Overview

Rambutan¹ is an exotic fruit that is found in Southeast Asia, especially Malaysia. Interestingly its name is due to its appearance. In Malay, the word “Rambut” means hair, and the fruit itself consists of a bright red outer shell covered in numerous soft hair-like spines that resemble a sea urchin. It is roughly the size of a ping-pong ball as well. Inside is where the fruit's edible part, the flesh, sits. Once peeled, the flesh itself is translucent and white which some may mistake as longan or even lychee.

However, compared to both the rambutan has a rather unique taste refreshing and sweet yet creamy with a hint of acidity. The rambutan is extremely popular, especially in Southeast Asia, and is enjoyed by everyone regardless of their age. It is also a very versatile fruit as well, it can be eaten fresh or used to make various types of desserts, such as ice creams, puddings, and shaved ice as well.

Some curries also use rambutan as an ingredient, even rambutan candies are widely available on the market. Because of the tropical heat, storing it can be challenging. However, compared to other fruits, the rambutan can be easily preserved.

The most common method of storing rambutan is to seal it inside a can with syrup in it and this is done on a large scale usually in large manufacturing factories, which also makes rambutan affordable for everyone. In recent years, rambutan has gained popularity not only in the Asian market but in the international market as well. Besides its affordable price and easy storage. The fruit also contains a high nutritional value which is beneficial to improving one's general health, especially the heart.

Nutritional value of rambutan

Rambutan is packed with various nutrients² such as vitamins, minerals, and other various compounds that are essential for our health. For example, the pulp consists of around 2 grams of fiber which is equivalent to the same amount of apples, pears, and pineapples.³

Fibre plays an important role in improving our health as it helps to promote the growth of healthy gut bacteria, which are responsible for producing important nutrients such as short-chain amino acids. Studies show that these short-chain amino acids are capable of improving certain gastrointestinal conditions such as inflammatory bowel disease.⁴

Furthermore, the rambutan fruit is rich in minerals, especially copper⁵, an important mineral for growth, and maintenance of the nervous and immune system. Consuming roughly 100 grams of it will fulfill 20% of your daily copper requirements. The fruit also contains a high level of Vitamin C, which helps in the absorption of minerals such as iron, besides that, it also acts as an antioxidant which helps to protect the cells of your body against damage.⁶ 

Impact of rambutan on heart health 

The nutrients and minerals found in Rambutan are extremely helpful in maintaining heart health. The fruit is capable of lowering blood pressure. This is due to the fact of the high potassium content in rambutan. Potassium is essential in the regulation of blood pressure. There has been research that demonstrates potassium’s potential to reduce blood pressure.⁷ Since high sodium levels are one of the main reasons for high blood pressure, potassium helps to minimize the effect of sodium by promoting sodium excretion.

Furthermore, potassium also eases the tension in the blood vessel walls, which also lessens the burden on the heart which leads to lower blood pressure.⁸ High cholesterol levels are associated with higher cardiovascular risk and it is important to maintain adequate cholesterol levels, and rambutan has the potential to do just that. Since rambutan contains dietary fibre, it can help to lower cholesterol levels. Dietary fibre found in rambutans is capable of absorbing cholesterol, which decreases hepatic absorption while promoting bile excretion, effectively reducing blood cholesterol levels.⁹

Besides that, Rambutan is rich in fibre, which is useful in promoting weight loss as obesity is one of the main risk factors for developing chronic heart condition.¹⁰ Those who have adequate intake of fibre also show a reduction in risk of obtaining coronary artery disease.¹¹ Oxidative stress is believed to be linked to developing cardiovascular conditions.

This is because oxidative stress occurs when the body is unable to reduce free oxygen species and other free radicals leading to the progression of diseases as these free oxygen species can interfere with and modify lipids, protein, and DNA structure causing a change in vascular structure and function contributing to atherosclerosis which is the main reason for most cardiovascular conditions.¹²

Hence, antioxidants play an important role in managing oxidative stress in our bodies. Foods that are rich in antioxidants such as rambutan can help to relieve oxidative stress, effectively reducing the chances of these free oxygen species interfering with our body function leading to a lower risk of developing cardiovascular diseases. 

Picking and storing a ripe rambutan 

To fully enjoy rambutan, one must know how to pick one that is ripe. First of all, take a look at the skin of the rambutan. Their colour generally ranges from green to bright red. When purchasing one it is advisable to choose the bright red one, orange or yellow skin with a slight tinge of red is advisable and ripe to consume as well.

However, avoid those with green skin as it is unripe, these would be lacking in taste and spoil easily. Rambutans that have turned brown or black a red flags as they indicate that the rambutan is already spoiled. Furthermore, spoiled rambutan has a mushy texture when squeezed.

So if you find one that is brown or has a mushy feeling when you press against it, it's time to throw it away. A spoiled rambutan may not have a huge difference in taste but beware as it can upset your stomach. Next, take a peek at the “hairs” of the rambutan as well, avoid choosing ones with black hairs as it is overripe.

Use your hands to gently squeeze the rambutan, aim for the ones that are just slightly underpressured but not too soft. Be careful not to use too much pressure as the rambutan skin is delicate. Once you open a rambutan the fruit should be white translucent and the taste should be sweet with a hint of acidity. 

To maintain its freshness, it is advisable to store rambutan in the correct method. First of all, choose a place that is cool and dry and away from direct sunlight. It is ideal to store the fruit between 7℃ to 10℃, hence keeping them in a fridge is ideal. Before you store the rambutan, wash it with water and remove any debris or dirt on it. Look out for any spoiled ones as well.

Next, peel the skin and store them in a container as this helps to save space in the refrigerator. Beware of excessive moisture as it can promote mould growth, ruining the rambutan. A common mistake while storing rambutan is storing it together with other fruits as they release ethylene gas which accelerates the ripening of rambutan causing it to spoil even faster.¹³

Summary

The rambutan is an amazing fruit that contains various essential nutrients for our health. The high content of fibre, antioxidants, vitamins, and minerals such as potassium, and copper are beneficial and play an important role in improving heart health. Furthermore, the fruit itself is easy to store and cheap yet packed with nutrients.

These nutrients can help to regulate blood pressure, lower cholesterol and decrease oxidative stress on the body as well as reduce weight which are important factors that contribute to a variety of cardiovascular conditions. Hence, I strongly recommend putting rambutan into your shopping list and giving it a try!