Food coloring

Food coloring spreading on a thin water film in the International Space Station

The orange color of carrots and many other fruits and vegetables arises from carotenoids.

The addition of food coloring, such as beta-carotene, gives margarine its yellow color.^[1]

Food coloring, or color additive, is any dye, pigment or substance that imparts color when it is added to food or drink. They come in many forms consisting of liquids, powders, gels, and pastes. Food coloring is used both in commercial food production and in domestic cooking. Food colorants are also used in a variety of non-food applications including cosmetics, pharmaceuticals, home craft projects, and medical devices.^[2]

Purpose of food coloring

People associate certain colors with certain flavors, and the color of food can influence the perceived flavor in anything from candy to wine.^[3] Sometimes the aim is to simulate a color that is perceived by the consumer as natural, such as adding red coloring to glacé cherries (which would otherwise be beige), but sometimes it is for effect, like the green ketchup that Heinz launched in 1999. Color additives are used in foods for many reasons including:^[4][5]

• To make food more attractive, appealing, appetizing, and informative
• Offset color loss due to exposure to light, air, temperature extremes, moisture and storage conditions
• Correct natural variations in color
• Enhance colors that occur naturally
• Provide color to colorless and "fun" foods
• Allow consumers to identify products on sight, like candy flavors or medicine dosages

History of artificial food colorants

The addition of colorants to foods is thought to have occurred in Egyptian cities as early as 1500 BC, when candy makers added natural extracts and wine to improve the products' appearance.^[6] During the Middle Ages, the economy in the European countries was based on agriculture, and the peasants were accustomed to producing their own food locally or trading within the village communities. Under feudalism, aesthetic aspects were not considered, at least not by the vast majority of the generally very poor population.^[7] This situation changed with urbanization at the beginning of the Modern Age, when trade emerged—especially the import of precious spices and colors. One of the very first food laws, created in Augsburg, Germany, in 1531, concerned spices or colorants and required saffron counterfeiters to be burned.^[8]

With the onset of the industrial revolution, people became dependent on foods produced by others.^[7] These new urban dwellers demanded food at low cost. Analytical chemistry was still primitive and regulations few. The adulteration of foods flourished.^[7] Heavy metal and other inorganic element-containing compounds turned out to be cheap and suitable to "restore" the color of watered-down milk and other foodstuffs, some more lurid examples being:^[9]

• Red lead (Pb₃O₄) and vermillion (HgS) were routinely used to color cheese and confectionery.
• Copper arsenite (CuHAsO₃) was used to recolor used tea leaves for resale. It also caused two deaths when used to color a dessert in 1860.

Sellers at the time offered more than 80 artificial coloring agents, some invented for dyeing textiles, not foods.^[9]

...Thus, with potted meat, fish and sauces taken at breakfast he would consume more or less Armenian bole, red lead, or even bisulphuret of mercury. At dinner with his curry or cayenne he would run the chance of a second dose of lead or mercury; with pickles, bottled fruit and vegetables he would be nearly sure to have copper administrated to him; and while he partook of bon-bons at dessert, there was no telling of the number of poisonous pigments he might consume. Again his tea if mixed or green, he would certainly not escape without the administration of a little Prussian blue...^[10]

Many color additives had never been tested for toxicity or other adverse effects. Historical records show that injuries, even deaths, resulted from tainted colorants. In 1851, about 200 people were poisoned in England, 17 of them fatally, directly as a result of eating adulterated lozenges.^[7] In 1856, mauveine, the first synthetic color, was developed by Sir William Henry Perkin and by the turn of the century, unmonitored color additives had spread through Europe and the United States in all sorts of popular foods, including ketchup, mustard, jellies, and wine.^[11][12] Originally, these were dubbed 'coal-tar' colors because the starting materials were obtained from bituminous coal.^[13][5]

