Cereal Chem 64:356-358   |  VIEW ARTICLE

Note: Evaluation of Digitally Filtered Aquagram Signals of Wet and Dry Corn Mixtures.

C. R. Martin, Z. Czuchajowska, and Y. Pomeranz. Copyright 1987 by the American Association of Cereal Chemists, Inc. 

Standard deviations (AG-SD) of recorded signals from the Tag-Heppenstall (T-H) moisture meter for equilibrated and fresh blends of corn depended both on the quantity of wet corn in a blend and the difference in moisture contents of the blend components. The signals were subjected to Fourier transformation and digitally filtered. The correlation coefficient between the logarithm of the AG-SD of the filtered signal and the oven moisture content was 0.975 for equilibrated corn, free of broken corn and foreign material (BCFM) and damaged kernels. The AG-SD value for such corn at the 15.5% moisture level (the accepted upper limit for commercial corn) was up to 63 mV. In the presence of BCFM and damaged kernels in equilibrated corn, the AG-SD deviation increased at 15.5% moisture to 78 mV. No freshly blended samples had AG-SDs below 63 mV; in corn with an oven moisture up to 17.0%, the AG-SD of equilibrated samples increased to about 150 mV in the presence of heat- or mold-damaged kernels. Above 17.0% moisture, BCFM also increased the AG-SD. The correlation coefficient between AG-SD of the T-H signal and calculated standard deviation was 0.895. Moisture equilibration in well-mixed blends, as determined by AG-SD values, approached equilibrium at an exponential rate within two days at room temperature.