Longkong, a tropical fruit from Thailand

One of the tastiest tropical fruits, also used in traditional medicine

Photo of author

By Alex

Longkong, or langsat, is a tropical fruit that grows in clusters with fruits resembling small potatoes. It is native to Thailand and widespread in other Southeast Asian countries: actually, it is a mix between longan and lychee. Its flesh tastes both sweet and bitter at the same time. Nothing of the longkong is thrown away. In its native countries, in fact, the fruit and other parts of the plant on which it grows are used to treat various diseases and ailments, such as dysentery, malaria, and scorpion stings.

Want to try it? It’s not going to be easy. Basically it is produced for the domestic trade of the producing countries. Only a small portion of the production is exported.

What fruit is longkong?

The longkong is a tropical fruit from Thailand. It is a cross between the longan and the lychee and part of the Meliaceae family. The scientific name is lansium domesticum/parasiticum.

About 7 cm in size, it can have various shapes: round, elliptical or oval. It resembles a small potato, but grows in clusters covered with thin pale hairs. The more or less thick skin encloses a sweet, white, translucent flesh, which in turn contains flat green seeds. One to three in number, they are covered with a thick whitish aril and have a sweet-and-sour taste.

When young, the fruit is green. When it later reaches maturity, it turns yellow.

Longkong ripens during the period from July to September. Once picked, the fruit must be eaten within a short time otherwise the skin will blacken, while retaining the flavor of the inner flesh. It can be eaten raw, as a matter of course, or preserved in syrup.

Typologies of longkong

Thais make a distinction between 2 varieties of longkong, based on the thickness of the skin, which varies from 2 to 6 mm.

  • Thick: long gong, which is easier to peel directly with the hands by applying gentle pressure
  • Thin: langsad

Longkong plant: what it looks like

The longkong plant (Lansium parasiticum or Lanzones) is a species of tree belonging to the same family as mahogany.

Widespread in Southeast Asian forests, it is cultivated in Cambodia, Vietnam, Thailand, India, Indonesia, the Philippines, and Malaysia. In addition, this plant has also been transplanted to Hawaii and Suriname. It requires a typically tropical climate with high temperatures and similarly high humidity rates to grow well and produce much fruit.

The longkong tree is impressive in size: it can reach 30 meters in height, while the diameter of its trunk is about 70-80 centimeters.

It begins to bear fruit around 12 to 15 years of age. By the age of 20, it can produce more than 100 kilograms of fruit per year.

Let’s see what this plant looks like by analyzing its various parts.

  • Trunk: irregular and 70-80 cm

in diameter.

  • Roots: well anchored to the ground, they stick out and are clearly visible on the surface
  • Bark: grayish with dark spots
  • Wood: hard, thick and durable, it is used locally for the construction of rural houses
  • Chioma: very voluminous, consists of leaves resembling fine hair
  • Leaves: pinnate in shape, they are very thin
  • Gems: elliptical in shape, they can measure 20 cm in length and 10 cm in width
  • Sprout stems: max 12 mm long
  • Flowers: small and with short stems, they have a hard egg-shaped crown and a 2-millimeter-long stamen round at the top. These flowers are symbolic of the Sumatra region of Indonesia
  • Fruit: the longkong ripens between July and September; it can be eaten fresh or preserved in a syrup

Nutritional values of longkong

100 grams of fresh raw product provides 57 calories, broken down into carbohydrates, fiber and protein. Rich in vitamins, especially B and C, it also contains good amounts of iron, calcium and phosphorus. It contains virtually no fat.

How to eat longkong

Longkong is eaten without the peel. At the point where the stem fits into the skin, you exert a slight pressure with your fingers so that you can open the fruit easily. You then divide it into two parts and proceed by peeling off the skin. The pulp is translucent and, often, contains seeds. The longkong is enjoyed in this way, in all its fresh naturalness.

Once harvested, it should be eaten immediately because it blackens within 2 days and the taste is altered in a short time.

Here is a photo from which we can see some resemblance to lychee.

What the longkong tastes like

The flesh of the longkong is very sweet, but with a bitter and sour note that makes it thirst quenching. To give an idea, it tastes a bit like a mix of grape, banana. If still unripe, it comes out sour.

How to choose longkong

For optimal tasting, the longkong must be ripe to the right point, neither too sweet nor too sour. To tell if it is the right time to consume it, just look at the skin, which should turn yellow. If still green, it is a sign that the fruit is still unripe.

What are the properties of longkong?

Longkong is used in traditional medicine to treat various diseases and disorders.

Let’s look specifically at what properties it is credited with

  • Lows the levels of “bad” (LDL) cholesterol and increases those of “good” (HDL) cholesterol due to the presence of niacin
  • Keeps the cardiovascular system healthy due to the presence of fiber
  • Contrasts riboflavin
  • Protects the gastro-intestinal system and promotes proper bowel function again due to the presence of fiber
  • It helps thenervous system and strengthens the memory due to the presence of phosphorus
  • Preserves the wellbeing of bones and teeth due to the presence of calcium
  • It is a good antioxidant for skin, teeth, and eyes because of vitamin A

How to eat longkong

Besides as a simple fruit, in its places of origin, longkong is also used in the preparation of soups, jams sweet and sour sauces, snacks and desserts of various kinds. Commercially, longkong is also found in syrup, canned.

In China, they use this dried fruit to prepare sweet soups.

In cooking, the seeds are discarded because they are too bitter.

Other uses in traditional medicine

In places of production, all parts of the longkong are used. This fruit is also used in folk medicine, for example against intestinal worms and ulcers. More specifically, diarrhea and malaria are treated with the bark. Other uses of this fruit include:

  • Pulverized bark is used to treat scorpion bites
  • The skin is used to treat diarrhea
  • Pulverized seeds are used to lower fever
  • Burned skin is an excellent mosquito repellent

Other names for longkong

In different Southeast Asian nations, this tropical fruit is also called by other names, such as, langsat, duku, kokosan, lanzones, ceruring, lòn bon, buwa-buwa, gadu guda, and bòn bon.

In English, long kong is referred to by the terms “langsat” or “lanzones.”

Other tropical fruits

If you are interested in strange fruits from distant countries, or unusual crosses, find here more information: