Rambutan

Cloud' fruits and their relatives 

By: Anthea Phillipps 

In Borneo, the best known of these is the Rambutan (Nephelium lappaceum).

The word 'nephelium' comes from the Greek 'nephalos', meaning 'little cloud', and is thought to refer to the translucent white flesh inside the fruit, while 'rambutan' is derived from the Malay 'rambut', for hair, referring to the long soft spines covering the skin.

E.J.H.Corner, author of the "Wayside Trees of Malaya", mentions another name for the rambutan in Peninsular Malaysia, 'sanggul lotong', meaning 'the long hairs of the fruit are braided by the leaf-monkeys'.

Like the durian and the mangosteen, the rambutan was known to, and tasted by, early explorers who appeared to be unimpressed, as the fruit is hardly mentioned in their writings, except in passing.

One of the longer descriptions comes from John Crawfurd, the Resident of Singapore between 1823 and 1826, who wrote, in his "History of the Indian Archipelago":

"The rambutanÉ is an indigenous and peculiar fruit, about the size of a pigeon's egg, consisting of a skinny red covering, covered with soft spines, which encloses one large kernel enveloped in a small quantity of semi-transparent rich sub-acid pulp, the edible part of the fruit", finishing with "It is not much esteemed".

Rambutans are fairly small bushy trees cultivated throughout Malaysia and Indonesia, but the quality is quite variable.

The colour is usually some sort of red but there are also greenish-yellow and pinkish varieties.

Twist off the thin hairy skin to get at the translucent, juicy, sweet pulp surrounding the single seed.

The seed itself is not edible, (it is bitter and said to be narcotic), and the main drawback of most rambutans is that it is almost impossible to get the flesh off the seed without parts of the hard seed coat as well.

The rambutan is eaten mainly as a fresh fruit but is also canned (sometimes stuffed with pineapple chunks) on a small scale.

Dried fruit skins are said to be medicinal. Burkill's "Dictionary of the Economic Products of the Malay Peninsula" records the use of the roots in decoctions for treating fever; the leaves for poulticing and the bark as an astringent for diseases of the tongue.

In the northern part of Peninsular Malaysia and southern Thailand, the fruits and young shoots were used for dyeing silk.

Less well-known in Sabah, but becoming increasingly popular, is another species, the 'pulasan', (Nephelium ramboutan-ake), which is wild here, but which has quite a long history of cultivation, first in Java, and now in Thailand.

It has larger fruit, dark purple, almost black, in colour, (though there are also paler red, green and yellow varieties), with shorter, thicker spines, but equally sweet flesh, which is often easier to get off the seed.

In fact the pulasan is generally preferred to the rambutan when it is available. Fruits of the Giant Rambutan (Nephelium cuspidatum var.

robustum), which are covered in very curly hairs, are also referred to as 'pulasan' in Sabah but are rarely available, though William Wong, the Officer-in-Charge, of the Agricultural Research Station at Tuaran, tells me that there are a few cultivated tree at Kg. Kelatuan near Papar, south of KK, where it is called 'rambutan bayung'. All these can be seen at the Agricultural Research Station in Tenom, however.

Rambutans belong to the Soap-nut family, Sapindaceae, the name coming from the soapy chemicals, called saponins, in their fruits and sometimes their roots. Saponins dissolve and froth up in water and were once widely used as soap substitutes.

They are present in many plants, including the seeds and the fruit rinds (not the edible flesh!) of our wild rambutans to a greater or lesser extent.

In one related genus, Glenneia, they are so abundant in the fibrous flesh, that tasting the large mango-like fruits is almost like eating a piece of soap itself!

Glenneia is interesting for another reason as well - although it grows naturally in the Philippines, only one tree has ever been recorded from Sabah, in the remnant hill forest at the back of the Agricultural Research Station at Lagud Sebrang in Tenom.

This tree is still there. In large quantities saponins can break down blood cells and so they are frequently used as fish-poisons, but the toxicity varies widely according to the plant. Plants with toxic saponins have been employed in shampoos for killing lice and for washing clothes and jewellery.

Less toxic plants, or even perhaps the toxic ones, but in smaller amounts, have been used to treat epileptic fits and tooth decay.

Studies have also been carried out to see if the saponins could be effective against cancer cells, but so far without any positive results that I am aware of.