Bixa orellana (Annatto) is a native of Central and
tropical South America. The tree has been widely introduced
throughout the tropics as an ornamental or for its dyestuffs and
has become naturalised in many countries, including Jamaica. The
name comes from the Spanish conquistador, Francisco de Orellana,
who is credited with discovering the Amazon River in 1541.
The bush or small tree grows to around 2-3m in height and the
branches bear capsules covered with soft spines or hairs.
Although it requires tropical or sub-tropical conditions to
thrive, it is easy to cultivate and the trees reach maturity in
4-5 years and continue to bear up to 20 years.
A stem from an Annatto tree and dried capsules that have opened
to show the red seeds.
The town Annotto Bay, on the north coast of Jamaica, was
originally known by the Arawaks as "Guayguata" and was called
"Mellila" by the Spanish, the second city they established in the
Island. Presumably the English renamed it based on them finding
annatto trees being grown there? In 1774, the Post Master General of Jamaica,
Edward Dismore, established a Post Office in the town which opened on
the 1st January, 1774.
The Jamaica Railway Corporation commenced in 1845, making it one
of the first in the world. Originally between Kingston and
Spanish Town, the line through Annotto Bay to Port Antonio was
constructed around 1896, but closed in 1980.
It is considered that annatto extracts rank as the second most
economically important natural colour in the world [1,2,3] and it
is the most frequently used natural colour in the food industry
in the UK, being used to colour margarine and dairy products.
The major colour component is the apocarotenoid,
9'-cis-bixin, which accounts for over 80% of the annatto
pigment. It has been suggested  that over 2000 seeds have to
be harvested to get just one gram of bixin and additionally that
to produce one gallon of cheese colour, 240,000 seeds would have
to be harvested!
A recent estimate of the world production figures are that a
total of 14,500 metric tons of dried seed are harvested with
Brazil, Peru, Ecuador and Kenya contributing the major proportion
of this, with prices ranging from US $ 500 to 2,500 per metric
The first isolation of bixin is credited to Boussingault , who
in 1825 was living in Columbia and prior to his return to Paris
became a Colonel in Simon Bolivars' army. The structure of bixin
though, was not determined until 1961  and there was some
controversy surrounding this since it is unusual in being an
example of a cis-carotenoid rather than trans-,
common for most carotenoid structures. The first appreciation of
geometric isomerism in bixin was by Paul Karrer, a former student
of Alfred Werner. Karrer
was awarded a
Nobel Prize in Chemistry in 1937 for his research
on "Carotenoids, Flavins and Vitamin A and B2"
cis-bixin (monomethyl ester)
trans-norbixin (dicarboxylic acid)
In addition to bixin, numerous other pigments have been
characterised from annatto extracts  including: six
apocarotenoids (C30 and C32), eight diapocarotenoids (C19, C22,
C24, C25) and a carotenoid derivative (C14). These are all in
minor proportions. Norbixin is obtained by alkaline hydrolysis of
bixin to give a water soluble di-carboxylic acid. It is thought
that most extraction procedures cause changes in the structure
with trans- bixin being the more thermodynamically
stable and produced by heating the cis- isomer. This
may explain why both cis- and trans- norbixin
result from alkaline hydrolysis.
An example of an HPLC of annatto extracts is available at the
site under Chromolith(R) RP-18 endcapped menu
and a simulation of
this in JCAMP-DX format has been produced.
A chloroform extract produced the following UV/Vis spectrum. Note that it has been
suggested that quartz cells should NOT be used for determining
the spectrum since the sample will undergo rapid degradation in
the presence of light with wavelength below 300nm.
The 1% extinction coefficients for Peaks II and III of bixin
(470, 501nm) and norbixin (453, 482nm) have been reported  to
be 3016, 2714 and 3208, 2867 respectively.
The Raman spectrum of bixin has been published  and shows
strong bands at 1525, 1190, 1155 and 1010 cm-1.
The various colour codes to denote annatto extracts are:
European Community Identification number: Food color E-160b
USA: 21 CFR 73.30 Food Chemicals Codex
EINECS number: 289-561-2
Orange-3, CI Natural Orange 4, Orlean
Color Index (1982) number 75120
There have been recent concerns about the use of artificial dyes in foodstuffs and
a trend towards the use of "natural" dyes. Annatto extracts have generally been
classified as safe and in the US treated as exempt from certification as a colour
additive in food.
Annatto extact samples have been designated as "direct - alkali or oil extracts" and
as "indirect - solvent extraction methods". Alkali extraction gives mainly cis-bixin
and the salt of cis-norbixin. Hot oil is known to aid in the conversion
of the cis-bixin to trans-norbixin which is slightly more soluble
and used in oil based foods like margarine. It is of interest then that decomposition
products of bixin appear to be more prevalent in commercial samples that have undergone
processing with some form of heat treatment; for example, toluene levels as high as
12 ng/kg and m-xylene as high as 200 ng/kg in oil extracted seeds .
This might suggest that the indirect methods have an advantage in terms of quality?
Phytochemical and Ethnobotanical Database reports nearly 300
chemicals identified in Bixa orellana.
Annatto extracts from leaves, roots and seeds have traditionally
been used for medicinal purposes by South American Indians for
the treatment of wounds and to treat diarrhea and asthma .
Extracts from annatto have been shown to have a hyperglycaemic
 "Dye Plants and Dyeing", J and M Cannon and G Dalby-Quenet,
Timber Press, (Jan 1 2003), ISBN 0881925721.
 "Natural Food Colorants", Chapter 6, edited by G.J. Lauro and
F.J. Francis, Marcel Dekker, Inc, N.Y. 2000, ISBN 0-8247-0421-5
 "Natural Colourants and Dyestuffs",
FAO Report 1995, ISBN 92-5-103747-7
 J.B. Boussingault, Ann. Chem., 1825, 28, 440-444.
 M.S. Barber, A. Hardisson, L.M. Jackman, B.C.L. Weedon, J.
Chem. Soc., 1961, 1625.
 A.Z. Mercadante, A. Steck, H. Pfander, Phytochemistry, 52,
 L.F.C. de Oliveira, S.O. Dantas, E.S. Velozo, P.S. Santos,
M.C.C. Ribeiro, Journal of Molecular Structure 435, (1997),
 M.J. Scotter, L.A. Wilson, G.P. Appleton, and L. Castle,
J. Agric. Food Chem. 2000, 48, 484-488.
 E.Y. Morrison, H. Thompson, K. Pascoe, M. West and C.
Fletcher, Trop. Geogr. Med., 43, 1991, 184-188.
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Copyright © 2004-2014 by Robert John
Lancashire, all rights reserved.
Created and maintained by Prof. Robert J.
The Department of Chemistry, University of the West Indies,
Mona Campus, Kingston 7, Jamaica.
Created 7th November 2004. Links checked and/or
last modified 8th August 2014.