Many synthesized dyes were easier and less costly to produce and were superior in coloring properties when compared to naturally derived alternatives.^[9] Some synthetic food colorants are diazo dyes. Diazo dyes are prepared by coupling of a diazonium compound with a second aromatic hydrocarbons.^[14][15] The resulting compounds contain conjugated systems that efficiently absorb light in the visible parts of the spectrum, i.e. they are deeply colored. The attractiveness of the synthetic dyes is that their color, lipophilicity, and other attributes can be engineered by the design of the specific dyestuff. The color of the dyes can be controlled by selecting the number of azo-groups and various substituents. Yellow shades are often achieved by using acetoacetanilide. Red colors are often azo compounds.^[15] The pair indigo and indigo carmine exhibit the same blue color, but the former is soluble in lipids, and the latter is water-soluble because it has been fitted with sulfonate functional groups.

Regulation

History of regulation

Concerns over food safety led to numerous regulations throughout the world. German food regulations released in 1882 stipulated the exclusion of dangerous minerals such as arsenic, copper, chromium, lead, mercury and zinc, which were frequently used as ingredients in colorants.^[16] In contrast to today, these first laws followed the principle of a negative listing (substances not allowed for use); they were already driven by the main principles of today's food regulations all over the world, since all of these regulations follow the same goal: the protection of consumers from toxic substances and from fraud.^[7] In the United States, the Pure Food and Drug Act of 1906 reduced the permitted list of synthetic colors from 700 down to seven.^[17] The seven dyes initially approved were Ponceau 3R (FD&C Red No. 1), amaranth (FD&C Red No. 2), erythrosine (FD&C Red No. 3), indigotine (FD&C Blue No. 2), Light Green SF (FD&C Green No. 2), Naphthol yellow 1 (FD&C Yellow No. 1), and Orange 1 (FD&C Orange No. 1). Even with updated food laws, adulteration continued for many years and this, together with more recent adverse press comments on food colors and health, has continued to contribute to consumer concern about color addition to foodstuffs.

In the 20th century, the improvement of chemical analysis and the development of trials to identify the toxic features of substances added to foods led to the replacement of the negative lists by lists of substances allowed to be used for the production and the improvement of foods. This principle is called a positive listing, and almost all recent legislations are based on it.^[7] Positive listing implies that substances meant for human consumption have been tested for their safety, and that they have to meet specified purity criteria prior to their approval by the corresponding authorities. In 1962, the first EU directive (62/2645/EEC) approved 36 colorants, of which 20 were naturally derived and 16 were synthetic.^[18] This directive did not list which food products the colorants could or could not be used in. At that time, each member state could designate where certain colors could and could not be used. In Germany, for example, quinoline yellow was allowed in puddings and desserts, but tartrazine was not. The reverse was true in France.^[8] This was updated in 1989 with 89/107/EEC, which concerned food additives authorized for use in foodstuffs.^[19]

Current regulation

While naturally derived colors are not required to be certified by a number of regulatory bodies throughout the world (including the U.S. FDA), they still need to be approved for use in that country. Food colorings are tested for safety by various bodies around the world and sometimes different bodies have different views on food color safety.

FDA's permitted colors are classified as subject to certification or exempt from certification in Code of Federal Regulations - Title 21 Part 73 & 74, both of which are subject to rigorous safety standards prior to their approval and listing for use in foods.^[20]

• Certified colors are synthetically produced and are used widely because they impart an intense, uniform color, are less expensive, and blend more easily to create a variety of hues. There are nine certified color additives approved for use in the United States. Certified food colors generally do not add undesirable flavors to foods.
• Colors that are exempt from certification include pigments derived from natural sources such as vegetables, minerals, or animals. Nature derived color additives are typically more expensive than certified colors and may add unintended flavors to foods. Examples of exempt colors include annatto, beet extract, caramel, beta-carotene, turmeric and grape skin extract. This list contains substances which may have synthetic origins, such as nature identical beta-carotene.

