The BACIS Archives

[ POM - 98021 ]

• Some Aspects of the Adulteration of Natural Isolates

INTRODUCTION

Because there is a lot of confusion about the adulteration of natural isolates, it seems worthwhile to discuss "how" and "why" this is performed.

DISCUSSION

Adulteration generally means the act of lowering the standard or character of a product by the addition of one or more inferior ingredients.
Natural isolates may, for instance, concern essential oils, oleoresins, gums, absolutes or other natural extractives. These isolates consist of several hundreds of chemical compounds, which can be organoleptic characteristic substances (so-called character-impact compounds), essential compounds, balance compounds and artefacts.
The adulteration of natural isolates in fact covers a wide range of actions, such as: standardising, reinforcement, liquidising, reconstitution, commercialising.
These types of adulteration will be discussed below.

Standardising
Natural isolates are mixtures of chemical compounds. The concentration of the organoleptic characteristic compounds in these mixtures can vary or deviate from standardised ranges, due to climatic and/or ecological reasons. One can standardise the content of characteristic substances by adding the products, e.g. either isolated from an other natural source or produced synthetically.

Examples are:

- citral (ex litsea cubeba oil or synthetic) to standardise lemon oil;

- 1,8-cineole (ex eucalyptus globulus oil) to standardise rosemary oil;

- camphor (ex camphor oil) to standardise labiate oils.

Reinforcement
Reinforcement is more or less an extension of standardising. When the quality of the natural isolates can be improved, there is always the temptation of adding an exaggerate amount of the characteristic compound to improve the quality and to make the end product more "olfactive value for money".

Liquidising
Some natural isolates are solids or semi-solids as, for instance, gums, oleoresins and certain absolutes. To liquidise these materials a series of solvents are known, e.g. benzyl benzoate, propylene glycol, triethyl citrate, isopropyl myristate, dialkyl phthalates, isononylphenol.

Reconstitution
There are natural isolates, such as rose oil, jasmine oil or orange flower oil, which are too expensive for application in more economic (cheaper) functional perfumery as, for instance, in perfumes for soap, detergents or other household products. Therefore these naturals are reconstituted, that is to say the natural isolate is rebuilt (compounded) with a mixture of natural or so-called nature-identical chemical compounds; after a more or less thorough analysis of the identities and quantities of the main constituents. It will be clear that it is quite impossible to reconstitute the complete natural product, because natural isolates consist of several hundreds of chemical compounds, of which many are unknown.

Commercialising
By commercialising of a product is meant to lower the quality of it in order to make it more profitable.
It will be clear that the "reconstituted oils" are also examples of "commercial oils". Sometimes genuine natural isolates are diluted with reconstituted ones. Although commercialising of a product appears to be a fraudulent act, it necessarily not ought to be. Sometimes a buyer cannot afford to pay the cost price of the natural, therefore he is willing to buy a commercialised product. However, he wants to know. Of course, real fraudulent commercialising also exists.

Commercialising of natural isolates is, for instance, carried out by:

• dilution with low-volatile solvents as mentioned under "Liquidising";
• using cheaper naturals to dilute the original ones with, for example, orange terpenes (mainly d-limonene) in citrus oils; turpentine in pinus and labiate oils;
• replacing characteristic compounds by cheaper synthetics (nature-identical), e.g. linalool & its acetate in bergamot, lavender, petitgrain oil etc. Synthetic linalool can be detected by the presence of dehydro- and dihydrolinalool (derived from methylheptenone) or of plinols (derived from pinanol). alpha-Terpineol, borneol en acetate in labiate oils.