Microencapsulation chemistry

Photoprotection of Vitamins in Skim Milk by Aqueous Soluble Lycopene - Gum Arabic Microencapsulated. Journal of Agricultural and Food Chemistry, Vol. 55, No. 2, (January 2007), pp. 323-329, ISSN 0021-8561. 

Friedel-Crafts chemistry in, 12 160 pH control in, 14 33 polymer colloid, 20 376 use of steam in, 23 238-240 Industrial products, microencapsulated,... 

More complex geometries have been developed [40] and the influence of the geometrical structure has been examined. Although straight-through microchannel emulsification has been developed [39,41], the production rates are still low compared to those obtained with standard emulsification methods. However, the very high monodispersity makes this emulsification process very suitable for some specific fechnological applicafions such as polymeric microsphere synfhesis [42,43], microencapsulation [44], sol-gel chemistry, and electro-optical materials. 

Scher HB, Rodson M, Lee KS. Microencapsulation of pesticides by interfacial polymerization utilizing isocyanate or aminoplast chemistry. Pest Sci 1998 54 394-400. 

Hogan, S.A., McNamee, B.F., O Riordan, E.D., O Sullivan, M. (2001). Microencapsulating properties of sodium caseinate. Journal of Agricultural and Food Chemistry, 49, 1934-1938. 

In the early 1990s, Fuji Photofilm Ltd. Introduced Copiart 3 proofing materials, which also depended on HABI chemistry. The chemistry used the lower cost o-Cl-HABI and Leuco Crystal Violet along with tribromomethyl phenyl sulfone, which were microencapsulated in selected vehicles. The image stabilization was achieved by a thermal aftertreatment, which ruptured the microcapsules, which then interacted with phenidone, or other reducing agents to prevent subsequent color formation. 

Microencapsulation covers a broad range of methods. A great number of variants exist around the above-described methods. The methods may also be combined. Engineers and scientists must refer to much scientific and technological knowledge, especially in chemistry. This includes ... 

Evangelou, V. P. 1995b. Pyrite Oxidation and its Control. Acid Mine Drainage, Surface Chemistry, Molecular Oxidation Mechanisms, Microbial Role, Kinetics, Control, Ameliorates, Limitations, Microencapsulation. CRC/Lewis Press, Boca Raton, FL. 

Two types of microencapsulation are known in the art based upon the shellwall forming chemistry. These are interfacial polymerization and in-situ polymerization. Encapsulating plastic shellwalls are synthesized at the 0/W (Oil-in-Water) interface of a pesticide emulsion by reacting oil-soluble monomers dissolved in the pesticide with water-soluble monomers added to the emulsion. This process is referred to as interfacial polymerization. 

A recent innovation in in-situ microencapsulation is the development of acid-triggered release of pesticide from the microcapsules [12]. Diols and aldehydes are reacted to form an acid labile acetal moiety. The acetal is then reacted with isocyanate to create a prepolymer. The prepolymer is a polyisocyanate cmitaining the acid labile moiety and suitable for in-situ shellwall polymerization. The prepolymer is dissolved into a pesticide, emulsified into water, and shellwall formed in-situ. Under alkaline or neutral pH conditions in a container, the insecticide is safely contained in the microcapsules. Acid could be added to the spray tank to rapidly release capsule contents prior to application. Alternate shellwall chemistry for in-situ microencapsulation utilizes etherified urea-formaldehyde prepolymers in the oil phase that are self-condensed with acid catalyst to produce encapsulating aminoplast shellwalls [13]. This process does not have the problem of continuing CO2 evolution. Water-soluble urea-formaldehyde and melamine-formaldehyde prepolymers can be selected to microencapsulate water or aqueous solutions [14]. 

With the recent advance of biotechnology and polymer chemistry, the use of microparticle systems will continue to grow for a variety of applications. The objective of this article is to provide a review of the technical aspects of the microencapsulation techniques that have been widely used in the pharmaceutical industry and recent advances of the technology so that the pharmaceutical scientists can take full advantage of the existing assets of this area in developing new microparticle systems. 

Hall DR, Nesbitt BF, Marrs GJ, (ireen ASJ, Campion DG, Critchley BR. 1982 Development of microencapsulated pheromone formulations, pp. 131-143 in Insect pheromone technology chemistry and applications. ACS Symp Scr 190, Washington DC. 

How does microencapsulating the catalyst change the reactivity of the catalyst and the reaction, in terms of the choice of the solvent one should use for the chemistry ... 

McNamee BF, O Riordan ED, O Sullivan M. 1998. Emulsification and microencapsulation properties of gum arabic. Journal of Agricultural and Food Chemistry 46 4551 555. 

Drusch S, Serfert Y, Scampicchio M et al. (2007) Impact of physicochemical characteristics on the oxidative stability of fish oil microencapsulated by spray-drying. Journal of Agricultural and Food Chemistry 55 11044-11051. 

Li, W. Zhang, X.-X. Wang, X.-C. Niu, J.-J. Preparation and characterization of microencapsulated phase change material with low remnant formaldehyde content. Materials Chemistry and Physics (2007), 106(2-3), 437-442. 

Kirby, C.J. and Law, B. 1987. Development in the microencapsulation of enzymes in food technology. In Chemical Aspect of Food Enzymes, ed. A.T. Andrews. London, U.K. Royal Society of Chemistry. 

Romo-Hualde, A. Yetano-Cunchillos, A. L Gonzalez-Ferrero, C. Saiz-Abajo, M. J. Gonzalez-Navarro, C. J., Supercritical fluid extraction and microencapsulation of bioactive compounds from red pepper Capsicum annum L.) by-products. Food Chemistry (2012) 133, 1045-1049. 

Saenz, C. Tapia, S. Chavez, J. Robert, P, Microencapsulation by spray drying of bioactive compounds from cactus pear (Opuntia ficus-indica). Food Chemistry (2009) 114, 616-622. 

Gharsallaoui, A. Roudaut, G. Beney, L. Chambin, O. Voilley, A. Saurel, R., Properties of spray-dried food flavours microencapsulated with two-layered membranes Roles of interfacial interactions and water. Food Chemistry (2012) 132, 1713-1720. 

Kim, Y.D., Moor, C.V. 1996. Microencapsulation properties of gum arabic and several food proteins Spray-dried orange oil emulsion particles. Journal of Agricultural Food Chemistry, 44(5) 1314-1320. 

Rosenberg M., Kopelman I.J., and Tahnon Y., 1990. Factors affecting retention in spray drying microencapsulation of volatile materials. Journal of Agricultural and Food Chemistry, 38,1288-1294. 

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