Influence of pre-treatment on drying on the drying kinetic of a local okro (Hibiscus ersculentus) variety.

The present work consists is aimed at studying the influence of pre-treatment on the drying on the drying kinetic of a local Okro variety. Experiments were performed in an forced convection electric drier at an air speed of 2 m s −1 within the temperature range 40-55°C. The Okro sample were blanched before drying. During experimentation, the mass of the Okro sample, the ambient air temperature and relative humilities were continuously recorded. From the experimental results recorded, the curves of loss of weight with drying time were drawn. Several models were tested to model the drying kinetics. The Midilli & al. model had the highest R 2 value (99.72%), the lowest MSE and a very reduced χ 2 value. This model described best, the drying behaviour of Okro. The effective diffusivity varied from 4,462 10 −9 to 2,941 10 −9 m 2 s −1 for the non-blanched Okro samples and from 4,662 10 −9 and 3,452 10 −9 m 2 s −1 for blanched samples. The activation energy was found to be 779 Kj mol −1 .