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Comparison of Laboratory and Pilot-Plant Corn Wet-Milling Procedures¹

¹Journal paper 16,892 of the Iowa Agriculture and Home Economics Experiment Station, Ames, IA. Research Project 0178 supported by the Center for Crops Utilization Research, the Iowa Agriculture and Home Economics Experimental Station, and the U.S. Department of Agriculture. ²Graduate research assistant, Department of Food Science and Human Nutrition, Iowa State University, Ames. ³Professor, Department of Food Science and Human Nutrition, and Professor-in-Charge, Center for Crops Utilization Research, Iowa State University, Ames, IA 50011. Corresponding author. E-mail: ljohnson@iastate.edu ⁴Research geneticist, USDA-ARS, Dept. of Agronomy, Iowa State University, Ames. ⁵Laboratory research technician, Center for Crops Utilization Research, Iowa State University, Ames. ⁶Professor, Department of Statistics, Iowa State University, Ames.

One waxy and three regular yellow dent corn hybrids were wet milled by using two scales of laboratory procedures (modified 100-g and 1-kg) and a pilot-plant procedure (10-kg). The modified 100-g and 1-kg laboratory procedures gave similar yields of wet-milling fractions. Starch yields and recoveries were significantly lower for the pilot-plant procedure, whereas gluten and fiber yields were greater because of their high contents of unrecovered starch. Protein contents of the starches obtained by all three procedures were within commercially acceptable limits (<0.50% db for normal dent corn and <0.30% for waxy corn). Rankings for starch yields and starch recoveries for the four hybrids, having very different physical and compositional properties, were the same for all three procedures. The harder the grain, the lower the yield and recovery of starch. Least significant differences (P < 0.05) for starch yield were 0.8% for the modified 100-g procedure, 1.2% for the 1-kg procedure, and 2.0% for the pilot-plant procedure.