Common name: Kokum

Kokum is a Mangosteen (Garcinia mangostana) relative originating in humid tropical India; its natural range is limited to the Western Ghats and the West Coast of the subcontinent, extending from near Matheran, in the hills to the east of Mumbai (Bombay), south through the states of Goa and Karnataka to Kerala.

It is a slow-growing tree that can reach heights of up to 20 m (66 ft). However, it is more typically 10 to 15 m (33 to 50 ft) tall with a slim, low-branching trunk supporting a densely leafy pyramidal crown. The bark is dark grey or dark brown, scaly, rough, and sometimes mottled with lichens, mosses, and algae that thrive in the humid conditions where the tree grows.

Leaves are lance-shaped or elongated-oval, 5 to 10 cm (2 to 4 in) long, crimson red and soft when they emerge, then become dark, glossy green and leathery. Arranged in pairs along stems, they remain on the tree in all seasons.

Flowers are small, with fleshy, waxy pink petals, and female and male flowers are on separate trees. They are borne directly on the stems, singly or in clusters of up to four and bloom in the dry winter season. They are followed on female trees by small round fruit, 3 to 4 cm (1.2 to 1.6 in) in diameter.

The fruit are green when young, become dark purple-red when ripe, and have a thick rind that encloses soft, juicy pulp containing six to eight kidney-shaped seeds. Kokum is a heavy bearer, each female tree producing hundreds of fruits that ripen around the start of the rainy season.

Edible uses

Edible oil or fat - The seed yields 25 to 35% of an edible, white or pale yellow buttery fat known as 'Kokum Butter'. Grinding, steaming, and pressing the seed releases the fat, which is then filtered and churned into a solid, buttery mass. Kokum butter has a melting point of around 40°C (104°F) and remains solid at room temperature. Its melting properties and buttery consistency make it suitable for confectionery, including use as a Cocoa Butter Equivalent (CBE) to extend or replace Cocoa butter (from Theobroma cacao) in chocolate manufacturing. It is also widely used in its native range as a substitute for Ghee, the clarified dairy butter common in Indian cooking.

Syrup or cordial - The fruit rind is juicy and sour, and is made into a syrup known as 'Kokum syrup'. It is made by mixing the rind with cane sugar and packing the mixture into sealed drums, which are left to stand. After a week, the mixture is pressed and strained to produce a syrupy liquid, which is usually bottled. It is an intensely deep purple-red syrup with a pleasing fruity taste, served diluted with tap or soda water to make a refreshing drink.

Non-alcoholic drink - Kokum rind is indispensable in making 'Sol Kadi', one of southern India's most popular beverages. A vividly pink drink, it is made by soaking the rind in hot water to extract the colour and flavour, then mixing the resulting liquid with fresh coconut milk, salt, garlic and green chillies.

Souring agent - Some of the rind is also reserved for drying, after brining, to make a souring agent known as 'Malabar tamarind', commonly used in southern Indian cooking, especially fish curries.

Material uses

Natural skin care - Kokum butter is also an ingredient in cosmetics, especially skin moisturising, lip balm and lipstick products. The seed's fat is also used in its pure form to soothe chapped or cracked lips, fingers and feet.​

Natural carrier base - The seed's fat also serves as a base for ointments, allowing medicinal ingredients to be added, such as liniments for treating sore muscles and strains.

Livestock feed - The seed cake left over from pressing the fat is high in protein and is used mainly as an ingredient in livestock feed.

Environmental uses

Species conservation - Wild trees are threatened by habitat loss, leading the International Union for Conservation of Nature and Natural Resources (IUCN) to list the species as vulnerable. Cultivating it in home gardens and on farms can help ease pressure on dwindling wild populations.

Health uses

Natural slimming aid - The rind is rich in hydroxycitric acid, a bioactive plant metabolite sometimes touted as an anti-obesity drug, which reportedly inhibits the conversion of carbohydrates into fats. Hydroxycitric acid is also present in high concentrations in the fruit rind of Garcinia cambogia (Garcinia gummi-gutta).

Climate

Kokum grows naturally in humid subtropical and tropical lowland to mid-elevation climates, generally frost-free areas with annual lows of 18 to 25°C, annual highs of 27 to 35°C, annual rainfall of 2000 to 5000 mm and a dry season of 7 months or less.

Growing

New plants are usually started from seed and cuttings, with cuttings from known female and male trees considered best practice to establish a good male-to-female ratio for successful pollination and fruit production. Seeds germinate very slowly, and seedling trees start to flower and bear fruit only at about seven to eight years old. Yields vary considerably but average about 12 kg (26 lb) of fruit per tree per year.

Performs best on free- to slow-draining clay and loam soils of a moderately acid to neutral nature, generally with a pH of 5.0 to 7.5, and on sites with full to partial sun exposure. It tolerates permanently wet or waterlogged soils.

Problem features

There appear to be no records of escape and naturalisation anywhere in the world. The likelihood of it becoming a problem weed is low because the fruit and seed are relatively large and not easily dispersed.

Books

• Attokaran, M. 2011, Natural food flavors and colorants, Institute of Food Technologists, Wiley-Blackwell Publishing, Oxfordshire

• Dastur, J. F. 1964, Useful plants of India and Pakistan : a popular handbook of trees and plants of industrial, economic, and commercial utility, 2nd ed., D. B. Taraporevala Sons, Bombay

• Farooqi, A. A. & Sreeramu, B. S. 2004, Cultivation of medicinal and aromatic crops, Hyderabad University Press, Hyderabad

• Gunstone, F. D. 2011, Vegetable oils in food technology : composition, properties and uses, 2nd ed, Wiley-Blackwell, Hoboken, New Jersey

• Jamieson, G. S. 1943, Vegetable fats and oils : their chemistry, production, and utilization for edible, medicinal and technical purposes, 2d ed, Reinhold, New York

• Janick, J., & Paull, R. E. 2008, The encyclopedia of fruit & nuts, CABI Publishing, Wallingford, Oxfordshire

• Martin, F. M., et al. 1987, Perennial edible fruits of the tropics : an inventory, U.S. Dept. of Agriculture (USDA), Agricultural Research Service, U.S. Government Printing Office (GPO), Washington, D.C.

• Parrotta, J. A. 2001, Healing plants of peninsular India, CABI Publishing, Wallingford, Oxfordshire

• Seidemann, J. 2005, World spice plants: economic usage botany taxonomy, Springer-Verlag, Berlin