Characterization of Volatile Aroma Constituents in Avocados (Persea americana Mill) Grown in Sri Lanka

The volatile components of avocados were isolated by Tenex GC and analysed by capillary Gas Chromatography linked with Mass Spectrometry. A total of 73 components were detected as avocado volatiles, of which 70 compounds comprising 99% of the isolates were positively identified. Sixteen of the identified compounds have not been previously been reported as avocado volatiles including butanal, oct-1-ene, dimethyl cyclohexane, nonan-2-one and tetradecanoic acid. In ripe avocados, C-6 alcohols and aldehydes were the major group of volatiles with trans-hex-3-en-1-ol as the mos.t abundant constituent of 22.04%. The C-6 aldehyde, cis-hex-2-enal accounted to 6.66% of the aroma isolates in the ripe fruits. Terpenoids were the predominant class of constituents in unripe avocados. One monoterpene, limonene (2.97%) and ten sesquiterpenes were identified, B-caryophyllene being the major terpene (14.25%)followed by B-franescene (10.92%) and a-cubebene (10.2%) as the main hydrocarbons. In an olfactory assessment at odour port during GC, six aroma compounds were described possessing the characteristics green flavour of avocado. The C-6 alcohols and aldehydes were significant components of aroma together with several compounds deriving from fatty acid precursors. The oxidative decomposition of carotenoids leads to the formation of terpenoids, in unripe avocados.

AGRIEAST 2009 (8) p.19-29