Abstract

Physical and mechanical properties of food crops gain importance during design, improvement and optimization of separation and cleaning. In this study, some physical and mechanical properties of corn seeds were determined as a function of moisture content in the range of 5.15 to 22% d.b. The average length, width, thickness and arithmetic diameter were increased by 6, 2.2, 1.66, and 3.3%, with increasing moisture content, respectively. In the moisture range from 5.15 to 22% d.b., the results showed that, the thousand seed mass increased from 267.7 to 305.8 g, the porosity from 31.41 to 45.98%, the static angle of repose from 42 to 57, and the coefficient of friction on compressed plastic, plywood and galvanized iron sheet surfaces were increased from 0.36 to 0.67, 0.36 to 0.6 and 0.38 to 0.57, respectively. The bulk density decreased from 679.1 to 632 kgm^-3 and true density increased from 999.33 to 1170.49 kgm^-3. Moreover, surface area and volume increased as the moisture content increased. The rupture energy of the grains increased in magnitude with an increase in moisture content, while rupture force was decreasing.

Key words: Mechanical properties, corn, rupture force, coefficient of friction, repose angle.