Nootkatone

Synthetic Ingredient Overview

• 🏭 Manufacturer: Evolva, IFF, other biotech or flavor houses

• 🔎 IUPAC Name: 4,4a,5,6,7,8-hexahydro-3,6,8,8-tetramethyl-1(2H)-naphthalenone

• 🧪 Synonyms: (+)-Nootkatone, 1(10)-Aromadendren-9(10)-one

• 🧬 Chemical Formula: C₁₅H₂₂O

• 📂 CAS N°: 4674-50-4

• 📘 FEMA: 3166

• ⚖️ Molecular Weight: 218.33 g/mol

• 📝 Odor Type: Zesty–Citrus

• 📈 Odor Strength: Very high (odor threshold ≈ 800 ppb)

• 👃🏼 Odor Profile: Powerful grapefruit peel, zesty citrus, woody, vetiver, green, earthy, herbal, tobacco-like

• 👅 Flavor Profile: Grapefruit-like at 0.1–0.3 ppm; perceptible in beverages at 0.3 ppm; bitterness increases above 50 ppm

• ⚗️ Primary Uses: Citrus enhancement, grapefruit reconstructions, woody-vetiver profiles, tropical-tobacco modifiers

• 🧴 Appearance: Almost colorless to pale yellow oily liquid (orange-tinted in commercial grades)

What is Nootkatone?

Nootkatone is a bicyclic conjugated sesquiterpene ketone. Though it occurs naturally in grapefruit peel oil (≈ 0.3%), its commercial form is produced synthetically via oxidation of valencene, a terpene extracted from orange juice oil. The process typically involves oxidizing agents such as tertiary-butyl chromate, or modern bioconversion pathwaysusing engineered enzymes. These processes yield a high-purity, cost-effective source of nootkatone that is widely used in fragrance, flavor, and pest control.

Nootkatone's structural class places it in the oxygenated sesquiterpenes, making it stable, tenacious, and potent at low concentrations.

Olfactory Profile & Perfumery Applications

👃🏼 Odor Characteristics:
Zesty and fresh, with dominant grapefruit peel and citrus top notes. Background impressions of woody vetiver, green-earthy tobacco, and mild herbal sharpness. It provides lift, realism, and persistence in citrus accords and modern fruity fragrances.

⚗️ Functional Roles in Formulation:

• Top-note enhancer in grapefruit, bergamot, and bitter orange compositions

• Adds depth to vetiver, green, and earthy bases

• Blends effectively with hexenyl esters, aldehydes, citrus oils, woody materials

• Used in modern fougères, ozonic-fruity colognes, and tropical accords

• Subtle contributor to gunpowder, tobacco, or aromatic smoky facets

🧴 Compatible with:
Bergamot oil, hexyl acetate, hexenyl butyrate, ambrettolide, isobornyl acetate, limettal, aldehyde C12 MNA

Industrial & Technical Uses

Nootkatone is approved for broad use beyond perfumery, including:

• Flavor industry: Grapefruit flavor in beverages, confections, gums (FEMA 3166)

• Insect repellency: Proven efficacy against ticks, mosquitoes, bed bugs, lice

• Environmental sustainability: Volatile, biodegradable, non-persistent

• Pharmaceutical & cosmetic use: Low dermal toxicity, permitted in personal care

🔬 Production Notes:

• Extracted valencene from orange peel oil (≤ 0.4%)

• Oxidized chemically (e.g., CrO₃, oxygen + metal salts) or via enzyme fermentation (Evolva patented process)

• Bioconversion routes allow for "natural" classification under some regulatory schemes

Regulatory & Safety Overview

• IFRA: Not restricted under current IFRA 51st Amendment; recommended to follow general terpene ketone guidelines

• EU Allergens: Not listed among the 26 declarable allergens

• FEMA GRAS: FEMA 3166 – recognized as safe for flavor use in foods

• ECHA (REACH): Registered; not classified as hazardous under CLP

• Toxicology:

  • No sensitization, genotoxicity, or phototoxicity in standard testing

  • Low oral and dermal toxicity

  • Not classified as PBT or vPvB

  • Readily biodegradable

✅ Considered safe and sustainable for perfumery, flavor, insect repellent, and environmental applications under current regulatory frameworks.

Sources

• Perfume and Flavor Chemicals – Steffen Arctander

• The Nootkatones – John C. Leffingwell, Ph.D.

• Flavors and Fragrance Chemistry, Bioprocessing and Sustainability

• Flavor, Fragrance, and Odor Analysis

• A Fragrant Introduction to Terpenoid Chemistry – Charles S. Sell

• PubChem CID 1268142 – National Center for Biotechnology Information

• CDC & Evolva – Nootkatone insect repellent licensing data