Vahid Mohammadpour; Mohamad Taghi Hamed Mosavian
Abstract
Frying is an important unit operation used widely both in domestic and industrial cooking. Reduced pressure (vacuum), microwave, deep fat and pan frying are the most important methods of food frying. Final product has good organoleptic quality (colour, texture, and flavour). The accuracy of the knowledge ...
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Frying is an important unit operation used widely both in domestic and industrial cooking. Reduced pressure (vacuum), microwave, deep fat and pan frying are the most important methods of food frying. Final product has good organoleptic quality (colour, texture, and flavour). The accuracy of the knowledge of mass transfer parameters (effective diffusivity coefficient, dimensionless Biot number and mass transfer coefficient) in the case of frying is essential and important for designing, modeling and process optimization. This study is undertaken to develop a more realistic approach for determining mass transfer parameters during frying of potato slices for cylindrical coordinates. These parameters were evaluated from the plots of dimensionless concentration ratios against time in sunflower liquid oil at and . Effective diffusivity coefficient, dimensionless Biot number and mass transfer coefficient ranged between to , to and to , respectively. Effective diffusivity coefficient and mass transfer coefficient were found to increase with an increase in frying temperature, whereas Biot number decreased. An Arrhenius type of relationship was found between the frying temperature and effective diffusivity coefficient.
Vahid Mohammadpour; Mohamad Taghi Hamed Mosavian; Ahmad Etemadi
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 ...
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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
