for the Bidwell-Sterling method. Results correlated and showed a linear correpondence which adjusted to a high determination coefficient (R2=0,9991). Humidity percent curves shiwed that low humidity coffee pulp stabilizes in less time, but in all three cases minimum time was 1,5 h. When % standard deviation of data obtained at each 10 min interval was studied, it was found that using 3 repetions per sample guarantees <0,05% standard deviation between the 3 samples after 1 h. The method proposed has a strong correlation to the Bidwell-Sterling method and presents advantages to it in the amount of repetitions that can be done simultaneously, it is less laborious, it doesn´t require specialized personnel, it is cheaper, and represents less environmental contamination.
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Palabras clave
Cáscara de café, Contenido de humedad, Método del horno, Destilación, 633.73 Café