Encapsulation of active agents as microdispersions in homogeneous

Abstract

A method for effectively encasing an active agent such as a chemical compound, a seasoning, a flavoring, or a nutrient such as vitamins and minerals, including liquids, as a time-stable but releasable dispersion in a homogeneous polymeric encapsulating matrix of a modified starch, a gum or a protein material such as gelatin and casein to provide a concentrate of the active agent. The method is characterized in that the agent to be encased is mixed with the encapsulating material under conditions of rigorous and intimate mechanical working with applied high shearing stress but without phase-separating mechanical compression and compaction forces and in the presence of a limited quantity of water and sufficient heat to ensure the formation of a viscous, semi-solid, homogeneous paste constituting a mobile mass or plastic melt. The melt, consisting of a homogeneous matrix with the encased agent distributed therethrough as a microdispersed phase, is then formed into any desired shape, while avoiding phase-separating compaction and compression forces, and dried to provide a product stable against loss and deterioration of the encased agent. In a preferred embodiment of the invention the encased agent is gradually released from the enveloping matrix at a rate dependent on the rate of hydration of the matrix.