AInsights Entry for Alpha-Sinensal (CAS: 17909-77-2)

1. Identity & Chemical Information

• Common Name(s): Alpha-sinensal
• IUPAC Name: (2E,4E)-2,6-dimethyl-8-(propan-2-ylidene)octa-2,4,6-trienal
• CAS Number: 17909-77-2
• FEMA Number: Not available
• Other Identifiers: Not available
• Molecular Formula: C13H18O
• Molecular Weight: 190.28 g/mol

Alpha-sinensal is a sesquiterpene aldehyde characterized by its conjugated double bonds and an aldehyde functional group. The presence of these functional groups contributes to its distinctive odor profile, which is often described as citrusy and fresh. The structure-odor relationship is significant as the aldehyde group is known to impart a sharp, fresh note, while the conjugated system can enhance the intensity and diffusion of the scent.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Alpha-sinensal is primarily recognized for its citrus-like aroma, which is both fresh and slightly sweet. It is often described as having a strong, diffusive character that can impart a vibrant, zesty note to formulations. The odor threshold for alpha-sinensal is not well-documented, but its impact is typically noticeable even at low concentrations, making it a valuable component in both flavor and fragrance applications. In sensory roles, it often serves as an impact note, providing a burst of freshness and realism to citrus accords.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Alpha-sinensal is naturally found in citrus oils, particularly those derived from oranges. It is formed through the oxidative degradation of limonene, a common terpene in citrus fruits. This compound is relevant to "natural flavor" and "natural fragrance" designations, as it can be sourced directly from natural citrus oils or synthesized through natural processes.

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

4. Use in Flavors

Alpha-sinensal is used extensively in flavor formulations, particularly in citrus profiles such as orange, lemon, and lime. It functions as an impact note, enhancing the authenticity and brightness of citrus flavors. Typical use levels in finished food or beverage products range from 0.1 to 5 ppm, depending on the desired intensity and the complexity of the flavor system. It is generally stable under acidic conditions but may degrade under high heat or prolonged exposure to air, necessitating careful formulation considerations.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance applications, alpha-sinensal is valued for its ability to impart a fresh, citrusy top note. It is commonly used in colognes, air fresheners, and personal care products. Typical concentration ranges vary from trace amounts to 0.5% in the final product, depending on the desired effect and product type. Its volatility makes it a prominent top note, contributing to the initial impression of a fragrance.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: Not explicitly listed as FEMA GRAS, but components of citrus oils are generally recognized as safe.
• European Union: Regulated under (EC) No 1334/2008; specific FL number not assigned.
• United Kingdom: Follows EU regulations post-Brexit with no significant divergence reported.
• Asia: Limited specific data; generally follows international guidelines for citrus-derived compounds.
• Latin America: Brazil and MERCOSUR countries typically align with international citrus oil regulations.

Explicit approvals for alpha-sinensal are limited, but it is often included under broader citrus oil regulations. Harmonized assumptions apply, with some variability in country-specific guidelines.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

Alpha-sinensal's safety profile is primarily assessed through its use in citrus oils. Oral exposure is considered safe within typical flavor use levels, with no specific ADI or MSDI established. Dermal exposure in fragrance applications is generally well-tolerated, though IFRA guidelines should be consulted for specific product types to avoid sensitization. Inhalation exposure is minimal due to its low volatility, but occupational exposure should be managed with standard safety practices.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Alpha-sinensal is prized for its ability to enhance citrus profiles with a fresh, authentic note. It synergizes well with other citrus components and can be used to brighten and lift complex formulations. Formulators should be cautious of its volatility and potential for oxidation, which can lead to off-notes if not properly stabilized. It is often under-used in non-citrus applications where a hint of freshness could be beneficial.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

Data on alpha-sinensal is well-established in terms of its sensory profile and natural occurrence. However, specific regulatory approvals and toxicological data are less documented, often inferred from broader citrus oil studies. Industry practices are generally consistent, though some undocumented variability exists in formulation approaches.

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 2026-04-28 07:25:37 GMT (p2)