Effect of Moisture Content on the Physical Properties of Sunflower Seeds (helianthus annuus l.) for Development of Power Operated Sunflower Seed Decorticator

Sunflower (Helianthus annus L. ) is one of the principle oil-seed crops and is among the four major oilseed crops in the world. The physical and mechanical properties such as bulk density, true density, angle of internal friction, porosity, static coefficient of friction are necessary for the design of transport, process and storage structures of the sunflower seeds. Hence, a study was conducted to evaluate physical properties of the sunflower seeds under different moisture contents. The physical and mechanical properties were evaluated as a function of moisture content of grain varying from 10 % to 14 % (w. b). The average length, width, thickness, mass of 100 seeds and angle of repose ranged from 12.54 to 12.91 mm, 5.57 to 5.93 mm, 3.88 to 4.36 mm, 6.08 to 6.36 g and 23.9 to 26.8 as the moisture content increased from 10 % to 14 % d. b. , respectively. At the above moisture range, as the bulk density decreased linearly from 435 to 432 kg/m3, true density increased linearly from 769.2 to 806.5 kg/m3. The porosity was decreased from 43.5 to 38.7 % and the static coefficient of friction increased from 20 to 22, 18 to 19, 15 to 16 for wood, galvanized steel and glass surfaces, respectively as the moisture content was increased from10-14 %.