Azo dyes Amaranth

The decolourization of the azo dye amaranth was also investigated using atomic hydrogen permeating through a Pt-modified palladized Pd sheet electrode. The decolouration products were separated by RP-HPLC in an ODS column. The isocratic mobile phase was 0.1 M aqueous orthophosphoric acid. The flow rate was 1.2 X 10 2 cm3/s and decomposition products were detected at 236 nm. The RP-HPLC system separated two analytes with retention times of 3.4 and 4.5 min, as demonstrated in Fig. 3.47. The peaks were... 

M. Karkmaz, E. Puzenat, C. Guillard and J.M. Herrmann, Photocatalytic degradation of the alimentary azo dye amaranth. Mineralization of the azo group to nitrogen. Appl. Catal. B Environ., 51 (2004) 183-194. 

In our laboratory, this method was appUed to the purification of food mono-azo dyes. Amaranth, New Coccine, and Sunset Yellow FCF were purified at 99.7%, 99.5%, and 99.3%, respectively, from 1-23 g of commercial dyes. Continued research has led to the purification of impurities present in commercial Sunset Yellow FCF that include RS-SA (trisodium salt of 3-hydroxy-4-[sulfophenyl] azo-2,7-naphthalene disulfonic acid), GS-S A (1 -[4-sulfophenyl]azo)-2-naphthol-6,8-disulfonic acid), DONS (disodium salt of 6,6 -oxybis-2-naphthalene sulfonic acid), and 2N-SA (sodium salt of 4-[(2-hydroxy-l-naphthalenyl)azo]benzenesulfonic add). The method successfully isolated GS-SA from Sunset Yellow FCF. " ... 

Anonymous. HPTLC detection of the azo dye amaranth as an adulterant of Bilberry extract, CAMAG application note F35, March 2007. 

Azo dyes Allura Red AC, Amaranth, Azorubine, Brilliant Black BN, Brown FK, Brown HT, Lithol Rubine BK, Ponceau 4R, Red 2G, Sunset Yellow, Tartrazine Triarylmethane (triphenylmethane) dyes Brilliant Blue FCF, Fast green FCF, Green S, Patent Blue V... 

Amaranth (E 123, Cl Food Red 9) is a mono azo dye, with the chemical name trisodium 3-hydroxy-4(4-sulfonato-l-naphtylazo)-2,7-naphthalenedisulfonate) (or trisodium 2-hydroxy-l-(4-sulfonato-l-napthylazo) naphthalene-3,6-disulfonate). The calcium and potassium salts are also permitted. Amaranth is a reddish-brown powder or granules, soluble in water, sparingly soluble in ethanol, with a maximum absorption in water at 520 nm (Ei " = 440). It has been banned in the US since 1976. " Amaranth can be used also as a dye for cosmetics, synthetic fibers, leather, papers, and some plastics. 

One of the first reports on yeast-mediated color removal by a putative process of biosorption of azo dyes by yeast (Rhodotorula sp.) biomass belongs to [31]. Yeast species such as Kluveromyces marxianus removed the diazo dye remazol black B [10], Candida catenulata and Candida kefyr removed more than 90% of amaranth by biosorption [6]. Biosorption uptake of the textile azo dyes remazol blue, reactive black, and reactive red by S. cerevisiae and C. tropicalis varied according to the selected dye, dye concentration, and exposure time [5, 7]. In a recent screening work carried out by [32], from the 44 yeast strains tested for their decolorization ability, 12 of them removed the dye Reactive Brilliant Red K-2BP by biosorption, among them the following were identified S. cerevisiae, Saccharomyces uvarum, Torulopsis Candida, and Saccharomycopsis lipolytica. 

Figure 9. Structures of azo dyes acid green 25 (AG25), basic blue 9 (BB9), direct red 23 (DR23), acid orange 7 (A07) and amaranth (Am).

Reduction of the azo dye piontosil to produce the antibacterial drug sulfanilamide (Fig. 4.38) is a well-known example of azo reduction. This reaction is catalyzed by cytochromes P-450 and is also carried out by the reductases in the gut bacteria. The reduction of azo groups in food coloring dyes such as amaranth is catalyzed by several enzymes, including cytochromes P-450, NADPH cytochrome P-450 reductase, and DT-diaphorase, a cytosolic enzyme. 

