The Effect of Rice (Oryza sativa L.) Types and Moisture Contents on Terminal Velocity

Terminal velocity (Vt) is one of the important parameters often required in the pneumatics processes of some postharvest activities. This value is influenced by many factors such as grain type and shape, moisture content, etc. and this is still very difficult to find in Indonesian references. Therefore, this study aims to investigate the effect of types and moisture contents on the terminal velocity of rice. Three rice types namely Javanica (Oryza sativa subsp. Javanica), Japonica (Oryza sativa subsp. Japonica), and Indica (Oryza sativa subsp. Indica) with 9%, 14%, and 19% (w.b) moisture contents (M) were investigated in factorial design 3 × 3 with three replications for each treatment combinations. Terminal velocity values were measured using a hot wire anemometer in a self-constructed apparatus. The results showed that rice types and moisture contents strongly affected the terminal velocity (p < 0.05), however, there was no significant types and moisture contents’ interaction effect on the terminal velocity. Japonica was found to have the largest terminal velocity and Indica had the smallest. The relationship between the moisture content and terminal velocity was expressed as Vt= 0.060M+8.084, Vt= 0.061M+7.676 and Vt= 0.083M+7.056 for Japonica, Javanica, and Indica respectively.