Abstract
This study was performed to develop thin layer drying equations for low temperature. Thin layer drying tests of short grain rough rice were conducted at three low temperature levels of 15, 25, $35^{\circ}C$ and two relative humidity levels of 30, $50\%$, respectively. The measured moisture ratios were fitted to the selected four drying models (Page, Thompson, Simplified diffusion and Lewis model) using stepwise multiple regression analysis. The overall drying rate increased as the drying air temperature was increased and as relative humidity was decreased, but the effect of temperature increase was dominant. Half response time (Moisture ratio=0.5) of drying was affected by both drying temperature and relative humidity at drying temperature of below $25^{\circ}C$, but at $35^{\circ}C$ was mainly affected by drying temperature. The results of comparing coefficients of determination and root mean square error of moisture ratio for low drying models showed that Page model was found to fit adequately to all drying test data.