Tartrazine is an azoic food additive with dye function, internationally labeled as INS102 and in Europe with the number E102. It is a pyrazolone derivative and is used in various food, cosmetic, and pharmaceutical products to impart a bright yellow color.

Description of the raw materials used in its production:

• Sulfanilic Acid - An aromatic amine compound.
• Pyridine - An organic compound used as a solvent and catalyst.
• Sodium Chloride - Common salt.
• Sodium Hydroxide (NaOH) - Caustic soda.

Industrial chemical synthesis of Tartrazine, step by step:

• Diazotization - Sulfanilic acid is converted into a diazonium compound through a reaction with sodium nitrite in an acidic environment.
• Coupling - The diazonium compound is then reacted with a solution of pyridine and sodium chloride. During this reaction, an azo bond (–N=N–) is formed between the two compounds.
• Isolation - The formed tartrazine precipitates out of the solution and is isolated via filtration.
• Purification - The crude tartrazine is purified through crystallization, usually using hot water or a sodium hydroxide solution.
• Quality control - Once Tartrazine is obtained, it undergoes various quality checks to ensure it meets specifications.

It occurs in the form of a yellow powder.

Cosmetics

It is a restricted ingredient as IV/44 (CI 19140) III/189 (Acid Yellow 23; Acid Yellow 23 Aluminum lake)  a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported: Trisodium 5-hydroxy-1-(4-sulphophenyl)-4-((4-sulphophenyl)azo)pyrazole-3-carboxylate and its insoluble barium, strontium and zirconium lakes, salts and pigments.

Colorant. This ingredient has the function of colouring the solution in which it is inserted in a temporary, semi-permanent or permanent manner, either alone or in the presence of the complementary components added for colouring.

Hair dyeing. It is an ingredient that adds a colouring to the hair that can be temporary, semi-permanent or permanent depending on what other ingredients are added to achieve the result. The pH for hair dyeing is generally between 9 and 10.

Safety

The problem with azo dyes (monoazo or diazo) is photocatalytic degradation leading to oxidation and the subsequent formation of impurities such as aromatic amines, some of which have carcinogenic activity.

Commercial applications

Food. Used to color a variety of food products, such as beverages, candies, ice creams, and baked goods, to impart a yellow or orange hue.

Cosmetics. It can be used in cosmetic products like soaps, shampoos, and other personal care products.

Pharmaceutical. Used as a coloring agent in some medications for capsules and tablets.

Inks and Paints. Used as a pigment in inks and paints to give a bright yellow color.

Textile Industry. It can be used as a dye for fabrics.

Studies

Tartrazine is a well-known synthetic colorant that is frequently and widely used in foods (such as soft drinks and candies), pharmaceuticals and cosmetics to make them appealing to customers. The acceptable daily intake of tartrazine in food, proposed by the FAO and WHO, is 7.5 mg/kg. Tartrazine has low toxicity, but its excessive ingestion can result in allergy, asthma, migraine and hyperactivity. It may also trigger sleep disorders in children. Given the potential risks to humans, tartrazine has been banned in countries including Norway and Austria. Increasing concern has been paid to health issues provoked by food additives used in China; the types of foodstuff and the maximum amount of additives allowed have been strictly set by Chinese regulation (GB2760-2014). Tartrazine, a coloring agent used on yellow croaker (Pseudosciaena crocea), in tsukemono and in wine, has been banned by the Ministry of Health of the Republic of China. However, it is still used illegally and in excess in various food products due to its high economic benefits. Hence, developing a time-efficient, cost-effective and sensitive method to detect tartrazine in foodstuff is necessary (1).

