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Relationships Among Grain Sorghum Quality Factors¹

¹Journal Series no. 11781. Agricultural Research Division, Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln. ²Graduate research assistant and associate professor, respectively, Departments of Biological Systems Engineering and Food Science and Technology, University of Nebraska-Lincoln, Lincoln, NE 68583-0726. ³Currently, graduate research assistant, Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108. ⁴Corresponding author. E-mail: bsen004@unlvm.unl.edu ⁵Professor and Head, Department of Biometry, University of Nebraska-Lincoln, Lincoln, NE 68583-0712.

Correlations among grain sorghum quality factors (proximate composition, physical properties, and water absorption properties) were evaluated. Samples of 46 commercial hybrids (24 and 22 from crop years 1993 and 1994) were analyzed for starch, protein, crude free fat, test weight, absolute density, 1,000 kernel weight, percent kernel abraded, water absorption index, initial water absorption rate, and moisture saturation point. Test weight, absolute density, and percent kernel abraded were positively correlated among themselves (r > 0.5). Protein was negatively correlated with both test weight and absolute density (r < -0.5), while moisture saturation point showed negative correlations with test weight, absolute density, 1,000 kernel weight, and percent kernel abraded (r < -0.4). Principal component factor analysis through the covariance matrix explained 95% of the total variation of quality factors among hybrids (two factors), and, through the correlation matrix, 85% of the total variation (five factors). Water absorption rate decreased with increasing starch content of grain sorghum kernels as water absorption rate increased and amount of water for saturation decreased with softening of kernels.