FlavScents AInsights Entry: 1-Acetyl Indole (CAS: 576-15-8)

1. Identity & Chemical Information

1-Acetyl indole, also known as 1-(1H-indol-3-yl)ethanone, is a single chemical compound with the CAS number 576-15-8. It is identified by the FEMA number 2730. The molecular formula for 1-acetyl indole is C10H9NO, and it has a molecular weight of 159.19 g/mol. This compound features an indole core structure with an acetyl group attached to the nitrogen atom, which contributes to its characteristic odor profile. The presence of the indole ring is significant in determining its odor properties, often described as floral and slightly animalic, which is relevant in both flavor and fragrance applications.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

1-Acetyl indole is known for its distinctive odor, which is often described as floral, with nuances of jasmine and a subtle animalic undertone. It has a moderate intensity and diffusion, making it suitable for use as a background note or modifier in complex fragrance compositions. The taste and odor thresholds for 1-acetyl indole are not well-documented, but its sensory role is typically as an impact note that adds depth and complexity to both flavors and fragrances.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

1-Acetyl indole is not commonly found in nature but can be synthesized through various chemical pathways. It is not typically associated with natural flavor or fragrance designations due to its synthetic origin. However, it can be formed through the acetylation of indole, a process that can occur under specific conditions in laboratory settings. Its role in natural products is limited, and it is primarily used in synthetic formulations.

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

4. Use in Flavors

In flavor applications, 1-acetyl indole is used to impart a floral and slightly animalic note, often enhancing the complexity of floral and fruity flavors. It is typically used in low concentrations, with industry-typical use levels ranging from 0.1 to 5 ppm in finished food or beverage products. Its stability under various conditions, such as heat and pH, is generally good, although it may be susceptible to oxidation. Formulators should consider its impact on the overall flavor profile and use it judiciously to avoid overpowering other notes.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

1-Acetyl indole is utilized in a variety of fragrance families, including floral, oriental, and chypre compositions. It serves as a modifier or impact note, providing a unique floral-animalic character that enhances the realism and depth of the fragrance. Typical concentration ranges in fragrance formulations are from trace amounts up to 0.5%, depending on the desired effect. It contributes primarily to the middle notes of a fragrance, offering moderate volatility.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

In the United States, 1-acetyl indole is recognized as GRAS (Generally Recognized As Safe) by FEMA for flavor use. In the European Union, it is subject to the regulations outlined in Reg. (EC) No 1334/2008, although specific FL number status may not be clearly reported. The regulatory status in the United Kingdom post-Brexit aligns closely with EU standards. In Asia, including Japan and China, and in Latin America, such as Brazil and MERCOSUR, regulatory frameworks may vary, and formulators should verify compliance with local authorities.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, 1-acetyl indole is considered safe within the typical use levels in flavor applications, with no specific ADI or MSDI established. Dermal exposure in fragrance use should be monitored for potential irritation or sensitization, although it is generally regarded as safe under IFRA guidelines. Inhalation exposure is primarily relevant in occupational settings, where adequate ventilation and protective measures should be in place. The risk profiles for food and fragrance applications are similar, with no significant differences noted.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

1-Acetyl indole is valued for its ability to add complexity and depth to both flavors and fragrances. It synergizes well with other floral and fruity notes, enhancing their richness. Common formulation pitfalls include overuse, which can lead to an overpowering animalic character. It is frequently under-used in formulations where a subtle floral-animalic nuance is desired but not achieved due to conservative dosing.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on 1-acetyl indole is well-established, particularly in terms of its sensory profile and use in fragrance applications. However, there are gaps in specific numeric values for taste and odor thresholds, as well as detailed regulatory status in some regions. Industry practices are generally consistent, but formulators should verify specific regulatory requirements and safety considerations for their intended applications.

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 2026-01-21 00:44:32 GMT (p2)