Section
| HS Code | 115658 |
| Product Name | Carmoisine |
| Synonyms | Azorubine; CI Acid Red 14; Food Red 3 |
| E Number | E122 |
| Colour Index Number | 14720 |
| Cas Number | 3567-69-9 |
| Ec Number | 222-657-4 |
| Molecular Formula | C20H12N2Na2O7S2 |
| Molecular Weight | 502.43 g/mol |
| Appearance | Dark red to maroon powder or granules |
| Solubility | Soluble in water; slightly soluble in ethanol |
| Primary Use | Synthetic azo food colourant |
| Maximum Absorbance | Approximately 516 nm in water |
As an accredited Carmoisine factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Carmoisine, 25 kg, packed in a double polyethylene-lined fibre drum, sealed with tamper-evident closure and labeled with product and batch information. |
| Container Loading (20′ FCL) | Carmoisine dye is loaded into a 20′ FCL container in sealed packaging, palletized and secured with labels and shipping documents. |
| Shipping | Carmoisine is typically shipped as a non-hazardous powder in sealed, clearly labeled containers, protected from moisture, light, and contamination. It is generally not classified as dangerous for transport under ADR/IMDG/IATA; use ambient conditions, avoid excessive heat, and follow standard chemical handling and local shipping regulations. |
| Storage | Store Carmoisine in a cool, dry, well-ventilated area in a tightly closed, properly labeled container. Protect from moisture, direct sunlight, and heat. Keep separate from strong oxidizing agents and incompatible materials. Prevent dust generation and avoid inhalation. Use secondary containment to control spills. Keep away from food, drink, and animal feed, and close containers when not in use. |
| Shelf Life | Typically 2–3 years when stored cool, dry, and protected from light and moisture; exact shelf life depends on formulation and storage conditions. |
Within carbonated beverage production, carmoisine is handled as a bulk water-soluble disodium azo salt conforming to the purity criteria of Commission Regulation (EU) No 231/2012 and the JECFA Combined Compendium for Food Additives, and its legal dosing ceiling in the European Union is governed by Regulation (EC) No 1333/2008 Annex II; in flavoured non-alcoholic drinks the EU maximum permitted level is 50 mg/L, which places the practical formulation range between 0.005 g/L and 0.05 g/L. Production lines typically target 20–35 mg/L for cherry, red berry, and pink grapefruit shades, with final colour strength controlled by spectrophotometric absorbance at 516 nm through a 1 cm transmission cell after degassing the sample. The downstream process begins with preparation of a 1–5 wt% aqueous stock solution in stainless steel make-up tanks at 30–40 °C, followed by filtration through ≤ 25 µm mesh and in-line positive-displacement metering into the beverage stream after flash pasteurisation and before carbonation; dissolved oxygen is held below 0.5 mg/L in the treated water because residual oxygen accelerates reductive cleavage of the azo chromophore, a degradation route that becomes more pronounced when ascorbic acid is present, requiring segregated dosing lines and low-temperature filling at 4–8 °C. Terminal product types produced under these conditions include carbonated soft drinks, still flavoured waters, juice-based drinks, and sports drinks, with the caveat that transparent PET packaging without UV-barrier film is an operational boundary when the same shade is required across a 6–12 month shelf-life; quantification of fade under specific retail lighting requires pilot-scale light-box exposure rather than extrapolation from bench beaker data.
