Loss of lipid material during the dehulling of oilseeds with different structural characteristics.

The loss of lipid material by migration to the hull during the dehulling of oilseeds with different structural characteristics was evaluated. The samples selected -three sunflower hybrids and a safflower cultivar- were processed under optimal dehulling operating conditions and with two passes through a dehuller. From the SEM micrographs of the samples it was possible to observe structural differences which affect the mechanical properties of the pericarps and, consequently, the dehulling process. The black-hull sunflower hybrid exhibited residual hull percentages lightly above those recommended by the industry after one pass through the dehuller, therefore, this hybrid should not be further processed to avoid oil losses due to migration to the hull. On the other hand, the safflower cultivar and the high stearic high oleic sunflower hybrid and the traditional striped-hull sunflower require two passes through the dehuller, but this resulted in an oil loss due to migration to the hull of over 0.9 % per gram of grains processed. These results suggest the need to reach 'compromise' decisions based on economic impact studies in the face of the variables that originate simultaneously both positive and negative effects.