Experimental study of bitter guard, green peas and okra's drying characteristics in fluidized bed dryer

The main objective of this paper is to study the drying characteristics of Indian bitter guard (Momordica Chorantia) (4cm dia, 4mm thick and 90% moisture content wet basis [w.b] ), green peas (Pisum sativum) (8 mm dia 75% moisture content w.b) and okra generally known as lady's finger (Hibiscus esculenta) (1.5 cm dia, 5 mm thick 91% moisture content w.b) in a fluidized bed dryer (FBD) with inlet air temperatures 50, 60 and 70°C at fixed inlet air velocity of 2.1 m/s. Drying rate, effective diffusivity, drying time and activation energy were evaluated for the above three temperature ranges. The drying curves from experimental results were fitted to fifteen mathematical models from previous literature and also compared the determination coefficient (R²), reduced chi square (χ²) and root mean square (RMSE) value of fifteen models. From Arrhenius equation, the activation energy was found to be 16.63 kJ/mol (bitter gourd) and 26.61 kJ/mol (green peas), where the Arrhenius factor (D0) was 2.939 × 10⁻⁷ m²/s and 1.9796 × 10⁻⁵ m²/s respectively.