Sugar confectionery lines utilise carmoisine in pectin jellies, gelatine gums, and high-boiled sweets not as a dry powder but as a filtered aqueous solution, because direct dusting into a 145–150 °C vacuum-cooked syrup creates localised colour streaks and fails to disperse before the cooling belt. The legal reference is Regulation (EC) No 1333/2008 Annex II, where E122 is listed for several sugar confectionery subcategories with maximum limits that depend on the specific food category; a production facility targeting EU-compliant exports must verify the exact Annex II entry for the final recipe, while raw material purity is verified against Commission Regulation (EU) No 231/2012 and the JECFA specification. Formulation addition ratios range from 0.005 % to 0.03 % w/w of final product mass, with 20–80 mg/kg typical for translucent pectin gels and 50–150 mg/kg for deeply coloured hard candy, always measured as active dye rather than commercial powder. In the process, carmoisine is first dissolved at 1–2 wt% in deionised water at 40–50 °C, then dosed into the cooled syrup stream after the vacuum cook stage and after acidulant addition; a continuous motionless mixer is installed before the starch mogul or batch roller to bring colour variance below 1.5 CIELAB ΔE*ab as measured by a handheld sphere spectrophotometer on hot syrup. The main operational conflict occurs when the dye encounters high dissolved sugar and low pH simultaneously: at pH 2.8–3.2 the visible absorbance maximum should be re-established on the acidified syrup because the λmax can shift relative to neutralised stock solution, and the target shade specification must therefore be fixed at the final pH rather than on the neutralised stock solution. Terminal artefacts include clear hard candy, pectin jellies, gelatine gums, and sugar-panned chewing gum centres; for fat-based fillings or long-term panned surfaces, the aluminium lake form is used instead of the sodium salt to limit migration of the water-soluble dye into the sugar shell during 40–45 °C pan-coating.
Aqueous tablet coating with hypromellose relies on complete de-agglomeration of carmoisine before it enters the spray line because any undispersed dye particle larger than the spray nozzle orifice creates visible specking on the tablet surface. Pharmaceutical-grade carmoisine is specified against the current Ph. Eur. Azorubine monograph and, where relevant, ICH Q3D for elemental impurity risk management; medicinal product colourants in the EU are also linked to Directive 2009/35/EC for colouring agents in medicines, while finished products for non-US markets use the water-soluble sodium salt and, for moisture-sensitive barrier applications, the aluminium lake. Formulation addition ratios are typically 0.05–0.5 % w/w of the tablet core mass for the soluble dye and 0.2–1.0 % w/w for the lake, depending on the colour intensity required in the film after 2–4 % weight gain. In production, carmoisine is dispersed in purified water at 20–30 °C under high-shear rotor-stator mixing at 3000–6000 rpm for 15–30 min, then incorporated into a hypromellose solution at 8–12 % solids; the pan-coating equipment is typically a side-vented, fully perforated drum running at 4–12 rpm with inlet air at 60–70 °C, bed temperature at 38–46 °C, and spray rate 8–15 g/min per kg of tablet bed. The main operational boundary is moisture: the sodium salt migrates into the coated cellulosic film if core moisture exceeds 3 % or if coating suspension hold time exceeds 4 h, producing uneven colour gradient; because carmoisine is not listed in 21 CFR Part 74 for use in foods, drugs, or cosmetics in the US market, batches produced with this dye must be labelled and sold only in authorised jurisdictions. Terminal product types include immediate-release film-coated tablets, sugar-coated tablet cores, and colour-matched hard capsule shells made by dipping pins in carmoisine-loaded gelatine solution.
