Modeling heat and mass transfer during drying of green coffee beans using prolate spheroidal geometry

Hernández-Díaz, W.N.; Ruiz-López, I.I.; Salgado-Cervantes, M.A.; Rodrı́guez-Jimenes, G.C.; Garcı́a-Alvarado, M.A.

doi:10.1016/j.jfoodeng.2007.08.025

Cited by 28 publications

(24 citation statements)

References 22 publications

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“…For the process optimisation the moisture and temperature evolution in coffee beans during the roasting process can be studied by modelling. In this way some researches have been investigated the heat and mass transfer during drying of green coffee (Burmester and Eggers, 2010;Hernandez-Díaz et al, 2008;Pérez-Alegría and Ciro-Velásquez, 2001) and coffee cherries (Sfredo et al, 2005). Limited data have been found to describe simultaneous heat and mass transfer during coffee roasting.…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling of heat and mass transfer during coffee roasting process

Fabbri¹,

Cevoli²,

Alessandrini³

et al. 2011

Journal of Food Engineering

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Section: Introductionmentioning

confidence: 99%

Numerical modeling of heat and mass transfer during coffee roasting process

Fabbri¹,

Cevoli²,

Alessandrini³

et al. 2011

Journal of Food Engineering

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“…Consequently, these models must be studied for each product and air condition to determine which model is best for predicting the EMC of the product in certain air conditions. Recent research has studied parchment alteration during drying (Borém et al, 2008), heat and mass transfer during drying (Hernández-Díaz et al, 2008), the thermal properties (Chandrasekar and Viswanathan, 1999;Pérez-Alegría and Ciro-Velásquez, 2001) and the physical properties of coffee grains (Chandrasekar and Viswanathan, 1999). No previous research has investigated the effects of the parchment on the drying process and the physical properties of coffee grains.…”

Section: Introductionmentioning

confidence: 99%

Hygroscopic equilibrium and physical properties evaluation affected by parchment presence of coffee grain

Corrêa

Oliveira

Rodrigues

et al. 2010

Span. j. agric. res.

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Physical properties are essential for the development of silos, transport calculations, separation and classification of grain and seeds. The present work evaluates the influence of the parchment on the drying and physical properties of coffee grains. The true density (ρ t ), bulk density (ρ b ) and porosity (ε) were evaluated for coffee grains (cv. Catuaí Amarelo) with and without parchment. Four mathematical models (Chung-Pfost, GAB, Modified Henderson and Oswin) were fitted to the experimental data to acquire desorption isotherms. The drying treatment was conducted in a factorial scheme with four levels of temperature (20, 35, 45 and 55°C) and five levels of relative humidity of the drying air (30, 40, 50, 60 and 80%) in a completely randomized design. The respective equilibrium moisture contents of the coffee grains were measured for each drying condition. No differences were observed among the products on the desorption isotherms. The pulped coffee with parchment (PP) had higher ε values than the pulped coffee without parchment (PR). The true density was higher for the PP coffee, but as the moisture content (X) increased, the true densities became more similar for the two samples. The ρ b was higher for the PP coffee than for the PR coffee. Higher initial and final values of ρ b were found for the PR and PP coffee, respectively. The Guggenheim-Anderson-de Bôer model was the model that best represented the experimental data for the drying process.Additional key words: density, drying, porosity, sorption isotherms. ResumenEvaluación del equilibrio higroscópico y de las propiedades físicas afectadas por la presencia de pergamino en los granos de café Las propiedades físicas son esenciales para el desarrollo de los silos y cálculos de transporte, separación y clasificación de granos y semillas. El presente trabajo evaluó la influencia del pergamino en el secado y en las propiedades físicas de los granos de café. Se evaluaron la densidad real (ρ t ), la densidad aparente (ρ b ) y la porosidad (ε) para los granos de café (cv. Catuaí Amarelo) con y sin pergamino. Se ajustaron cuatro modelos matemáticos (Chung-Pfost, GAB, Henderson Modificado y Oswin) a los datos experimentales para obtener isotermas de desorción. El tratamiento de secado se realizó en un esquema factorial con cuatro niveles de temperatura (20, 35, 45 y 55°C) y cinco niveles de humedad relativa del aire de secado (30, 40, 50, 60 y 80%) en un diseño completamente al azar. Se midió el contenido de humedad de equilibrio de los granos de café para cada condición de secado. No se observaron diferencias entre los productos en las isotermas de desorción. El café despulpado con pergamino (PP) presentó mayores valores de ε que el café despulpado sin pergamino (PR). La densidad real fue mayor para el café PP, pero según se incrementó el contenido de humedad (X), la densidad real se hizo más similar para ambas muestras. El ρ b fue mayor para el café PP que para el café PR. Los valores más altos iniciales y finales de ρ b se observaron en el café PR ...

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“…Hernandez-Diaz et al [10] reported a study on modelling heat and mass transfer during drying of green coffee beans using prolate spheroidal geometry. Three-dimensional governing equation in prolate spheroidal coordinate system was solved numerically.…”

Section: Drying Coffee Beansmentioning

confidence: 99%

“…Nilnont et al [13] performed finite element simulation for coffee drying to describe moisture diffusivity, shrinkage, equilibrium moisture content. It was shown that the mean diffusivity value of the coffee bean is 1.173 10 …”

Section: Drying Coffee Beansmentioning

confidence: 99%

A field survey on coffee beans drying methods of Indonesian small holder farmers

Siagian

Setyawan

Gultom

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Physical and sensory quality of Java Arabica green coffee beans W B Sunarharum, S S Yuwono, N B S W Pangestu et al. Abstract. Drying agricultural product is a post-harvest process that consumes significant energy. It can affect the quality of the product. This paper deals with literature review and field survey of drying methods of coffee beans of Indonesia farmers. The objective is to supply the necessary information on developing continuous solar drier. The results show that intermittent characteristic of sun drying results in a better quality of coffee beans in comparison with constant convective drying. In order to use energy efficiently, the drying process should be divided into several stages. In the first stage when the moist content is high, higher drying air temperature is more effective. After this step, where the moist content is low, lower drying air temperature is better. The field survey of drying coffee beans in Sumatera Utara province reveals that the used drying process is very traditional. It can be divided into two modes and depend on the coffee beans type. The Arabica coffee is firstly fermented and dried to moisture content of 80% using sun drying method, then followed by Green House model of drying up to moisture content about 12%. The latter typically spends 3 days of drying time. On the other hand, The Robusta coffee is dried by exposing to the sun directly without any treatment. After the coffee beans dried follow by peeled process. These findings can be considered to develop a continuous solar drying that suitable for coffee beans drying.

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Modeling heat and mass transfer during drying of green coffee beans using prolate spheroidal geometry

Cited by 28 publications

References 22 publications

Numerical modeling of heat and mass transfer during coffee roasting process

Numerical modeling of heat and mass transfer during coffee roasting process

Hygroscopic equilibrium and physical properties evaluation affected by parchment presence of coffee grain

A field survey on coffee beans drying methods of Indonesian small holder farmers

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