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Compositional, Physical, and Wet-Milling Properties of Accessions Used in Germplasm Enhancement of Maize Project¹

¹Journal Paper 18970 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 Experiment Station, and the United States Department of Agriculture. ²Graduate research assistant and professor, Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011. ³Corresponding author. E-mail: ljohnson@iastate.edu Phone: 515-294-0160. ⁴Research Geneticist, USDA-ARS, Corn Insects and Crop Genetics Research Unit, Department of Agronomy, Iowa State University, Ames, IA 50011. ⁵Professor, Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA 50011.

Forty-nine accessions used in the Germplasm Enhancement of Maize (GEM) project, two commercial hybrids (Pioneer Brand Hybrids 3394 and 3489), and two Corn Belt inbreds (B73 and Mo17) were evaluated for compositional, physical, and wet-milling properties. GEM accessions had lower starch contents (65.9–69.1% vs. a mean of 72.2% for the commercial hybrids) and greater protein contents (12.0–14.4% vs. a mean of 8.2% for the commercial hybrids) than did the improved Corn Belt material. Absolute densities were consistently higher for the GEM accessions compared with the commercial hybrids (1.320 vs. 1.265 g/cm³, respectively). The wet-milling characteristics of the GEM accessions were not nearly as good as for the commercial hybrids. Mean starch yields were only 54.3% for the GEM accessions versus 64.8% for the commercial hybrids. Residual protein levels in the starches recovered from the GEM accessions were much greater (0.45–2.03%) than for commercial corn hybrids (<0.3%).