Microencapsulation

Microencapsulation is a process in which tiny particles or droplets are surrounded by a coating to form small capsules with useful properties, generally used to incorporate food ingredients, enzymes, cells or other materials on a micrometric scale. The process encloses solids, liquids or gases within micrometric walls made of a soluble film, and in its simplest form a microcapsule consists of a uniform wall surrounding an interior core or fill, with the outer layer serving as the shell or membrane; common coating materials include ethyl cellulose, polyvinyl alcohol, gelatin, sodium alginate, formaldehyde resin, urea-formaldehyde, polyurea and maltodextrin. Flavor encapsulation is a particularly common food application of the technique, and its effectiveness depends on the physical and chemical properties of the material being encapsulated; modern microcapsules often depart from a simple spherical structure, with complex cores such as crystals, emulsions or nested microcapsules, and may carry multiple walls.