Moisture-dependent physical properties of kokum seed (Garcinia indica Choisy)

Abstract

Designing the equipment for processing, sorting and sizing of agricultural crops requires information about the crops' physical properties. The physical properties of kokum seed were evaluated as a function of moisture content in the range of 7.35 to 25.79% d.b. (dry basis). The average length, width, thickness and one thousand seed mass were 17.17 mm, 10.66 mm, 5.87 mm and 410 g, respectively, at a moisture content of 7.35% d.b. The average value of geometric mean diameter and sphericity were 10.19 mm and 59.75%, respectively, at moisture content of 7.35% d.b. As the moisture content increased from 7.35 to 25.79% d.b., the bulk density increased from 345 to 396 kg/m3, true density decreased from 1179 to 1070 kg/m3, and the corresponding porosity decreased from 65.73 to 55.46%; the repose angle and terminal velocity increased from 32.1 to 42.3° and 4.30 to 6.73 m/s, respectively. The static coefficient of friction increased on three structural surfaces namely, glass (0.59-0.73), stainless steel (0.81-0.87) and plywood (0.74-0.83) in the moisture range from 7.35 to 25.79% d.b. Linear regression equations were used to express the physical properties of kokum seeds as a function of moisture content.