Abstract :

The use of response surface methodology in predicting the moisture content reduction and drying rate of dried sweet potato slices was the objective of this work. Freshly harvested sweet potatoes were washed and peeled. Experiments were performed at drying temperatures of 60, 70 and 80oC, slice thicknesses of 0.4 cm, 0.6 cm, and 0.8 cm, and drying times of 60, 180, and 300 minutes. The moisture content and drying rate values were optimal at a drying temperature of 70oC, slice thickness of 0.6 cm and drying time of 180 minutes. Treated sweet potatoes have a lower moisture content of 0.1809 g water/g solid at a temperature of 70oC, thickness of 0.6cm and drying time of 180 minutes compared to 0.3522g water/g solid. Treated samples require less time and temperature to attain optimum moisture content. The three factors influenced the drying process significantly. Minimized moisture content increased sweet potato shelf life. The ANOVA result showed that the response surface methodology gave a high correlation coefficient (R2) of 0.9997 and 0.9987 for untreated and treated sweet potatoes, respectively.