Sea coconuts are a fascinating fruit with diverse origins and uses. It is important to note that palmyra palm fruits, or Borassus flabellifer, are labeled as Sea coconuts in Asian markets but are distinct from sea coconuts found in the Seychelle Islands.
Palmyra Palm Fruits
Palmyra Palm Sea Coconuts (Borassus flabellifer)
Sea coconuts, botanically classified as Borassus flabellifer, are the fleshy, aqueous endosperms of the palmyra or toddy palm fruit belonging to the Arecaceae family. The tropical palms are native to Southeast Asia, growing up to 30 meters in height, and are a species highly favored for their multi-purpose uses. When the palm fruits are young, they are harvested in clusters and cut open to reveal the jelly-like endosperms, sometimes known as seed sockets. Also, Sea coconuts have several regional names across Southeast Asia, including Ice Apple, Doub palm fruit, Munjal fruit, Tala, Tal, Nonku in India, Ton Taan in Thailand, and Buah Lontar and Siwalan fruit in Malaysia and Indonesia.
The palms produce moderately-sized round to ovoid fruits, averaging 15 to 25 centimeters in diameter, and the fruits grow in clusters just below the fronds. The palm fruits are semi-smooth, dense, and woody, displaying variegated hues of black and brown. When the fruits are harvested unripe, they are cut open to reveal a fibrous interior, encasing 1 to 4 flat seed endosperms. The endosperms are enveloped in a thin, pink to cream-colored protective layer, and beneath this layer, there is a firm, aqueous, and translucent-white, jelly-like flesh, known as a Sea coconut. The flesh has a consistency similar to lychees and is dense, containing a slender hollow center. Sea coconuts have a very mild flavor and are mostly appreciated for their juicy nature.
Sea coconuts are collected from the palmyra palm, a tree native to the Indian subcontinent and Southeast Asia. The palms have been growing wild in tropical climates since ancient times and have been spread throughout Asia via trade and human cultivation. Today palmyra palms are primarily found in southern India, Southeast Asia, and China. Thailand is considered the largest producer of Sea coconuts in the present day, and the fleshy endosperms are kept in their protective husks and exported to neighboring countries, including Singapore. Sea coconuts are a delicacy found through select local markets in India, Southeast Asia, and China. When in wet markets, the endosperms are stored in their husks, while in specialty grocers, the endosperms are removed and sold in clamshells in the refrigerated section.
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Culinary Uses of Palmyra Palm Sea Coconuts
In Southeast Asia, fresh Sea coconuts from palmyra palms are a delicacy sold in markets still encased in the unripe husks. Once opened, the flesh is eaten raw, blended into drinks, or incorporated into chilled desserts as a cooling ingredient. Sea coconuts have a firm, jelly-like flesh and sweet, subtly nutty flavor well suited for fresh or cooked preparations. The fruits should be peeled before consumption, and once the translucent flesh is revealed, it can be eaten straight, out of hand, or sliced into desserts. Sea coconuts have a relatively mild flavor and are mainly used to add texture to chilled desserts.
Sea coconuts are incorporated into cendol, a Southeast Asian dessert comprised of rice flour jelly, coconut milk, and syrup. Other toppings are also added to customize the chilled dessert, including Sea coconut, and the entire dish is consumed as an after-dinner refreshment or midday snack. Sea coconuts are also mixed into shaved ice or blended into drinks with coconut water and nut milk.
In addition to using the flesh raw, Sea coconuts can be simmered to develop a softer texture. In China, Sea coconuts are popularly simmered in a rock sugar mixture and served as a soup known as tong sui. There are many variations of tong sui served throughout Cantonese cuisine, and Sea coconuts are typically served with dried jujubes and longans, snow fungus, and pandan leaves. The soup is thought to bring balance to the body and remove heat to cool the senses. Sea coconuts can also be sliced, simmered, and served with poached pears, lotus seed desserts such as leng chee kang and are occasionally stirred into curries in India.
Beyond the fruits, the surrounding fibrous orange husk can be eaten when ripe, consumed out of hand, or grated into an aqueous mixture. This thick mixture is rolled into small pieces and fried as a snack dish known as taal-er bora or palmyra vadas in Bengali cuisine. The grated flesh is also wrapped in banana leaves and steamed in Malaysia, developing a sweet and earthy, caramelized pumpkin flavor. Sea coconuts pair well with other fruits such as lychees, longans, pineapple, and rambutans, spices including ginger, cinnamon, and cardamom, goji berries, ginseng, rose water, pandan leaves, and almonds.
