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-S/Lipodex D)/mass spectrometry was used for direct chiral evaluation of delta-hexa-, delta-octa-, delta-deca- and, in part, delta-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. delta-Hexalactone in greengage and pineapple as well as delta-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].