Paper presented at the IFEAT Int. Conference in Cape Town

A. betulina x crenulata essential oils tend to show a lot of variation in their chemical compositions,presumably due to the degree of hybridization and/or the chemotype of A. betulina genetic materialthat was involved in the crossing. These oils are nevertheless generally characterized by GC (FID) ashaving a medium limonene level (15-25%), varying concentrations of menthone/isomenthone (0-20%), with correspondingly inversely varying diosphenol (Ψ-diosphenol and diosphenol combined)concentrations (0-20%), medium to high pulegone concentrations (15-40%), varying amounts ofcis/trans-8-mercapto-p-menthan-3-one isomers (in a 1:4 to 3:4 trans:cis isomer ratio, but always moretrans than cis isomers present) and varying amounts of cis/trans-8-acetylthio-p-menthan-3-oneisomers (0.1-2%, in the same 8:1 trans:cis isomer ratio found in A. crenulata oil).GC trace of the essential oil of A. betulina x crenulata (typical)Although the identity of each of the compounds found in buchu oils has been known since 1975 [4] , itwas not until 1996 that the exact chemotaxonomy of the various buchu oils was described [3] . Untilthen the chemical composition of a general ‘buchu oil’, which could chemically look like any of theoils described above (or any mixture of them), was greatly dependant on the initial historicalagricultural source of the oil. In that the unique olfactory properties of each individual type of buchuoil was never formally described, due to the failure of buchu oil distillers to recognize or haveknowledge of the various types of buchu oils available, the use of each type of buchu oil forspecialized applications is poorly developed, thereby limiting the use of buchu oil to fewerapplications than their potential.Oils from specific species / chemotypes or blends of species / chemotypes may indeed have a desiredeffect in specific applications. Furthermore, inconsistencies in chemical compositions, and thereforealso olfactory characteristics, of general ‘buchu oils’, as a result of the variations in oils and thehistorical inability to accurately determine and control any such variations, have certainly also brandedbuchu oil as a raw material of inconsistent quality in the past. Large scale harvesting / poaching ofbuchu from wild sources, where many uncontrollable factors (e.g. wild fires, droughts, pests etc.)come to play, furthermore, made the availability of buchu plant material inconsistent, to say the least.When combining variablility of supply with great variations in composition / quality, it becomesobvious why buchu oil remained a niche product in the flavour and fragrance industry for such a long104