Encapsulated pigments

The most popular method of pigments encapsulation is spray-drying. Many papers present information about microencapsulation by spray-drying, and this method is most frequently used to protect pigments obtained from vegetables, fruits, flowers, and plants, for example, black carrot, curcumin, beetroot, or roselle. Application of natural polymers as shell to protect beetroot color increased the half-life of spray dried dye about three times, whilst pink color was stabile for about 8 weeks. In case of red roselle pigments stabilization, after microencapsulation, it was acceptable to extend the storage time under different water activities up to 4 months. ... 

Santos, T., Meireles, M., and Angela, A. 2012. Carotenoid pigments encapsulation Pundamentals, techniques and recent trend. Open Chem. Eng. J. 4 42-50. 

Fig. 12 Pigment encapsulation through an emulsion-Uke polymerization reaction. The process involves (1) formation of surfactant bUayers, (2) solubUizarion of monomer, and (5) free radical polymerization...

Figure 4.10 Example of pigment encapsulation through the adsorption of a comb-like stabilizer in conjunction with an amphiphilic copolymer. Redrawn from [74],...

Although the synthesis of polymer colloids has been known for almost a century, the elaboration of organic/inorganic particles is only in its infancy. Some fifty years ago, early methods focused primarily on pigment encapsulation for the paint industry, and were mainly motivated by the problem of pigment dispersion. Since then, research interest in polymer-encapsulated minerals and the so-called colloidal nanocomposites has exploded such that the subject now relates to a wide variety panel of inorganic particles including mineral oxides, aluminosilicates, metal colloids, and semiconductors. 

Nguyen D, Zondanos HS, Farrugia JM, Serelis AK, Such CH, Hawkett BS (2008) Pigment encapsulation by emulsion polymerization using macro-RAFT copolymers. Langmuir 24 2140-2150... 

In some cases, a pigment s thermal and chemical resistance can be improved by the encapsulation of the pigment particles by an iasoluble, colorless layer of metal oxide or oxide—hydroxide, eg, siUca, Si02. The function of such a shell is to prevent direct contact and reaction between the pigment surface and the organic matrix ia which the pigment is dispersed (11). 

Transferosomes represent another system of encapsulation using ultradeformable vesicle carriers for bioactive molecules, applied until now for direct transdermal drug delivery. They are built from polar lipids and have high flexibility, and are rich in unsaturated fatty acids and carotenoid pigments." ... 

Because most food matrices are water soluble, many efforts were directed to the formulation of lipophilic pigments (mainly carotenoids) into water-soluble formulations (powders or gels). For hydrophilic pigments like flavonoids, polar dried microcapsules are the most popular ways to stabilize their functionality. Extracts rich in P-carotene were encapsulated using three different encapsulation techniques (spray drying, drum drying, and freeze drying)." ... 

Barbosa, M.I.J., Borsarelh, C.D., and Mercadante, A.Z., Light stability of spray-dried encapsulated bixin with different edible polysaccharide preparations, in Proceedings of 3rd International Congress on Pigments in Food, Le Berre, Quimper, France, 2004, 53. 

Two main fields of application have been explored fine chemistry/ pharmacy (Hessel et al. 2004a) and fuel processing (Hessel et al. 2005d). A few investigations target manufacture of bulk chemicals or intermediates. In addition, the production of smart and functional materials is the focus, such as pigments (Wille et al. 2004), encapsulated delivery... 

Natural colours include annatto, anthocyanins, beetroot red (betalaines), caramel, carotenoids, cochineal and lac pigments, flavanoids, chlorophylls and tumeric. There is a trend towards encapsulating natural colours for food use, but this is not yet reflected in the extraction techniques described in the published analytical methods. Lancaster and Lawrence (1996) described the extraction and... 

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