Currently acknowledged as the sole species in its genus among tropical feather palms, the coconut (Cocos nucifera) once encompassed numerous other palm varieties. It embodies the essence of the tropical palm tree, symbolizing tropical coastlines and boasting numerous commercial and local applications. It is noteworthy that over 93 countries worldwide cultivate coconut trees. Indonesia leads as the top coconut producer globally, yielding 17.1 megatons, followed by the Philippines (14.8 megatons) and India (14.7 megatons). The extensive coast of Indonesia stretches across the nation, surrounded by the ocean, contributes significantly to this production. Moreover, the climate in Indonesia favors optimal coconut tree growth, solidifying its position as the largest coconut producer worldwide. This genus stands apart from its relatives through its distinctive traits, including the hard blackish inner fruit shell with three pores or ‘eyes’, and the sizable seed with an endosperm that contains partially liquid ‘coconut milk’.
Cocos nucifera
The coconut tree, a monoecious perennial palm, holds significant importance as a plantation crop, particularly in tropical and subtropical regions worldwide. It yields a solitary, sizable fruit. This palm species has expanded across numerous tropical lowland areas, propelled by both human intervention and the innate ability of its nut to remain afloat in the ocean for about a month. Belonging to the Arecaceae (Palmaceae) family, it stands out with its slender, often gracefully curved trunk that can reach heights of up to 100 feet, crowned with an array of long, elegantly drooping fronds. This palm consistently bears large clusters of small creamy yellow flowers, a few of which mature into the familiar yellow-green fruit, eventually drying and turning brown upon ripening. Diverse cultivated variations exist, such as the ‘Malay Dwarf’, characterized by its notably shorter trunk and abundant golden-yellow nuts.
Cultivation
The coconut tree thrives strictly in tropical regions and struggles in areas where temperatures regularly dip below 15 degrees Celsius. It boasts a widespread distribution across Southeast Asian countries like Malaysia, Indonesia, the Philippines, and numerous islands scattered between the Indian and Pacific Oceans.
Coconut farming faces multifaceted challenges at present. The primary hurdles include issues like palm senescence, severe abiotic and biotic stressors, market volatility concerning its products, and inadequate seedling production for replenishing aging palms. In addition, fruit production decline in older coconut palms stems from factors such as reduced leaf area, abiotic stressors like droughts, storms, cyclones, and tsunamis, along with diminished nutrient extraction abilities from the soil.
The coconut fruit and its embryo possess unique adaptive traits tailored for long-distance dispersal via oceanic currents, enabling eventual germination on sandy beaches. As a buoyant fruit, coconuts self-disseminate primarily via seawater, surviving for about 110 days and traveling distances of up to 4800 km. This mode of dispersal renders animal-mediated dissemination less feasible due to the large size and weight of the fruit.
Upon colonization on scattered islands, coconuts face minimal competition from other plant species and herbivorous attacks. Besides, their thick fibrous mesocarp and hard stony endocarp protect and maintain embryo viability while floating in saline water.
Coconut fruit development takes roughly 330 to 420 days after pollination before germination commences. Among palm species, coconut embryos exhibit adjacent ligular-type germination, involving the formation of a germinative button. During the initial 60 days post-emergence, no substantial leaf area develops, as the newly emerged shoots take this period to penetrate the thick husk. Then, energy supply for 360 days of growth comes from endosperm reserves and photosynthesis by the shoots post-emergence.
While seedlings occasionally grow in heated greenhouses in cooler climates, they rarely achieve significant size. Furthermore, the coconut thrives best in full sun, thriving in deep, porous soil with adequate moisture while also tolerating coastal conditions. Seeds germinate in a few months when whole, unhusked nuts are placed on their side on moist sand.
Pest, disease, and postharvest management
Commonly, coconut trees face a distinction between major and minor pests. The major troublemakers include Rhinoceros beetles, red palm weevils, leaf-eating caterpillars, and white grubs, while the minor nuisances consist of slug caterpillars, scale insects, mealybugs, cored bugs, termites, and mites. On the disease front, there are prevalent issues such as root wilt, leaf rot, bud rot, stem bleeding, Ganoderma wilt or basal stem rot, and the occurrence of immature nut fall.
Mould growth is a common issue observed on the husk surface, often instigated by diverse species of fungi. However, in most cases, these fungi do not infiltrate the coconut meat. Effective post-harvest management plays a crucial role in mitigating potential risks; ensuring careful harvesting methods to avoid mechanical damage becomes paramount, particularly when handling cracked fruit, as these cracks serve as gateways for microbial invasion. Waxing of coconuts can be used to extend their shelf-life and ideal storage temperature should be 0 to 1 degree Celsius.
Downstream products
The fruit of the coconut comprises three layers: the exocarp, mesocarp, and endocarp. Both the exocarp and mesocarp form the husk of the fruit, offering traditional and commercial applications. The mesocarp, commonly known as husk, serves as the most marketable part. It finds uses in producing rope, carpets, geotextiles, and growing media. Additionally, natural fibers from coconuts can replace synthetic fibers and steel in cement, enhancing qualities like tenacity, lightness, mechanical strength, impact resistance, and biodegradability while lowering production costs.
The endocarp, or brown shell, of the fruit, possesses three germination pores, visibly present on its outer surface. The endosperm divides into two edible parts: the white kernel and the clear liquid known as coconut water, lining the hard shell and filling the inner cavity of the endocarp, respectively.
