Corn dry milling as influenced by harvest and drying conditions
ABSTRACT SUBLOTS from a single variety of corn were harvested with moisture contents ranging from 17 to 32 percent, and with the picker-sheller set to yield shelled grain with high or low damage. Each sublot was then dried to 11 to 14 percent moisture at air temperatures ranging from —1 to 150 °C. Yields of prime products (low-fat grits and meal) from the dry milling of the lots increased and germ (source of corn oil) fraction yield decreased as corn dry-ing temperatures were lowered. Fat content of prime products showed no trend, while fat in the germ in-creased with lowering drying temperatures. Harvest moisture content and picker-sheller damage had minimal effect on product yields or on fat content. Recoverable oil was lowered by drying at 150 °C. The variables studied produced minimal effects on the brewers extract determination, which is a guide to the amount of carbohydrate in the product available for en-zymatic converison to sugars. The data indicate that corn harvested at 25 percent or less moisture and dried at 82 °C or lower air temperatures will yield optimum dry milling results with respect to product recovery and quality. This research is the first to show the effect of harvest moisture and sheller damage on the dry milling of corn, and it corroborates the effects of excessive drying tem-peratures on products obtained from dry milling.