Emulsion formula, encapsulation

A typical emulsion formula for encapsulation on pure gum may be expressed as follows ... 

According to Hergeth and coworkers [55], a minimum surface of the inorganic particles is needed to prevent secondary nucleation. To estimate this amount, a formula was derived for seeded emulsion polymerization with spherical particles and a water-soluble initiator [55]. This formula was based on the observation that primary particles are produced by a coUapse and micellization process of oligomeric chains. An upper limit for the particle size was estimated to be 100 nm for the encapsulation of silica with polyvinyl acetate. A relatively water-soluble monomer is applied here for more hydrophobic monomers this upper limit will be higher. Because the surface area needed to prevent secondary nucleation is proportional to the monomer conversion per unit of time, the encapsulation efficiency can be improved by using monomer-starved conditions. So far, mainly submicrometer particles have been encapsulated with this method. The encapsulation of the larger filler particles... 

There are many ways to microencapsulate active components, such as spray drying, film coating, coacervation, carrageenan entrapment, molecular encapsulation using P-cyclodextrin, double emulsions, liposomes, and microemulsions (Vilstrup, 2001). Of these, spray drying is currently the best technology available to the food industry to produce stable, cost-effective, microencapsulated ingredients or products. Spray dryers, first constmcted in 1878 (Hayashi, 1989), are now widely used in the dairy industry and, in a modified form, by infant formulae manufacturers. 

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