FlavScents AInsights Entry for 2-Nonanone (CAS: 821-55-6)

1. Identity & Chemical Information

• Common Name(s): 2-Nonanone, Methyl heptyl ketone
• IUPAC Name: Nonan-2-one
• CAS Number: 821-55-6
• FEMA Number: 2781
• Other Identifiers: FL No. 07.038
• Molecular Formula: C9H18O
• Molecular Weight: 142.24 g/mol
• Functional Groups and Structure–Odor Relevance: 2-Nonanone is a ketone with a methyl group attached to the second carbon of a nonane chain. The ketone functional group is crucial for its characteristic odor, which is often described as fruity and green, contributing to its use in flavor and fragrance applications.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

2-Nonanone is characterized by a fruity, green odor with moderate intensity and diffusion. It is often described as having a waxy, citrus-like scent, which can be perceived as fresh and clean. The compound is used as an impact note in various formulations, providing a crisp and vibrant character. While specific taste and odor thresholds are not widely documented, it is known to be effective at low concentrations, typical of many ketones used in flavor and fragrance applications.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

2-Nonanone occurs naturally in various fruits and essential oils, including apples, bananas, and citrus fruits. It can also be formed through the enzymatic degradation of fatty acids or via the Maillard reaction during food processing. Its presence in natural sources supports its designation as a "natural flavor" in certain regulatory contexts, depending on the extraction and processing methods used.

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

4. Use in Flavors

2-Nonanone is utilized in flavor formulations for its fruity and green notes, enhancing the authenticity and complexity of fruit flavors such as apple, banana, and citrus. It serves as both an impact note and a background modifier, contributing to the overall realism of the flavor profile. Typical use levels in finished food or beverage products range from 0.1 to 5 ppm, with higher concentrations potentially leading to overpowering or off-notes. The compound is generally stable under typical food processing conditions, though it may degrade under extreme heat or acidic conditions.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance applications, 2-Nonanone is valued for its fresh, green, and slightly waxy scent, fitting well within citrus, floral, and green fragrance families. It acts as a modifier and impact note, often used in trace amounts to enhance the freshness and complexity of a fragrance. Typical concentration ranges in formulations are from 0.01% to 0.1%, depending on the desired intensity and character. Its volatility places it primarily in the top to middle notes of a fragrance composition.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: Recognized as GRAS by FEMA for flavor use.
• European Union: Listed under Regulation (EC) No 1334/2008 with FL No. 07.038.
• United Kingdom: Follows EU regulations post-Brexit with no significant divergence reported.
• Asia: Approved for use in Japan and China, with specific regulations varying by country.
• Latin America: Generally accepted in Brazil and MERCOSUR countries, though specific approvals should be verified.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, 2-Nonanone is considered safe at typical flavor use levels, with no specific ADI or MSDI established, but it falls within the threshold of toxicological concern (TTC) for flavoring substances. Dermal exposure in fragrance applications is generally low risk, with no significant irritation or sensitization reported, aligning with IFRA guidelines. Inhalation exposure is minimal due to its low volatility, though occupational exposure should be managed with standard safety practices.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

2-Nonanone is prized for its ability to impart a fresh, green character to both flavors and fragrances. It synergizes well with other fruity and floral notes, enhancing complexity and realism. Formulators should be cautious of overuse, as excessive concentrations can lead to undesirable waxy or soapy notes. It is often under-utilized in complex formulations where its subtlety can provide depth without overpowering other components.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on 2-Nonanone is well-established, with comprehensive sensory and regulatory information available. While specific numeric thresholds for sensory perception are limited, industry practices provide reliable guidance for its use. Regulatory frameworks are consistent across major markets, though formulators should verify specific country requirements.

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 2026-07-02 06:54:29 GMT (p2)