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Rural Industries Research & Development Corporation
Chamomile for Oil and Dried Flowers
by Dr L.M. Falzari and Professor R. C. MenaryFebruary 2003
RIRDC Publication No 02/156 RIRDC Project No UT-28A
Chamomile is a new crop that will be added to the armoury of the Essential Oils Industry in Tasmania. Chamomile has been used in folk medicine throughout history. It is still used in the production of a medicinal tea that is renowned for its calming properties. The blue essential oil of chamomile is used in the pharmaceutical and cosmetic industries.
The three varieties tested in the project were Bona, New Bona and Bodegold. Both Bona and New Bona produce essential oil of similar chemical composition, while Bodegold produces oil of a different type. The two types may be useful for different purposes or in different markets.
Chamomile needs to be sown as early as possible in the spring to ensure adequate growth before it commences flowering. Late sowing restricts the ultimate size of the individual plants and therefore restricts the number of flowers produced. This restricts not only the yield of flowers per unit area but also the volume of oil that will be produced. Autumn sowing, although not successful during this project should be considered for future research as all indications are that chamomile will produce greater yields the earlier it is sown.
Optimum harvest time is determined by a combination of observation of the crop and repeated sampling of the flowers. Serial sampling in this project showed that flower yield, oil yield and the production of the pharmaceutically active compounds were all correlated. They were all related to the maturity of the flowers. More specifically, the optimum harvest time should occur when the flowers are fully open, with the white ray petals fully extended and the small, tubular florets of the yellow disc just beginning to open. At this stage the crop appears white and sampling should commence to ensure that the oil composition is of sufficient quality and that yield is sufficient to warrant commencement of harvest.
Because chamomile has a continuous flowering habit, several harvests will produce better yields than a single harvest at mid flowering. These harvests will be spaced about 10 days apart, depending on the weather conditions Differences were detected in the rate of maturity of the three varieties with Bona maturing earlier than either New Bona or Bodegold. No comparison was made between New Bona and Bodegold, as they were not grown concurrently. This will have an impact on the harvest window and may form part of the decision as to which variety a particular grower may sow.
Assessment was made of the expected yields of dry chamomile flowers and oil. It is estimated that most crops will produce approximately 1 tonne of dried flowers per hectare. Bodegold will produce a greater weight of dried flowers than Bona but these will have a lower concentration of oil.
Estimates of oil yield per hectare are more difficult to make. Oil yield is dependent upon the extraction process and it was shown that chamomile oil is released very slowly using the standard distillation procedure. Based on a two-hour distillation the expected yield of Bona is 3kg/ha and Bodegold 1kg/ha. If distillation is increased to four hours, the yields become 4.5kg/ha for Bona and 2.4kg/ha for Bodegold. No estimate was made for New Bona since it was shown that estimates based on the small-scale trial were extremely variable and therefore misleading.
Oil "quality" is a factor that must be determined by the market place. Analytical techniques are provided in the body of the report that allow the composition of the oil to be determined and which can be used as quality assurance procedures. The ratio of components in the oil is the important factor and these techniques will ensure consistency of oil composition in products sold.
Quality assurance of dried flowers will be based upon solvent extraction, as the absolute quantities of components in the flowers will be just as important as their ratios.
Assessment of the characteristics of chamomile distillation highlighted a problem for the commercialisation of this technology. This problem is associated with the length of time for which distillation must continue in order to obtain a given percentage of the total oil present in the flowers.
Distillation must continue for 6 hours in order to obtain 70-80% of the oil which would be obtained after 24 hours of distillation. Further research into the economics of the distillation process is required in order to determine what a commercially viable duration will be.
No pre-distillation treatment tested provided an improvement in the characteristic yield curve for chamomile distillation. The research did highlight that the packing of the distillation vat may prove an important factor in oil recovery.
The commercial prospects for chamomile production in Tasmania are good. The crop should be easily incorporated into the current suite of essential oils crops by growers extending the use of their current knowledge and infrastructure. Because the crop is new to Tasmania, aspects of production require further research but these should not impede the adoption of this crop in the near future.
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