EFFECTS OF MOISTURE CONTENT ON PHYSICAL PROPERTIES OF PADDY AND DEHUSKED RICE

The physical properties of rice are among the most important parameters for design of agricultural machine and other equipment for handling, planting, harvesting, processing, packaging and storing. This work is aimed at the determination of some of the physical properties of two varieties of rice at varying moisture content that are important in designing rice handling machine. The physical properties of two most popular produced rice varieties in Nigeria (FARO 44 and FARO 57) both paddy and dehusked at three different moisture content (5, 10 and 15%) were determined. Laboratory studies were carried out to determined physical properties of the two varieties of rice ((FARO 44 and FARO 57) important properties for the laboratory work includes: bulk density, unit density, roundness, axial dimensions, sphericity, projected areas, unit volume, unit weight, apparent density, were determined based on different moisture content and random sampling techniques. The results showed that minimum lengths of dehusked rice ranged from 4.57 - 5.29 mm while maximum lengths were between 8.21 - 8.25 mm. For paddy these lengths were minimally 7.65 - 8.78 mm and maximum lengths were 11.39 mm. The least range of minor diameters of dehusked rice was 4.57 - 5.29 mm and maximally these were 8.21 - 8.25 mm. Intermediate diameters were minimally 1.43 mm and maximally in the range of 2.71 - 2.78 mm for dehusked rice; for paddy these were 1.65 - 1.76 mm and 2.46 - 2.78 mm, respectively. Geometric mean diameters ranged between 3.31 - 4.05 mm. For paddy, projected area obtained within the range of 11.71 - 29.75 mm ². For dehusked rice, projected area obtained in the range of 8.79 - 21.19 mm ². Estimates of roundness were not higher than 33.6% for paddy or 54% for some grains of dehusked rice. The grains appeared more spherical than they were round since paddy were 35.3 - 48.3% spherical while dehusked grains were 39.8 - 59.4% spherical. Bulk densities ranged between 531.0 - 553.8 kg/m ³ and 839.6 - 852.7 kg/m ³ for dehusked forms of Faro 44 and Faro 57, respectively. True density was in the range of 1071.6 - 1566.2 kg/m ³.This study concludes that moisture content and variety affect the engineering property and is useful in the design, development of machine for processing and handling of rice products.