Moisture-Dependent Compressive Behavior of Wheat Kernels: Implications for Energy-Efficient and Resource-Conscious Grain Processing

Abstract

Improving grain size-reduction efficiency requires settings adapted to raw-material properties. This study examined how moisture, crosshead speed, imposed displacement, cultivar, and wheat quality group affect individual-kernel compression. Four cultivars representing bread and ‘other’ quality groups were tested at nominal moisture contents of 14–20% (wet basis), crosshead speeds of 5–30 mm min−1, and displacements of 1.8–2.2 mm. Maximum force, crushing energy, and apparent cracking were determined. Crosshead speed did not significantly affect maximum force and had a marginal effect on crushing energy. Displacement and cultivar explained the largest variability shares, while both responses reached their highest means at 18% nominal moisture. Lawina and Sikorka, both in the ‘other’ group, differed by approximately 36% in maximum force and 25% in crushing energy. The share without apparent cracking rose from approximately 5% at 14% to 96% at 20%. Unlike our earlier study of six quality wheat cultivars, this study compares bread and ‘other’ groups and examines differences between cultivars assigned to the same group. The findings inform product-specific screening; industrial energy and material savings remain to be verified.