Coloring Agents Examples


Colors play an influential role in the human’s perception of things present around them. For instance, a red sky during dawn and dusk looks much more appealing than the otherwise clear sky during the day. Several studies show that colors can influence our emotions and decision-making capacity to a great extent. In fact, several enterprises incorporate this power in their marketing strategies and even personify their brand names by using colors. Colorants or coloring agents are the dyes, pigments, or substance that imparts color used by cosmetics, pharmaceutical, and food industries to achieve the desired quality of their final products. They come in the form of powder, paste, and gel, and can either be produced synthetically or naturally. In the food industry, coloring agents impart color to the food and make it more appealing and palatable, and they are also used to prevent the offset of natural color over the prolonged shelf life of food products. In the cosmetic industry, coloring agents are employed to create a visual impression as well as to impart color to the skin when the cosmetic is applied. The pharmaceutical sector primarily uses coloring agents to brand products for simple identification and impact consumer perceptions of quality and flavor. The coloring agents are commonly identified by E numbers ranging from E100 to E199, and their use in products is regulated by the relevant government associations. Let’s take a look at a few examples of commonly used coloring agents.



the turmeric powder

Curcumin is a fluorescent bright yellow coloring agent with E number E-100. Most of us are familiar with the yellow color of Indian curries that is essentially produced by this coloring agent. It is naturally produced by the turmeric plant (Curcuma longa) belonging to the ginger family. Chemically, curcumin is a naturally occurring phenol with the chemical formula {C}_{18}{H}_{11}{NO}_{2}  responsible for the yellow color of turmeric. It is commonly used as a coloring agent in both the food and cosmetic industries. Although curcumin is hydrophobic in nature, it can easily dissolve in organic solvents and oils. Moreover, curcumin is also used as a flavoring agent and dietary supplement in several Asian countries. It is believed to have anti-inflammatory and anti-cancerous effects; however, there is not enough concrete evidence to support these arguments.

Quinoline Yellow WS

Quinoline yellow WS is a water-soluble greenish-yellow coloring agent with E number E-104 and molecular formula {C}_{21}{H}_{20}{O}_{6}. Commercially, quinoline yellow is sold by several other names including food yellow, acid yellow, etc. In chemical terms, quinoline yellow is a disodium salt of disulphonates of 2-(2-quinolyl)indan-1,3-dione. An aqueous solution of quinoline yellow shows a maximum wavelength of 416nm on the UV-visible absorption spectrum. It is mostly used in the manufacturing of foods like sauces, beverages, and decorative food materials. Although the use of quinoline yellow for food products is not permitted in Canada and the USA, these countries permit the use of this coloring agent in drugs and cosmetic manufacturing. To date, there has not been any long-term toxicity or carcinogenicity associated with the use of quinoline yellow.



Carmoisine, also known as Azorubine, is a red color azo dye denoted by the E number E-122. Chemically, carmoisine is a disodium salt of 2-(4 sulpho -1-naphthyl azo)-1-naphthol-4-sulphonic acid consisting of two naphthalene subunits. Like many other azo dyes, carmoisine is also derived synthetically from coal tar. It is generally used in the manufacturing of cosmetics, drugs, and certain food items including alcoholic beverages. Although the health effects of consuming carmoisine have not shown any mutagenic or carcinogenic properties, it is generally advised to limit the daily intake to 4mg/kg.

Ponceau 4R


Ponceau 4R is also a dark red colored azodye like carmoisine, and it is denoted by the E number E-124. Commercially, Ponceau 4R is available with several names, such as Acid Red, Brilliant Scarlet, New Coccine, etc.  It’s used to impart the red color to several food items such as candies, jellies, desserts, cakes, pastries, soups, soft drinks, canned beverages, and other food items. The chemical composition of Ponceau 4R includes trisodium salt of 2-hydroxy-1-(4- sulfonato-1-naphtylazo)-naphthalene-6,8-disulfonate. Like many other azo dyes, Ponceau 4R is also derived synthetically from coal tar. Although there is no evidence of carcinogenicity, hepatotoxicity, neurotoxicity, or reproductive and developmental toxicity associated with Ponceau 4R consumption, the possible ill effects or ponceau side effects include evoking reactive responses in people who already have an aspirin allergy and hyperactivity in young children and kids.

