Title: Indirect solar drying kinetics of sheanut (Vitellaria Paradoxa Gaertn.) kernels

Authors: Divine Nde Bup; Charles Fon Abi; César Kapseu; Clergé Tchiegang; Zéphirin Mouloungui

Addresses: Higher Institute of the Sahel, University of Maroua, P.O. Box 45, Maroua, Cameroon; Department of Process Engineering, ENSAI, University of Ngaoundere, P.O. Box 455, Ngaoundere, Cameroon ' Department of Chemistry, Advanced Teachers' Training College, University of Yaounde 1, P.O. Box 47, Yaounde, Cameroon ' Department of Process Engineering, ENSAI, University of Ngaoundere, P.O. Box 455, Ngaoundere, Cameroon ' Department of Food Science and Nutrition, ENSAI, University of Ngaoundere, P.O. Box 455, Ngaoundere, Cameroon ' Laboratoire de Chimie Agro-Industrielle, UMR 1010, ENSIACET, INP, INRA, Université de Toulouse, 4 allée Emile Monso, BP 74233, F-31432 Toulouse Cedex 4, France

Abstract: An indirect solar dryer was tested for drying sheanut kernels. The influence of tray distance from heat source, airspeed and particle size on drying kinetics was investigated. Optimum drying air parameters obtained in the dryer were airspeeds of 1 and 1.4 m/s and a temperature of 40°C-45°C. Sheanut kernel slices dried entirely in the falling rate period. Drying rate decreased with increase in particle size. The effect of particle size on the drying rate suggested that, the drying process was controlled by internal mass transfer mechanisms. Drying kinetics was modelled with characteristic drying curve and diffusive models. Effective moisture diffusivities of sheanut kernel slices calculated without shrinkage were greater than those calculated with the incorporation of shrinkage by a value of about 50%. Acid and peroxide values indicated that butter from the dryer could be classified either as Category 1 or 2 irrespective of the drying conditions to which the kernels were subjected.

Keywords: indirect solar drying; modelling; shrinkage; sheanut kernels; drying kinetics; Vitellaria Paradoxa Gaertn; particle size; internal mass transfer.

DOI: 10.1504/IJPTI.2014.064138

International Journal of Postharvest Technology and Innovation, 2014 Vol.4 No.1, pp.1 - 22

Received: 16 Oct 2013
Accepted: 16 Dec 2013
Published online: 30 Aug 2014 *

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