The chemistry of food flavour. I. Volatile constituents of passionfruit, Passiflora edulis

The volatile constituents of the purple-skinned passionfruit ( Passifora edulis Sims) have been investigated. The volatiles were concentrated, fractionated by gas chromatography and chromatography on silica gel, and the resulting fractions examined by combined gas chromatography-mass spectrometry. The majority of the components identified are esters derived largely from combinations of the alkan-1-ols (C1,2,4,6,8) the alkan-2-ols (C5,7),(Z)-and (E)-hex-3-en-1-ol,(2)-hex-4-en-1-ol,and benzyl alcohol, with acids of even carbon number (acetic, butanoic, hexanoic, octanoic, hex-3-enoic, oct-3-enoic, and 3-hydroxyhexanoic). The non-ester constituents include many of the above free alcohols, acetaldehyde, alkan-2-ones (C3,5,7,9,11), monoterpenes ((E)-ß-ocimene, 1,8-cineole, linalool, a-terpineol, citronellol, geraniol, citronellyl acetate, (Z) and(E) five-membered ring linalool oxides), and 1,1,6-trimethyl- l,2-dihydronaphthalene, ß-ionone, ?-hexanolac-tone, ?-octanolactone, and the lactone of 2-hydroxy-2,6,6-trimethylcyclohexylidene- acetic acid. Preliminary odour assessment of the constituents has indicated that volatile passionfruit flavour is complex. Many components, especially certain esters, are clearly important and one component, not yet completely characterized, may have particular significance.