Natural Nootkatone
Natural nootkatone is the sesquiterpene ketone that gives grapefruit its characteristic aroma, C15H22O, molar mass 218.34, CAS number 4674-50-4, obtained from botanical material or by biotransformation rather than by chemical oxidation. It occurs in grapefruit peel oil at well under one percent, and in the wood of Alaska yellow cedar, from which its name derives.
The compound is one of the strongest character impact materials in citrus flavour work. Its odour threshold is in the region of one part per billion in water, and it is the single molecule that separates a grapefruit profile from a generic citrus one, contributing a bitter, woody and slightly sulphurous grapefruit note that terpene hydrocarbons alone cannot produce.
Nootkatone reaches the trade as a white to pale yellow crystalline solid or a viscous liquid, since it melts a little above room temperature at around 36 degrees Celsius and is often shipped warm or as a solution. It is practically insoluble in water and freely soluble in ethanol, vegetable oils and citrus terpenes, so beverage use depends on an emulsion or a solubilised premix. The material is stable in neutral conditions but oxidises slowly on prolonged air exposure.
We source bulk Natural Nootkatone from top China manufacturers for our partners. The manufacturer is in Tianjin. A smaller requirement can ship in a combined container with other ingredients.
Please send the grade you need, the volume and your destination port, and we will come back with a solution and a price.
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- Function
- Flavours and Aromas
Specifications
| Item | Specification |
|---|---|
| Appearance | Crystalline solid or viscous liquid depending on temperature |
| Colour | White to pale yellow |
| Odour | Characteristic grapefruit, woody, true to reference sample |
| Assay by gas chromatography | 96.0 percent minimum |
| Identification by infrared spectrum | Conforms to reference spectrum |
| Residual valencene | 2.0 percent maximum |
| Melting range | 32 to 38 degrees Celsius |
| Optical rotation at 20 degrees Celsius | plus 165 to plus 200 degrees |
| Refractive index at 40 degrees Celsius | 1.5000 to 1.5100 |
| Water content | 0.3 percent maximum |
| Residue on ignition | 0.1 percent maximum |
| Residual solvent | Within permitted limits for the solvent used |
| Lead | 1.0 mg/kg maximum |
| Arsenic | 1.0 mg/kg maximum |
Common Markets Grades
The natural designation covers two distinct manufacturing origins, and buyers specify which they want. Nootkatone isolated by fractionation of grapefruit oil is the smallest volume and highest priced position, used where a from grapefruit statement is required. Nootkatone produced by biotransformation of valencene, itself recovered from orange oil or made by fermentation, is the mainstream natural grade and is the material behind most current supply.
Assay levels in trade run from 96 to 99 percent, with the balance being residual valencene and related sesquiterpenes. Because the neat material solidifies, it is commonly offered as solutions at 10, 20 or 50 percent in ethanol, triacetin, medium chain triglyceride or orange terpenes, and as spray dried encapsulates for dry mixes. Chemically oxidised nootkatone made from valencene with a peroxide or chromium based oxidant is a separate item and cannot carry a natural declaration, although the molecule is identical.
Applications
- Grapefruit flavours for carbonated soft drinks, sports drinks and flavoured water
- Citrus flavour compounds generally, added at trace level to lift and round the profile
- Alcoholic drinks, particularly gin, hard seltzer and grapefruit flavoured spirits
- Chewing gum and confectionery in the citrus direction, usually as an encapsulate
- Bitters and aperitif flavourings, where the bitter woody facet is wanted
- Fine fragrance, as a woody grapefruit note in fresh and fougere accords
- Personal care and household products with a citrus fragrance direction
- Insect repellent and pest control products, where it is registered as a biopesticide active against ticks and mosquitoes
- Functional beverage bases where a grapefruit signal is used to mask bitter actives
China Manufacturers of Natural Nootkatone
Top Natural Nootkatone manufacturers in China.
Company names and logos are the property of the manufacturers themselves. They are listed here because our own directory records them as producing this ingredient. A listing is not an endorsement by them, and we do not represent them or speak on their behalf.
Regulatory Status
In the United States nootkatone holds FEMA GRAS status as a flavouring substance under FEMA number 3166 and is used in food on that basis. Material sold as natural must meet the definition of a natural flavour in the food labelling regulations, which is why the biotransformation route rather than chemical oxidation is used for this grade. The United States Environmental Protection Agency has separately registered nootkatone as a biochemical pesticide active ingredient for use against ticks, mosquitoes and other biting insects, a registration distinct from its food status.
In the European Union nootkatone is an authorised flavouring substance on the Union list established under Regulation (EC) No 1334/2008 and carries a FLAVIS number in the ketone group, with no E number since flavourings are not assigned one. Where the substance is produced by fermentation or enzymatic conversion, the production organism and process must meet the general requirements for flavourings produced by biotechnological means. The Joint FAO and WHO Expert Committee on Food Additives has evaluated nootkatone within the alicyclic ketone flavouring group.
Manufacturing Process
The mainstream natural route begins with valencene, the sesquiterpene hydrocarbon precursor, which is recovered by vacuum fractionation of orange oil terpene fractions or produced by fermentation using an engineered yeast expressing a valencene synthase on a sugar feedstock. The valencene is then oxidised at the allylic position to the ketone by a biocatalyst: whole cell cultures of fungi or bacteria, or isolated enzyme systems such as cytochrome P450 monooxygenases or plant peroxidases, held in an aqueous or two phase reactor with careful control of oxygen supply and product inhibition.
Because nootkatone is poorly soluble in water and inhibits the biocatalyst, an organic phase or a resin is normally used to extract it as it forms. The reaction broth is separated, the organic phase is concentrated under vacuum, and the crude ketone is purified by short path vacuum distillation followed by crystallisation from a hydrocarbon or alcohol solvent at low temperature. Crystals are centrifuged, washed and vacuum dried, then either packed as the solid or dissolved to the declared strength in the specified carrier. The alternative botanical route simply fractionates grapefruit oil residues and crystallises the enriched cut, giving a low yield but an unambiguous origin.
