Common Name: Jengkol

General Information

Archidendron jiringa is an evergreen shrub or tree growing up to 20 metres tall. The straight bole can be unbranched for up to 10 metres, it is 60 - 90cm in diameter[].
The plant, and especially the seed, is a popular vegetable in southeast Asia. It is harvested from the wild, wild trees are often saved when the forest is cleared, and it is also cultivated around villages. The seed is often sold in local markets[]. The tree also supplies medicines, timber and a dye for local use.

Known Hazards

Djenkolic acid, an amino acid derivative, has been found in the seed. Ingestion of the seed can cause the formation of sharp needle-like crystals of djenkolic acid in the kidney or urinary tract. In severe cases, crystals of djenkolic acid have been found in urine. Indeed, people who are suffering from djenkolism show similar symptoms to those suffering from kidney or urinary stones, a condition for which it has been frequently mistaken[].

Botanical References

Range

E. Asia - Bangladesh. Myanmar, Thailand, Malaysia, Indonesia.

Habitat

Forests of humid and mountainous areas, as well as along river banks[]. A sub-canopy tree in primary and secondary rain forest and in evergreen forest[, , ].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	20.00 m
Pollinators	Moths, Insects
Cultivation Status	Cultivated, Semi-cultivated, Wild

Cultivation Details

A plant of the humid tropics, where it is found at elevations up to 1,600 metres. It grows best in areas where annual daytime temperatures are within the range 20 - 30°c, but can tolerate 12 - 40°c[]. It prefers a mean annual rainfall in the range 2,000 - 3,000mm, but tolerates 1,000 - 4,000mm[].
Grows well in full sun and in light shade[]. Prefers a well-drained soil[]. It is found growing on sandy soils, lateritic soils and reddish sandy clay on flat land and low undulating hills[]. Prefers a pH in the range 5.5 - 6.5, tolerating 4.5 - 7[].
Although most species in the family Fabaceae have a symbiotic relationship with bacteria on their roots that can fix atmospheric nitrogen, there is a report that this species does not have this relationship.

Edible Uses

Seed - raw or cooked[]. The seed has a powerful odour that many people find objectionable[]. Young seeds are often eaten raw[]. Generally the young seeds are believed to have a better flavour than older ones, though some people prefer to eat germinating mature seeds[]. The seedpod is 20 - 25cm long and 3 - 4cm wide, twisted in a wide spiral[].
Mature seeds contain djenkolic acid and need careful preparation to neutralize it. Traditionally, they are boiled in three changes of water[]. Sometimes the seeds are boiled in a mixture of water, wood ash, bamboo leaves and pieces of steel or nails, discarding the cook water a number of times[]. The resulting beans are said to be highly nutritious[].
Other ways in which the seeds are prepared are:-
1). Boiled thoroughly till the offensive smell has disappeared, then consumed with salt and grated coconut[].
2). Steeped for a couple of hours in salt water, before being fried in oil. This also removes most of the bad smell[].
3). Made into a local delicacy, called emping. After cooking, the cotyledons are flattened by hammering them one by one into the shape of small cakes which are sun-dried, and fried in coconut oil and sprinkled with salt before consumption[, ].
4). Buried for 14 days until they germinate, then dug up and washed clean, whilst at the same time the sprouts are cut off and thrown away[].
The latter way of preparation is said to minimize the danger of intoxication by jengkolic acid, crystals of which can cause kidney failure. It is recommended to drink much water when eating the seeds[].
A starch is also extracted from the seed[].

Young leaves - cooked[, ]. The very young wine-red shoots are consumed raw as a vegetable[].

Flowers[]. Eaten as a vegetable[].

Fruit[].

Medicinal

The seed is said to be good for relieving the symptoms of diabetes[, ].

The old leaves, burnt to ashes, are used against itching[, ]. The ashes of young leaves are used as wound powder for cuts (e.g. Circumcision)[]. They are also applied traditionally as a diuretic, but are poisonous when eaten in large amounts[].

Other Uses

The pods have been used as a source of purple dye for silk[, ].
The bark and leaves are used for dyeing matting black[, ]. To obtain this colour the mat is boiled with extract from the bark and then immersed in mud[].
A reddish dye is obtained from the seeds[].

The pods are used as a shampoo[]. The pulverised seeds are used, they are rich in saponins[].

The bark, leaves and seeds have insecticidal properties[].

The heartwood is white, the sapwood white or pinkish-white. The wood has a strong smell of garlic when fresh, it is soft, easy to saw and to work with[, ]. It is considered to be only suitable for cabinet work, interior joinery[, ].
The wood is used for fuel[, ].

Propagation

Seed -

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