The genus Cinnamomum

140 K.R. Dayananda, U.M. Senanayake and R.O.B. Wijesekera
(Tiwari, 1989). CO 2 is the most commonly employed SCF. CO 2 is available freely, it
is cheap, non-flammable, non-toxic and non-corrosive. It behaves either as a polar or
non-polar solvent depending on pressure and temperature employed. CO 2 is liquid
below its critical point (31.2 °C, 7.38 milli pascal pressure) and above that it exists as
a super critical fluid. The technical advantages of using SCFE for spices were studied
by Udayasankar (1989).
Coarsely ground cinnamon bark is extracted with supercritical CO 2 using pressures
of 300, 400, 500 and 600 bar. The yield is around 1.4% as compared to steam distilled
(0.5–0.8%). No significant differences were reported sensorily between the SCF extract
and steam distilled oil and extracts (Pruthi, 2001). L CO 2 extract of powdered bark is
a mobile oil without the dark coloured waxes and resins normally encountered with
the bark oleoresin prepared with chemical organic solvent. The CO 2 selective extract is
more soluble in foods, while the resinous compounds have a slight fixing effect on the
flavour components of cinnamon and cassia bark extracts. However, the SCFE process
is not practiced for commercial cinnamon or cassia oleoresin production because the
process is very costly and the product does not differ much in quality from the solvent
extracted product.
Cinnamon oleoresin
Oleoresins are solvent extracts of spices that contain the volatile oil, non-volatile resinous
material and the active ingredient that characterises the spice as hot or pungent when
such an ingredient is present. The solvents commonly used for the preparation of the
oleoresins are acetone, ether, ethanol, propanol or methylene chloride. Ethanol was at one
time the preferred solvent but is no longer used due to its high cost. Acetone is now the
most commonly used solvent for oleoresin production. In solvent extraction the selected
solvent is allowed to percolate down through coarsely ground spice which is loaded in a
percolator. The bottom drain of the percolator is kept open for the escape of air. When all
the material is soaked the bottom drain is closed and sufficient contact time is given to
reach the solutes into the solvent. After the contact time, the extract, called “micella”, is
drained and collected.
For oleoresin production either the Soxhlet extraction method or the batch counter
current extraction method (CCE) is industrially practiced. In the Soxhlet method the
solvent is allowed to percolate through the bed of material several times, which involves
continuous heating of the extract. In the CCE method, which is very widely used, the
powdered spice is packed in to a series of extractors and extracted with a suitable
selected solvent. The solvent moves from extractor to extractor and the dilute extract is
allowed to percolate through the spice. The concentrated extract obtained first from
each extractor is withdrawn for solvent removal in the production of oleoresin.
The micelle obtained from the extractor is distilled to get the finished product. Most
of the solvent (90–95%) present in the micella is recovered by normal atmospheric
pressure distillation, while the remaining solvent is taken off by distillation under
reduced pressure. The trace amounts of solvent are finally removed by either the
azeotropic or extractive distillation method using an innocuous solvent like ethyl
alcohol. Alternatively, bubbling nitrogen into the thick viscous material is carried out
to drive away the residual solvent. The maximum permitted residual limits for some of
the solvents are 30 ppm for acetone and chlorinated solvents, 50 ppm for methyl
alcohol and isopropyl alcohol and 25 ppm for hexane (CFR, 1995). After distillation