PARTICLE SIZE DISTRIBUTIONS OF GROUND CORN AND DDGS FROM DRY GRIND PROCESSING

Abstract

Ethanol production has increased in the past decade as a result of growth in the dry grind industry. In the dry grindprocess, the first step is grinding of corn. The particle size of the resulting ground corn can affect the fermentation processand the particle size of dried distillers grains with solubles (DDGS), a coproduct of dry grind processing. Few data are availablethat characterize particle size distributions of ground corn or DDGS. The objective was to determine particle size distributionsof ground corn and DDGS. Samples of ground corn and DDGS were obtained from nine dry grind plants; particlesize distribution, geometric mean diameter (dgw) and geometric standard deviation (Sgw) were determined. The dgw of groundcorn and of DDGS were not different among processing plants. The overall mean dgw of ground corn was not different fromthat of DDGS. Most of the ground corn (80 g/100 g) and DDGS (70 g/100 g) were recovered in the three largest particle sizecategories. The particle size distributions of ground corn were not correlated (r < 0.35) to particle size distributions of DDGS.