Isotopic methods for control of natural flavours authenticity

The use of natural flavours or essential oils often brings a clear marketing advantage in certain products (ice creams, soft drinks, sweets, etc.). The cost of natural flavours, however, is often a factor of 10 or more higher than the price of synthetic copies. Owing to this price advantage and to the difficulty of differentiating natural flavours from the same molecules made by chemical synthesis, it has been reported that synthetic flavours are sometimes sold as natural ones. Isotopic mass spectrometry (carbon‐13 and deuterium) have in the past made it possible in many cases to differentiate natural and synthetic molecules. Unfortunately, the possibility of isotopic marking or 13 C enrichment, more recently reported, renders, in some cases (such as vanilla), isotopic mass spectrometry of less interest nowadays. The SNIF–NMR TM method (site‐specific natural isotope fractionation measured by nuclear magnetic resonance) makes possible the measurement of the D/H ratios in several sites in the molecule (five in the case of vanillin). This isotopic fingerprint is very much correlated with the origin of the molecule (type of plant, biotechnology, synthesis) and therefore makes possible a real guarantee of the natural origin of many flavours.