Nutritional and Traditional Medicine Uses
Sea coconuts are a good source of calcium and phosphorus to protect the formation of bones and teeth and provide vitamin C to strengthen the immune system while reducing inflammation. The fruits also contain potassium to balance fluid levels within the body, antioxidants to guard the cells against damage caused by free radicals, and other nutrients, including zinc, iron, and B vitamins.
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In Eastern medicines, especially in Traditional Chinese Medicine, or TCM, Sea coconuts are considered a cooling food consumed to remove heat from the body. The fruits are typically eaten on hot days to prevent overheating, or they are incorporated into drinks to soothe sore throats and coughs and settle upset stomachs.
Storage Tips
In Southeast Asia, Sea coconuts have a short shelf life and are often kept in the husk to help extend their perishable nature. They are also popularly sold packaged in the refrigerated section of grocery stores or preserved in syrup in small cans. In some countries, the endosperms are allowed to mature and sprout, developing a spongy, crisp, and fluffy consistency similar to a sprouted coconut. The fruits have a short shelf life and will only keep for 1 to 2 days when exposed to air. It is recommended to keep Sea Coconuts in their fibrous skin in the refrigerator and not to peel the fruits until they are going to be used for consumption.
Cultural Significance
Palmyra palms are regarded as katpaha tharu, or the celestial tree, in the state of Tamil Nadu in southeastern India. The palm is sacred for its ability to be used in its entirety in various applications, and ancient texts have linked the tree with the goddess Panaiveriyamman, a fertility spirit that protects palm trees in the Hindu religion. Throughout Tamil Nadu, palmyra palms are planted around temples and have been decreed as the official tree of the Indian state. Beyond the fruits, palmyra palm fronds were used as paper to write religious texts, and it is rumored that the creator of Sanskrit first wrote the alphabet on the palm leaves.
World's Biggest Nut - Coco De Mer | Did You Know? | Doc Bites
Coco de Mer (Lodoicea maldivica)
Sea coconuts in Seychelles are classified as Lodoicea maldivica and are a rare, separate species sometimes known as coco de mer. Lodoicea, commonly known as the sea coconut, coco de mer, or double coconut, is a monotypic genus in the palm family. The sole species, Lodoicea maldivica, is endemic to the islands of Praslin and Curieuse in the Seychelles. It has the largest seed in the plant kingdom.
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Coco de Mer
It generally grows to 25-34 m (82-112 ft) tall. The leaves are fan-shaped, 7-10 m long and 4.5 m wide with a 4 m petiole in mature plants. However, juveniles produce much longer petioles, up to 9 m (30 ft) long. It is dioecious, with separate male and female plants. The male flowers are arranged in a catkin-like inflorescence up to 2 m (7 ft) long which continues to produce pollen over a ten-year period; one of the longest-living inflorescences known. While the functional characteristics of Lodoicea are similar to other trees of monodominant forests in the humid tropics, its unique features include a huge seed, effective funnelling mechanism and diverse community of closely associated animals.
L. maldivica is robust, solitary, up to 30 m tall with an erect, spineless, stem which is ringed with leaf scars. The base of the trunk is of a bulbous form and this bulb fits into a natural bowl, or socket, about 75 cm (30 in) in diameter and 45 cm (18 in) deep, narrowing towards the bottom. The crown is a rather dense head of foliage with leaves that are stiff, palmate up to 10 m in diameter and petioles of two to four metres in length. The leaf is plicate at the base, cut one third or more into segments 4-10 cm broad with bifid end which are often drooping. A triangular cleft develops at the petiole base. The palm leaves form a huge funnel that intercepts particulate material, especially pollen, which is flushed to the base of the trunk when it rains. The clusters of staminate flowers are arranged spirally and are flanked by very tough leathery bracts. The pistillate flowers are solitary and borne at the angles of the rachis and are partially sunken in it in the form of a cup. They are ovoid with three petals as well as three sepals. It has been suggested that they may be pollinated by animals such as the endemic lizards that inhabit the forest where they occur. Pollination by wind and rain are also thought to be important.
