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What is a Folded Oil?
What is FCF Bergamot?

What is a Folded Oil?

Folded oils are really part of flavouring process technology.

Folded oils are so-called because they have had some of the more volatile monoterpene hydrocarbons ("terpenes") removed, concentrating up the more valued oxygenated components. For example, in the case of citrus oils such as sweet orange, lemon or mandarin, removal of limonene and other hydrocarbons results in an oil which is more organoleptically powerful, flavoursome, & more characteristic of the source fruit. In addition, a folded oil will keep better (i.e. be less prone to degradation and the production of off-notes), perform better in product and be more soluble in alcohol and other food solvents/dispersing vehicles. Therefore flavouring companies might specifically prefer to use folded oils (or terpeneless oils, see below) as good quality flavouring ingredients. Folded oils do have disadvantages however - they may be very dark in colour and contain waxes etc.

Monoterpene hydrocarbons ("terpenes") may be removed by fractional high vacuum distillation and these by-products (lemon terpenes, petitgrain terpenes etc.) find uses in perfumery formulations as cheap ingredients. The final oil left in the 'pot' might be termed '4 x conc' or even '10 x conc.' or higher. However it is not the case that a 10 x conc. lemon oil for example will have ten times the flavouring intensity of normal lemon oil. In older processes, a 5 x conc citrus oil might be further distilled down (often also removing sesquiterpene hydrocarbons) in a separate still with an efficient fractionating column to produce 'terpeneless' oils, which dissolved (say) in a given strength of aqueous alcohol. Obviously because these oils are concentrated down from a larger bulk, they have increased value. Once again, adulteration rears its ugly head, and reconstituted terpeneless oils synthesised from fatty aldehydes (aldehyde C8, aldehyde C10 etc), monoterpene alcohols (linalol, geraniol, citronellol etc) and other minor components, have successfully fooled many trade buyers. Although folded oils generally refer to those generated by fractional high vacuum distillation, a number of other processes will produce concentrated or terpeneless oils, such as countercurrent solvent extraction, or solid phase extraction methods. Further, developments in distillation technology such as commercial spinning band or rotating drum stills etc. now can increase yields will less energy input and thus lower artefact formation - in fact the technology is such now that separation can be effected just using mechanical energy alone.

High vacuum fractional distillation is a purely physical process and so will produce essential oils which can be termed as completely natural. But many certifying organisations will not accept chemical solvent-extracted folded oils or terpeneless oils as qualifying for natural status, although some might certify products concentrated using natural ethanol. Some companies may use a combination of products from ethanol extraction and fractional distillation to produce more concentrated flavouring oils. Sub-critical water extraction may be useful also to de-wax oils etc. and would arguably be a natural process, but these techniques are largely experimental.

I am not aware of aromatherapeutic uses for folded oils - largely because, surely, most aromatherapists prefer to deal with "whole" oils, not specific fractions (although they often seem to use ylang ylang oil fractions, and are not generally aware that ylang ylang oil 'complete' is still a mix of fractions, and not a whole oil. But I digress...). Further concentrating up fatty aldehydes and monoterpene alcohols (as occurs in folded oils) may increase the irritation/sensitisation potential.

What is FCF Bergamot?

FCF (furano-coumarin free). At the present time I understand that new data may be presented shortly on regarding the toxicity of furano-coumarins. All I can say at present is that bergamot oil is often, if not invariably, adulterated, and/or comes from mixed origins (Ivory Coast bergamot oil often being passed off or added to Calabrian produced oils, especially in times of shortage). I personally prefer the richness and depth of the non-FCF oil, which also keeps better. The FCF oil can be prepared from the normal oil by distillation - although there are also various chemical ways of doing this, and methods based on chemo-physical principles, such as selective absorption which relies on the trapping of the larger furanocoumarin molecules within a the matrix of an inert substance. A distillation process producing FCF bergamot would produce a natural oil. I will leave the producers to argue the case for the other processes...


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