Particle Size Distribution in Milled Sorghum Grains of Different Corneousness

Abstract

The particle size distribution of milled samples of three varieties of sorghum [Sorghum bicolor (L) Moench] coded V₃, V₆ and V₈ was determined by sieve analysis. The moisture content of the grains ranged between 9.83 and 10.60%, wet weight basis. The milling was carried out on whole grains using a laboratory pin mill while the sieving was carried out using six metric standard sieves of 810, 572, 500, 400, 315 and 210 µm apertures. The particle size distribution was displayed graphically by plotting the size frequency bar charts. From the investigation it was concluded that the particle size (d) distribution of milled sorghum grains is bimodal at the 210-315 µm and 500 572 µm size ranges; that the less corneous the grain the less pronounced is the 500 572 µm size range peak and that the more corneous the grain the more resistant it is to comminution even at increased milling intensity. There was a significant difference (p<0.05) among the grain varieties in terms of particle size distribution.


Journal of Agriculture, Science and Technology Vol. 2 (1) 1999: 1-7