Volatiles of avocado fruit

Volatile constituents of avocado mesocarp were isolated by concurrent steam distillation/solvent extraction in the Likens-Nickerson apparatus using pentaneether as solvent. The extracts which resulted were concentrated in a Kuderna-Danish concentrator and analysed using gas chromatography and linked gas chromatography-mass spectroscopy (GC-MS) employing capillary columns of contrasting polarity. Hydrocarbons (mainly sesquiterpenes) and alkanals were the predominant constituents present. In the immediate extract of the avocado mesocarp, β-caryophyllene (60%) was the main sesquiterpene, followed by α-humulene (5.9%), caryophyllene oxide (4.8%), α-copaene (4.5%) and α-cubebene as the main hydrocarbons; alkanals were present, but only in low concentrations. In the extract prepared following storage (2h) of the mesocarp at room temperature, β-caryophylene (28.8%) was the main sesquiterpene, followed by β-copaene (10.7%), a cadinene isomer (8.5%), α- and β-cubebene (7.7%), α-farne-sene (5.3%) and octane (4.8%) as principal hydrocarbons; decenal (6.3%) and heptenal (3.2%) were the main aldehydes.