Protein Encapsulation Theory by Spray Drying

Encapsulation involves the incorporation of active ingredients such as flavors, enzymes, cells or other materials in small capsules. The choice of excipients for encapsulation is very important for the encapsulation efficiency and protein stability within the matrix. Applications of this technique have increased in the food and pharmaceutical industries since the encapsulated materials can be protected from moisture, heat or other extreme conditions. Thus their stability is improved and their viability maintained. Powder formation can lower the water activity of the material, the reactivity and the diffusivity of encapsulated compounds, and the diffusivity of residual water. In the food industry microencapsulation is often associated with the already discussed retention of flavor compounds during drying and storage. In pharmaceutical applications, the purpose of microencapsulation is to control the release and improve the bioavailability of active ingredients. 

The exclusion of water from the environment of a protein may provide resistance to chemical modification of the protein structure during processing and storage. Processes such as freeze-drying and spray drying have been employed to prepare solid-state dosage forms of pharmaceutical proteins with vastly reduced water content. Several theories of protein encapsulation in glassy materials have been proposed based on the three considerations mentioned in Section 6.4.2.3  

Enzyme In trehalose solution Enzyme In a spray-dried particle 

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