Cereal Chem 44:488 - 498. | VIEW
Comparison of the Wet-Milling Properties of Opaque-2 High-Lysine Corn and Normal Corn.
S. A. Watson and K. R. Yahl. Copyright 1967 by the American Association of Cereal Chemists, Inc.
The physical and chemical properties of a high-lysine corn hybrid, recessive for the opaque-2 gene, were compared with those of two normal hybrid corns. The wet-milling characteristics of the three corns were compared by a conventional procedure. Comparisons of physical and milling properties were somewhat confounded by wide differences in composition: 13.6% protein for opaque-2 and 10.4% and 8.0% for the normal corns; 64.4% starch for opaque-2, 71.4 and 73.6% for the normal corns, respectively. Opaque-2 kernels were about three-fourths as large as normal kernels, 22 vs. 31 g./100 kernels; they were 12 and 15% lower in kernel density and bulk density, respectively. Upon steeping, opaque-2 corn swelled to twice the volume of normal corn and contained 52.3% moisture (42.8 and 44.6% for the normal corns). Aqueous extraction of dry ground aliquots solubilized 6.5% of the dry substance from opaque-2 (4.5% from normal corn). As predicted from analytical data, the wet-milling of opaque-2 corn produced high yields of steepwater, germ, oil, and fiber and low yields of gluten-protein and starch. The amount of lysine in steepwater-protein was about the same for both types of corn, but gluten-protein from opaque-2 was significantly higher in lysine and tryptophan than that from the normal corn. Higher lysine values were accompanied by lower zein contents in the glutens. Starch recovered from the opaque-2 corn was similar in all properties to normal starch.