LISTING
DESCRIPTION
Irvingia gabonensis is a species of African trees in the genus Irvingia, sometimes known by the common
names wild mango, African mango, bush mango, dika or ogbono.
They bear edible mango-like fruits, and are especially valued for
their fat- and protein-rich nuts.
DETAILED
DESACRIPTION
Distribution and habitat
Irvingia
gabonensis is indigenous to the humid forest zone from the northern tip of
Angola, including Congo, DR Congo, Nigeria, Côte d'Ivoire and south-western
Uganda.
It is planted in
parts of this area, e.g. in south-western Nigeria and southern
Cameroon, and also in Côte d'Ivoire, Ghana, Togo and Benin.
Biophysical limits
The tree is present
in the tropical wet and dry climate zone.[3] Dika grows naturally
in canopied jungle, gallery forests and semi-deciduousforests. It grows at
altitudes from 200–500 m with annual rainfalls from 1200–1500 mm.[1] Supported
temperature ranges from 20° to 38 °C under slightly shaded to very bright,
clear skies. Deep soils with more than 150 centimetres (59 in) are needed
with a moderate fertility and good drainage. pH can range from 4.5
to 7.5.
Description
Irvingia
gabonensis grows straight, up to a height of 40 metres (130 ft) and 1
metre (3 ft 3 in) in diameter.[1] It has buttresses to
a height of 3 metres (9.8 ft). The outer bark is smooth to scaly
with grey to yellow-grey color. The crown is evergreen, spherical and dense.
Leaves are elliptic, one margin is often a little
rounder than the other, acuminate, dark green and glossy on the upside. Flowers
are yellow to greenish-white in small panicles.[1] The flowers are
bisexual. The fruit is nearly spherical, green when ripe with a bright orange
pulp. The stone is woody and contains one seed. Seedling germinate epigeally.[1]
Ecology
Irvingia
gabonensis is pollinated by Coleoptera, Diptera, Hymenoptera and Lepidoptera.[1] It flowers from
March to June and has two fruiting seasons: from April to July and from
September to October.[2] Seeds are dispersed
by specialized vertebrates as elephants and gorillas. By reducing the number of
those animals, the spread and regeneration of dika decreases and it becomes
dependent on human planting.[4]
Uses
Humans eat the
fruits fresh, leading to the misnomer, African mango.[1] The fruits are
processed into jelly, jam, juice and sometimes even wine.[3] The pulp has also
been used to prepare black dye for cloth coloration.
The seed coat has to be cracked
open to get to the endosperm. Seeds, also called
dika nuts, are eaten raw or roasted. Mostly however they are pounded to butter-
or a chocolate-like block.[4] Seeds can be pressed
to produce an edible oil (solid at ambient temperatures) or margarine used for
cooking. The oil can also be processed further to soap or cosmetics.[4] The press cake can be used as
cattle feed or as thickening agent for soup. Seeds can
be ground or crushed and used as a thickening and flavoring agent in soups and
stews.[1] They can also be
made into a cake called "dika bread" for preservation.[1]
The wood is hard and
therefore used for heavy construction work as making ships' decks or railway
ties.[1] Dead branches are
used as firewood.[4]
The trees are used
in agroforestry systems
to shade other crops, especially cocoa and coffee. They are also used to reduce
erosion. Cities have started using them to shade streets, as shelter belts, or
for beautification.
Thousands of tons of
dika seeds are traded each year, mostly within Africa.
Clinical research
A review of clinical
research on consuming dika for weight management found irregularities in
testing methods and reporting. The study concluded, "Due to the paucity
and poor reporting quality of the randomized clinical
trials, the effect of I.
gabonensis on body weight and
related parameters are unproven. Therefore, I.
gabonensis cannot be
recommended as a weight loss aid. Future research in this area should be more
rigorous and better reported."[5]
Nutritional aspects of Irvingia gabonensis
Nutritive value of
the kernels per 100 g edible portion, which corresponds to about 2918 kJ of
energy:[4]
|
Fat
|
67 g
|
|
Carbohydrate
|
15 g
|
|
Protein
|
8.5 g
|
|
Water
|
4 g
|
|
Calcium
|
120 mg
|
|
Iron
|
2.4 mg
|
Besides the
mentioned components, kernels of Irvingia
gabonensis contain traces of thiamine, riboflavin and niacin. The approximate fatty acid composition is
myristic acid 33–70%, lauric acid 20–59%, oleic acid 1–11%, palmitic acid 2% and stearic acid 1%.[4] The contained amino
acids are reasonably balanced for human nutrition. Since lysine,tryptophan, valine, threonine, isoleucine and phenylalanine have high
concentrations in the seed, first limiting amino acids are methionine and cysteine.[4]
Unlike the pulp of
some other Irvingia spp., the pulp of the fruit of Irvingia gabonensis tastes juicy and sweet and is eaten
fresh. Nutritive value per 100g edible portion of fruit pulp, which corresponds
to 255 kJ of energy: energy:
|
Water
|
81 g
|
|
Carbohydrate
|
15.7 g
|
|
Protein
|
0.9 g
|
|
Fat
|
0.2 g
|
|
Phosphorus
|
40 mg
|
|
calcium
|
20 mg
|
|
7 mg
|
|
|
Iron
|
2 mg
|
The fruit pulp's
flavor components include zingiberene, cinnamic acid, dodecanal and dodecanol. This results in spicy-earthy,
fruity, wine-yeast flavor notes.[4]
Cultivation
Until some years
ago, 90% of dika products were harvested from scattered, wild trees.[2] Dika trees were not
cultivated systematically, because it was believed, that it takes up to 15
years until a tree bears fruit. Although they were not planted, their
occurrence is high because they were also rarely lumbered. In a plantation
using marcots (air-layering plants), flower production was observed two to four
years after planting.[2] Germination from
seeds is low and when they are not handled carefully, most fail.[2] The seeds are mostly
extracted by breaking them by hand.[2]
Breeding
The domestication of dika is in its
early stages.[2] Around 1990, vegetative propagation allowed mass replication and selection. Grafting, budding, air-layering, marcotting and
cuttings are feasible when they are applied to young wood.[2]
Future developments
An elite germplasm
bank should be built up.[2] This germplasm could
then be used for vegetative propagation to improve the farmers welfare with
improved plant material. Farmers could also be supported in cultivation. Future
breeding aims are: multiple
bearing – carrying fruits
several times a year, precocity – fruiting at younger age, split fruits – nuts which release the seed by
themselves and good form – dwarfing is especially valued,
because it simplifies harvest.[2] Invention of a
nut-cracking device would help the further dispersion of the tree. A selection
for "drawability", which could be used by food technology seems
probable.
PRICE
$17.57/KG OR $7.99/IB
For more information:
mobile: +2348039721941
contact person: emeaba uche
e-mail: emeabau@yahoo.com
website: www.franchiseminerals.com
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