Abstract

MUNOZ-NEIRA, Milton Javier; ROA-ARDILA, Manuel Fernando  and  CORREA-CELI, Carlos Rodrigo. Comparative analysis of drying coffee beans using microwave and conventional oven. Rev.fac.ing.univ. Antioquia [online]. 2020, n.95, pp.100-108. ISSN 0120-6230.  https://doi.org/10.17533/udea.redin.20191151.

This article reports a comparative study of experimental results obtained during the drying of Castilla-variety coffee beans from Santander, Colombia. They were performed by two means: thermal and electromagnetic radiation. Twenty experiments were carried out, ten tests in a microwave cavity at 2,450 MHz-1,080W, and ten tests using a conventional electric oven with temperature controlled at 50 ± 2°C. Experiments were made using samples of coffee beans with parchment, without parchment, and of the only-parchment. For each sample, dimensionless moisture ratio and diffusion coefficients were determined, according to the second law of Fick. We found that the diffusion coefficient of the samples dried in a microwave cavity was twenty-two times higher than the diffusion coefficient of samples dried with thermal radiation. Likewise, it was observed that samples in conventional oven showed a uniform temperature, in contrast with those heated by microwave radiation. Such results are useful for designing hybrid systems for drying coffee beans.

Keywords : Grain drying; drying curve; diffusion coefficient; microwave drying.

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