Common Name: Annatto

General Information

Bixa orellana is a small but fairly fast-growing evergreen shrub or small tree growing from 2 - 8 metres tall. The bole can be 10 - 30cm in diameter[, , ].
This is a plant that is very important to the lives of local people, providing as it does a very wide range of foods and materials[]. It is commonly grown in many areas of the tropics, especially the Americas, as an ornamental and is also often cultivated for the red substance that surrounds the seeds and which is widely used as a dye, food colouring, flavouring and insect repellent[, , , ].

Known Hazards

None known

Botanical References

Range

S. America - Argentina, Paraguay, Brazil, Bolivia, Peru, Ecuador, Colombia, Venezuela, the Guyanas; C. America - Panama to Mexico.

Habitat

Coastal and inland thickets[]. Tropical forests[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	5.00 m
Growth Rate	Fast
Pollinators	Bees
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Annatto requires a frost-free, warm, humid climate. It can grow at elevations from sea level up to 2,200 metres in tropical to subtropical climates where a mean annual rainfall of 2,500 - 5,000mm is distributed throughout the year[]. It can withstand droughts of up to 4 months, but thrives best with well distributed rainfall and a dry season for seed ripening[]. It prefers a mean annual temperature in the range 28 - 32°c, with a mean maximum temperature of 22 - 27°c and a mean minimum temperature of 18 - 26°c[].
An easily grown plant, it succeeds on almost all soil types, preferring a moist, but well-drained neutral or slightly alkaline soil in a sunny position[, ]. Prefers a slightly acid soil according to another report[]. Prefers a pH in the range 5.5 - 7.5, tolerating 4.5 - 8.5[]. It grows into a larger tree when planted in deeper and more fertile soil, rich in organic matte[].
Plants commence fruiting when quite young[]. Trees can commence bearing fruit when only 2 years old[, ].
Seed-grown plants take longer to flower than vegetatively propagated ones, and do so sparingly. Under favourable conditions, fruiting commences 18 months from planting or earlier, and full crops of seeds are obtained after 3 - 4 years[].
Seed yields reach their peak when the trees are 4 - 5 years of age, usually a decline become evident around 12 years, but productivity can continue for up to 20 years[].
Seed yields from 0.5 - 5 tonnes/ha per year have been reported, but usually yields are between 800 - 1,500 kg/ha[].
20 - 50g of dye can be obtained from 1 kilo of seed[].
In Puerto Rico and the Virgin Islands, flowering occurs mainly in spring and fruiting chiefly in the summer[].
In some areas the tree can produce flushes of fruits at several times through the year[].

Edible Uses

The seeds are relatively tasteless[]. They are briefly steeped in hot oil which is then strained and cooled to be used as a flavouring in various dishes[]. The whole seeds can be ground into a paste with various other spices, which gives a more pronounced flavour[]. The seeds have a high nutritive value, containing a small amount of fatty oil (5%) and about 13% of protein[].

The ground seed is red and this can be used to colour foods[].

A yellow colour is obtained from the seed coat, and this is widely used as a colouring in margarines etc in the food industry[]. It is a harmless, non-carcinogenic dye[].

Medicinal

The medical properties of annatto are poorly understood, but it is a bitter, astringent, purgative herb that reputedly destroys intestinal worms, lowers fever, improves digestion and has expectorant effects[].

A decoction of the leaves is used as a treatment for dysentery[], and to reduce vomiting during pregnancy[].
The leaves are applied to the head and to sprains to relieve aches[]. A decoction is gargled as a cure for mouth and throat infections. The leaves may also be used in baths to relieve muscular aches, fevers, colic or to get rid of worms in children[, ]. The fresh shoots are steeped in water, which is then used as a eyewash for inflamed eyes[]. The leaves can be picked as required and used fresh or dried[].
The sap from the leaf petiole is soaked in hot water with rum, then used to remove secretions from encrusted eyelids as a treatment for blepharitis[].
Young shoots are applied locally as a poultice on abscesses[].

