Foodstuff dyes

D.M. Milojkovic-Opsenica, K. Lazarevic, V. Ivackovic and Z.Lj. Tesic, Reversed-phase thin-layer chromatography of some foodstuff dyes. J. Planar Chromatogr.-Mod TLC, 16 (2003) 276-279. 

GC-MS Volatility/molecular Large organic Dissolved in solvent Molecular identification, % 10s Foodstuffs, dyes, resins... 

Flame ionization detectors (FID), 171,361-372 applications of TLC-FID systems, 369 coated rod systems, 366-369 tubular systems, 365 TLC-FID systems, 362-369 coated rod systems, 364-369 tubular systems, 362-364 Flame diermionic ionization detector (flll>), 369 Flat-bed chromatography, 3 Flavonoids, 717-722 distribution, 717 practical experiments, 719-722 structure, 717 TLC of, 718-719 Fluorescence, 939 measurement of, 208-210 for quantitative determination in TLC, 281-287 Fluorgenic detection Q>esticide detection system), 810-811 Folic acid, 1051 Food additives, 803 Food dyes, 1006-1014 Foodstuff dyes, 1004... 

The reducing action of sulphurous acid and sulphites in solution leads to their use as mild bleaching agents (for example magenta and some natural dyes, such as indigo, and the yellow dye in wool and straw are bleached). They are also used as a preservative for fruit and other foodstuffs for this reason. Other uses are to remove chlorine from fabrics after bleaching and in photography. 

Because traces of iron reduce the brilliance of many dyes, wood tanks have long been preferred to steel in the manufacture of dyes. Similarly, vinegar and sour foodstuffs are processed in wood tanks because common metals impart a metallic taste. Ease of fabrication may be the reason for using wood tanks in less accessible areas to which ready-made tanks of other materials caimot be easily moved. 

Lebensmittel, n.pl. provisions, victuals food nourishment, sustenance, -farbe, /. food color, food dye. -gewerb(e), n. foodstuff industry. -untersuchung, /. investigation of foods, food research. 

Perez Urquiza, M. and Beltran, J.L., Determination of dyes in foodstuffs by capillary zone electrophoresis, J. Chromatogr. A, 898, 271, 2000. 

CZE has been employed for the analysis of another set of dyes in foodstuffs. The chemical structures, numbers and names of the dyes included in the investigation are listed in Fig. 3.142. A fused-silica capillary column of 57 cm length (50 cm effective length 75 jum i.d.) was employed for the separations. The capillary was conditioned by 1.0 M NaOH for 20 min followed by 10 min wash with water and 10 min wash with the running buffer. The buffer was prepared by adding NaOH to 10 mM phosphoric acid to reach pH 11.0. The capillary was thermostated at 25°C and the separation voltage was 20 kV. A hydrodynamic injection mode was applied (0.5 psi, 4 s, 21 nl) and spectra of... 

The electropherogams demonstrate the baseline separation of dyes even in the presence of complicated accompanying matrices such as mint syrup. The LOD and LOQ values were between 1.0 - 1.7 and 3.2 - 5.5 jUg/ml, respectively, and the RSD of migration time and peak areas ranged 1.3 - 1.8 per cent and 2.0 - 3.1 per cent. The migration times of the dyes were Tartrazine, 9.97 min Sunset yellow FCF 6.73 min Amaranth, 8.41 min New coccine, 7.49 min Allura red AC, 5.43 min Patent blue V calcium salt, 4.23 min. The amounts of synthetic dyes found in commercial samples are compiled in Table 3.38. It has been stated that the analysis time is rapid and the method makes possible the separation and determination of these dyes at ppm levels in various foodstuffs [186],... 

JJ.B. Nevado, C.G. Cabanillas and A.M.C. Salcedo, Method development and validation for the simultaneous determination of dyes in foodstuffs by capillary zone electrophoresis. Anal. Chim. Acta, 378 (1999) 63-71. 