Red No. 2 123a Amaranth (azo dye)b Red Used as coloring in wines, alcohols, and roe (prohibited in the United States)... 

In our laboratory, this method was applied to the purification of food mono-azo dyes [3]. Amaranth, New Coc-cine, and Sunset Yellow FCF were purified af 99.7%, 99.5%, and 99.3 %, respectively, from 1-2.5 g of commercial dyes. Continued research has led to the purification of impurities present in commercial Sunset Yellow FCF... 

Synonyms Amaranth FD C No. 2 Whortleberry red 3-Hydroxy-4-[(4-sulfo-l-naphthalenyl) azo]-2,7-naphthalenedisulfonic acid trisodium salt Chemical/Pharmaceutical/Other Class Azo dye Chemical Formula 20-HnN2O10S3Na3... 

Some persons are sensitive to azo dyes, with reactions including recurrent urticaria. Children with sensitivity to amaranth have exhibited behavioral changes. 

Because azo dyes, as amaranth, are the most widely used food colorants and are water soluble, they were bonded to selected polymers via a sulfonamide linkage. However, the azo linkages in the dyes themselves were unstable to intestinal microbial action and do not meet the requirements of biological stability because they are cleaved in the gut to yield absorbable aromatic amines. Hence a variety range of chromophore classes have been reported to be incorporated into polymers. For the anthraquinone class of chromophores, the basic water insolubility was changed by converting a portion of the backbone to sulfonic acids that impart anionic solubilizing functions. However, this meant that fewer chromophores could be attached and less intense colors would result. 

Other compounds of food significance that have recently been the focus of attention using ME-AD approach are dyes. Artificial dyes are commonly added to foodstuffs with the purpose of enhancing their attractiveness. Since almost all of these additives are prepared by chemical synthesis, their presence in foods is the cause of extensive consumer mistrust since they may lead to adverse health effects and because their consumption is regulated by law. A rapid analysis of azo-dyes in food by using ME-AD has been reported [33]. Eive azodyes (yellow AB, Red 2G, Sunset Yellow, New Coccine, and Amaranth) were separated in less than 300 s and determined in soft drinks (liquid sample) and candies (solid sample), both with minimal sample preparation but still performed off chip. ... 

As with sulfur dioxide, the reaction of ascorbic acid with azo dyes frequently used in combination, for example in fruit drinks, leads to dye degradation. The stability of the most frequently used dyes (at pH 3.0 and 4.0) in the presence of ascorbic acid decreases as follows Tartrazine > Sunset Yellow FCF = Amaranth, Ponceau 4R > Azorubine > Brilliant Black BN. 

Fig. 5 Chemical structures of indigoid (indigotine) and azo (amaranth, allura red, black PN, and tartrazine) dyes.

Amaranth Supra Hexacert Red No. 2 Hexacol Amaranth B Extra Hidacid Amaranth Hidacid Amaranth 21-6008 Hispacid Red AM Japan Food Red No. 2 Japan Red 2 Japan Red No. 2 Java Amaranth KCA Foodcol Amaranth A Kayaku Amaranth Kayaku Food Colour Red No. 2 Kiton Ruhine S L Red 3 L Red Z 3050 Lissamine Amaranth AC Maple Amaranth Naphthol Red LZS Naphthol Red S Naphthol Red S Cone. Specially Pure Naphthol Red S Specially Pure Naphthol Red SI Necol Amaranth Neklacid Red A PuriColor Red ARE 27 Rakuto Amaranth Red No. 2 Red dye no. 2 Ritacid Red G Rouge Solid E S-Azo Ruhine San-ei Amaranth Sandal Amaranth I Shikiso Amaranth Solar Red O Takaoka Amaranth Tertracid Red A Toyo Amaranth Triacid Amaranth A Trisodium salt of 1-(4-sulfo-1 -naphthylazo)-2-naphthol-3,6-disulfonic acid Usacert Red No. 2 Victoria Ruhine O Victory Scarlet Water Red 176574 Whortleberry Red Wool Bordeaux 6RK Wool Red 40F... 

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