Effect of Variety, Pretreatment and Dryer Operational Parameters on the Drying Characteristics of Potato Slice Using Solar Cabinet Dryer with Heat Storage System

In the present work, effect of potato variety, pretreatments (5% brine, 0.5% potassium Meta bi-sulphite (KMS) and blanching at 70°C for 3 minutes) and airflow mode on drying kinetics and effective moisture diffusivity of potato slices was investigated in a cabinet solar dryer with a heat storage system. The experiment was conducted in a full factorial design arranged in a completely randomized block design and the drying kinetics was modelled using commonly used well known equations. From the result; potato variety, air flow mode (natural vs. forced convection) and pre-treatments significantly affected the drying kinetics of the slice in which the brine-treated sample took a shorter drying time followed by blanched and KMS-treated slices. However, the blanched sample exhibited a higher effective moisture diffusivity and drying rate than untreated and KMS-treated samples. Brine treated sample has the lowest effective moisture diffusivity and drying rate. Tolcha variety dried faster than the Jalo variety followed by the Gera variety. The goodness of fit to the tested models were also evaluated based on R2, chi-square and RMSE values in which a model with the highest R2 ,lowest X2 and RMSE values were selected as a best fitted model. As result, Boltzmann model with R2 (0.9985) was the best fitted model in Blanched sample, whereas Midihilli and Kucuk model was best fitted with brine-treated and control samples, with R2 values ranging from 0.9995 in the control sample to 0.9999 in the brine-treated sample.