Know in one minute about Rambutan Rambutan taste like a sweet/ sour refreshing flavor. Also known as the King of Fruits in Southeast Asia. The fruit has thick and translucent juicy flesh with soft spines or hairs in its shell Each fruit contains a single oval seed with a multicolored peel that is slightly bitter. All parts of fruits such as pulp, seed, and peel have medicinal properties. Effective against germs.  Treat diabetes, heart disease, and organ injury and remove harmful radicals from the body.  Reduce oxidative stress, obesity, brain disorders, inflammation, and pain.

Introduction

Rambutan (Nephelium lappaceum L) belongs to the family Sapindaceae. It is an attractive tropical fruit, valued for its refreshing flavor and unusual appearance. This plant is related to lychee, pulasan, and longan. Rambutan taste is less aromatic than lychee.

The name ‘rambutan’ is derived from the Malay word ¨Rambut¨, meaning ¨Hair¨ thus it is also named hairy litchi. It is widely known and revered in Southeast Asia as the King of Fruits. People consume this fruit in fresh, canned, or processed forms such as juice, marmalade, jam, and jellies. 

This plant produces seeds and peels (rind) as major residues that are discarded. However, these residues are rich in nutrients and bioactive constituents and also have medicinal properties (1).

Geographical distribution

The plant is native to Malaysia and Indonesia. It is also cultivated in China, Australia, India, Taiwan, Madagascar, Philippines, Singapore, South Africa, Syria, Thailand, Vietnam, and Congo. 

Botanical description

The rambutan is a medium-sized evergreen tree with a soft thorn that covers the fruit surface.

• Height

About 12-30 m tall with grayish brown branches.

• Leaves

Glossy green with 3–11 leaflets.

• Flower

The flowers are small with yellowish-green to white and have no petals. It has a mild sweet scent and is rich in nectar that attracts bees.

• Fruit

Rambutan fruits are produced in clusters of 10 to 12 oval or round fruits. Ovoid berry has a thin leathery skin that is covered with flexible hairy spines.

The color varies from pinkish to red, yellow to orange-red, or bright red to maroon. The fruits are distinctive for their large size and unique odor.

The custard-like flesh has an exquisite flavor and is at the same time aromatic and sweet with a strange balsamic taste.

• Seed

The seed is single large, bright brown, and ovoid (2).

Nutritional value of Rambutan fruit

Rambutan fruit is made up of the following parts: total weight (27.4%), peel (13.2%), pulp (11.7%), seed (2.53%), and embryo (1.60%).

The daily vitamin C requirement for the average adult (75–90 mg) can be met by consuming about 10–12 rambutans. Intake of this fruit provides 2–6% of the daily recommended intake for minerals (Phosphorus, potassium, magnesium, iron, zinc) (3).

Pulp

Rambutan pulp contains 63 calories per 100 g with no cholesterol. It also carries water content (83 g), proteins (0.8 g), and carbohydrates (14.5 g). 

This fruit is rich in potassium (63–81 mg), calcium (22–31 mg), phosphorus (11–13 mg), and magnesium (9–13 mg).

It is an excellent source of vitamin C (20–45 mg), iron (3 mg), and crude fiber (0.38).

Pulp also contains micronutrients like manganese (0.26–0.38 mg), boron (0.12–0.16 mg), zinc (0.09–0.11 mg), and copper (0.08–0.10 mg).

The fat content in the pulp is lower compared to the rambutan seed (4).

Seed

The seeds of this plant contain high amounts of fat (14%–41%) and carbohydrates (28%–46%).

It is also composed of humidity (34.4%), ash (1.2%), protein (7.8 %), and crude fiber (11.6 %).

Besides, the seeds appear to have a good amount of tannins, saponins, and fats, including oleic, linoleic, and arachidic acids. The presence of most of the essential amino acids makes seed flour a good source of protein.

Rambutan seeds show narcotic effects like drowsiness, sleep, stupor, insensibility, and pain relief due to the presence of alkaloids in them (5).