Indigo-5,5 -disulfonic acid, disodium salt, C.I. Acid Blue 74, 73015 [860-22-0, Indigotin I, indigo carmine, is approved almost worldwide as a food colorant, and has gained some significance as a dye for foodstuffs, cosmetics, and pharmaceuticals. 

European Union. In the EU colorants which may be used in foodstuff are regulated in 94/36/EC On Colours for Use in Foodstuff. (Table 5.5). Food additives listed in EEC Directives are assigned E numbers. Approved dyes within the EU are also defined as food additives and thus carry E numbers. A substance with an E code and number is valid throughout the EU (E = EEC number of food additives). 

Table 5.5 Synthetic dyes which can be used in foodstuff (excerpt from 94/36/EC, Annex 1)...

Purity criteria of colours for use in foodstuff are regulated in the EU under Directive 95/45/EC [4], According to the legislation food dyes that are placed on the market, must meet special purity requirements An example for C.I. Food Yellow 4 (tartrazine) is shown here ... 

Legislation covers all chemicals, including dyes. Only the use of chemicals and colorants in foodstuffs, food-packaging materials, or pharmaceuticals is mentioned here. The exposure level of dyes is generally very low, but people are inadvertently exposed to dyes and other synthetic chemicals for these applications through dermal contact. Therefore, the use of colorants is especially regulated in many countries. General requirements on dyes for the incorporation into packa-... 

The migration tendency of colorants depends on the dye structure, the plastic or paper material in which it is incorporated, and whether the foodstuff is oil- or water-based. 

Table 8.6 Threshold concentration of metals in dyes used in packaging material for foodstuffs...

Colorless additives of dye preparations must also be listed if used for the above-mentioned purposes. For example, in Germany they must be listed in various BgVV recommendations for dyes, paper, and plastics used for articles coming into contact to foodstuffs. 

Because of their ingestion a different situation exists for food dyes, and their toxicological investigation is the most comprehensive one (see Section 5.5). The colorants approved for food coloration in the EEC are regulated in 94/36/EC (On Colours for Use in Foodstuff). Purity criteria for these colors for use in foodstuff are regulated under 95/45/EC. The regulation is continually updated. 

A wide variety of natural and synthetic dyes are used to color foodstuffs. Florida oranges, often a natural green color when ripe, are sometimes dyed orange with synthetic dyes. Since some synthetic dyes cause illness, their use is restricted, or excluded, even in the coloration of textiles. In the United States, the Pure Food, Drug, and Cosmetic Act enables the Food and Drug Administration (FDA) to control the dyes in foods. This is why these dyes are given names with the prefix FD C or External D C. 

In more recent times, through parallel developments in chemical science and engineering, natural materials that once formed the basis for colouring, dyeing, and flavouring, for foodstuffs, perfumery, pharmaceuticals, and textiles, gradually have been superseded by substances similar or even the same from the point of view of chemical nature, but which have little direct connection with the flora and fauna of the planet. (The substitutes are facsimiles, not extracts.)... 

Adhesives Organic and inorganic bases Coolants Cleaners colorants (pigments and dyes) Fragrances Inks Paints Plasticisers (e.g., in plastics) Polymers (rubbers and plastics) Sealants Solvents Stabilisers Synthetic fibres Varnishes Biocides Detergents Fertilisers Fuels Foodstuff additives and flavourings to foodstuffs Medicinal products (for humans and animals) Plant protection products Radioactive substances... 

FC finishes alone do not sufficiently prevent coffee, tea and other foodstuffs from dyeing nylon and wool carpets with coloured spots, especially when these liquids are not quickly removed. Stain blocking for these carpets is achieved by the combination of FC products with syntans. The latter are also used for wet fasmess improvement of acid dyed nylon (see Chapter 13). Stain repellency is promoted by hydrophobic finishes, mostly fluorocarbons, but with decreasing costs also by... 

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