Title: Equipment's role on the drying process of chestnut (Castanea sativa Mill.) fruits

Authors: Hugo Manuel Lamas; Elsa Cristina Dantas Ramalhosa; Alcina Maria Miranda Bernardo de Morais

Addresses: Mountain Research Centre (CIMO), ESA – Polytechnic Institute of Bragança, Campus de Stª Apolónia, Apartado 1172, 5301-854 Bragança, Portugal ' Mountain Research Centre (CIMO), ESA – Polytechnic Institute of Bragança, Campus de Stª Apolónia, Apartado 1172, 5301-854 Bragança, Portugal ' CBQF – Centro de Biotecnologia e Química Fina – Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Dr. António Bernardino Almeida, 4200-072 Porto, Portugal

Abstract: In the present work, drying of chestnut (Castanea sativa Mill.) fruits was performed at different air temperatures in three equipments - convection oven, parallel flow tray dryer and fluidised bed dryer, at temperatures between 40 and 100°C. Newton diffusion approach and two-term models were found to be adequate in describing the moisture ratio and drying rates along time. For the same temperature, the dehydration processes that involved higher air velocities were > 1.6 times faster. On the other hand, for the same equipment the highest temperature (100°C) induced a drying rate ten times faster than the lowest temperature (40°C), reducing drying time. Apparent diffusivity ranged between 7.03 × 10−11 m2 s−1 (40°C, convection oven) and 1.06 × 10−9 m2 s−1 (100°C, fluidised bed dryer). In convection oven experiments, the diffusivity in function of temperature was well described by an Arrhenius type function, with an activation energy of 4.08 × 104 J mol−1.

Keywords: chestnut fruits; air drying; equipment impact; convection oven; parallel flow tray dryer; fluidised bed dryer; drying modelling; Newton model; diffusion approach model; two-term model; apparent diffusivity; activation energy; Castanea sativa mill; drying time; temperature; dehydration processes; air velocities.

DOI: 10.1504/IJCAET.2015.068337

International Journal of Computer Aided Engineering and Technology, 2015 Vol.7 No.2, pp.273 - 286

Published online: 31 Mar 2015 *

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