Averages with the same letter within rows are not significantly different (p < 0.05).
* See Table 13.1 for complete names of the molecules.
The aroma composition can explain the original flavor of Tahitian vanilla and show slight differences between the main cultivars. As seen before, the originality of Tahitian vanilla is not only due to its flavor but also due to its oily texture.
The fatty acid composition has been a topic of interest to better understand the physical and sensory properties of Tahitian vanilla, which is oilier (see the section on Sensory Properties).
Some previous chemical studies of vanilla beans related to the presence of fatty acids or fatty acid derivatives. The major components identified were oleic or palm-itic acid (Purseglove et al., 1981; Adedeji et al., 1993; Lechat-Vahirua and Bessiere, 1998). A comprehensive study of the lipidic fraction of three vanilla bean species V. tahitensis, V. planifolia, and Vanilla madagascariensis by GC revealed discriminating fatty acid compositions, with a predominance of linoleic acid among 31 fatty acids in every species (Ramaroson-Raonizafinimanana, 1988). Moreover, many additional lipidic components were identified: phytosterols (Ramaroson-Raonizafinimanana et al., 1998), hydrocarbons (Ramaroson-Raonizafinimanana et al., 1997), and two new product families: long-chain γ-pyrones (Ramaroson-Raonizafinimanana et al., 1999) and long-chain β-diketones (Ramaroson-Raonizafinimanana et al., 2000).
At the “Etablissement Vanille de Tahiti,” work on the lipid extract aims at characterizing Tahitian vanilla and its different cultivars by the fatty acid composition. Derivatives of fatty acids are analyzed by HPLC. About 10 fatty acids were identified and the identification was confirmed by GC for a few of them (Brunschwig et al., 2007). Six common fatty acids coming from primary metabolites such as triglycerides were quantified: linolenic 18:3, linoleic 18:2, palmitic 16:0, oleic 18:1, stearic 18:0, and erucic 20:1 acids. Four very-long-chain monounsaturated fatty acids, rarely found in plants, were identified in vanilla beans: nervonic (24:1), ximenic (26:1), octacosen-19-oïc acid (28:1), and lumequeic (30:1) acids. These fatty acids derive from secondary metabolites (supposed β-diketones) and their composition may be much more variable than that of the primary metabolites (Ramaroson-Raonizafinimanana, 1988).