Coconut water, a versatile natural product, serves various purposes globally. Its low acidity, well-balanced sugar content, and isotonic mineral composition make it an ideal rehydration and sports drink. Furthermore, it finds use in plant tissue culture as an organic supplement, containing glucose, fructose, sucrose, sorbitol, biotin, nicotinic acid, and plant growth regulators like zeatin. The matured coconut water can be used to prepare nata de coco, which is a gelatinous delicacy formed by the action of a microorganism, Acetobacter xylinum, in a culture medium of coconut water. Nata de coco is also prepared from coconut skimmed milk.
Coconut proves its versatility as a calorie-rich source loaded with vitamins and minerals. It is consumed in various forms such as fresh nuts, tender coconuts, coconut oil, and copra meal. The coconut kernel offers an excellent mineral profile including copper, calcium, iron, manganese, magnesium, potassium, and zinc. Moreover, it serves as a rich source of vitamin B complex, comprising folates, riboflavin, niacin, thiamine, and pyridoxine.
Coconut undergoes diverse processing methods, resulting in a range of downstream products like desiccated coconut powder, virgin coconut oil, coconut chips, coconut milk, and preserved tender nut water. Coconut milk, an oil-in-water emulsion with water as the continuous phase and oil as the dispersed phase, is manually extracted from grated meat at home, while industrial scales use screw presses or hydraulics. Shredded coconut finds widespread use in Asian desserts and cuisine.
Coconut milk is used as substitute of dairy cream that is made by grating fresh coconut flesh and then working that with water, traditionally by hand. Coconut milk can be further processed into coconut jam that is commonly known as kaya in Southeast Asia.
The versatile coconut oil serves numerous purposes, from biodiesel production to reducing cardiovascular diseases, acting as a surfactant in laundry detergents, aiding preterm newborn health, forming edible packaging, extracting medium-chain triglycerides, and serving as a potential cutting fluid and industrial bio-lubricant. Coconut oil composite materials can double as energy and strain sensors and even serve as a raw material for α-amylase synthesis and nutritious snack production from coconut oil cake.
In the health industry, coconut oil offers protection against UV rays, boosts metabolism, withstands high cooking temperatures, and exhibits properties enhancing dental health and wound healing. It plays a pivotal role as a soap and moisturizer in the beauty and cosmetic realm, safeguarding hair from damage and functioning as a makeup remover and brush cleaner. The applications extend to non-toxic insect repellents, stain removers, deodorants, a quick energy source, and a wooden furniture polisher, making coconut oil an indispensable part of everyday life.
Unique among vegetable oils, coconut oil boasts approximately 48% lauric acid in its fatty acid composition. It contains caprylic acid, capric acid, myristic acid, palmitic acid, stearic acid, oleic acid, and linoleic acid. Research suggests its potential in protecting against heart disease, diabetes, cancer, and various chronic health issues. Additionally, it exhibits antibacterial, antiviral, antifungal, antioxidant, low glycemic index, hepatoprotective, and immune-enhancing properties.
Two primary types of coconut oil exist: refined, bleached, and deodorized copra oil (RCO) and virgin coconut oil (VCO). VCO, extracted from fresh coconut endosperm through a wet process, is colorless, rancidity-free, rich in medium-chain triglycerides, and highly versatile as a cooking medium. It is gaining traction for its limited pharmacotherapeutic properties in modern society.
With its smaller particle size compared to mineral oil, VCO penetrates dry, frizzy hair better, making it a favored ingredient in various hair care and cosmetic products for a shinier look. The residue left after the extraction of oil from copra is referred to as coconut oilcake which is mainly used as a cattle feed.
Further readings:
Boateng, L., Ansong, R., Owusu, W., & Steiner-Asiedu, M. (2016). Coconut oil and palm oil’s role in nutrition, health and national development: A review. Ghana medical journal, 50(3), 189-196.
Kappally, S., Shirwaikar, A., & Shirwaikar, A. (2015). Coconut oil–a review of potential applications. Hygeia JD Med, 7(2), 34-41.
Gupta, A., Gupta, N., Shukla, A., Goyal, R., & Kumar, S. (2020, April). Utilization of recycled aggregate, plastic, glass waste and coconut shells in concrete-A review. In IOP Conference Series: Materials Science and Engineering (Vol. 804, No. 1, p. 012034). IOP Publishing.
Lima, R. D. S., & Block, J. M. (2019). Coconut oil: what do we really know about it so far?. Food Quality and Safety, 3(2), 61-72.
Manikantan, M. R., Pandiselvam, R., Beegum, S., & Mathew, A. C. (2018). Harvest and postharvest technology. The coconut palm (Cocos nucifera L.)-Research and Development perspectives, 635-722.
Marina, A. M., Man, Y. C., & Amin, I. (2009). Virgin coconut oil: emerging functional food oil. Trends in Food Science & Technology, 20(10), 481-487.
Patil, U., & Benjakul, S. (2018). Coconut milk and coconut oil: their manufacture associated with protein functionality. Journal of food science, 83(8), 2019-2027.
Prades, A., Dornier, M., Diop, N., & Pain, J. P. (2012). Coconut water uses, composition and properties: a review. Fruits, 67(2), 87-107.
Roopan, S. M. (2016). An overview of phytoconstituents, biotechnological applications, and nutritive aspects of coconut (Cocos nucifera). Applied biochemistry and biotechnology, 179, 1309-1324.
Satheesh, N. (2015). REVIEW ON PRODUCTION AND POTENTIAL APPLICATIONS OF VIRGIN COCONUT OIL. Annals: Food Science & Technology, 16(1).
Shankar, P., Ahuja, S., & Tracchio, A. (2013). Coconut oil: a review. Agro Food Industry Hi-Tech, 24(5), 62-64.
Yong, J. W., Ge, L., Ng, Y. F., & Tan, S. N. (2009). The chemical composition and biological properties of coconut (Cocos nucifera L.) water. Molecules, 14(12), 5144-5164.
