Native to West Malaysia, the name rambutan is derived from the Malay word which means hairy. The outer part of the fruit is hairy and the flesh inside is tender and fleshy. It tastes sweet and sour like a grape. Though it is imported in Southeast Asia, Rambutan is imported all around the world. The fruit resembles the appearance of lychees. Similar to lychees, it is found in bunches with stems sticking out of them. Rambutan could also have a greenish-yellow or orange exterior.

The tree of Rambutan is 15 to 25 meters tall which produces fruits twice every year. The fruit has the size golf ball which is covered with shells having reddish to orange spines appearing like hair. This covering could be peeled to expose pale white fruit inside. The flowers possess a fairly sweet aroma which is white or green in color. An average tree produces from 5000 to 6000 fruits each year whereas some trees may produce 10000 fruits in a year

Rambutans are usually harvested at the peak of maturity. Harvesting stops further ripening of the fruit. Storage is quite a major problem for the fruit because, during storage, the fruit rapidly loses its quality in appearance, due to shriveling and browning of the rind. Additionally, longer storage also causes the fruit to soften and the pulp to become rather watery and leaky, which seriously affects the fruit quality and ultimately the market price and consumer acceptance. Standard storage practices need to be stringently followed in order to maintain freshness and high fruit quality.

History

Nephelium lappaceum has its origin in Southeast Asia and is widely cultivated in Malaysia (80,000 tonnes), Indonesia (148,000 tonnes), Thailand (430,000 tonnes), and the Philippines (20,000 tonnes). To the people of Malaysia, Thailand, the Philippines, Vietnam, Borneo, and other countries of this region, the rambutan is a relatively common fruit. Thailand is a major producer and exporter of rambutan, where the ‘Rong-in variety is the most popular variety commercially, with demand increasing annually.

Plant

Rambutan is an evergreen, medium-sized, and much-branched tree that grows from 15 to 25 m tall having an erect trunk of 40 to 60 cm diameter. The bark is dark brownish to grey. The twigs are pubescent and terete which becomes glabrescent. It bears alternate leaves which are pinnately compound. Petioles are 1 to 3.5 mm thick and 1.5 to 16 cm long. Leaflets are pale green, pubescent, soft, alternate to sub-opposite. Fruits are formed in loose clusters of 10 to 18. Fruit is a drupe having one ovule developed. It is green while young which turns yellow and red. It is round to ovoid in shape measuring 3.5 to 4.5 cm wide and 4.5 to 6 cm long and weighs 20 to 60 g. Skin is leathery orange or yellow which is covered with fleshy pliable spines. Seeds are glossy brown, flattened oval measuring 1 to 1.3 cm.

Health Benefits of Rambutan

This fruit provides great amounts of natural sugars such as calcium, phosphorus, iron, copper, potassium, magnesium, manganese, vitamins B3, A, C, and Vitamin B9. Rambutan is a great source of minerals and vitamins that assist to strengthen bones, lose weight and also provide anti-parasitic properties. The juice of leaves promotes a healthy scalp and seeds possess anti-diabetic properties. Seeds possess equal proportions of saturated and unsaturated fatty acids such as arachidic (34 percent) and oleic (42 percent) acids.

1. Anti-viral? activities

The conducted study shows that geraniin possesses antiviral activities against DENV-2 by preventing the mechanism of viral attachment. It shows an effect through E protein during the early stage of the virus life cycle. It suppresses early viral gene transcription as well as replication. An exact mechanism through which geraniin inhibits DENV-2 gene transcription is unknown.  In vivo experiments, determination of the efficacy of geraniin for protection against DENV-2 challenge would be helpful as it could affirm the capability of geraniin to be developed further as an anti-dengue agent. (1)

2. Anti-diabetic activity

Studies show that Rambutan peels phenolic extract displayed high antioxidant as well as antiglycation activities in vivo and in vitro. Further study assessed anti-diabetic activities of Rambutan peel phenolic extract in a mouse model of Type II diabetes? promoted by streptozotocin incorporated with a high-fat diet. The results show that Rambutan peel phenolic extract promoted body weight and lowered the fasting level of blood glucose of the diabetic mice. The extract lowered the serum levels of total cholesterol?, creatinine?, and triglyceride, and glycated serum protein in diabetic mice. Rambutan peels phenolic extract recovered glycogen content in mice liver? which promoted the activity of glutathione peroxidase and superoxide dismutase and lowered lipid peroxidation in diabetic mice. Rambutan peel phenolic extract protected tissue structure of the liver, pancreas?, and kidney?. Moreover, Rambutan peel phenolic extract lowered mesangial index and inhibited expression of TGF-β in kidneys? of diabetic mice. (2)

3. Prevent coronary heart disease?

Coronary heart is the deposition of fat accumulated in cells lining the walls of the coronary artery? and blocking the flow of blood. This disease makes the arteries? in the heart narrow. When it gets worsened, the oxygen supply blood to the heart can be lowered through the bloodstream and causes damage to the heart. Vitamin B3 has the ability to convert fats, carbohydrates, and proteins into energy. These fats prevent excess cholesterol in the body.

