Food, coloration

Because of the multiple conjugated olefinic stmcture in the molecule, pure crystalline carotenoids are very sensitive to light and air and must be stored in sealed containers under vacuum or inert gas to prevent degradation. Thus, commercial utilization as food colorings was initially limited however, stable forms were developed and marketed as emulsions, oil solutions and suspensions, and spray-dried forms. 

Table 3. Commonly Used Artificial Food Colors...

This proliferation in the use of color additives was soon recognized as a threat to the pubHc s health. Of particular concern were the practices of a dding poisonous colorants to food, and of using dyes to hide poor quaUty or to add weight or bulk to certain items. References 5—14 provide additional information on the history of food colorants and thek regulation. Reference 15 provides more information regarding the appHcations, properties, specifications, and analysis of color additives, as well as methods for the determination of colorants in products. 

The disputes that followed these events centered around interpretation of the 1938 act, which states that "The Secretary shall promulgate regulations providing for the listing of coal-tar colors which are harmless and suitable for use in food..." The FDA felt that harmless meant that a colorant must be safe regardless of the amount used, that is, harmless per se and on this basis deHsted the colorants in question. The food-color manufacturers argued that the FDA interpretation of the law was too strict, that a color additive need only be harmless when properly used, and that the FDA should estabHsh safe limits. They also contended that the conditions used for the new animal feeding tests were too severe. 

References 23—31 cover various aspects of food coloring technology in the United States and internationally. 

W. C. Bainbridge, Ind. Eng Chem. 18, 1329—1331 (1926). Development of the food color industry in the United States. Interesting historically. 

C. Cal2olari, L. Coassini, and L. ToUat, QuademiMerceol 1, 89—131 (1962). Synthetic Food Colors. Reviews the regulation of food colors in various countries, the toxicity of the intermediates used to prepare them, and the toxicity of the degradation products of colorants. 

Food Colors, National Academy of Sciences, Washington, D.C., 1971. A general treatment of food colors, including their history, use, regulation, safety, and properties. 

S. H. Hochheiser, Synthetic Foods Colors in the United States A. History Under Regulation, University Microfilms International, 83-04269, Ann Arbor, Mich., 1986. An excellent history of the development of legislation to control colorants used in foods, dmgs, and cosmetics. 

A. Weissler, Food Technol, 38, 46 (May 1975). FDA Regulation of Food Colors. Outdated but interesting. 

B. T. Hunter, Consumer Bulletin, 20—24 (May 1973). U.S. Certified Food Dyes—A look at the record of governmental failure to safeguard America s food products. A criticism of government s role in controlling the use of food colors. 

A Search for Safer Food Dyes," Business Week, (Feb. 21, 1977). Some thoughts on the future of the food color business. 

T. E. Furia, ed.. Current Aspects of Food Colorants, CRC Press, Inc., West Palm Beach, Fla., 1977. An update on food colorant technology. 

R. Goto, Yuki Gosei Kagaku Kyokai Shi 24, 493—500 (1966). Food Colors. A review of the kinds, properties, and appHcations of food colors. 

J. Noonan, "Color Additives in Foods" in Handbook of Food Additives, The Chemical Rubber Co., Cleveland, Ohio, 1968, pp. 25—49. Food colors— their description, properties, regulation, and use. 

J. Walford, ed.. Developments in Food Colours, Vols. 1 and 2. Elsevier AppHed Science, London, 1980 and 1984. Includes chapters on synthetic and natral food colors used in the United States, and on the influence of color on the perception and choice of food. 

Hnnatto Food Colors Charles Hansen s Laboratory, Milwaukee, Wis. A brief description of what annatto is and how it is used. 

In addition to the U.S. certified coal-tar colorants, some noncertified naturally occurring plant and animal colorants, such as alkanet, annatto [1393-63-17, carotene [36-884] C qH, chlorophyll [1406-65-17, cochineal [1260-17-9] saffron [138-55-6] and henna [83-72-7], can be used in cosmetics. In the United States, however, natural food colors, such as beet extract or powder, turmeric, and saffron, are not allowed as cosmetic colorants. 

Carotenoids have two general characteristics of importance to the food iadustry they are not pH sensitive ia the normal 2—7 range found ia foods, and they are not affected by vitamin C, making them especially important for beverages. They are more expensive than synthetic food dyes and have a limited color range. In their natural environment they are quite stable, but they become more labile when heated or when they are ia solution. Under those conditions, there is a tendency for the trans-double bonds to isomerize to the cis-stmcture with a subsequent loss of color iatensity. The results of controlled tolerance and toxicity tests, usiag pure carotenoids, iadicate that they are perfecdy safe as food colors (132). 

The use of natural dyes as food colorants evolved over a period spanning thousands of years. During that period, by trial and error, some dyes were found to be safe while others were not. By comparison, the development of synthetic dyes as food colorants has taken place over a comparatively short time. During that period, some synthetic dyes considered safe by existing health standards were used as food colors. Later, with iacreased knowledge, these were found to create health problems and were removed from the marketplace. The manufacture of synthetic dyes for use on foods creates more of a health and environmental problem than natural dyes, but offers greater variety and stabiUty of color (see Dyes, environmental chemistry). 

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

While a single vant performs little more than a pseudo random-walk, multiple-vant evolutions are ripe with many interesting (Conway Life-rule-like) patterns, particularly when the background lattice food color is shown along with the moving... 

Carotene, a yellow food-coloring agent and dietary source of vitamin A, can be prepared by a double Wittig reaction between 2 equivalents of jS-ionvlideneacetaldehyde and a diylide. Show the structure of the /0-carotene product. 

Methods are described for determining the extent to which original natural color is preserved in processing and subsequent storage of foods. Color differences may be evaluated indirectly in terms of some physical characteristic of the sample or extracted fraction thereof that is largely responsible for the color characteristics. For evaluation more directly in terms of what the observer actually sees, color differences are measured by reflectance spectrophotometry and photoelectric colorimetry and expressed as differences in psychophysical indexes such as luminous reflectance and chromaticity. The reflectance spectro-photometric method provides time-constant records in research investigation on foods, while photoelectric colorimeters and reflectometers may prove useful in industrial color applications. Psychophysical notation may be converted by standard methods to the colorimetrically more descriptive terms of Munsell hue, value, and chroma. Here color charts are useful for a direct evaluation of results. 

Photoelectric-Colorimetric Method. Although the recording spectrophotometer is, for food work at least, a research tool, another instrument, the Hunter multipurpose reflectometer (4), is available and may prove to be applicable to industrial quality control. (The newer Hunter color and color difference meter which eliminates considerable calculation will probably be even more directly applicable. Another make of reflection meter has recently been made available commercially that uses filters similar to those developed by Hunter and can be used to obtain a similar type of data.) This instrument is not a spectrophotometer, for it does not primarily measure the variation of any property of samples with respect to wave length, but certain colorimetric indexes are calculated from separate readings with amber, blue, and green filters, designated A, B, and G, respectively. The most useful indexes in food color work obtainable with this type of instrument have been G, which gives a... 

The methods described make possible the objective measurement of color of foods and a designation in standardized psychophysical terms. However, the psychological significance of food colors is not directly apparent from results expressed... 

Opening the packages and testing for package integrity and changes in food color, flavor, odor, or taste. 

Caseins are used as food colorants because they make a nice base of opaque white, which can then be tinted with other colors as required. 

Food processing steps may change food color. 

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