a study of the quality of a local herbal tea and volatiles of parinari ...

The SPME method identified 11 compounds from the P. curatellifolia headspace and
these comprised esters (54.5 %), alcohols (18.2 %), sesquiterpenes (18.2 %) and
heteroatoms (9.1 %). Upon using the CFMD, the relative number of class of identified
compounds were esters (42.9 %), alcohols (28.6 %), heteroatoms (14.2 %) and carbonyls
(14.2 %). These results revealed that in P. curatellifolia fruits, using both methods the
compounds extracted most were esters. This is because esters are the prime components
of the characteristic aroma of fruits (Sanz et al., 1997).
The esters ethyl hexanoate, isoamyl isovalerate and ethyl benzoate were extracted using
the SPME but not with the CFMD method. This could be due to the high molecular
weights of these compounds which are above (144g/mol). The vacuum (1.0 bars) used in
the CFMD may not have been able to suck these high molecular weight esters. The
chemical composition of the SPME fiber may also have contributed to the adsorption of
these compounds and hence enabling their extraction. The sesquiterpenes α-bergamotene
(204.35 g/mol), β-Farnesene (204.35 g/mol) and alcohol 2.6-diter butyl-4-methyl-phenol
(220.35 g/mol) were extracted using the SPME method and not by the CFMD method.
This is not surprising because of their high molecular weights and the chemical
composition of the PDMS fiber used in SPME. Both methods extracted the compounds
ethyl butyrate, ethyl isovalerate, phenyl acetonitrile and phenyl alcohol. Joulain et al.,
(2004) also established the presence of ethyl butyrate in P. curatellifolia collected from
Thohoyandu, Venda South Africa using a vacuum headspace concentration method and
was the third most abundant compound after 2-phenylethanol and ethyl pentanoate.
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