Extraction Technologies For Medicinal And Aromatic Plants - Unido

EXTRACTION TECHNOLOGIES FOR MEDICINAL AND AROMATIC PLANTS
odor similar to that of the oil. Thus, this condensate has some value. The
sale of rose water (otto of rose) for use in weddings in the sub-continent is
probably the only way by which the distiller realizes the value of the condensate.
In practically all other cases, the condensate is wasted. Table 2 gives
estimates of the values of wasted oil in the condensate in India for some
essential oils. The estimate is conservative because it does not include oil
physically carried with the condensate. Even this conservative estimate is a
mind-boggling number and is particularly important in the social context of
developing countries like India where marginal farmers are main contributors
to the overall produce. The value of the recovered oil from central distillation
facilities and pro rata distribution of the value will be a big bonus to the
small farmer and can certainly stop the downslide. Table 2 shows a major
contribution from Mentha arvensis. If the relatively high value fl avor sector is
included, for India alone the value of wasted oil can easily reach US$ 100
million. On a rough estimate, the combined number for the South East Asian
countries can be upwards of US$ 160 million. It must be noted that these
numbers are simple statistics. They do not refl ect in any way the high value
that can be gained when the recovered oil is blended with the main distilled
oil fraction to obtain a premium grade of the respective essential oil.
Table 2: Loss of essential oils in distillation condensate water. Production fi gures
are for India only
Essential oil
Production,
2006,
million tonnes
Unit price,
2006
Volume,
2007
139
Oil lost in
water, kg*
Value of oil
lost in water,
$/yr
Arvensis 28,000 $ 14/kg 35,000 MT 5.6-7x10 6 46-58x10 6
Basil 100 $ 8/kg 100 MT 1x10 4 8.2x10 4
Citrodora 100 $ 8/kg 100 MT 1x10 4 7.4x10 4
Citronella 300 $ 8/kg 300 MT 3x10 4 2.52x10 5
Peppermint 450 $ 23/kg 450 MT 4.5x10 4 1.3x10 5
Spearmint 250 $ 23/kg 300 MT 2.5x10 4 7.2x10 4
Total 29,200 36,200 MT 5.72-7.72x10 6 47-59x10 6
* Data refer to 100 kg water per kilogram oil. Solubility of oil in water is 1000 ppm.
8.6.1 Polymeric Adsorption Process
Various techniques, such as cohobation, poroplast extraction
and adsorption, which can be used to recover the dissolved substances,
have been discussed in the literature. Polymeric adsorbents can be advantageously
used to recover dissolved essential oil components. Several investigators
have established the utility of adsorption in this context beyond
doubt. One study showed that although cis-rose oxide could not be detected
in the condensate, this valuable component was found in the recovered oil