Synthetic food colors, as distinguished from color additives derived from natural materials, have been commonly used in food products around the world since the early 20th century. They are usually water-soluble chemical substances which have been made in a laboratory or factory environment and can be used in foods without any further processing. The benefits of using synthetic food colors in comparison to the natural food colors are stability over the heat, light and oxygen, and resistance to microbial contamination. In addition, synthetic food colors can be mass-produced at a much lower cost than natural food colors. However, for safety reasons, synthetic food colors have always been strictly controlled by legislation in the world. Not all synthetic food colors have been approved by the Food and Drug Administration (FDA).
Azo dyes in synthetic food colors
Within the synthetic food colors, azo dyes are the largest group and are able to provide coloring shades from yellow, red, blue, and black. Azo dyes are much more stable than most of the natural food dyes. They are stable in the whole pH range of foods, and do not fade when exposed to light or oxygen. This makes azo dyes account for approximately 60-70% of all dyes used in food manufacture. Azo dyes contain the azo group -N=N- as part of their structure. Most azo dyes contain only one azo group (mono azo), but some contain two (diazo), three (triple azo) or more (poly azo). The most commercial important are mono azo dyes, diazo dyes, and triple azo dyes, whereas poly azo dyes are much less important.
The generation of azo dye color originates from a two-step chemical synthesis reaction. The first step leading to a diazo compound from the reaction of an aromatic amine via formation of nitrosamine and diazo hydroxide. The second step immediately follows by the coupling of the diazo compound with various reactive aromatic systems. Due to the p-electrons across the two aromatic moieties and the azo groups, a conjugated system exists that is able to absorb visible light of specific wavelengths, resulting in the color of the compounds. Destruction of the azo-group leads to cleavage into two aromatic amines resulting in the loss of the color. The color of the azo dyes can be controlled by the choice of substituents and the number of azo groups. For example, the shade of yellow color is achieved by using acetoacetic acid arylides and heterocyclic compounds, while the shade of red is produced by reacting aniline derivatives as diazo components with naphthol derivatives. If a benzidine derivative is used instead of the aniline derivative, a blue shade is produced [1].
Our products
Alfa Chemistry's synthetic food colors are synthesized using high quality ingredients and advanced technology, and they can be safely applied in the food field. The main list of synthetic food colors that we are able to offer is listed below.
 Synthetic Food Colors |
|---|
| Product Name | Color Sample | Color Index No. | E-Number | C.I.Food | FD&C Colors |
|---|
| Tartrazine | 
| 19140 | E102 | Yellow 4 | Yellow No. 5 |
| Sunset Yellow | 
| 15985 | E110 | Yellow3 | Yellow No.6 |
| Ponceau 4R | 
| 16255 | E124 | Red 7 | __ |
| Allura Red | 
| 16035 | E129 | Red 17 | Red No.40 |
| Erythrosine | 
| 45430 | E127 | Red 14 | Red No.3 |
| Amaranth | 
| 16185 | E123 | Red 9 | __ |
| Brilliant Blue | 
| 42090 | E133 | Blue 2 | Blue No.1 |
| Indigo Carmine | 
| 73015 | E132 | Blue 1 | Blue No.2 |
| Quinoline Yellow | 
| 47005 | E104 | __ | Yellow No.10 |
| Carmoisine | 
| 14720 | E122 | __ | __ |
| Chocolate Brown HT | 
| 20285 | E155 | __ | __ |
| Patent Blue V | 
| 42051 | E131 | __ | __ |
| Black PN | 
| 28440 | E151 | __ | __ |
| Green S | 
| 44090 | E142 | __ | __ |
- The color samples shown in the table are only approximate.
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Note: FD&C colors are the colors especially for the foods, drugs and cosmetics industry.
Reference:
- Konig, J.; Food colour additives of synthetic origin. Colour Additives for Foods and Beverages. 2015, 35-60.
For Research Use Only. Not for use in diagnostic or therapeutic procedures.