The roots are digestive and diuretic[]. A decoction is taken orally to control asthma[]. An infusion of the root in water and rum is used to treat venereal diseases[]. A tea made from the root is used to treat oliguria and jaundice[].

The seeds are used as an aphrodisiac, emmenagogue, expectorant and vermifuge[, , ]. They are used to treat asthma and nasal cavity problems[]. A macerated seed decoction is taken orally for the relief of fevers[]. In a syrup, they are used in the treatment of pharyngitis and bronchitis[].
The ground seeds are applied to burns in order to prevent blistering and scarring[].
The seeds are harvested as the fruits split open, and can be dried for later use[]. They can also be soaked in hot water - the resulting sediment is pressed into cakes for use in medicines and dyes[].

The pulp surrounding the seed is made into an astringent drink used to treat cancer, dysentery and kidney infections[, ].
The fruit pulp is used as a rub on the skin to prevent sores, probably from sunburn[].

The dye obtained from the seed coat is used as an antidote for prussic acid poisoning caused by eating poorly treated Manihot esculenta[, ].

Sap from the bark and crushed leaves is used as a treatment for skin rashes[].

A decoction of the bark is used as a treatment for malaria; angina and asthma[].

The leaves contain cyanidine and ellagic acid[].

Agroforestry Uses:

The plant is amenable to pruning and can be grown as a hedge[, ]. Plants are tolerant of hard trimming[].

Other Uses

A red dye, known as annatto, is obtained from the fruit[]. The dye is obtained from the seed coat[]. The dye is used to colour cloth, and is also used by native people as a cosmetic for painting the skin and as a lipstick[]. It is also used in the cosmetic production of nail gloss, hair oil, lipstick and soap, as well as in the production of floor wax, furniture and shoe polish[]. The colour rapidly fades when exposed to light and air[].
A waxy substance that has paralytic action on mammalian intestinal parasites is present in the seed coat[].
Bixin extracted from the seed coat is used in India as an insect repellent[].
The red dye obtained from the seed is applied to the skin to repel mosquitoes and other biting insects[, ].
Annatto paste filters out the ultraviolet rays of sunlight, thereby protecting the skin from excessive sunburn[].

The bark from the branches of the trees yields a water-soluble gum that is similar to gum arabic[].

The seeds contain a characteristic pleasant-smelling essential oil[].

It is said that fire can be started by the friction of 2 pieces of the soft wood[].

A fibre for cordage has been obtained from the bark of the tree[, , ].

The sapwood is whitish and the heartwood light brown or yellowish. The wood is soft, light in weight (specific gravity 0.4), porous, weak and not durable[].
The stems and branches are used for fuel[].

Propagation

Seed - the plant is usually grown from seed taken from freshly gathered ripe pods, which germinate better than dry ones[]. Mature seeds, taken directly from fresh fruits, germinate readily in 7 - 10 days under moist conditions[]. Seed is sown directly in the field, 2 - 5 seeds per hole in well-prepared soil, usually at the beginning of the rainy season. After germination only one seedling per hole is retained[]. Seedlings may also be raised in planting trays; they are transferred to 1 kg bags containing a soil mixture and kept in the nursery for 3 - 4 months before they are transplanted into the field[].
Cleaned, sun-dried seeds retain viability for over one year, but their germination rate falls to 12% in 3 years[]
Cuttings in sand. Hardwood cuttings of 8mm or more in diameter readily root when a root hormone suitable for hardwood cuttings is applied. Roots are produced in abundance in 7 - 9 weeks. Rooted cuttings are first transferred into pots or bags and kept in a nursery and can be transplanted to the field after 3 months[]. Propagating by cuttings allows selection of high-yielding, rapidly growing cultivars that flower early and profusely and bear fruit within 2 years[].
Air layering
Budding

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