Thin Layer Drying Kinetics of Solar-Dried Amaranthus hybridus and Xanthosoma sagittifolium Leaves

Abstract

The aim of the study was to model the solar drying characteristics of the leaves of Amaranthus hybridus and Xanthosoma sagittifolium dried in thin layers. Fresh leaves were obtained from Centre for Biodiversity Utilisation and Development (CBUD) farms, trimmed into strips of 0.3x3 cm and loaded into cabinet solar dryers up to a 5 mm layer. Drying was monitored and moisture loss determined by loss in weight of samples at hourly interval. Drying data were fitted to five thin layer models, namely; Newton’s, Page’s, Modified Page, Handerson and Pabis and Logarithmic Models by Non-linear Regression Analysis, the effective diffusivity was also determined for the two leafy vegetables. All five models showed a good fit between observed and predicted values with Page’s Model resulting in the highest r2 and lowest RMSE and χ2 and hence the best model to describe the solar-drying characteristics of the two vegetables.