Characterization of the natural vanilla samples of different botanical and geographical origin based on the aromatic profile

Vanilla is one of the most popular flavouring agents in various foods, beverages, pharmacies, and cosmetics. Natural sources of the vanilla flavour are the pods of tropical orchid plants: Vanilla planifolia, Vanilla tahitensis, and Vanilla pompona. Vanilla planifolia is the most widely traded species followed by Vanilla tahitensis. Although the characteristic vanilla aroma is mainly due to vanillin (4-hydroxy-3-methoxybenzaldehyde), the vanilla pods consist of many other volatile compounds. Like vanillin, ethyl vanillin (3-ethoxy-4-hydroxybenzaldehyde), which is 3 to 4 times more intense than vanillin, is also widely used as a less expensive flavouring agent than vanilla extracts to imitate or enhance the vanilla aroma. Currently, all ethyl vanillin supplied to the global market is produced by chemical catalysis, and up to now the presence of ethyl vanillin in natural vanilla extracts has not been reported yet. The aim of this study was to characterize the aroma profiles of vanilla pod extracts in order to discriminate between different geographical origins and different botanical species. Ten vanilla samples from Madagascar, Mexico, French Polynesia, Papua New Guinea and La Réunion were collected. These samples were of two different botanical species: Vanilla planifolia and Vanilla tahitensis. The hydroalcoholic extracts were analysed by GC-MS/MS and about 50 volatile organic compounds (VOCs) belonging to different chemical classes were quantified. The different content of VOCs was able to distinguish the two botanical species, but not the geographical origins. Moreover, the GC-MS/MS analysis did not detect ethyl vanillin above the detection limit in any of the vanilla pod samples. The absence of ethyl vanillin in vanilla pods was also confirmed by researching its glycosylated precursor by means of UHPLC-HRMS.