DRYING CHARACTERISTICS OF BEAN ANALOG - A SORGHUM BASED EXTRUDED PRODUCT

Bean analog is a novel bean-like re-formed product made from the extrusion of three flour combinations (sorghum, wheat and soy). This product was evaluated under three drying conditions, namely oven, infrared and solar drying, and were fitted to empirical and semi-empirical models. Infrared drying produced the highest drying rate of all methods. Effective moisture diffusivity (EMD), which is an indication of drying rate, ranged from 6.8x10(-10) to 1.74x10(-9), 2.05 to 9.22x10(-9) and 8.70x10(-10) to 6.10x10(-9) m(2)/s for the oven, infrared and solar dried bean analog, respectively. Low EMD for oven drying, against expectation, is attributed to low heat transfer due to limited air circulation. Page equation fitted the drying data better than Lewis, and Henderson and Pabis, with higher R-2 values. Oven dried samples rehydrate better compared with others, which can be attributed to slower drying impact on structural changes.