2000 Volume 62 Issue 3 Pages 140-148
Heated air drying of soybean kernels with high-moisture content using circulation dryer has resulted in physical damage in the form of seadcoat cracks, seadcoat wrinkles and broken kernels, which are caused by the moisture gradient inside the kernel and the circulation of kernels. To prevent soybean from drying damage, a soybean dryer controlling relative humidity of air using a humidifier was newly developed, and the examination of the method of circulating the kernels and controlling the temperature and the humidity of air was carried out. It experimentally appeared that the intermittent circulation of kernels and the drying air, of which relative humidity was gradually decreased from 45% to 30% at constant temperature of 30°C, made the percentage of soybean drying damage less than 5% when soybean kernels had the initial moisture content of more than 20%. In comparison with the conventional heated air drying, the new drying method controlling relative humidity of air provided higher drying speed and lower running cost as well as less soybean drying damage.