In exhaust dyeing of wool, silk, polyamide 6/6.6, and vegetable-tanned leather, technical-grade carmoisine (C.I. Acid Red 14) is applied as an acid dye because its sulfonated naphthalene structure ionically binds to protonated amino groups in protein and polyamide fibres when the dyebath is run below the isoelectric point. Regulatory compliance for this non-food application is covered by REACH (EC) No 1907/2006 registration, and the downstream dyed article may be tested for azo-releasable amines under EN ISO 14362-1:2017 for textiles and ISO 17234-1:2015 for leather, and for washing and light fastness under ISO 105-C06 and ISO 105-B02; carmoisine is not normally selected for high-lightfastness automotive textiles, where its light fastness on wool is typically moderate and must be verified for the intended end use. The formulation addition ratio is 0.5–2.5 % on weight of dry fibre for deep red shades and 0.05–0.2 % for pastel and skin tones, with the exact quantity determined by exhaust dyeing trials in laboratory infrared heating pots before scale-up. The process uses a stainless-steel jet or overflow dyeing vessel at a liquor ratio of 1:8–1:12, with the dyebath set at 30–40 °C, pH adjusted to 4.0–5.5 with acetic acid or a buffered acid donor, then ramped at 1–2 °C/min to 90–98 °C for wool or 40–60 °C for chrome-free vegetable-tanned leather, and held for 30–60 min; after exhaustion the fabric or leather is rinsed in fresh water and fixed with cationic dye-fixing auxiliary where improved wet fastness is required. Terminal product types include dyed wool yarn and fabric, silk scarves, nylon warp-knitted intimate apparel components, and non-automotive upholstery and garment leather.
Although carmoisine is predominantly associated with food, cosmetic-grade material is permitted in the EU as CI 14720 under Regulation (EC) No 1223/2009 Annex IV, and the raw material must comply with the purity constraints of Regulation (EU) No 231/2012 where the identical dye chemical is used in personal care products; manufacturers exporting to the US must verify that CI 14720 is not listed in 21 CFR Part 74 for the relevant cosmetic use before formulation. Formulation addition ratios are low: 0.0005–0.02 % w/w of final product mass, with 0.002–0.01 % common in liquid soap, bubble bath, and bath bomb compositions because carmoisine is highly tinctorially strong in water. The downstream process first disperses the powder in a small volume of water at 20–40 °C before adding it to the cooled surfactant base after neutralisation and below 60 °C; in solid bath bomb production, the pre-dissolved dye is sprayed onto a citric acid–sodium bicarbonate blend in a ribbon or ploughshare mixer operating at 15–25 rpm, with residual moisture kept below 0.5 % w/w to prevent premature effervescence and colour bleeding. The critical operational boundary is pH and cationic charge: carmoisine suffers shade dulling and precipitation in formulations containing cationic polymers, quaternary ammonium conditioning agents, or concentrated alkaline bases above pH 9, and long exposure to daylight in clear packaging can lead to photodegradation, so opaque or tinted containers and low-temperature storage below 35 °C are used. Terminal product types include liquid hand soap, bubble bath, bath salts, bath bombs, and shampoo, but the dye is not the colourant of first choice for leave-on skin products where long-term skin staining or light exposure risks require dedicated patch and UV-light stability testing.
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Carmoisine, commonly listed as Azorubine, is a synthetic monoazo colorant supplied as a red-to-maroon disodium salt with Colour Index designation CI 14720, CAS registry 3567-69-9, and European additive code E122. The molecular formula is C20H12N2Na2O7S2 and the relative molecular mass is 502.43 g mol−1. In dilute aqueous solution, the absorption maximum occurs near 516 nm; the resulting shade is red with a maroon cast, which distinguishes it from shorter-wavelength reds such as Allura Red AC. Commercial grades include food-grade powder, granular material, and aluminium lake forms. Food-grade E122 must meet the purity requirements of Commission Regulation (EU) No 231/2012; industrial Acid Red 14 grades intended for textile dyeing or technical use are not food-grade and should not be used interchangeably. The water-soluble acid dye is freely soluble in water, sparingly soluble in ethanol, and practically insoluble in vegetable oils, so its application is concentrated in aqueous food systems, water-based confectionery coatings, syrups, and aqueous cosmetic gels.
Commercial synthesis follows the standard two-stage azo route: diazotization of 4-aminonaphthalene-1-sulfonic acid in acid solution, followed by alkaline coupling with 4-hydroxy-1-naphthalenesulfonic acid. The resulting disodium salt is isolated by filtration, washed, and dried. Granular grades typically exhibit lower dusting than powder grades, and the particle size distribution of the selected grade influences dispersion time in high-solids media. Buyers should confirm batch-specific color strength and particle size because these parameters affect dosing accuracy and visual yield in production.
