Determination of Effective Diffusivity Coefficient and Activation Energy of shelled pistachio by using fluidezed bed dryer

مجله پژوهشهای علوم و صنایع غذایی ایران

Article 1, Volume 3, Issue 2 - Serial Number 6, October 2007   

Document Type: Research Article

DOI: 10.22067/ifstrj.v3i2.1759

Authors

Vahid Mohammadpour^{* 1}; Mohamad Taghi Hamed Mosavian²; Ahmad Etemadi¹

¹Ferdowsi University of Mashhad

²Department of Food Science and Technology, Ferdowsi University of Mashhad, Mashhad, Iran.

Abstract

Knowledge of desorption kinetics is essential to predict the behavior of the material during drying
process and to design dryer equipment .The main objective of this study is to obtain the effective
diffusivity coefficient and activation energy of shelled pistachio. Another goal is to find drying
kinetics of shelled pistachio in fluidized bed dryer and so thin-layer characteristics of shelled
pistachios were determined experimentally as a function of temperature and air velocity .Accordingly,
6 mathematical models (Two term model, Exponential model, Logarithmic model, Page model,
Modified page model and Henderson & Pabis model) for describing the thin-layer drying behavior of
shelled pistachios were investigated. Tests were conducted using four air temperature (25,30,45 and 60
C) ,and three air velocities (6, 8 & 10m/s).Out of the 6 models considered ,the two term model were
considered to be the most suitable for describing the drying behavior of the shelled pistachios .Also,
for high air temperature and velocity, Henderson-Pabis model proved to be suitable .Results showed
that air velocity and operating temperature enhanced the kinetics of drying of shelled pistachio and the
drying air temperature had a great effect on the drying kinetics. By using of Fick’s second Law the
effective diffusivity coefficient and activation energy of pistachio was determined.
Keywords : Effective Diffusivity Coefficient, Activation Energy, Drying Kinetics, Fluidized Bed
Dryer, Pistachio Drying