In the United States, FD&C numbers (which indicate that the FDA has approved the colorant for use in foods, drugs and cosmetics) are given to approved synthetic food dyes that do not exist in nature, while in the European Union, E numbers are used for all additives, both synthetic and natural, that are approved in food applications. The food colors are known by E numbers that begin with a 1, such as E100 (turmeric) or E161b (lutein).^[21] The safety of food colors and other food additives in the EU is evaluated by the European Food Safety Authority. Color Directive 94/36/EC, enacted by the European Commission in 1994, outlines permitted natural and artificial colors with their approved applications and limits in different foodstuffs.^[8] This is binding to all member countries of the EU. Any changes have to be implemented into their national laws within a given time frame. In non-EU member states, food additives are regulated by their national authorities, which usually, but not in all cases, try to harmonize with the laws adopted by the EU. Most other countries have their own regulations and list of food colors which can be used in various applications, including maximum daily intake limits.

Permitted colorants

E.U.

E numbers 102-143 cover the range of artificial colors. For an overview of currently allowed additives see here . Some artificial dyes approved for food use in the EU include:

• E104: Quinoline Yellow
• E122: Carmoisine
• E124: Ponceau 4R
• E131: Patent Blue V
• E142: Green S

U.S.

In the US, the following seven artificial colorings are generally permitted in food (the most common in bold) as of 2016. The lakes of these colorings are also permitted except the lake of Red No. 3.^[22]

• FD&C Blue No. 1 – Brilliant Blue FCF, E133 (blue shade)
• FD&C Blue No. 2 – Indigotine, E132 (indigo shade)
• FD&C Green No. 3 – Fast Green FCF, E143 (turquoise shade)
• FD&C Red No. 3 – Erythrosine, E127 (pink shade, commonly used in glacé cherries)^[23]
• FD&C Red No. 40 – Allura Red AC, E129 (red shade)
• FD&C Yellow No. 5 – Tartrazine, E102 (yellow shade)
• FD&C Yellow No. 6 – Sunset Yellow FCF, E110 (orange shade)

Two dyes are allowed by the FDA for limited applications:

• Citrus Red 2 (orange shade) - allowed only to color orange peels.
• Orange B (red shade) - allowed only for use in hot dog and sausage casings (not produced after 1978, but never delisted)

Many dyes have been delisted for a variety of reasons, ranging from poor coloring properties to regulatory restrictions.^[24] Some of these delisted food colorants are:

• FD&C Red No. 2 – Amaranth, E123
• FD&C Red No. 4^[25][26]
• FD&C Red No. 32 was used to color Florida oranges.^[24][25][27]
• FD&C Orange Number 1 was one of the first water-soluble dyes to be commercialized, and one of seven original food dyes allowed under the Pure Food and Drug Act of June 30, 1906.^[24][25]
• FD&C Orange No. 2 was used to color Florida oranges.^[24]
• FD&C Yellow No. 1, 2, 3, and 4^[25]
• FD&C Violet No. 1^[25]

Global harmonization

Since the beginning of the 1960s, JECFA has promoted the development of international standards for food additives, not only by its toxicological assessments, which are continuously published by the WHO in a "Technical Report Series", but furthermore by elaborating appropriate purity criteria, which are laid down in the two volumes of the "Compendium of Food Additive Specifications" and their supplements. These specifications are not legally binding but very often serve as a guiding principle, especially in countries where no scientific expert committees have been established.^[7]

In order to further regulate the use of these evaluated additives, in 1962 the WHO and FAO created an international commission, the Codex Alimentarius, which is composed of authorities, food industry associations and consumer groups from all over the world. Within the Codex organization, the Codex Committee for Food Additives and Contaminants is responsible for working out recommendations for the application of food additives, the General Standard for Food Additives. In the light of the World Trade Organizations General Agreement on Tariffs and Trade (GATT), the Codex Standard, although not legally binding, influences food color regulations all over the world.^[7]

