EFFECT OF INITIAL MOISTURE CONTENT ON THE THIN LAYER DRYING CHARACTERISTICS OF HAZELNUTS DURING ROASTING |
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| Authors: | Murat Özdemir Ferda G. Seyhan A. Özdeş Bodurb Y. Onur Devres |
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| Affiliation: | 1. Food Science and Technology Research Institute, TUBITAK-Marmara Research Center , P. O. Box. 21, Gehze, Kocaeli, 41470, Turkiye E-mail: E-mail: mozdemir@mam,gov.tr;2. Department of Food Engineering , Istanbul Technical University , Maslak, Istanbul, 80626, Turkiye E-mail: E-mail: onur@devres.net |
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| Abstract: | ABSTRACT Effect of initial moisture content on the thin layer drying characteristics of hazelnuts during roasting was described for a temperature range of 100-160°C, using several thin layer equations. The effective diffusivity varied from 2.8×10?7 to 21.5×10?7m2/s over the temperature and moisture range. Temperature dependence of the diffusivity coefficient was described by Arrhenius-type relationship. The activation energy for moisture diffusion was found to be 2703 kJ/kg, 2289 kJ/kg and 2030 kJ/kg for the initial moisture content of 12.3% db, 6.14% db, and 2.41% db, respectively. Two-term equation gave better predictions than Henderson and Pabis and Thompson equations, and satisfactorily described thin layer drying characteristics of hazelnut roasting. A generalised mathematical model with the linear temperature dependence for moistured, non-treated and pre-dried hazelnuts were also developed. |
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| Keywords: | Mathematical Modelling Hazelnut Diffusivity Activation Energy Drying Roasting |
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