Notes

Akpınar and Biçer (2003) investigated the single layer drying behavior of apple slices in a convective type cyclone dryer and performed the mathematical modeling by using single layer drying models. The experiments were conducted at drying air temperatures of 60, 70 and 80oC and drying air velocities of 1 and 1.5 m/s. The mathematical model describing the single layer drying curves was determined by nonlinear regression analysis. Considering the parameters such as drying time, drying rate, moisture transfer and velocity and drying air temperature it is suggested that the apple slices be dried at the above optimum processing conditions. The Logarithmic model could adequately describe the single layer drying behavior of apple samples, when the effect of the drying air, velocity and sample area on the constant and coefficients of the logarithmic model were examined. The moisture transfer from the apple slices occurring during the falling rate period of drying was characterized by determining the diffusion coefficient into the air experimentally.
Velic et al. (2004) investigated airflow velocity influence on the kinetics of convection drying of apples, heat transfer and average effective diffusion coefficients. Drying was conducted in a convection tray drier at drying temperature of 60oC using regtangle-shaped (20x20x5mm) apple samples. Rehydration ratio was used as a parameter for the dried sample quality. Kinetic equations were estimated by using an exponential mathematical model. The result of calculations corresponded well with experimental data. Two well-defined falling rate periods and a very short constant rate period at lower air velocities was observed. With an increase of airflow velocity an increase of heat transfer coefficient and effective diffusion coefficient was found. During rehydration, about 72% of water removed by the drying process was returned.
Kaya et al. (2007) investigated drying characteristics of apple slice and the dependence on different drying air parameters. The drying parameters include air temperature (35, 45 and 55oC), air velocity (0.2, 0.4 and 0.6m/s) and relative humidity. Experiments were conducted using air temperatures at velocities at and relative humidity (40%, 55% and 70. The aim of this study was to examine the influence of the three different drying parameters on the drying kinetics of the red delicious apple. It was concluded that with a constant relative humidity, equilibrium moisture content decreases with increasing temperature. At a constant temperature, equilibrium moisture content increases with increasing equilibrium relative humidity. Increasing the temperature or velocity of the drying air decreases the total drying time, while decreasing the relative humidity decreases it. An increase either in velocity or temperature or decrease in relative humidity, increases effective diffusivity coefficient.