Vanilla

The fatty acid composition demonstrates that Tahitian vanilla is richer in fatty acids and that it could discriminate Polynesian cultivars. Cured Tahitian vanilla beans have an average fatty acid content higher than other vanillas in the world (an average of 2.5% of dry matter compared to 1.2–2.4%), which may explain the attractive glossy and oily aspect of the pods (Brunschwig et al., 2007). Tahitian vanilla beans contain mainly polyunsaturated fatty acids (with a preponderance of linoleic acid from 55% to 65%) and monounsaturated fatty acids (from 20% to 30%) with a remarkable content of monounsaturated long-chain fatty acids (5%–13%), and not much of saturated fatty acids (about 15%). These data consolidate the data of Ramaroson-Raonizafinimanana et al. (1988).

TABLE 13.3 Fatty Acid (FA) Composition (%) of Lipid Extract from Different Cultivars of Tahitian Vanilla (Uncured Beans)

	Parahurahu	Tahiti long	Haapape	Tahiti	V. tahitensis*
No. of samples	8	6	8	8	1
16:0–palmitic	9.8a	10.4a	9.4a	9.6a	8.2
18:0 + 20:1 stearic + eructic	3.9a	4.4b	3.9a	4.7b	3.6
18:1ω9–oleic	15.7a	17.5b	15.2a	15.3a	12.9
18:2ω6–linoleic	53.9a	58.1b	63.7d	61.2c	67.4
18:3ω3–linolenic	3.7b	2.8a	2.5a	2.2a	1.3
Total common FA	87.0a	93.2b	94.7c	93.0b	93.3
24:1ω9–nervonic	6.6c	3.5b	2.4a	3.5b	4.5
26:1ω9–ximenic	2.0c	1.3b	0.9a	1.3b	1.0
28:1ω9–octasen-19oïc	2.1b	1.1a	1.0a	1.2a	0.6
30:1ω9–lumequeic	2.2b	0.9a	0.9a	1.0a	0.5
Total long-chain FA	12.9c	6.8b	5.2a	7.0b	6.7
Saturated FA	13.7a	14.8a	13.3a	14.3a	11.8
Monounsaturated FA	28.6d	24.3c	20.4a	22.3b	19.5
Polyunsaturated FA	57.6a	60.9b	66.2d	63.4c	68.6
Unsaturated FA	86.2a	85.2a	86.6a	85.7a	88.2
Total (ppm)	9147a	12,950b	16,978b	14,152b	—

Averages with the same letter within rows are not significantly different (p < 0.05).

* GC quantitation (Ramaroson-Raonizafinimanana, 1988).

The cultivars from French Polynesia show quite different fatty acid compositions, as illustrated by Table 13.3. The intra-tahitensis chemodiversity is highlighted by a factorial discriminant analysis, showing that Parahurahu is very specific with a significantly higher content of monounsaturated long-chain fatty acids (especially nervonic acid) and linolenic acid (Figure 13.10).