Head-space volatiles of Gethyllis afra and G. ciliaris fruits ("kukumakranka")

Abstract

The head-space volatiles of Gethyllis afra and G. ciliaris fruits collected in the South Western Cape Province of South Africa were analysed by solid phase micro-extraction (SPME) followed by gas chromatography coupled to mass spectrometry (GC-MS). Twenty-nine compounds were characterized in the fruit of G. ciliaris representing 96.5% of the total composition. Major compounds include pentacosane (19.2%); ethyl octanoate (18.0%); ethyl isovalerate (11.7%); ethyl hexanoate (9.1%) and ethyl benzoate (7.4%). These compounds may be the major contributors to the fruity-sweet odour of G. ciliaris. Forty-three compounds were identified in the fruit of G. afra representing 87.9% of the total composition with alpha-pinene (11.2%), n-butyl n-butyrate (8.5%), isoamyl acetate (8.1%), beta-pinene (6.4%) and 2-methylbutyl butyrate (5.8%) as main constituents. These major constituents may impart the banana/piney/fruity odours associated with the G. afra. The compounds identified in the volatiles of the two fruits in amounts greater than 1% include ethyl butyrate, ethyl isovalerate, isobutyl 3-methyl butyrate, ethyl octanoate and ethyl benzoate.