Convective hot air drying of blanched yam slices

In this study, a laboratory convective hot air dryer was used for the thin layer drying of blanched yam slices and experimental moisture ratio was compared with Newton, Logarithmic, Henderson and Pabis, modified Henderson and Pabis, approximation of diffusion, modified page 1, two-term exponential, Verma et al. and Wang and Singh models. Among all the models, the approximation of diffusion model was found to satisfactorily describe the kinetics of air-drying of blanched yam slices. The increase in air temperature significantly reduced the drying time with no constant rate period but drying occurs in falling rate period. The effective diffusivity values varied between 7.62 x 10(-8) to 9.06 x 10(-8) m(2) s(-1) and increased with increase in temperature. An Arrhenius relation with an activation energy value of 8.831 kJ mol(-1) showed the effect of temperature on moisture diffusivity.