Mechanical properties of rough and dehulled rice during drying

Abstract

This work aimed to determine the mechanical properties of rough and dehulled rice grains, for different moisture contents, by obtaining their rupture force, deformation, maximum compression force and proportional deformity modulus under a compression test. Rice grains, with moisture content varying from 0.12 to 0.30 (d.b.), were subject to an uniaxial compression in order to analyze these properties. On reducting moisture content the rupture force increased from 37.2 to 70.6 N for dehulled rice and 48.0 to 79.5 N for rough rice. The average compression force varied from 131 to 171 N for dehulled rice and 203 to 283 N for rough rice. The value range of proportional deformity modulus was from 5.5 x 10⁹ to 7.4 x 10⁹ Pa for dehulled rice and 9.5 x 10⁹ to 12.3 x 10⁹ Pa for rough rice. Rough rice presented more resistance to compression compared to dehulled rice.