Modeling effective moisture diffusivity of wheat (Tajan) during air drying

Drying conditions can greatly affect the physical and mechanical properties of grains. The drying process must be controlled to reduce or minimize drying damage. In this paper the thin layer drying behavior of wheat (Tajan) in a convective dryer is experimentally investigated. The mathematical modeling by using thin layer kinetics drying models available in literature was performed. Drying experiments were conducted at inlet drying air temperatures of 35, 45, 50, 60 and 70 degrees C and at a fired drying air velocity of 0.3 m/s and initial moisture content of 0.26-0.27 (d.b.). The effects of drying air temperature on the model's parameters were predicted by a linear regression analysis. The constants and coefficients of this model were be explained in terms of drying air temperature. A correlation coefficient (r) of 0.99 was found for the multiple regression model of moisture content during the drying process using different temperature values. Values of the diffusion coefficients for the whole kernel ranged from 2.28 x 10(-11) to 1.14 x 10-(10) m(2)/s.