Sources of pigments

Dufosse, L. et ah. Microorganisms and microalgae as sources of pigments for food use a scientific oddity or an industrial reality Trends Food Sci. Technol, 16, 389, 2005. 

Lucerne is one of the most widely grown forage crops on a worldwide basis and is used commonly in livestock diets. It is a good source of many nutrients and in the past the inclusion of lucerne meal was considered to be essential in diets for a wide range of animals as a source of unidentified factors. Currently lucerne meal is used in poultry diets as a source of pigments to provide a yellow colour in egg yolks, shanks and skin (e.g. Karadas et al, 2006). 

Phycobilins phycoerythrin phycotyanin Natural food colorings Red and blue-green al e e.g., P. cruentum Natural source of pigmentation Borowdtzka, 1993 Roman et aL, 2002... 

Chlorophylls Natural food and beverage colorants Aquatic plants and bacteria e.g., S. platensis and A. flos-aquae Anticancer activity, natural source of pigmentation Bhattacharya and Shivaprakash, 2005 Chernomorsky et al, 1999 de Oliveira Rangel-Yagui et oL, 2004 Donaldson, 2004 Egner et oL, 2001 Kay, 1991 Sarkar et al., 1994... 

Phylloquinones, such as vitamin Ki (37) (Fig. 6.2) are found in all green plant tissues menaquinones and other naphthoquinones are found in bacteria, ngi, and a number of plant families. Naphthoquinones occur free or as glycosides within the plants. They are usually colored and may serve as a source of pigmentation in some plants. 

Alam, A.U., Creger, C.R. and Couch, J.R. (1968) Petals of aztec marigold, Tagetes erecta, as a source of pigment for avian species. J. Food Sci. 33, 635-636. 

In fact, San Baudelio cannot be considered as belonging to the Camino de Santiago and the masters probably used different sources of pigments and techniques of painting than the typical medieval masters in the pilgrim route. Work is in progress in the area to identify other sites that can be related with San Baudelio. 

Azobisnittiles are efficient sources of free radicals for vinyl polymerizations and chain reactions, eg, chlorinations (see Initiators). These compounds decompose in a variety of solvents at nearly first-order rates to give free radicals with no evidence of induced chain decomposition. They can be used in bulk, solution, and suspension polymerizations, and because no oxygenated residues are produced, they are suitable for use in pigmented or dyed systems that may be susceptible to oxidative degradation. 

Ultramarine Pigments. Ultramarines are derived from lazurite [1302-85-8] (lapis lazuli), a semiprecious stone, which was the natural source of ultramarine blue for hundreds of years. Ultramarines can be prepared in many shades. Examples of commercially significant ones ate ultramarine blue, ultramarine violet, and ultramarine pink. The ultramarine pigment having a green shade can also be prepared but it is not commercially available. The first German patent issued in 1877 was for the manufacture of ultramarine red (42). 

A primary source of environmental pollution from printing ink comes from the metal-based pigments used, as well as various resins, waxes, and drying agents that are also part of the inks. These materials are added to inks regardless of the source of the oil. As a result, petroleum inks are just as suitable for landfill disposal under U.S. EPA regulations as are vegetable oil inks. 

Dyes. Sodium nitrite is a convenient source of nitrous acid in the nitrosation and diatozation of aromatic amines. When primary aromatic amines react with nitrous acid, the intermediate diamine salts are produced which, on coupling to amines, phenols, naphthols, and other compounds, form the important azo dyes (qv). The color center of the dye or pigment is the -N=N- group and attached groups modify the color. Many dyes and pigments (qv) have been manufactured with shades of the entire color spectmm. 

The first chromium compound was discovered in the Ural mountains of Russia, during the latter half of the eighteenth century. Crocoite [14654-05-8] a natural lead chromate, found immediate and popular use as a pigment because of its beautihil, permanent orange-red color. However, this mineral was very rare, and just before the end of the same century, chromite was identified as a chrome bearing mineral and became the primary source of chromium [7440 7-3] and its compounds (1) (see Chromiumand chromium alloys). 

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