Pineapple sesquiterpenes

Sesquiterpenes recovered by solvent extraction were identified in pineapple fruit Ananas comosus Merr.) from Cote d Ivoire. The authors suggested that some of the sesquiterpenoids found were derived from germacrene precursors [6]. The same authors studied the identification of trace compounds with impact character in pineapple fruit Ananas comosus Merr.). Some potent compounds were an undecatriene, an undecatraene, and ethyl esters [5]. 

Previous studies (Z) showed evidence for the presence of at least 20 sesquKerpene hydrocarbons in pineapple. These researchers identified 7 sesquiterpenes (1 tentative). We confirmed the presence of 3 of the sesquiterpenes and identified p-copaene, y-muurolene, a- and p-selinene in addition. Mass spectral data indicated the presence of other sesquiterpene hydrocarbons and oxygenated sesquiterpenes which we have been unable to characterize at present. 

The sulfur containing ester, 3-methylthiopropyl acetate, is reported for the first time in pineapple. This compound bears a relationship to the major esters, methyl and ethyl 3-methylthiopropanoate. It has been previously identified in apples (24), beer (25), wine (26) and whisky (27). The sesquiterpene hydrocarbon, cyclocopacamphene, is another newly reported pineapple constituent. This constituent was previously reported in vet iver oil (28). 

Pineapple Ananas comosus, Bromeliaceae) aroma consists of about 200 alcohols, esters, lactones, aldehydes, ketones, monoterpenes, sesquiterpenes and other volatiles. About 80% of the total volatile substances are esters. The main components in the green fruit are ethyl acetate, ethyl 3-(methylthio)propionate (8-189) with a distinctive pineapple aroma and ethyl 3-(acetoxy)hexanoate (8-190). The ripe fruit contains, as the main esters, ethyl acetate, (2J ,3i )-butane-2,3-diol diacetate (8-191) and ketone 3-hydroxy-butan-2-one. An important compound for the typical character of pineapple aroma, as in strawberry aroma, is 2,5-dimethyl-4-hydroxy-2//-furan-3-one (furaneol), present as a glycoside, and 2,5-dimethyl-4-methoxy-2H-furan-3-one. 

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