Decortication is the mechanical removal of the outer husk or shell from oilseeds such as sunflower or soybean before pressing or solvent extraction, raising meal protein content and improving oil extraction efficiency.
In trade practice
Processing plants use rubber-roll or impact decorticators followed by aspiration to separate hull from kernel; the degree of hull removal is checked by fibre analysis of the resulting meal. For sunflower, full decortication is the basis of HiPro meal, which commands a premium in feed markets. Buyers specify the maximum crude fibre level in the meal as an indirect measure of decortication efficiency. Incomplete decortication is a common cause of meal failing the protein and fibre thresholds stated in the purchase contract.
In a specification
A meal specification references the target crude protein minimum and crude fibre maximum on a dry-matter basis as the primary indicators of decortication degree.