Encapsulation technology

A unique feature of in situ encapsulation technology is that polymerization occurs ia the aqueous phase thereby produciag a condensation product that deposits on the surface of the dispersed core material where polymerization continues. This ultimately produces a water-iasoluble, highly cross-linked polymer capsule shell. The polymerization chemistry occurs entirely on the aqueous phase side of the iaterface, so reactive agents do not have to be dissolved ia the core material. The process has been commercialized and produces a range of commercial capsules. 

Solvent Evaporation. This encapsulation technology involves removing a volatile solvent from either an oil-in-water, oil-in-oil, or water-in-oH-in-water emulsion (19,20). In most cases, the shell material is dissolved in a volatile solvent such as methylene chloride or ethyl acetate. The active agent to be encapsulated is either dissolved, dispersed, or emulsified into this solution. Water-soluble core materials like hormonal polypeptides are dissolved in water that contains a thickening agent before dispersion in the volatile solvent phase that contains the shell material. This dispersed aqueous phase is gelled thermally to entrap the polypeptide in the dispersed aqueous phase before solvent evaporation occurs (21). 

Laboratory Manager, Encapsulation Technology Center 3M Company, St. Paul, Minnesota... 

Coating/encapsulation technologies for pharmaceuticals, textile apparel, and manufactured parts such as in the automotive industry... 

Desizing, 10 302 Desliming, 22 279, 282 Desmycosin, 15 292 Desolvation encapsulation technology,... 

Encapsulation processes, 16 438-451 centrifugal extrusion, 16 449—450 in situ, 16 445 key feature of, 16 444 rotational suspension separation, 16 450 spray chilling, 16 448 spray-dry, 16 447—448 Encapsulation spinning, 16 26 Encapsulation technologies... 

See also Flavor encapsulation, Glass encapsulation applications of, 11 553—557 encapsulation technologies, 11 530-543, 543-553... 

Polymer encapsulation technology (PET) was designed to stabilize radioactive materials and wastes. Polymer encapsulation uses nonvolatile polymers with excellent heat resistance, low water solubility, chemical stability, and excellent radiation resistance. Once materials have been mixed with the encapsulant, the mixture expands and hardens. This process prevents radioactivity from escaping and confines radioactive particles to the polymer structure. 

In recent years, specific requirements with regard to shelf-life stability and tailor-made release behaviour led to the development of a range of specific encapsulation technologies such as glass-encapsulated flavours or seamless capsules with liquid cores. 

In addition to the necessary protection of the contents of the emulsion droplets, effective encapsulation technology requires that the release of the active matter be controlled at a specified rate. Benichou et aL (2004) have demonstrated that a mixture of whey protein isolate (WPI) and xanthan gum can be successfully used for the controlled release of vitamin Bi entrapped within the inner aqueous phase of a multiple emulsion. The release profile, as a function of the pH of the external aqueous phase, is plotted in Figure 7.25. We can observe that the external interface appears more effectively sealed against release of the entrapped vitamin at pH = 2 than at pH = 4 or 7. It was reported that an increase in the protein-to-potysaccharide ratio reduced the release rate at pH = 3.5 (Benichou et aL, 2004). More broadly, the authors suggest that compatible blends of biopolymers (hydrocolloids and proteins) should be considered excellent amphiphilic candidates to serve as release controllers and stability7 enhancers in future formulations of double emulsions. So perhaps mixed compatible biopolymers wall at last allow researchers to... 

Incorporation of the appropriate kinds of (nano)particles into heterogeneous mixed biopolymer systems may offer new opportunities for the generation of novel structures having interesting physicochemical properties. In particular, the concept of particle structuring at liquid-liquid interfaces may have future possibilities in food-based biopolymer-based delivery and encapsulation technology. 

Colton CK. Engineering challenges in cell encapsulation technology. Trends Biotechnology 1996, 14, J58-J62. 

Several generations of vanadium metal catchers have been developed (1, 2), leading to an improved activity retention at high vanadium levels on catalyst. The recent progress in nickel tolerance with new nickel encapsulation technologies is just as dramatic. 

Other advantages of microfabricated devices include faster response times, and the fabrication of multiple test sites for simultaneous replicate assays in one microfabricated device. This analytical redundancy provides a safeguard that is not easily attained in a conventional macroscale analyzer, where duplicate assays represent the usual extent of repetitive assay of a sample. Encapsulation technology used in the microelectronics industry may also be applicable to microscale devices and could be extended to operations over a wide range of environmental conditions of humidity, and temperature. 

Ignoffo, C. M., Shasha, B. S., and Shapiro, M., Sunlight ultraviolet protection of the Heliothis nuclear polyhedrosis virus through starch-encapsulation technology, J. Invertebrate Pathol., 57, 134, 1991. 

All the above dispersions lead to droplets. These droplets must be transformed into solid like particles by a stabilization process. Table 1 provides the most usual encapsulation technologies by crossing dispersion methods and stabilization methods. Table 1 is not an exhaustive list. 

This chapter considers the issues relating to the delivery of bioactives through foods. The choice of materials for encapsulation of bioactives, the formulation of the encapsulated delivery system and the processes used for their manufacture are discussed. Examples of materials and processes used for the manufacture of encapsulated fat-soluble and water-soluble bioactives and encapsulated probiotics are given. The effectiveness of various encapsulated delivery systems for protection of bioactive ingredients and new trends in encapsulation technology are covered. The... 

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