In beverage and syrup batching, dry powder addition directly into high-solids media is not the standard industrial route. The colorant is typically prepared as a 1–5% aqueous stock solution in demineralized water at 40–50 °C under low-shear agitation. This pre-dissolution step prevents colour specks and supports uniform distribution in batch tanks made of 316L stainless steel. The dissolution vessel should be covered because airborne powder retention on wet vessel walls creates a particulate cross-contamination source. Once in solution, the dye can be metered into the main mix using a positive-displacement pump with flow control. In fruit syrup concentrates with soluble solids above 60°Brix, the stock solution should be added after sugar dissolution and pH adjustment, because localised high-viscosity zones slow molecular diffusion and may cause temporary colour streaks. In clear beverages, filtration through a 10 μm or finer filter after dosing is used in some lines to remove any undissolved fractions; published line-specific data for this configuration is limited.
Carmoisine is stable under conventional pasteurisation conditions in weakly acidic media, but it is not resistant to reductive breakdown. Ascorbic acid, sulfites, and cysteine cleave the azo bond and shift the absorption spectrum toward colourless or yellow-brown degradation products. A vitamin-fortified beverage containing ascorbic acid at 100–300 mg/L may show measurable colour loss during accelerated storage at 40 °C and 75% relative humidity over 4–8 weeks; packaged UV exposure can amplify loss when the bottle allows transmission below 380 nm. The specific degradation rate is strongly matrix-dependent, and published data for all commercial beverage formulations is limited. Thermal degradation during retort operations is less severe than reductive degradation, but long hold times in retorted fruit preparations can reduce colour strength. The dye remains soluble and anionic across the pH range used in foods; precipitation is not a typical failure mode except when cationic gums or quaternary ammonium compounds are introduced, because sulfonated azo dyes form insoluble complexes with cationic polymers. Formulators should therefore avoid direct contact with cationic conditioning agents in the same premix.
Light-induced fading is moderate. In clear glass, the dye fades more rapidly than in PET bottles with UV barrier; the difference is measurable using a xenon arc accelerated weathering cabinet according to ISO 105-B02 or a beverage-specific light cabinet. The manufacturer’s certificate of analysis typically reports colour strength at 516 nm and hue through a spectrophotometric method; batch-to-batch variation in colour strength for food-grade material is usually controlled within ±5%.
Under Commission Regulation (EU) No 231/2012, the food additive identity for E122 includes a minimum dye content of 85% on a dry basis. Water-insoluble matter is restricted to ≤0.2%, subsidiary dyes to ≤1.0%, and organic compounds other than colouring matters are controlled as specified. Heavy-metal limits follow the general food additive specification: lead ≤2 mg/kg, arsenic ≤3 mg/kg, cadmium ≤1 mg/kg, and mercury ≤1 mg/kg when measured by the methods referenced in the regulation. The Certificate of Analysis should state the dye content, subsidiary dye content, water-insoluble matter, heavy-metal results, and loss on drying. Official control laboratories typically use spectrophotometry at the absorption maximum for total colour content and high-performance liquid chromatography with diode-array detection for subsidiary dye profiling.
| Parameter | Compliance-grade E122 limit | Typical analytical approach |
|---|---|---|
| Total dye content | ≥85% on dry basis | Spectrophotometry at λmax |
| Water-insoluble matter | ≤0.2% | Gravimetric after aqueous dissolution |
| Subsidiary dyes | ≤1.0% | HPLC with diode-array detection |
| Lead | ≤2 mg/kg | ICP-MS or atomic absorption |
| Arsenic | ≤3 mg/kg | ICP-MS or atomic absorption |
| Cadmium | ≤1 mg/kg | ICP-MS |
| Mercury | ≤1 mg/kg | ICP-MS |
Under Regulation (EC) No 1333/2008, foods containing E122 must bear the warning that the colourant may have an adverse effect on activity and attention in children. The acceptable daily intake for Carmoisine is 4 mg/kg body weight per day based on the EFSA evaluation of the Southampton colour group. Use levels are product-specific and set in Annex II to Regulation (EC) No 1333/2008; the colourant is not listed as a permitted food colour additive by the United States Food and Drug Administration for general food use. Codex Alimentarius provisions may recognise the additive as INS 122, but national adoption differs.
