Rukam or Rukem (Flacourtia rukam) is the name of a fruit-producing tree which is said to be native to Indonesia. The existence of rukam trees is becoming rare in Indonesia, because these trees are planted as garden plants instead of commercial fruit cultivation plants.
To eat the fruit in a unique way, the rukam fruit must be massaged before eating to remove the astringent taste of this rare fruit. Rukam trees and fruit in several areas in Indonesia are also known as Rukem, Ganda Rukem, Gerendang (Java), klang tatah halves (Kalimantan).
In English this Rukan or Rukem fruit is called Indian Prune. In several other countries, several names are given such as Rukam (Philippines), Ta Khop Thai (Thailand), Rukam Manis, Rukam Gajah, Rukem (Malaysia), Jawa Rukamu (Japan). Whereas in Latin, this rare plant is called Flacourtia rukam or also (synonym) Flacourtia euphlebia.
Rukam (Family: Flacourtiaceae) is found in Southeast Asia and also India. This tree grows in the wet tropics up to an altitude of 1,500 m above sea level. However, in the wild it is found to be able to grow at an altitude of 2,100 m above sea level. Its natural habitat is in primary and secondary forest. This plant has sufficient adaptation to the range of temperature, rainfall, and soil conditions. The rukem tree reaches 20 m in height with the trunk and branches usually curved and grooved. On the stem of the rukam there are thorns that can reach 10 cm in length.
This rukam fruit comes from a tree that can grow from 5-15 meters. The stems have spines that can grow up to 10 cm long. Along with the times, now there are also rukam plants that do not have thorns. The new leaves are brownish red. The mature leaves are serrated ovals. It can reach 16 cm in length and about 7 cm in width. A series of male and female yellow-green axillary flowers emerge from the leaf axillae. The fruit is round with a length of about 2 cm. The fruit is green, red, or dark red.
Rukam fruit is a type of buni fruit that is round in shape, flattened round to ovoid breech with a diameter of 2-2.5 cm. The fruit is light green to pink or purplish green to dark red. Rukem fruit has whitish flesh. At the end of the fruit there are still 4-8 small pistil marks, similar to a beak, in the shape of a circle. Rukem fruit with flat seeds, as many as 4-7 points. This rare fruit contains a lot of sour water.
Rukem fruit (Flacourtia rukam) can be eaten directly but has a slightly astringent taste. To get rid of this astringent taste, the rukam fruit must be massaged first until it feels slightly soft and then eaten. Rukem fruit can also be used as salad and pickles, or mixed with sugar to make jam. Young fruit can be used as a traditional medicinal ingredient which is efficacious for treating diarrhea and dysentery.
The plant can be propagated by seed or grafting. Plants from seeds will begin to bear fruit at the age of 7-8 years, while from grafts at the age of 3-4 years.