Multidimensional gas chromatography/mass spectrometry: A powerful tool for the direct chiral evaluation of aroma compounds in plant tissues I. 5‐alkanolides in fruits

On‐line coupled multidimensional gas chromatography (DB‐5/Lipodex D)/mass spectrometry was used for direct chiral evaluation of δ‐hexa‐, δ‐octa‐, δ‐deca‐ and, in part, δ‐dodecalactone in various fruits. Whereas in raspberry the ( S )‐enantiomers predominated [enantiomeric excess (ee) values from 45.0 to 100%], the ( R )‐enantimomers prevailed in apricot, coconut, greengage, mango, pineapple, plum and yellow plum (ee values from 14.4 to 100%). Variations between ( S )‐ and ( R )‐enantiomers depending on chain length were found in red and yellow passion fruit, peach and strawberry. δ‐Hexalactone in greengage and pineapple as well as δ‐dodecalactone in coconut were found to occur in these fruits in approximately racemic form [ee values 10.8% ( R ) and 4.4% ( R ) as well as 5.2% ( R ), respectively].