4. Source of Vitamin C

Vitamin C is an essential antioxidant that helps in strengthening the immune system of the body to counteract free and harmful radicals. It supports in lowering inflammation? of cells and also promotes the absorption of iron which is vital for good blood health. Besides collagen forming compounds, Vitamin C is essential to repair and build skin tissue, joints, and bones.

5. Strengthen bones

Intake of Rambutan provides adequate amounts of iron, calcium, and phosphorus to the body. The body utilizes it when these elements are broken down for repairing and forming strong bones and promote stable growth. It lowers the chances of bone diseases and fractures.

6. Sperm health

A high intake of Vitamin C is associated with the healthy development of sperms. It might be possible that deficiency of Vitamin C in males might be the reason for conceiving children. The daily intake of 500 milligrams of Vitamin C is recommended for good sperm health. Consume Rambutan fruit which provides healthy amounts of Vitamin C that assist to enhance the quantity and quality of sperm.

7. Normalizes blood pressure

Hypertension? does not show any symptoms, it is known as a silent killer. It causes damage in blood vessels that could result in heart disease, stroke?, heart disease, and other serious health ailments. Being overweight or obese also increases the chances of developing high blood pressure. The fruit has low saturated fat and calories which is suitable for hypertension patients.

8. Antioxidant activity

Antioxidants promote the defenses of the body against harmful compounds known as free radicals.  Pollution such as toxins, smog, and cigarette smoke, and sun rays creates free radicals. Moreover, the skin of the fruit also possesses antioxidants that could be boiled in water and could be ingested to reap these health benefits. The study shows that seeds, pulp, and skin possess strong polyphenolic compounds known as flavonoids. Flavonoids are called pigments for flower coloration which produce blue/red or yellow pigmentation in plants.

9. Promotes skin health

Seeds help to enhance the appearance and health of the skin. Make the paste of the seeds and apply it to the skin to obtain a clearer as well as even complexion. Use the paste of the seeds daily to smoothen and soften the skin and also improve the texture of the skin. Rambutan also hydrates the skin. This fruit contains manganese and Vitamin C which supports the production of collagen and act as an antioxidant that counteracts the damage made by free radicals. It makes the skin look young and healthy for a longer time period.

10. Healthy hair

Rambutan possesses an antibacterial property that is helpful for treating dandruff and other scalp problems such as itching?. It contains Vitamin C which helps to nourish the scalp as well as hair. Rambutan has copper which is helpful in treating hair loss, intensifies hair color and prevents premature graying. It contains protein that assists to strengthen hair roots. Vitamin C in Rambutan adds shine to the hair. Apply Rambutan juice to the hair and let it remain for about 15 minutes before shampooing.

Origin and distribution

It is just a well-known thought that rambutan is indigenous to Malaysia and Indonesia. The initial record of rambutan trees reveals that they were grown by the Malayan jungle people about their short-term settlements, an exercise followed to date. Rambutan trees are today discovered expanding naturally in Southern China, the Indochina region as well as Southeast Asia. With ever-increasing popularity among non-Asians and growing interest in rambutan globally, the fruit is at present regarded as essential agricultural produce. It really is developed in a commercial sense in Indonesia, Malaysia, Philippines, Thailand, Brunei Darussalam, Sri Lanka, Australia, Hawaii, Vietnam, and also Central America. Even just in 1981, rambutan was cultivated commercially on approximately 700 ha of land in Singapore. Fast urbanization meant rambutan plantations shall no longer be present in Singapore. To satisfy the requirements of the individuals, Singapore has remained the biggest importer of rambutan on the planet, comprising a lot more than 60% of world imports.

Types of Rambutan

• Lebakbooloos
• Seematjan
• Seenjonja
• Maharlika
• Sectangkooweh
• Seelengkeng
• Seekonto

Traditional uses

• Pulp is used in folkloric medicine for fevers.
• Fruit is useful to provide relief from dysentery and diarrhea?.
• Leaves are used as a poultice on temples for alleviating headaches.
• For thrush, use the decoction made from bark.
• In Malaysia, root decoction is used to treat fever?.
• In China, fruit is used for severe? dysentery and as a warm carminative in cold dyspepsia?.
• Boil the peel and drink the liquid to cure dysentery and fevers.

Precautions                    

• It contains fructose which promotes resistance to insulin? that could worsen diabetes as it could cause a spike in the level of blood sugar.
• It could be harmful to blood pressure patients because the sugar turns into alcohol in ripened fruit.
• Avoid consuming seeds as they could be fatal.

How to Eat         

• The fruits could be canned, frozen, and thawed.
• Rambutan could be processed into jellies, jams, mixed fruit cordials, fruit rolls, and fruit juices.
• Roasted seeds are consumed.
• Add it to fruit salads.
• It could be used in smoothies, desserts, cocktails, jams, yogurt, chutney, jellies, salsa, soup, and syrups.

Storage

The short shelf life and perishability of Rambutan are major issue that limits the export of this fruit to the world market. Salicylic acid and lukewarm treatment increase the shelf life, but still, there is a need to develop new methods which can facilitate a longer storage time, so that the fruit can be exported to distant countries without damaging the taste, flavor, and quality of the fruit.

References