C. Chemical Composition

NIR Proximate Analysis

The chemical composition (protein, oil, and starch concentration) of corn is measured using Near-infrared transmission spectroscopy (NIR). The NIR uses unique interactions of specific wavelengths of light with each sample. It is calibrated to traditional chemistry methods, to predict the concentrations of oil, protein, and starch in the sample. This procedure is nondestructive to the corn.

Chemical composition tests for protein, oil, and starch in fall 2016 were conducted using a 550- to 600-gram sample in a whole-kernel Foss Infratec 1241 Near-Infrared Transmittance (NIR) instrument. The NIR was calibrated to chemical tests, and the standard error of predictions for protein, oil, and starch were about 0.27%, 0.25%, and 0.66%, respectively. Comparisons of the Foss Infratec 1229 used in previous Harvest Reports to the new Foss Infratec 1241 in fall 2016 on 21 laboratory check samples showed the instruments averaged within 0.25, 0.26, and 0.25% points of each other for protein, oil, and starch, respectively.  Results are reported on a dry basis percentage (percent of non-water material).