Optimum Process Parameters and Thermal Properties of Moisture Content Reduction in Water Yam Drying
C. Ezedinma Henry *
Department of Chemical Engineering, NnamdiAzikiwe University, P.M.B. 5025, Awka, Anambra State, Nigeria.
T. Nwabanne Jospeh
Department of Chemical Engineering, NnamdiAzikiwe University, P.M.B. 5025, Awka, Anambra State, Nigeria.
E. Onu Chijioke
Department of Chemical Engineering, NnamdiAzikiwe University, P.M.B. 5025, Awka, Anambra State, Nigeria.
O. Nwajinka Charles
Department of Agriculture and Bioresource Engineering, NnamdiAzikiwe University, P.M.B. 5025, Awka, Anambra State. Nigeria.
*Author to whom correspondence should be addressed.
Abstract
The determination of optimum process parameters for moisture content reduction in water yam drying using a hot air dryer was the aim of this work. Gravimetric method was used to determine the moisture content. Design of experiment was used with slice thickness, airspeed and temperature as the independent factors. Thermal properties such as effective moisture diffusivity and activation energy were determined. The result showed that slice thickness, airspeed and temperature have significant influence on the moisture content reduction. The effective moisture diffusivity ranged from 2.84 x 10-5 m2/s to 8.10 x 10-5 m2/s. The activation energy was 30.592kJ/mol. Minimum moisture content value of 11.98% was obtained at slice thickness of 2mm, airspeed of 2 m/s and temperature of 70oC. The quadratic model best described the drying process. The hot air dryer can conveniently be used for moisture content reduction in water yam slices which will increase its shelf life.
Keywords: Water yam, drying, optimization, effective moisture diffusivity, thermal properties