Although both are red azo colorants, Carmoisine and Ponceau 4R differ in hue angle and regulatory status. Carmoisine has a longer-wavelength absorption maximum and gives a slightly more maroon or blue-red shade; Ponceau 4R appears redder and less maroon. This difference is visible in berry and cherry fillings, where a direct one-to-one substitution changes the perceived fruit identity. The following table summarises selected comparative data for product selection.
| Property | Carmoisine | Ponceau 4R | Allura Red AC |
|---|---|---|---|
| European code / Colour Index | E122 / CI 14720 | E124 / CI 16255 | E129 / CI 16035 |
| CAS registry | 3567-69-9 | 2611-82-7 | 25956-17-6 |
| Approximate λmax in aqueous solution | 516 nm | 505 nm | 504 nm |
| Hue character | red to maroon | red | red-orange |
| FDA food listing | not listed | not listed | FD&C Red 40 |
| EU labelling warning for child-activity effects | required | required | required |
Replacement trials should not rely solely on colour strength. The maroon shift in Carmoisine may require reduction of a blue shade component or adjustment of caramel content in brown sugar systems. In a bakery jam filling cooked at 90 °C for 15 min, the hue of Carmoisine can appear more stable than in a clear beverage exposed to ascorbic acid, because the jam matrix is less redox-active and the low water activity limits the mobility of reducing agents. However, published data for this specific configuration is limited. When migration into a surrounding casing or white fat-based cream is a concern, the water-soluble dye remains in the aqueous jam phase, while an aluminium lake is the appropriate particulate variant for low-moisture coatings and dry blends because it does not bleed into oil phases.
Carmoisine also appears in aqueous cosmetic formulations and external pharmaceutical colouring. The applicable regulatory status is different from food; in the EU cosmetic regulation, CI 14720 may be used as a colourant under the conditions set in Regulation (EC) No 1223/2009 Annex IV. For pharmaceutical coatings, the aluminium lake is often preferred over the water-soluble dye because it provides uniform colour in film-coated tablets without migration into the tablet core. The lake is prepared by precipitating the dye on an alumina hydrate substrate; the dye content of a lake is not fixed and must be confirmed by the manufacturer. In lipophilic systems, the water-soluble acid dye has negligible solubility and is not used; the lake provides dispersion rather than true solution.
Carmoisine lake is insoluble in water and acids, and its dispersion requires high-shear mixing in aqueous suspensions. The lake particles are typically sized for coating applications; particle size distribution is measured by laser diffraction and should be specified by the buyer because coarse fractions cause clogging of spray nozzles in pan-coating equipment. In tablet-coating suspensions at 10–15% solids, sediment must be avoided by continuous low-shear agitation. Published process guidance for specific Carmoisine lake grades is limited. Non-food Acid Red 14 grades used in textile dyeing are not manufactured under the same food-additive hygiene controls, and their impurity profile may differ substantially; these grades should never be used in food or pharmaceutical applications.
Compared with anthocyanin-based red concentrates, Carmoisine has a smaller molecular weight, no pH-dependent flavylium cation equilibria, and stronger tinting intensity. Anthocyanin colorants shift red to blue or brown as pH rises, whereas sulfonated azo reds maintain hue in acidic foods. The technical choice between Carmoisine and a natural red therefore involves not only shade and cost but also process pH, reducing-agent load, packaging UV transmission, and regulatory label requirements.