Only when it begins to produce flowers, which can vary from 11 to 45 years or more old, is it possible to determine the sex of the plant visually. The nectar and pollen are also food for several endemic animals. The inflorescences are interfoliar, lacking a covering spathe and shorter than the leaves. The staminate inflorescence is catkin-like, one to two metres long by about 8 cm (3 in) in width and produces pollen over a period of 8 to ten years. The fruit is bilobed, flattened, 40 to 50 cm long ovoid and pointed, and contains usually one but occasionally two to four seeds. The epicarp is smooth and the mesocarp is fibrous. The endosperm is thick, relatively hard, hollow and homogenous. During germination, a tubular cotyledonary petiole develops that connects the young plant to the seed.
Evolution and Distribution
Despite the proximity of the Seychelles to Africa, the broader diversity of palm life on the islands are considered to be slightly closer phylogenetically to that of south Asia. A genetic sequencing study of Lodoicea and other palms showed similarity between south Asiatic palms and Lodoicea. The ancestral dispersal to the Seychelles may have occurred as Tertiary palm relatives native to Gondwanaland rode the Indian subcontinent during its northward continental drift, whereupon populations were deposited on the modern day Seychelles.
Divergence between the palm populations would then follow from the isolation of the archipelago from the rest of Gondwonaland. Evidence suggests at least a proportion of the diversity of Flora on the islands are of "very ancient origin", perhaps being evidence of the persistence of some aboriginal Indian subcontinental species, of which the ancestors of Lodoicea may have been a member. A 2020 genetic-sequencing study of palm species found genetic evidence for an oceanic dispersal of the ancestors to modern Lataniieae palms, from south Asia to the Mascarene and Seychelle islands.
Though modern viable coco de mer fruit are too heavy to float and thus would be unable to disperse oceanically, genetic evidence suggests that ancestors to Lataniieae palms underwent evolutionary periods of relatively rapid increases in seed size, with Lodoicea serving as the most extreme example. For this reason, the ecological and genetic factors explaining the large size of Lodoicea fruit to such an extreme are of interest to evolutionary biologists. The divergence of size in Lodoicea fruit subsequent to its isolation from ancestors has been cited as an example of island gigantism, which describes the tendency for traits or organisms to increase in size over evolutionary time subsequent to isolation from a primary population on an island.
One hypothesis asserts that competition between parent tree and its progeny, as well as competition between sibling offspring, drove the large size of the coco de mer fruit. The hypothesis suggests that because coco de mer fruit fall directly at the base of their parental tree, there is strong competition between parent and offspring for resources, within which the already-established parent tree has a large asymmetric advantage. A related hypothesis states that low light availability in the rainforest understory favoured juveniles which could quickly produce tall and wide initial leaves, to maximize photosynthetic area as quickly as possible; which would be made possible by a large, nutrient-rich seed.
The species was formerly known as the Maldive coconut. Its scientific name, Lodoicea maldivica, originated before the 18th century when the Seychelles were uninhabited. In centuries past, the fruit that fell from the trees and ended up in the sea would be carried away eastwards by the prevailing sea currents. The nuts can only float after the germination process, when they are hollow. Until the true source of the nut was discovered in 1768 by Dufresne, it was believed by many to grow on a mythical tree at the bottom of the sea. European nobles in the sixteenth century would often have the shells of these nuts polished and decorated with valuable jewels as collectibles for their private galleries.
Conservation Status
Lodoicea maldivica is officially classified as an endangered species by the International Union for Conservation of Nature (IUCN), with only approximately 8,000 wild mature trees left as of 2019. The history of exploitation continues today, and the collection of nuts has virtually stopped all natural regeneration of populations with the exception of the introduced population on Silhouette.
| Feature | Palmyra Palm Sea Coconut (Borassus flabellifer) | Coco de Mer (Lodoicea maldivica) |
|---|---|---|
| Botanical Name | Borassus flabellifer | Lodoicea maldivica |
| Native Region | Southeast Asia, Indian Subcontinent | Seychelles (Praslin and Curieuse Islands) |
| Fruit Size | 15-25 cm diameter | 40-50 cm long |
| Endosperm | Fleshy, aqueous, jelly-like | Thick, relatively hard, hollow |
| Conservation Status | Not endangered | Endangered |
| Common Uses | Culinary (desserts, drinks), Traditional Medicine | Primarily of conservation and botanical interest |
