Vanilla

Then, several studies of Tahitian vanilla aroma composition highlighted its originality compared to V. planifolia by the presence of major phenolic compounds, including the widely mentioned anisyl compounds present in higher amounts, and less frequently the presence of minor compounds. The different studies of Tahitian vanilla describe the aroma as composed of the following molecules (see Table 13.1 for chemical structure) whose contents differ from V. planifolia as detailed later.

Ten major phenolic compounds are listed below:

a. Vanillin, p-hydroxybenzaldehyde, vanillic acid, and p-hydroxybenzoic acid (Fayet et al., 1987; Ranadive, 1992; Langella et al., 2003) usually quantified in V. planifolia to authenticate natural vanilla.

b. Four anisyl compounds characteristic of Tahitian vanilla: i. Anisyl alcohol and anisic acid, which are with vanillin the most concentrated compounds in Tahitian vanilla beans. They have been identified by GC–MS (Adedeji et al., 1993), confirming previous works (Shiota and Itoga, 1975; Lhuguenot, 1978; Tabacchi et al., 1978; Rey et al., 1980; Purseglove et al., 1981; Larcher, 1989; Hartman, 2003). ii. p-Anisaldehyde (Tabacchi et al., 1978) and methyl anisate (Shiota and Itoga, 1975; Adedeji et al., 1993; Lechat-Vahirua and Bessiere, 1998; Sostaric et al., 2000), which are less concentrated.

c. Other phenolic compounds in nonnegligible amounts: protocatechualde-hyde, protocatechuic acid, syringic acid, and p-hydroxybenzyl alcohol (Fayet et al., 1987).

Minor components with various chemical functions:

d. Aromatic esters: anisyl acetate, anisyl formate, and methyl cinnamate (Shiota and Itoga, 1975; Adedeji et al., 1993; Sostaric et al., 2000; Hartman, 2003).

e. Other phenolic compounds (Shiota and Itoga, 1975; Scharrer, 2002).

f. Aldehydes, ketones, and lactones: 2,4-decadienal, 3-methylpentanal, 2-methyl-2-pentanone, 1-methoxy-2-propanone, isovaldehyde, and gamma nonalactone (Adedeji et al., 1993; Lechat Vahirua and Bessiere, 1998; Scharrer, 2002).

g. Monoterpenes (α-pinen, β-pinen, limonen, linalool, terpinen-4-ol, and α-terpineol (Scharrer, 2002).

h. Aliphatic esters (for instance, ethyl hexanoate, ethyl nonanoate, and ethyl decanoate) (Sostaric et al., 2000).

i. Heterocyclic compounds, aliphatic acids, and alcohols (Fayet et al., 1987).

j. Derivatives of anisyl compounds (Da Costa and Pantini, 2006).

TABLE 13.1 Major Aroma Molecules Identified and Quantified in Tahitian Vanilla

Family	Molecule Name	Used	R1	R2	R3	R4
Vanillyl	Vanillyl alcohol	Van_alc	CH2OH	OCH3	OH	H
	Vanillin	Van	COH	OCH3	OH	H
	Vanillic acid	Van_ac	COOH	OCH3	OH	H
p-Hydroxybenzyl	p-Hydroxybenzyl alcohol	Phb_alc	CH2OH	H	OH	H
	p-Hydroxybenzaldehyde	Phb	COH	H	OH	H
	p-Hydroxybenzoic acid	Phb_ac	COOH	H	OH	H
	Methyl p-hydroxybenzoate	Me_paraben	COOCH3	H	OH	H
Anisyl	Anisyl alcohol	Anis_alc	CH2OH	H	OCH3	H
	Anisaldehyde	Anis_ald	COH	H	OCH3	H
	Anisic acid	Anis_ac	COOH	H	OCH3	H
	Methyl anisate	Me_anis	COOCH3	H	OCH3	H
Protocatechuyl	Protocatechualdehyde	Pro_ald	COH	OH	OH	H
	Protocatechuic acid	Pro_ac	COOH	OH	OH	H
Isovanillyl	Isovanilline	Isovan	COH	OH	OCH3	H
Others	Syringic acid	—	COOH	OCH3	OH	OCH3