Patent Blue V

Patent Blue V

Patent Blue V, also known as Food Blue 5, is a coloring agent denoted by the E number E-131. It is a synthetic triphenylmethane dye whose chemical composition includes sodium or calcium salt of [4-(α-(4-diethylaminophenyl)-5-hydroxy- 2,4-disulfophenylmethylidene)-2,5-cyclohexadien-1-ylidene] dimethylammonium hydroxide and the molecular formula is {C}_{27}{H}_{31}{N}_{2}{O}_{7}{S}_{2} · {0.5Ca}. In the food industry, it is primarily used in the manufacturing of gelatin desserts and beverages such as blue Curaçao. In the medical sector, patent blue V plays an essential role in a diagnostic technique called lymphography. It is used as an indicator or staining agent to detect anomalies in the lymph nodes. Moreover, it is also used as a stain to indicate dental plaque. Several studies have shown that consumption of Patent Blue V is associated with allergic reactions ranging from itching and nausea to hypotension and anaphylactic shock.

Green S


As the name suggests, Green S is a green color dye denoted by the E number E-142. It is commercially available with several other names, including Food Green S, Lissamine Green, Wool Green BS, or Acid Green 50. Chemically, Green S is a synthetic coal tar triarylmethane dye with the molecular formula {C}_{27}{H}_{25}{N}_{2}{O}_{7}{S}_{2}{Na}. Although Green S is widely used as a food coloring agent in several countries, it is not permitted to be used as a food additive in some countries, such as Canada, United States, Japan, and Norway. Apart from being a coloring agent in the food, drug, and cosmetic industry, Green S also plays an important role in the diagnosis of various eye disorders, including dry eye. Green S is poorly absorbed and mostly excreted intact, according to studies on its absorption, distribution, metabolism, and excretion. These studies suggest that consumption of Green S is not associated with any kind of mutagenic or carcinogenic toxicity.



Tartrazine is a synthetic lemon yellow azo dye denoted by the E number E-102. It is commercially available with several other names, including Yellow 5 Lake, Acid Yellow 23, Food Yellow 4, Lemo Yellow, etc. Chemically, Tartrazine is a trisodium salt of 4-sulfonatophenyl-4-(4-sulfonatophenylazo)-5-pyrazolone-3-carboxylate) with the molecular formula [kate]{C}_{16}{H}_{9}{N}_{4}{Na}_{3}{O}_{9}{S}_{2}[/katex]. It is primarily used to make foods more aesthetically pleasing from a visual viewpoint. Tartrazine is typically found in processed commercial meals that are artificially yellow or green in color, or that consumers anticipate to be brown or creamy in appearance. It’s commonly used to tint fake lemon filling in baked items a brilliant yellow color.  Common examples of food items include desserts and confectionaries such as ice creams, and gummy bears, beverages such as sports drinks and soft drinks, snacks, and other processed food such as cereals, chips, etc.

Allura Red AC

Allura Red AC is a red-colored azo dye commonly used as a coloring agent to impart a red color to various food items and has the E number E 129. The chemical composition of Allura red AC consists of water-soluble disodium salt of 2 – hydroxy-1-(2-methoxy – 5-methyl-4-sulfonatophenyl azo) naphthalene -6- sulfonate, denoted by the chemical formula {C}_{18}{H}_{14}{N}_{2}{Na}_{2}{O}_{8}{S}_{2}. An aqueous solution of Allura Red AC shows a maximum wavelength of 504 nm on the UV-visible absorption spectrum. It is one of the most widely used food coloring agents and can commonly be found in cotton candies, soft drinks, and other food items. Although Allura red is primarily used in the manufacturing of food items and for aesthetic purposes such as tattoo ink and cosmetic products, it is occasionally used to color pharmaceutical pills, such as the antihistamine fexofenadine.

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