These seeds are soft, crunchy, slightly bitter in flavor and toxic in fresh form. However, after roasting the seed powder is similar to that of cocoa powder. In addition to this, roasted rambutan seed powder is not toxic and thus can be safely consumed (6).

Peel

Rambutan peels have a high protein (6.36 g) and lipids (0.89 g) per 100 g with a low-calorie count. It contains some minerals like magnesium (0.15 mg), potassium (0.57 mg), iron (0.29 mg), and calcium (0.51 mg). Copper (0.070 mg), manganese (0.14 mg), zinc (0.080 mg), vitamin C, phenolic compounds, and tannin are also present in the rind of rambutan (7).

How does rambutan taste?

Rambutan fruit is edible, juicy, whitish, translucent, or pale pink with an eccentric sweet or mild sour flavor.

Furthermore, the exotic aroma of this fruit is the interaction of fruity-sweet and fatty-green odors similar to human sweat. This is due to the possible contribution of “civet-like”-sweaty, spicy, and woody notes (8).

Rambutan Benefits

1. Benefits of Rambutan peel

• Prevent dengue virus infection

Dengue is caused by the dengue virus however, rambutan peel contains geraniin (tannin) that inhibits viral attachment to the cell. Therefore, this fruit peel acts as an anti-dengue agent that suppresses phase dengue viral infection (9).

• Manage diabetes and cholesterol levels

Rambutan peel is rich in phenolic compounds that increase body weight and lower blood glucose levels. It also reduces cholesterol levels in the blood and effectively protects the liver, kidney, and pancreas (10).

• Antioxidant properties

Rambutan peels have high polyphenolic compounds that show high antioxidant and free radical scavenging activities. These activities are comparable to vitamin C, a-tocopherol, grape seed, and green tea (11).

This peel also delays lipid oxidation thus, can be used for the stabilization of sunflower oil and delayed oil rancidity (12).

• Treat inflammation

Rambutan peel contains phenolic compounds that remove harmful radicals and protect against cellular damage. It also reduces oxidative stress and DNA damage. Thus, peels of this fruit treat arthritis by reducing inflammation, swelling, and stiffness of joints, tendons, muscles, and cartilage (13).

• Treat obesity

Rambutan peel contains a bioactive compound that inhibits the formation of fat cells. Thus,  peel prevents body weight gain, declines the size of adipocytes, and manages obesity (14).

• Antimicrobial properties

Phenolic compounds such as geraniin, ellagic acid, rutin, quercetin, and corilagin found in rambutan peel act as natural antibacterial substances. These compounds inhibit the growth of various bacteria and protect the body from many infections (15).

• Enhance sunscreen protection

Phenolic compounds like tannins and flavonoids in rambutan peel act as a natural additive that increases sun protection factor (SPF) value. Thus this fruit peel may be used as a natural substance for the rambutan-based sunscreen (16).

Benefits of Rambutan pulp

• Presence of antioxidants

Rambutan pulp contains natural antioxidants such as vitamin C, vitamin E, carotenes, and xanthophylls. It is also rich in tannins and phenolic compounds like geraniin, ellagic acid, quercetin, corilagin, and rutin. These antioxidants remove harmful radicals from the body, prevent oxidative stress, and protect the cells against damage (17).

• Anti-inflammatory properties

Rambutan pulp inhibits the expression of cytokines that cause inflammation and reduce inflammation (18).

• Antimicrobial properties

Rambutan pulp is rich in glycosides, tannins, phenols, and flavonoids which suppress the growth of bacteria and fungi (19).

• Slow down the progression of cancer

Polyphenolic compounds like phenols and flavonoids in the fruit of rambutan fight against cancer cells. It inhibits the proliferation of cancer cells and induces shrinking and apoptosis (20).

• Anti-allergic properties

Rambutan pulp can inhibit the enzyme released when the body responds to allergens. Thus this pulp treats immune dysfunction (21).

