Fake Vanilla
Vanilla extract from orchid pods costs typically 20 times more than synthetic vanillin, and varies with demand and crop production. This has resulted in counterfeit vanilla essence appearing, claiming to be the natural extract when it is in fact either purely synthetic or natural extract diluted with synthetic vanillin. This may sound a trivial matter, but the integrity of ingredients is a very important issue in the food industry, and vanilla is one of the most commonly used flavourings.

Spotting the fake
Chromatography can be used to identify simple fakes. Chromatography separates a mixture like natural vanilla extract into its chemical components. Comparison of a suspected fake with genuine vanilla and a standard mixture may reveal there are components missing or added. Complex fakes are more difficult to identify this way, and other methods may be used in conjunction.

diagram: chromatogram of vanilla diagram: chromatogram of vanilla
diagram: chromatogram of vanilla
diagram: chromatogram of vanilla diagram: chromatogram of vanilla
diagram: chromatogram of vanilla diagram: chromatogram of vanilla
diagram: chromatogram of vanilla

Issues

Isotope Analysis

The vanilla orchid is among a group of plants that follow a different pathway for photosynthesis compared with most others. There are fewer steps in this pathway, and this has an effect on the proportion of carbon-13 atoms present. 13C reacts slightly slower than 12C, and so the more steps, the lower the proportion in the products.

All sources of synthetic vanillin, including the petrochemical route, are from plant material using the pathway with more steps. Synthetic vanillin therefore has a lower proportion of 13C than natural vanilla extract.

The ratio of 13C/12C is found using stable isotope ratio analysis (SIRA) with a mass spectrometer. From this the "isotopic deviation" is calculated, with these typical values:

"Natural" Vanilla from pods 16.8 - 20.4
"Synthetic" Vanillin 26.8 - 32.7
Eugenol (Oil of cloves) - 30.8
Guaiacol (Petrochemical) - 32.7
Lignin (Paper waste) - 27.4


The key point is that the ratio of 13C/12C in vanilla extract from vanilla pods is significantly lower than vanillin from all other sources.

Naturally Speaking

The term natural is sometimes applied to vanilla flavouring made from paper waste, as the starting material (trees) is "natural" and renewable. Vanillin cannot be made by this method without the use of chemical processing, however.

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