Effects of insect-infested kernels on bulk flow properties of wheat

• Moisture content had significant effect on bulk physical properties of wheat.
• Presence of insect infested kernels affects the physical and flow properties of bulk wheat.
• Insect infested kernels increase the angle of repose of bulk wheat.
• Dust produced from insect activity increases the chances of localized compaction of wheat in grain bins.

Insect damage to kernels during storage affects the processing quality of wheat and as well as bulk wheat properties, which in turn causes hopper flow problems such as funnel flow, ratholing, arching, or flushing. This study focused on kernel damage by Rhyzopertha Dominica F. (lesser grain borer), one of the most commonly found insects in wheat, and resulting changes in physical properties, such as bulk density, tapped density, true density, and angle of repose, and in flow properties, such as basic flowability energy, stability, aeration, compressibility, and permeability. Bulk and tapped densities of sound hard red winter wheat kernels and infested wheat kernels were about 720 kg/m3 and 775 kg/m3, respectively. Compressibility index (CI), Hausner ratio (HR), and angle of repose of infested wheat kernels were higher than for sound hard red winter wheat kernels, indicating decreased flowability. Grain dust and insect-infested kernels could form localized compacted areas within the grain bins, resulting in uneven flow during discharge. Results from this study indicate that the presence of insect-infested kernels could lead to arching and bridge formation in grain bins, thus affecting the flow characteristics of bulk wheat.