Characterization of Breakage Behavior of Corn Kernel During Handling Operations

Highlights Breakage varied significantly based on variety, moisture, and impact. Micropore characteristics had a negative correlation with breakage susceptibility. Breakage tester rotational speed and variety had no significant effect on breakage constants. Abstract. During rail transit, vibration and uneven terrain cause mechanical damage to grains due to repeated load impacts within the grain mass. Damaged grains are more susceptible to deterioration, yet the effects of transit-induced grain breakage have not been extensively studied. This research evaluated the breakage characteristics of 10 hybrid corn varieties at varying depths of a railcar for grains at 13.5%, 15.5%, and 17% w.b. moisture content through simulated laboratory experiments. Physical, mechanical, and micropore characteristics of the kernels were analyzed to establish their relationships with kernel breakage. Breakage susceptibility was assessed using the NDSU breakage tester mimicking the impact forces at corresponding railcar depths. The interaction of corn variety, moisture content, and rotation speed significantly affected breakage susceptibility and breakage rate (p < 0.05). Both breakage susceptibility and rate increased with higher rotational speeds and lower moisture content. The variety and rotation speed had no significant effect on the breakage constant, which ranged between 1.21 and 1.52, comparable to the Wisconsin and Stein breakage testers. A positive correlation (r = 0.836) was found between breakage susceptibility and breakage rate. Breakage attributes were negatively correlated with mechanical properties such as rupture energy, compressive stress, and deformation. Micropore properties showed negative correlations with compressive breaking stress and deformation. Several physical properties, including surface area, sphericity, flatness, aspect ratio, and both equivalent and geometric diameters, exhibited a negative correlation with pore surface area. The results suggest that corn kernels located at the bottom of the rail car are more prone to breakage, and the NDSU breakage tester shows potential as a standard tool for assessing kernel breakage. Additionally, further analysis should be pursued to understand how micropores influence the transport of moisture during conditioning, soaking, and drying and relate to the physical attributes of corn kernels. Keywords: Breakage susceptibility, Corn kernel, Micropores, Physical and mechanical properties, Postharvest processing, Transportation.