Effect of moisture content on physical properties of finger (eleusine coracana) millet

Abstract

Design of harvesting, grading, cleaning, processing, grain handling equipment, grain storage structures and transport machineries requires the physical, mechanical, aerodynamic properties of grains. Linear dimensions like length, width, thickness, geometric mean diameter sphericity are necessary for selection of sieve separator and calculation of grinding power for size reduction whereas surface area and volume are for modelling of grain drying, aeration, heating and cooling. Bulk density determines the capacity of storage and transport system, whether true density used for separation equipment and porosity determines the resistance to air flow during aeration and drying of seeds. Terminal velocity helps in designing the cleaning system and frictional coefficient is necessary for design of agricultural product handling equipment. Effect of moisture content on physical properties of finger millet were studied in the range of 0.065 to 0.265 kg kg-' dry matter and result was found that length, width, thickness, geometric mean diameter, surface area, volume and sphericity increased from 1.61 to 1.81 mm, 1.58 to 1.84 mm, 1.41 to 1.61 mm and 1.53 to 1.75 mm, 7.05 to 9.35 mm2, 1.75 to 2.69 mm3 and 0.95 to 0.96, respectively. True density obtained by proximate composition method was found lower than the true density obtained by toluene displacement method. Interstice was observed decreased with increase of moisture content from 0.26 to 0.01 m3. Coefficient of friction and terminal velocity increased from 0.536 to 0.774 and 1.22 to 2.02 ms"1 with increase of moisture content.