Coloring matter

White Hydroxide. Tlie soda sinter process appHed to bauxite or bauxite residue produces a hydroxide that is completely free from organic coloring matter and is very wliite. A value of more than 95% is obtained on the GE brightness scale relative to Ti02 as followed in the paper (qv) industry. Tliis compares to about 70% on the same scale for the nomial Bayer product. Tlie wliite hydroxide is preferred in the paper, toothpaste, and artificial marble industries. 

Mordant Dyes. MetaUizable azo dyes are appHed to wool by the method used for acid dyes and then treated with metal salts such as sodium chromate [7775-11-5] sodium dichromate [10588-01-9] and chromium fluoride [1488-42-5] to form the metal complex in situ. This treatment usually produces a bathochromic shift ia shade, decreases the solubUity of the coloring matter, and yields dyeiags with improved fastness properties. The chromium salts can be appHed to the substrate before dyeiag (chrome-mordant or chrome-bottom method), together with the dye ia a single bath procedure (metachrome process), or as a treatment after dyeiag (afterchrome process). 

White chocolate has been defined by the European Economic Community (EEC) Directive 75/155/EEC as free of coloring matter and consisting of cocoa butter (not less than 20%) sucrose (not more than 55%) milk or soHds obtained by partially or totally dehydrated whole milk, skimmed milk, or cream (not less than 14%) and butter or butter fat (not less than 3.5%). 

The principal coloring matter in turmeric and its oleoresin is curcumin [458-37-7] (l,6-heptadiene-3,5-dione, l,7-bis[4-hydroxy-3-methoxy-phenyl] (45), an orange-yeUow, crystalline powder, insoluble in water and ether but soluble in ethanol and glacial acetic acid. It has a reported melting point of 180-183°C. 

The first synthetic dyestuff, mauveine, was discovered by Perkin in 1856 in the UK and led to many investigations of the derivatives of coal tar as potential coloring matters. The first dia2onium salt derived from picramic acid was prepared in 1858 and is still the basic chemistry behind coundess commercial products. Despite these inventions, in 1900 the vast majority of dyestuffs were still of natural origin. Now at the end of the century the situation has changed dramatically synthetic dyes dominate. 

The Colourindex (5), categori2es all coloring matters according to apphcation characteristics. The following are the main types currendy of interest as dyes. 

Flavones. These compounds are the most widely distributed natural coloring matter formerly used as dyestuffs. The term flavone was first suggested in 1895 (69), and is indicative of their yellow color ijlavus, Latin for yellow). They have lost their commercial value as dyes since the advent of synthetic dyes in 1856. 

Later it was found growing in South America where the Indians used the red dye from the seeds as a body paint. An extract of the seeds appears on the market as annatto. This extract is used in coloring butter, margarine, and cheese such as Leicester cheese. In Mexican and South American cuisine, it finds special use as a flavor and coloring matter. The seeds are sold under the name achiote in many Latin grocery stores and markets. Ann at o is available as an aqueous solution, as an oleaginous dispersion, and a spray-dried powder. 

Flechte, /. lichen plait, twist skin eruption, flechten, v.t. plait, twist, braid, interweave, Flechten-far toffi m. lichen coloring matter, -rot, n, orcein, -saure, /. fumaric acid (old name). -stSrkemehl, n. lichenin, moss starch, -stoffe, m.pl. lichen substances. 

After evaluating all the materials provided by Ascolor Biotech, the Codex Ali-mentarius Commission (Rotterdam meeting, March 2002) stated, There will not be any objections to use the red coloring matter Arpink Red in ... 

Lobbying by other P-carotene producers — In addition to approvals of mixed carotenes from palm oil, P-carotene from Dunaliella microalgae, and other natural products, the EU Health and Consumer Protection Directorate General was asked for an opinion on the safety of P-carotene from a dried biomass source, obtained from a fermentation process with Blakeslea trispora for use as a coloring matter for foodstuffs. 

Capitan, F. et ah. Determination of colorant matters mixtures in foods by solid-phase spectrophotometry, AmZ. Chim. Acta, 331, 141, 1996. 

Wahl, H., and Le Bris, M.-T., Recent Prog. Chem. Nat. Synth. Coloring Matters Relat. Fields 507 (1962). 

Excipients should be listed in the composition using their Ph Eur name (or one from another national pharmacopeia from an EEA member state), the International Nonproprietary Name, or an exact scientific designation, other than for materials such as preservatives or coloring agents which can be identified by an E-number. Third country pharmacopeial names may be acceptable. Coloring matter is subject to the provisions of specific legislation in the EEA. 

With the exception of antimicrobial preservatives and antioxidants (see below) and coloring matter (for which an identity test should be available), it is not normally necessary to test for the presence of excipients in finished products. 

Dyes, often also called coloring matters or colorants, are intensely colored, soluble organic substances used to impart color to fibrous materials (see Textbox 66). Not all colored and soluble organic substances, however, are dyes only those whose molecules have a considerable structural complexity are useful for imparting color to other materials. Moreover, a substance is considered a dye only if the color it imparts is fairly permanent, that is, resistant to fading and disappearance. 

Lac is derived from lac resin, the hardened secretion of the lac insect, the only known resin of animal origin. The lac insect, Kerria lacca, formerly known as Laccifer lacca, is a natural parasite of a variety of trees in large areas of southern Asia. Three different products are derived from lac resin lac dye, lac wax, and shellac. To obtain the lac resin, twigs encrusted with the secretion of the insects are cut down from the trees, then the incrustation is separated from the twigs, washed with water, and filtered. The wax and shellac, which are insoluble in water, remain as a solid residue of the filtration, while the soluble red dye (lac) is obtained as a powder when the water from the filtered solution is evaporated. The coloring matter in lac dye is an organic compound known as laccaic acid. 

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