Rambutan: A Weird Hairy Fruit from Indonesia

Rambutan (Nephelium lappaceum) is a medium-sized tropical tree and is native to the Indonesian region, and other regions of tropical Southeast Asia. The name also refers to the edible fruit the tree produces. It has similarities to several other edible tropical fruits including the lychee, longan, and mamoncillo. The name "rambutan" is derived from the Malay word rambut meaning "hair", a referral to the plenteous hairy protuberances of the fruit. In Vietnam, It is referred to as chôm chôm (meaning messy hair).

The fruit is native to Indonesia and is popularly grown in various countries throughout the region and has spread from there to parts of Asia, Africa, Oceania, and Central America.

Rambutan is an evergreen tree with alternate and pinnate leaves that range between 3 to the 11 leaflets and has small flowers. Rambutan trees can be male (producing only staminate flowers with no fruit produced), female (producing flowers that are only functionally female), hermaphroditic (producing flowers that are female with little percentage of male flowers). The fruit is a round to oval single-seeded berry, borne in a loose pendant cluster of 10 to 20 together. The leather-like skin is reddish(rarely orange or yellow), and covered with fleshy pliable spines, hence the name, which means "hairs". The spines play a role in the transpiration of the fruit and this may affect the quality of the fruit. Rambutan is not a climacteric fruit, this means it ripen only on the tree and appear not to produce a ripening agent after being harvested.

The flesh of the fruit (known as aril), is translucent, whitish or pale pink, with a sweet, mildly acidic flavor that is similar to that of grapes. Its single seed is glossy brown, soft and contains equal amount of saturated and unsaturated fats that may be cooked and eaten. The peeled fruits can be eaten raw, or cooked and eaten; first, the grape-like fleshy aril, then the nutty seed, with nothing going to waste.

Rambutan is an important fruit tree of humid tropical Southeast Asia, traditionally cultivated in Indonesia, Malaysia, and Thailand. It is a popular garden fruit tree and propagated commercially in small orchards. In 2005, Thailand was the largest producers of rambutan at 55.5%, followed by Indonesia at 30.2% and Malaysia at 11.9% giving a massive total of 97% of the world's supply of rambutan. The major cultivation centers in these countries include Thailand (Surat Thani province), Indonesia (Java, Sumatra, and Kalimantan).

The fruits are usually sold fresh. They are used in making jams and jellies, or canned. The evergreen nature of rambutan trees make them beautiful landscape specimens.

Rambutan fruit contains diverse nutrients but in modest amount, with only manganese having up to 16% of the Daily Value per 100g consumed. Its seed contains equal portions of saturated and unsaturated fatty acids where arachidic (34%) and oleic (42%) acids, respectively, are highest in fat content. The pleasant fragrance of rambutan fruit comes from numerous volatile organic compounds.

Rambutan fruit generally has a short shelf life in ambient conditions but implementing methods that can extend its shelf life becomes a production advantage. Treatments like irradiation and the use of hot-forced air can help in fruit preservation. Of the two, irradiation has recorded significant success.