Cereal Chem. 70:662-666   |  VIEW ARTICLE

Effect of Wheat Moisture Content on Hardness Scores Determined by Near-Infrared Reflectance and on Hardness Score Standardization.

W. R. Windham, C. S. Gaines, and R. G. Leffler. Copyright 1993 by the American Association of Cereal Chemists, Inc. 

Near-infrared reflectance instrumentation provides an empirically measured scale for wheat hardness. The hardness scale is based on the radiation-scattering properties of meal particles at 1,680 and 2,230 nm. Hard wheat meals usually have larger particle sizes than soft wheat meals. The objective of this study was to determine the sensitivity of near-infrared reflectance wheat hardness measurements to moisture content, and to make the hardness score (HS) independent of moisture by correcting hardness measurements for the actual moisture content of measured samples. Forty wheat cultivars composed of hard red winter, hard red spring, soft red winter, and soft white winter were used. Wheat kernel sample groups were stored at 20, 40, 60, and 80% rh. After equilibration, the samples were ground, and the meal was analyzed for HS and moisture. Averaged across wheat sample and relative humidity treatments, HS were 48, 50, 54, and 65 for 20, 40, 60, and 80% rh, respectively. HS from storage at 80% rh (13.4% meal moisture) were higher (P less than 0.05), and HS from storage at 20% rh (9.3% meal moisture) were lower (P less than 0.05) than the control values, which had an intermediate meal moisture content (11%). Within each class of wheat, HS increased as moisture content increased. An algorithm was developed to correct HS to 11% moisture. The correction provided HS that were nearly independent of moisture content.