Benefits of Rambutan seed

• Rich in nutrients

Rambutan seed is an excellent source of protein, crude fat, carbohydrate, fiber, vitamin B, and minerals. It is rich in antioxidants (polyphenols) like tannins and flavonoids such as geraniin, corilagin, and ellagic acid. These compounds have beneficial effects on human health and protect against various chronic diseases (22).

• Treat diabetes

Rambutan seeds contain bioactive compounds that reduce the blood glucose level in the blood. Therefore, the rambutan seed may lower elevated blood glucose levels and increase insulin sensitivity (23).

• Anti-tumor properties

Trypsin inhibitors in rambutan seed show activity that reduces the incidence of cancers. Moreover, it also shows inhibitory activity against the AIDS virus (24).

• Reduce the risk of heart disease

Rambutan seeds contain bioactive compounds that decrease the bad cholesterol and increase the good cholesterol levels in the blood. Thus, this seed not only treats diabetes but also reduces the risk of heart disease by decreasing oxidative stress (25).

• Treat pain and brain disorders

Phenolic compounds such as tannins and saponins in rambutan seed show central nervous system depressant and muscle relaxant activity. It blocks the detection of a painful or injurious stimulus by sensory neurons and shows sedative effects (26).

• Antimicrobial properties

Rambutan seeds contain phenolic compounds that fight against various germs and protect the body from infections and disease (26).

The side effects of rambutan 

Raw seed, boiled seed, and roasted seed of rambutan are non-toxic and safe upon oral administration (up to 2.5 g/kg). Peel fruit has low digestive stability and low gastrointestinal absorption in raw form.

This fruit has a long history of human use and is considered to be safe in a moderate amount. However, if you are allergic you should avoid its use. Let’s look at some of these side effects.

1. Risk of anaphylaxis

Rambutan fruit may cause allergic symptoms like painless swelling under the skin, flushing (reddening of the skin), and skin rash. It can also cause respiratory (rhinitis, chest tightness, stridor, and wheezing) symptoms.

Some people also face cardiovascular  (syncope) and gastrointestinal (nausea and vomiting) symptoms. Thus if the person has any of these symptoms should consult with the doctor and discontinue their consumption (27).

2. Risk of organ damage

Rambutan peel did not show any adverse effect in moderate amounts (5,000 mg/kg). However, higher dosage may affect the liver, kidney, and spleen (28). A high dose may also decrease the body weight and food consumption in the animal. Although these studies are based on animals no one knows its long-term effect on humans.

3. Presence of anti-nutrients

Rambutan peel, fruit, and seed contain the anti-nutrient compound. These compounds are saponins, alkaloids, hydrocyanic acid, phenols, oxalate, tannins, and phytates but at tolerable concentrations (29).

Q&A

1. What does a rambutan taste like?

Rambutan pulp is mostly consumed fresh and is famous for its bright color, prominent look, and strong flavor. It has a refreshing sweet and sour, slightly grape-like, and gummy taste.  On the other hand, the seed and peel are bitter. 

2. What is the English name of a rambutan?

Rambutan is also known as hairy lychee in English, mamon chino, chôm chôm are other names. 

3. Is rambutan good for you?

Rambutan fruit is nutritious and contains vitamin C, vitamin E, carotenes, and xanthophylls. It also contains natural antioxidants like tannins and phenolic compounds like geraniin, ellagic acid, quercetin, corilagin, and rutin. These compounds repel mosquitoes, and germs (bacteria and viruses), and treat obesity, diabetes, heart disease, cancer, inflammation, and pain.

4. How do you eat a rambutan?

Rambutan fruits are harvested as they ripen because it is non-climacteric. It is usually consumed fresh as a salad or processed into various products like juice, marmalade, jam, candies, and jellies. It is also stuffed with a piece of pineapple and canned in syrup, liquor, and juice. Rambutan seeds and peels can be used as flour and seasoned nuts because they are a good source of fiber (30).