Cereal Chem 63:22-26   |  VIEW ARTICLE
Gross Composition of Coarse and Fine Fractions of Small Corn Samples Ground on the Stenvert Hardness Tester.

Y. Pomeranz, Z. Czuchajowska, and F. S. Lai. Copyright 1986 by the American Association of Cereal Chemists, Inc. 

Corn from each of three hybrids differing in kernel hardness was separated into seven classes based on sphericity. Kernels from the separated corn classes were ground with a Stenvert hardness tester, and the ground material was sieved to obtain two main fractions: coarse (greater than 0.710 mm in diameter) and fine (less than 0.500 mm in diameter). Oil, protein, and ash were determined for the ground corn kernels and the sieved coarse and fine fractions. In addition, the sieved corn fractions were examined, before and after defatting, by near-infrared reflectance spectroscopy at 1,680 nm. The amount of hand-dissected germ, expressed as a percentage of kernel weight, was unaffected by kernel size; germ size was directly proportional to kernel size. The germ oil content varied among the three hybrids. Whole corn from the three hybrids varied in oil content for the classes separated according to sphericity. For the three hybrids, there was no consistent correlation between percent of germ and percent of oil in the whole kernel. The oil content of the ground and sieved coarse and fine fractions differed widely for the three hybrids and among the kernels separated by sphericity. The coarse fraction was low in ash and the fine fraction was high in ash. Corn sphericity was highly correlated with the oil content of the group coarse fraction. Generally, there were high positive linear correlations between oil and ash and negative correlations between near-infrared reflectance and oil or ash of the ground coarse fraction. The effects of corn hardness on particle size and oil or ash content of the coarse fraction were confirmed for eight corn hybrids dried under various commercial conditions. It is concluded that the Stenvert hardness tester has potential for predictive determination of yields of products and their gross composition in dry-milled corn.