RELATING DRYING RATE CONSTANT TO HEAD RICE YIELD REDUCTION OF LONG-GRAIN RICE
Long-grain rough rice was dried at various rates and durations and milled to determine head rice yield. The 
drying data were described by a Newton equation, and the resultant head rice yield reduction data were described by an 
empirical rate equation. Effects of drying condition, variety, harvest moisture content, and storage time prior to drying 
were investigated, but only the first two of those variables significantly affected the drying rate constant, and the first 
three of those variables significantly affected the head rice yield reduction. Head rice yield reduction was directly related 
to the drying rate constant. At a given drying rate constant, head rice yield reduction increased with drying duration. An 
empirical model was developed to predict the head rice yield reduction as a function of drying rate constant and drying 
duration. This model may lead to optimal control of rice dryers in terms of minimizing head rice yield reduction during 
the drying process.