Evaluation of the Dehydration Kinetics of Cassava (Manihot Esculenta) Slices Dried Using a Refractance WindowTM Dryer
Abstract
The dehydration kinetics of cassava slices dried using a Refractance WindowTM, a novel contact surface drying technique, is presented in this study. The dryer was constructed by modifying a laboratory water bath. Cassava slices of 3 mm thick were dried on the Refractance WindowTM, and the moisture content of the slices was measured as the drying progressed. A water temperature between 75 80 oC was
maintained beneath the plastic film. Drying curves were obtained from the drying data, and the thin layer
model that best fit the drying data was determined. The bulk density and rehydration ratio of the dried
cassava were determined. The cassava slices were observed to dry to about 5 % moisture content after
210 minutes. The regression analysis results showed that the Haghi and Ghanadzadeh thin layer model
best described the drying data for 3 mm thick sized cassava slices. The Mean Bias Error (MBE), the
Coefficient of Determination (R2), the Root Mean Square Error (RMSE) and the Chi-square (?2) values
were -8.83x10-6, 9984.34x10-4, 4.20x10-4 and 4.41x10-4 respectively. The Rehydration Ratio increased to
a steady value of 3.17 in about 180 minutes.
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