Wet milling characteristics of high oil corn hybrids

In a study covering two crop years, high oil corn (HOC) hybrids were compared to normal yellow dent corn in laboratory wet milling tests. In the first crop year, six HOC hybrids were wet milled to determine milling characteristics using a normal yellow dent hybrid as a control. Milling fractions were analyzed for fat, protein, fiber and ash content. HOC hybrids had significantly greater steepwater and germ yields, and lower starch yields (58.6 to 61.5% db) when compared to the dent (65.4% db). Germ oil contents for HOC hybrids (52.5 to 57.1% db) were significantly higher than that of normal yellow dent (45.3% db). Germ floatation was better for HOC than for dent, allowing easier germ separation. In the second crop year, effects of moisture content at harvest, drying condition and storage time on HOC wet milling yields and milling fraction composition were investigated. Drying air temperatures were ambient, 40, 60, and 80 °C. One HOC hybrid was harvested at moisture levels of 30% and 21% wet basis (wb) and wet milled over a period of 29 weeks after harvest to observe harvest and postharvest effects on milling. No significant effects of storage time were observed on milling characteristics. HOC hybrids had no unusual storage characteristics and wet milled in much the same manner as the normal yellow dent hybrid, as measured by germ floatation, skimming and starch quality.