Low-temperature, low-relative humidity drying of rough rice

The use of low air temperatures (26-34 degrees C) and relative humidities (19-68%) to dry thin-layer samples of rough rice to the desired 12.5% moisture content was investigated. Drying rates and durations and their effects on the quality parameters of head-rice yield, color, and pasting viscosity of long- and medium-grain rice cultivars harvested at 19.6% and 17.5% moisture contents, respectively, were determined. Results showed that dehumidification of the drying air had greater potential for increasing drying rates at 26 degrees C than at 30 and 34 degrees C. Low drying air temperatures and relative humidities had no adverse effects on head-rice yield or color compared to controls. Peak and final viscosities of low-temperature and low-relative humidity dried samples were similar to controls. (C) 2010 Published by Elsevier Ltd.