Mathematical Modelling of Thin-Layer Drying Characteristics of Red Gram (Cajanus cajan)

Thin layer drying characteristics of red gram as affected by initial moisture contents (18.34, 22.25 & 27.39% d.b), temperatures (45, 55 & 65°C) and velocities (0.5, 1.0, & 1.5 ms⁻¹) were investigated using a hot air thin layer drying system. The red gram drying process occurred in falling rate period indicating that the diffusion is dominating moisture movement mechanism in drying process. The drying process showed the dominating effect of temperature on drying rate of red gram. Along this the influence of initial moisture content and velocity was seen only at initial stages of drying. The drying curveswere fitted with eight thin layer models (Newton, Page, Modified page, Logarithmic, Wang & Singh, Midilli, Henderson & Pabis, and Two term) in which Two term model found to describe the drying kinetics of red gram satisfactorily at all the drying conditions investigated.