Optimizing conditions for experimental oat dehulling

The determination of groat percentage in experimental oat breeding lines re quires the dehulling of oats. Here, we report the results of our efforts to optimize dehulling conditions so that the most accurate and reliable resul t can be obtained. Hand dehulling was always reliable and accurate, however , it was the most time-consuming and tedious of the methods studied. Two me chanical methods of oat dehulling, compressed-air dehulling and impact dehu lling, also frequently provided reliable results, however, results were str ongly influenced by dehulling conditions. Optimal dehulling conditions repr esented compromises between unfavorable extremes. Correct aspiration streng th was critical to accurate groat percentage determination. We have found t hat a secondary aspiration is highly desirable after compressed-air dehulli ng to remove hulls remaining with the groats after dehulling. Also, increas ed mechanical stress on oats as exerted either by the number of passes thro ugh the impact dehuller, or by the air pressure in the compressed-air dehul ler, resulted in higher dehulling efficiency, but increased groat breakage as well. Dehulling efficiency decreased as moisture increased from 7.5 to 1 5%, but increased as moisture was further increased to 30%. In contrast, gr oat breakage with impact dehulling decreased as moisture increased from 7.5 to 30%. A new equation for goat 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 doe s not influence the groat percentage.