fd&c blue no. 2 aluminum lake (c.i. 73015 (Al))

Full Material List

N/A

Identifiers

CAS (Single)	16521-38-3
FEMA	N/A
EINECS	240-589-3
Synonyms	acid blue 74-aluminum lake aluminum (2E)-3-oxo-2-(3-oxo-5-sulfo-1H-indol-2-ylidene)-1H-indole-5-sulfonic acid aluminum 2-(1,3-dihydro-3-oxo-5-sulfo-2H-indol-2-ylidene)-2,3-dihydro-3-oxo-1H-indole-5-sulfonic acid complex aluminum 3,3'-dioxo-(d2,2-biindoline)-5,5'disulfonate aluminum 3,3'-dioxo-(delta2,2-biindoline)-5,5'disulfonate 73015 aluminum lake aluminum, 2-(1,3-dihydro-3-oxo-5-sulfo-2H-indol-2-ylidene)-2,3-dihydro-3-oxo-1H-indole-5-sulfonic acid complex (d2,2- biindoline)-5,5'-disulfonic acid, 3,3'-dioxo-, aluminum salt c.i. 73015 (Al) C.I. acid blue 74-aluminum lake C.I. food blue 1-aluminum lake C.I. food blue 1:1 C.I. pigment blue 63 certolake indigo carmine ci 73015 (Al) fd&c blue no. 2 aluminum lake (c.i. 73015 (Al)) FD&C blue no. 2-aluminum lake food blue 1-aluminum lake food blue 1:1 food blue no. 2-aluminum lake indigo carmine-aluminum lake indigo disulfonic acid, aluminum salt indigotine-aluminum lake 1H- indole-5-sulfonic acid, 2-(1,3-dihydro-3-oxo-5-sulfo-2H-indol-2-ylidene)-2,3-dihydro-3-oxo-, aluminum complex japan blue 2 aluminum lake japan food blue no. 2 aluminum lake pigment blue 63
JECFA Food Flavoring	N/A
JECFA Food Additive	N/A
DG SANTE Food Flavourings	N/A
DG SANTE Food Contact Materials	N/A
FDA UNII
CoE Number	N/A
XlogP3-AA	N/A
Molecular Weight	449.3748386
Molecular Formula	C16 H10 Al N2 O8 S2

Properties

Food Chemicals Codex Listed	No
Appearance	blue powder (est)
Assay	96.00 to 100.00
Specific Gravity	N/A
Lbs/Gal (est)	N/A
Refractive Index	N/A
Melting Point	N/A
Boiling Point	N/A
Flash Point	32.00 Â°F. TCC ( 0.00 Â°C. ) (est)
Acid Value	N/A
Vapor Pressure	N/A
Vapor Density	N/A
logP (o/w)	1.63
Soluble In	N/A
Occurrence	not found in nature

Organoleptic

Organoleptic Notes	Odor and/or flavor descriptions from others (if found).
Odor	N/A
Flavor	N/A

AInsights BETA

FlavScents AInsights Entry for FD&C Blue No. 2 Aluminum Lake (C.I. 73015 (Al)) (CAS: 16521-38-3)

1. Identity & Chemical Information

Common Name(s): FD&C Blue No. 2 Aluminum Lake, Indigotine Aluminum Lake
IUPAC Name: Disodium 3,3'-dioxo-2,2'-biindolylidene-5,5'-disulfonate aluminum salt
CAS Number: 16521-38-3
FEMA Number: Not applicable
Other Identifiers: C.I. 73015 (Al)
Molecular Formula: C16H8N2Na2O8S2·Al
Molecular Weight: Approximately 792.85 g/mol
Functional Groups and Structure-Odor Relevance: FD&C Blue No. 2 Aluminum Lake is a synthetic dye composed of indigotine bound to aluminum hydroxide. It is primarily used for its vibrant blue color rather than any odor or flavor characteristics.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

FD&C Blue No. 2 Aluminum Lake is primarily used as a colorant and does not possess significant odor or flavor characteristics. Its sensory role is limited to visual impact, providing a vivid blue hue to products. It does not contribute to taste or aroma profiles and is not used for its sensory properties in flavor or fragrance formulations.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

FD&C Blue No. 2 Aluminum Lake is a synthetic compound and does not occur naturally. It is produced through the sulfonation of indigo, followed by conversion to the sodium salt and subsequent precipitation with aluminum hydroxide to form the lake. This process is entirely synthetic, and the material is not associated with any natural flavor or fragrance designations.

