Drying Kinetics of Cauliflower in a Hot Air Dryer

Cauliflower florets of 4 cm size were dried at three different drying air temperatures viz., 55, 60, and 65°C, with 60 m.min⁻¹ of drying air velocity. The drying data were fitted to different semi-theoretical and empirical models viz., Newton, Page, Henderson and Pabis, Logarithmic, two-term, two-term exponential, Verma et al., Modified Henderson, Midilli, and Wang and Singh models, based on the moisture ratios. The Midilli model was the best fit over other models and satisfactorily described the thin-layer drying characteristics of cauliflower. The effective diffusivity varied from 12.37 X 10⁻⁹ to 3.77 X 10⁻⁹ m².s⁻¹ over the temperature range studied. The temperature dependence of the diffusivity coefficient was described by the Arrhenius-type relationship. The activation energy for moisture diffusion was found to be 42.41 kJ. Mol⁻¹.