Some engineering properties of white kidney beans (<i>Phaseolus vulgaris</i> L.)

Abstract

Some engineering (physical and mechanical) properties of white kidney bean grains (Phaseolus vulgaris L.) were determined as a function of moisture content in the range of 10.01 to 25.00% dry basis (d.b.). The average length, width and thickness were 8.638, 16.747 and 4.958 mm, at a moisture content of 10.01% d.b., respectively. Nonetheless, the thousand grain mass increased from 472.5 to 696.2 g, the projected area from 128.13 to 198.83 mm², the true density from 1128.05 to 1290.85 kgm^-3, the porosity from 39.79 to 56.38% and the terminal velocity from 5.51 to 8.50 ms^-1 in the moisture range from 10.01 to 25.01% d.b. The static coefficient of friction of white kidney bean grains increased linearly against surfaces of six structural materials, namely, rubber (0.501 to 0.727), stainless steel (0.384 to 0.468), aluminium (0.345 to 0.499), galvanized iron (0.346 to 0.489), medium density fibreboard (MDF) (0.325 to 0.426) and glass (0.287 to 0.345) as the moisture content increased from 10.01 to 25.00% d.b. The shelling resistance of white kidney bean grains decreased as the moisture content increased from 105.18 to 71.44 N.

Key words: Engineering (physical and mechanical) properties, white kidney beans, moisture content, thousand grain mass, static coefficient of friction.