Natural food dyes

Natural food colors can make a variety of different hues

Carotenoids (E160, E161, E164), chlorophyllin (E140, E141), anthocyanins (E163), and betanin (E162) comprise four main categories of plant pigments grown to color food products.^[28] Other colorants or specialized derivatives of these core groups include:

• Annatto (E160b), a reddish-orange dye made from the seed of the achiote
• Caramel coloring (E150a-d), made from caramelized sugar
• Carmine (E120), a red dye derived from the cochineal insect, Dactylopius coccus
• Elderberry juice (E163)
• Lycopene (E160d)
• Paprika (E160c)
• Turmeric (E100)

Blue colors are especially rare.^[29] One feasible blue dye currently in use is derived from spirulina.

To ensure reproducibility, the colored components of these substances are often provided in highly purified form. For stability and convenience, they can be formulated in suitable carrier materials (solid and liquids). Hexane, acetone, and other solvents break down cell walls in the fruit and vegetables and allow for maximum extraction of the coloring. Traces of these may still remain in the finished colorant, but they do not need to be declared on the product label. These solvents are known as carry-over ingredients.

Criticism and health implications

Widespread public belief that artificial food coloring cause hyperactivity in children originated with Benjamin Feingold a pediatric allergist from California, who proposed in 1973 that salicylates, artificial colors, and artificial flavors cause hyperactivity in children;^[30] however, there is no evidence to support broad claims that food coloring causes food intolerance and ADHD-like behavior in children.^[31]:452[32] It is possible that certain food coloring may act as a trigger in those who are genetically predisposed, but the evidence is weak.^[33][34]

After concerns were expressed that food colorings may cause ADHD-like behavior in children,^[33] the collective evidence do not support this assertion.^[35] The US FDA and other food safety authorities to regularly review the scientific literature, and led the UK Food Standards Agency (FSA) to commission a study by researchers at Southampton University of the effect of a mixture of six food dyes (Tartrazine, Allura Red, Ponceau 4R, Quinoline Yellow WS, Sunset Yellow and Carmoisine (dubbed the "Southampton 6")) on children in the general population. These colorants are found in beverages.^[33][36] The study found "a possible link between the consumption of these artificial colours and a sodium benzoate preservative and increased hyperactivity" in the children;^[33][36] the advisory committee to the FSA that evaluated the study also determined that because of study limitations, the results could not be extrapolated to the general population, and further testing was recommended".^[33] The U.S. FDA did not make changes following the publication of the Southampton study, but following a citizen petition filed by the Center for Science in the Public Interest in 2008, requesting the FDA ban several food additives, the FDA reviewed the available evidence, and still made no changes.^[33]

The European regulatory community, with an emphasis on the precautionary principle, required labelling and temporarily reduced the acceptable daily intake (ADI) for the food colorings; the UK FSA called for voluntary withdrawal of the colorings by food manufacturers.^[33][36] However, in 2009 the EFSA re-evaluated the data at hand and determined that "the available scientific evidence does not substantiate a link between the color additives and behavioral effects" for any of the dyes.^{[33][37][38][39][40]}

Chemical structures of representative colorants

• Food colorants, natural
• 
  Betanin, a magenta dye, mainly produced from beets.
• 
  Anthocyanin, a red to blue dye depending on functional groups and pH.
• 
  beta-Carotene, a yellow to orange colorant.

• Food colorants, synthetic
• 
  Indigo Carmine, which is blue.
• 
  Allura Red AC, which is red.
• 
  Quinoline Yellow WS, which is yellow.

See also

• Azo compound
• Acid dye
• E number
• Federal Food, Drug, and Cosmetic Act
• Food additive

References

External links

• Food coloring at Encyclopædia Britannica
• FDA/CFSAN Food Color Facts
• Natural Food Colors (Food-Info)
• Report on the Certification of Color Additives by US FDA
• NATCOL: What are natural food colours?
• CSPI: Food Dyes Pose Rainbow of Risks