Comparative Study of Three Solar Drying Methods of Adensonia digitate L. (Baobab Leaves using Drying Kinetics and Empirical Drying Models)
S. A. Okaiyeto
*
Department of Agricultural Engineering, Ahmadu Bello University, Zaria, Nigeria.
Nathaniel Oji
Department of Agricultural and Bio-Environmental Engineering Federal Polytechnic, Kaduna (KADPOLY), Nigeria.
Y. A. Unguwanrimi
Department of Crop Science, Faculty of Agriculture, Kaduna State University, (KASU), Kaduna Nigeria.
*Author to whom correspondence should be addressed.
Abstract
A comparative study of three drying methods of baobab leaves have been conducted and reported. Mixed mode solar drying, indirect mode solar drying and open sun drying of baobab leaves were conducted based on three drying models viz a viz Lewis,. Page and Henderson and Pabis models were employed in this research. Baobab leaves dried faster when dried under the mixed mode on-farm solar dryer. Drying time reduced considerably using the mixed mode on-farm solar dryer. Drying data were fitted into Lewis, Page and Henderson and Pabis models. Henderson and Pabis model (R2=0.9999, 0.9611, 0.9656; X2= 1.0297, 0.7931, 0.7710; RMSE= 0.5859, 0.6898, 0.6802 and MBE= -0.4.135, -0.4.231, -0.4176) gave the best prediction for the mixed mode drying). In the same way Henderson and Pabis model (R2=0.7450, 0.7699, 0.8243; X2= 1.9025, 0.4026, 0.2006; RMSE= 1.0684, 0.5181, 0.4058 and MBE= -0.8966, -0.3823, 0.2789) gave the best prediction for the indirect mode drying of baobab leaves. Effective moisture diffusivity of baobab leaves varied between -6.382 X 10-04 and -1.108 X 10-03 m2/s.
Keywords: Drying, solar, baobab leaves, mixed mode dryer, indirect mode dryer