Moisture Content and Physical Properties of High-Moisture Agricultural Material Dried by Impinging Stream Dryer

摘要

The objective of this research was to study the drying of high-moisture agricultural material using an impinging stream dryer with multi-stage drying concept. Okara was used in this study as the test agricultural material. Experiments were performed in one-stage and two-stage drying. The final moisture content of the okara at several drying conditions was examined. The physical properties of dried okara were analyzed in terms of color and rehydration ability. It was found from the experiment that with the use of multi-stage drying concept the moisture content of okara could be significantly reduced within a very short period of time. In terms of physical properties, it was observed that the dried okara was darker, redder and more yellow than the fresh okara. Drying at higher temperatures led to higher color changes values of the dried okara. The effect of okara feed rate on the redness and yellowness was not significant, except for the lightness;;drying at lower okara feed rates led to a darker dried okara. An increase in the drying temperature and a decrease in the okara feed rate led to a higher rehydration ability of the okara.