Microencapsulation:
Definition: It is the process by which individual particles or droplets of solid or liquid material (the core) are surrounded or coated with a continuous film of polymeric material (the shell) to produce capsules in the micrometer to millimetre range, known as microcapsules.
Microencapsulation (Cont.):
Morphology of Microcapsules: The morphology of microcapsules depends mainly on the core material and the deposition process of the shell. 1- Mononuclear (core-shell) microcapsules contain the shell around the core. 2- Polynuclear capsules have many cores enclosed within the shell. 3- Matrix encapsulation in which the core material is distributed homogeneously into the shell material. - In addition to these three basic morphologies, microcapsules can also be mononuclear with multiple shells, or they may form clusters of microcapsules.
Morphology of Microcapsules (Cont.):
Microencapsulation (Cont.):
Coating material properties: •Stabilization of core material. •Inert toward active ingredients. •Controlled release under specific conditions. •Film-forming, pliable, tasteless, stable. •Non-hygroscopic, no high viscosity, economical. •Soluble in an aqueous media or solvent, or melting. •The coating can be flexible, brittle, hard, thin etc.
Microencapsulation (Cont.):
Coating materials:
Gums: Gum arabic, sodium alginate, carageenan.
Carbohydrates: Starch, dextran, sucrose
Celluloses: Carboxymethylcellulose, methycellulose. Lipids: Bees wax, stearic acid, phospholipids. Proteins: Gelatin, albumin.
Microencapsulation (Cont.):
Benefits of Microencapsulation:
1- microorganism and enzyme immobilization.
- Enzymes have been encapsulated in cheeses to accelerate ripening and flavor development. The encapsulated enzymes are protected from low pH and high ionic strength in the cheese. • The encapsulation of microorganisms has been used to improve stability of starter cultures.
Benefits of