Cereal Chem 62:108-112   |  VIEW ARTICLE
Determination of Corn Hardness by the Stenvert Hardness Tester.

Y. Pomeranz, C. Czuchajowska, C. R. Martin, and F. S. Lai. Copyright 1985 by the American Association of Cereal Chemists, Inc. 

Hardness was determined by density and by the Stenvert Hardness Tester (SHT) in three pairs (dent and flint) of isogenic lines. In addition, seven samples (separated according to size and shape from each of three commercial hybrids) were evaluated by density, the SHT, and near-infrared reflectance (NIR) at 1,680 nm. Other determinations made on the fractions separated from the three hybrids included test weight, kernel weight, and moisture, fat, protein, and ash contents. The SHT measured resistance to grinding, height of column of ground corn (as index of packing and fluffiness) and ratio of coarse to fine particles (determined by weight of sieved fractions or estimated by volume of fractions in the receptacle of the tester). The three dent isogenic lines were higher in kernel weight and lower in hardness parameters than their flint counterparts. The three commercial hybrids showed consistent differences in gross composition and hardness. Some consistent differences in composition or hardness were established among the fractions separated according to size and shape (sphericity). Within each fraction separated by size and shape there were consistent differences among the three hybrids in density, fat and protein contents, NIR of ground corn, and the parameters from the SHT. Generally, the round kernels (higher sphericity) were higher in flintlike characteristics than the flat kernels.