Optimizing Conditions for Experimental Oat Dehulling

Abstract

ABSTRACTThe determination of groat percentage in experimental oat breeding lines requires the dehulling of oats. Here, we report the results of our efforts to optimize dehulling conditions so that the most accurate and reliable result can be obtained. Hand dehulling was always reliable and accurate, however, it was the most time‐consuming and tedious of the methods studied. Two mechanical methods of oat dehulling, compressed‐air dehulling and impact dehulling, also frequently provided reliable results, however, results were strongly influenced by dehulling conditions. Optimal dehulling conditions represented compromises between unfavorable extremes. Correct aspiration strength was critical to accurate groat percentage determination. We have found that a secondary aspiration is highly desirable after compressed‐air dehulling to remove hulls remaining with the groats after dehulling. Also, increased mechanical stress on oats as exerted either by the number of passes through the impact dehuller, or by the air pressure in the compressed‐air dehuller, resulted in higher dehulling efficiency, but increased groat breakage as well. Dehulling efficiency decreased as moisture increased from 7.5 to 15%, but increased as moisture was further increased to 30%. In contrast, groat breakage with impact dehulling decreased as moisture increased from 7.5 to 30%. A new equation for groat percentage calculation has been introduced where the mass of hulled oats remaining after dehulling is subtracted from the mass of the original oat sample, so that poor dehulling efficiency does not influence the groat percentage.