Cereal Chem 63:39-43   |  VIEW ARTICLE
Comparison of Methods for Determination of Hardness and Breakage Susceptibility of Commercially Dried Corn.

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

Hardness and breakage susceptibility were determined in eight samples of corn dried under commercial conditions and equilibriated to 12.2-12.4% and 16.1-16.5% moisture. Hardness was determined by density, the Stenvert Hardness Tester (SHT), near-infrared reflectance (NIR) at 1,680 nm, and ratio of coarse to fine in the SHT-ground corn. Breakage susceptibility was measured by the Stein tester (with a shear-grinding action), the centrifugal impact Wisconsin tester (WBT), and the U.S. Grain Marketing Research Laboratory (USGMRL) corn-on-corn impact tester. The higher moisture decreased density, increased NIR, and increased the time to grind in the SHT. Breakage susceptibility was much higher for the corn at 12% than for the 16% moisture corn. Susceptibility to breakage at either moisture level was about six times higher in the WBT than in the USGMRL tester. The large effect of moisture was consistent for the three mechanical methods of testing breakage susceptibility. Additional differentiation among the samples (especially those with low damage levels) was obtained by a green dye test on corn retained on a 12/64-in. screen after the grain was passed through the WBT and USGMRL tester. Correlation coefficients among and between hardness and breakage susceptibility parameters were much higher for the 12% than for the 16% moisture corn.