Tartrazine is a food colour that activates the transcriptional function of the human oestrogen receptor alpha in an in vitro cell model. Since oestrogens are cholestatic, we hypothesised tartrazine will cause periportal injury to the liver in vivo. To test this hypothesis, tartrazine was initially administered systemically to mice resulting in a periportal recruitment of inflammatory cells, increased serum alkaline phosphatase activity and mild periportal fibrosis. To determine whether an oestrogenic effect may be a key event in this response, tartrazine, sulphonated metabolites and a food additive contaminant were screened for their ability to interact with murine oestrogen receptors. In all cases, there were no interactions as agonists or antagonists and further, no oestrogenicity was observed with tartrazine in an in vivo uterine growth assay. To examine the relevance of the hepatic effects of tartrazine to its use as a food additive, tartrazine was orally administered to transgenic NF-κB-Luc mice. Pre- and concurrent oral treatment with alcohol was incorporated given its potential to promote gut permeability and hepatic inflammation. Tartrazine alone induced NF- κB activities in the colon and liver but there was no periportal recruitment of inflammatory cells or fibrosis. Tartrazine, its sulphonated metabolites and the contaminant inhibited sulphotransferase activities in murine hepatic S9 extracts. Given the role of sulfotransferases in bile acid excretion, the initiating event giving rise to periportal inflammation and subsequent hepatic pathology through systemic tartrazine exposure is therefore potentially associated an inhibition of bile acid sulphation and excretion and not on oestrogen receptor-mediated transcriptional function. However, these effects were restricted to systemic exposures to tartrazine and did not occur to any significant effect after oral exposure (2).

Tartrazine is a synthetic organic azo dye widely used in food and pharmaceutical products. The current study aimed to evaluate the possible adverse effect of this coloring food additive on renal and hepatic structures and functions. Also, the genotoxic potential of tartrazine on white blood cells was investigated using comet assay. Twenty adult male Wistar rats were grouped into two groups of 10 each, control- and tartrazine-treated groups. The control group was administered orally with water alone. The experimental group was administered orally with tartrazine (7.5 mg/kg, b.wt.). Our results showed a marked increase in the levels of ALT, AST, ALP, urea, uric acid, creatinine, MDA and NO, and a decreased level of total antioxidants in the serum of rats dosed with tartrazine compared to controls. On the other hand, administration of tartrazine was associated with severe histopathological and cellular alterations of rat liver and kidney tissues and induced DNA damage in leucocytes as detected by comet assay. Taken together, the results showed that tartrazine intake may lead to adverse health effects (3).

• Molecular Formula:   C₁₆H₉N₄Na₃O₉S₂
• Molecular Weight:  534.356
• CAS:  1934-21-0
• EC number:  217-699-5

Synonyms:

• Yellow 5
• Food Yellow 4
• 4,5-Dihydro-5-oxo-1-(4-sulfophenyl)-4-((4-sulfophenyl)azo)-1H-pyrazole-3-carboxylic acid, trisodium salt
• Trisodium 5-oxo-1-(4-sulfonatophenyl)-4-[(E)-(4-sulfonatophenyl)diazenyl]-4,5-dihydro-1H-pyrazole-3-carboxylate
• 3-Carboxy-5-hydroxy-1-p-sulfophenyl-4-p-sulfophenylazopyrazole trisodium salt
• Colour Index Number 19140
• PubChem Substance ID 24899885
• MDL number MFCD00148908
• EC Number 217-699-5
• Beilstein Registry Number 69850

References_________________________________________________________________________

(1) Song J, Zhang Y, Huang Y, Fan Y, Lai K. Rapid Tartrazine Determination in Large Yellow Croaker with Ag Nanowires Using Surface-Enhanced Raman Spectroscopy.  Nanomaterials (Basel). 2018 Nov 23;8(12). pii: E967. doi: 10.3390/nano8120967.

(2) Meyer SK, Probert PME, Lakey AF, Axon AR, Leitch AC, Williams FM, Jowsey PA, Blain PG, Kass GEN, Wright MC. Hepatic effects of tartrazine (E 102) after systemic exposure are independent of oestrogen receptor interactions in the mouse.  Toxicol Lett. 2017 May 5;273:55-68. doi: 10.1016/j.toxlet.2017.03.024. 

(3) Khayyat L, Essawy A, Sorour J, Soffar A. Tartrazine induces structural and functional aberrations and genotoxic effects in vivo.  PeerJ. 2017 Feb 23;5:e3041. doi: 10.7717/peerj.3041.