Effect of Grain Moisture Content and Roller Mill Gap Size on Various Physical Properties of Yellow Dent Corn Flour

Corn has six main varieties grown globally for animal feed, human consumption, and commercial/industrial purposes. Flour is an end-product of corn dry-milling. Products that are derived from corn flour often show differences in physical, chemical, and pasting properties due to corn varietal differences, milling methods, differences in flour particle sizes, and drying temperatures. The study aimed to determine the effect of different moisture contents of yellow dent corn and roller gap sizes, on the physical properties of the resulting corn flour. The possibility to use the flour in the manufacturing of animal feed and ethanol production was also considered. Yellow dent corn grain with moisture contents (MC) of 8%, 14.0%, and 18%, and roller gap sizes (GAP) of 0.1016 mm, 0.2032 mm, and 0.3048 mm were used. The Witt corrugated roller mill equipment with rollers of 1/32 inches corrugations was used to produce fine grits and flours. The particle sizes obtained were between 0.54 mm and 0.75 mm which increased with an increase in MC and GAP. Grain with 8% MC and GAP of 0.1016 mm and 0.2032 mm, and grain with 14.0% MC and GAP of 0.1016 mm can produce flour of particle sizes good for swine feed. Grain with 8% MC and GAP of 0.3048 mm and grain with 14.0.0% MC and GAP of 0.1016 mm and 0.2032 mm can produce flour of particle sizes good for ruminant feed. Grain with 18% MC and GAP of 0.1016 mm, and grain with 14.0% MC and GAP of 0.2032 mm can produce flour of particle sizes good for poultry feed. GAP of 0.1016 mm and 8% MC can produce flour of particle sizes suitable for the ethanol production industry. Flour preparation should purposely be done based on grain MC and GAP. The geometric mean diameter of particle sizes ranged from 0.54 mm-0.75 mm, and the geometric mean diameter of particle sizes increased with increasing MC and GAP. Also, grains with 8% MC had the highest loss in flour, and the higher moisture of 18% significantly affected the red color of flour.