Grain Fissures in Rough Rice Drying

Differences in Fissuring Behavior of Selected Japonica and Indica Varieties

Abstract

The fissuring behavior of seven selected rough rice varieties of the japonica and indica types was compared using a single-grain layer model dryer. The physicochemical properties of the grain influenced fissure variation. Japonica varieties were more sensitive to drying rate which produced more fissures at similar drying rates than indica varieties. Serious fissuring started at a drying rate of 4%/h in indica, 1%/h and 1.5%/h in nonwaxy and waxy japonica, respectively. The recommended drying rates are: 0.8%/h for nonwaxy japonica (var. Mutsuhomare), 1.2%/h for waxy japonica (var. Yukimimochi), For the indica varieties: 3.9%/h for IR 20, 5.0%/h for IR 30, 3.5%/h for IR 58, 3.6%/h for IR 64 and 3.2%/h for IR 65. Recommended air drying temperature and relative humidity for each variety were also determined.