Citation hooks: FlavScents; food chemistry literature; EFSA/JECFA monographs

4. Use in Flavors

FD&C Blue No. 2 Aluminum Lake is not used for its flavor properties but as a colorant in food and beverage products. It is commonly found in confectionery, beverages, and dairy products to provide a blue color. Typical use levels in food products range from 2 to 100 ppm, depending on the desired intensity of color. The compound is stable under a variety of conditions, including heat and pH variations, making it suitable for a wide range of applications.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance applications, FD&C Blue No. 2 Aluminum Lake is used to impart color to products such as soaps, shampoos, and other personal care items. It does not contribute to the fragrance profile but serves as a visual enhancer. Typical concentrations in these products are qualitative, focusing on achieving the desired color intensity. The compound is stable and does not affect the volatility or scent profile of the fragrance.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

United States: Approved by the FDA for use in food, drugs, and cosmetics. It is listed under 21 CFR Part 74.
European Union: Permitted as a food additive under Regulation (EC) No 1333/2008 with E number E132.
United Kingdom: Follows EU regulations post-Brexit, allowing its use as a food additive.
Asia: Approved in countries like Japan and China for similar uses as in the US and EU.
Latin America: Generally accepted in countries like Brazil, subject to local regulations.

Explicit approvals exist in these regions, with harmonized assumptions across many countries. However, specific use levels and applications may vary.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

Oral Exposure: Considered safe for consumption within established limits. The ADI set by JECFA is 0-5 mg/kg body weight.
Dermal Exposure: Generally regarded as non-irritating and non-sensitizing in cosmetic applications.
Inhalation Exposure: Not typically a concern due to its use as a non-volatile colorant.

The risk profiles for food and fragrance applications are similar, with safety assessments supporting its use within regulated limits.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

FD&C Blue No. 2 Aluminum Lake is valued for its vibrant color and stability across various formulations. It synergizes well with other colorants to achieve a wide range of hues. Formulators should be aware of potential regulatory restrictions on use levels and ensure compliance with regional guidelines. Overuse can lead to regulatory non-compliance, while underuse may result in insufficient color intensity.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

Data on FD&C Blue No. 2 Aluminum Lake is well-established, with comprehensive regulatory and safety evaluations. Industry practices are well-documented, though specific formulation details may vary. Known data gaps are minimal, with most information readily available through authoritative sources.

Citation hooks: FlavScents

QA Check

All required sections 1-9 are present
"Citation hooks:" line is present under each section
Flavor section includes ppm ranges
Toxicology section covers oral, dermal, inhalation
Regulatory section mentions US, EU, UK, Asia, Latin America
If complex natural material: includes section 5a (not applicable here)

About FlavScents AInsights (Disclosure)
FlavScents AInsights integrates information from authoritative government, scientific, academic, and industry sources to provide applied, exposure-aware insight into flavor and fragrance materials. Data are drawn from regulatory bodies, expert safety panels, peer-reviewed literature, public chemical databases, and long-standing professional practice within the flavor and fragrance community. Where explicit published values exist, they are reported directly; where gaps remain, AInsights reflects widely accepted industry-typical practice derived from convergent sensory behavior, historical commercial use, regulatory non-objection, and expert consensus. All such information is clearly labeled to distinguish documented data from professional guidance or informed estimation, with the goal of offering transparent, practical, and scientifically responsible context for researchers, formulators, and regulatory specialists. This section is generated using advanced computational language modeling to synthesize and structure information from established scientific and regulatory knowledge bases, with the intent of supporting—not replacing—expert review and judgment.

Generated 2026-01-16 19:21:37 GMT (p2)

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