On-line gas chromatography combustion/pyrolysis isotope ratio mass spectrometry (HRGC-C/P-IRMS) of major volatiles from pear fruit (Pyrus communis) and pear products

Using extracts obtained by simultaneous distillation extraction (SDE) as well as liquid liquid extraction (LLE) of self-prepared juices from pear fruits (n = 20) and from commercial pear products (juices, n = 11; brandies, n = 16; baby food, n = 8), on-line capillary gas chromatography-isotope ratio mass spectrometry was employed in the combustion (C) and the pyrolysis (P) modes (HRGC-C/P-IRMS) to determine the δ13CV-PDB and δ2HV-SMOW values of major pear flavour constituents. In addition to butyl acetate 1, 1-butanol 2, hexyl acetate 3, 1-hexanol 4, as well as the 'pear esters' methyl E,Z-2,4-decadienoate 5, ethyl E,Z-2,4-decadienaote 6, and ethyl E,E-2,4-decadienoate 7, each originating from the fruit, the δ13CVPDB and δ2HV-SMOW data of commercial synthetic and “natural” (biotechnologically derived) 1-7 were determined.