831

14: Vegetable oils and fats

Garcinia L.

Sp. pl.: 443 (1753), Gen. Pl. ed. 5: 202 (1754).

GUTTIFERAE (CLUSIACEAE)

x = 8, 16; Garcinia indica: 2n = 48

Major species and synonyms
— Garcinia indica (Thouars) Choisy in DC., Prodr. 1: 561 (1824), synonyms: Brindonia indica Thouars (1804), Garcinia microstigma Kurz (1877).
— Garcinia morella (Gaertn.) Desr. in Lamk, Encycl. 3: 701, t. 405, f. 2 (1792), synonyms: Mangostana morella Gaertn. (1790), Garcinia lateriflora Blume (1825), Garcinia gaudichaudii Planch. & Triana (1860).

— Garcinia indica: kokam butter tree, Goa butter, mangosteen oil tree (En). Brindonnier (Fr).
— Garcinia morella: tamal, Indian gamboge tree, Mysore gamboge tree (En). Indonesia: kemenjing kebo (Javanese), jawura, manggu leuweung (Sundanese). Malaysia: kandis (Peninsular). Philippines: maladambo (Tagalog), ugau (Bikol), kandis (Manobo).

Garcinia is a large genus that occurs mainly in the Old World tropics. South-East Asia hosts about half the total number of species and is the major centre of diversity. Garcinia indica probably originates from India (Western Ghats). It is also cultivated in India (lower slopes of the Nilgiri hills, West Bengal and Assam) and many other tropical Asian countries, including islands in the Indian Ocean. Garcinia morella is widespread, from Sri Lanka, India, Bangladesh and southern China throughout northern South-East Asia, but is not cultivated.

Garcinia indica and Garcinia morella both have multifarious uses. Their seeds are sources of edible fat known as 'kokam butter' or 'kokam fat' for Garcinia indica and 'tamal' for Garcinia morella. Kokam butter is used as a confectionery butter but because it solidifies with a rough surface it is often mixed with other fats. Kokam butter is also used as an adulterant of ghee (Indian clarified butter) and as an extender of or alternative for cocoa butter. Medicinally and in cosmetics, kokam butter is made into creams that are applied to ulcers, cracked lips and hands. Low-quality, non-edible grades of kokam butter are used to make candles and soap. The sweet and sour dried rind of the fruit of Garcinia indica, also called kokam, is added to curries as a condiment and is processed into juices and syrups. In medicine, the fruit of Garcinia indica is used as an anthelmintic and to treat piles, dysentery, tumours, pains, heart problems, gall bladder problems and age-related diseases such as diabetes.
Tamal fat is mainly used in cooking as a substitute for ghee. It is somewhat softer than kokam butter and less suitable for confectionery. It is also a source of stearin and is made into soap with fairly good lathering and detergent properties. The fruit pulp of Garcinia morella is eaten. After wounding, the bark of Garcinia morella exudes a brilliant golden-yellow resinous sap, called 'gamboge', which is used for dyeing and as a colouring agent for varnish, lacquer, paints and ink. It can be used in watercolours as it emulsifies well in water. In Burma (Myanmar) robes of monks are dyed with it. Gamboge is rarely used medicinally at present but it has purgative, emetic and vermifuge properties. Sap from the root is applied to heal cuts.
The seed cake of both species remaining after oil extraction is a very good and cheap cattle feed and a fertilizer. Cake of kokam seed is added to feed concentrates for lactating cows. The greyish-white wood of Garcinia indica is suited for paper pulp, that of Garcinia morella is made into boxes and temporary structures. In South-East Asia, Garcinia morella is also used as vigorous rootstock for mangosteen (Garcinia mangostana L.). When kokam seed cake was combined with urea and applied to a dry-season rice crop in India, the recovery of N increased by 25%. The seed cake can also be recycled through anaerobic fermentation to produce biogas and enriched manure. It can be used to substitute cowdung for up to 33% without reducing biogas production.

Annual kokam seed production in India (Western Ghats) has been estimated at about 500 t, producing about 200 t kokam butter. Some export of the condiment kokam (dried rind) from India to Zanzibar is reported, but kokam butter hardly enters international trade. No statistics are available for tamal or Indian gamboge.

Total lipid content of dry seed of Garcinia indica is about 50% and comprises about 88% neutral lipids, 4 % glycolipids and 3% phospholipids. The neutral lipids consist of 85% triglycerides, 8% free fatty acids and 3% diglycerides. The fatty acid composition is approximately stearic acid (38—56%), oleic acid (30—53%) and lesser amounts of palmitic and linoleic acids. The glycolipids are primarily digalactosyl diglyceride (40%) and monogalactosyl diglyceride (20%), while the main phospholipid is phosphatidyl ethanolamine (75%). The fat has a very distinct melting point (39.5—40°C) which is near the melting point of pure oleodistearine. At room temperature, the fat is solid, hard and greyish. Kokam butter is traded as light grey or yellowish, egg-shaped balls with a greasy feel and bland oil taste. Refined and deodorized kokam butter is white and compares favourably with other fats. When kokam butter is combined with a smaller amount of 'phulwara butter' obtained from seed of Diploknema butyracea (Roxb.) H.J. Lam (synonym Madhuca butyracea (Roxb.) J.F. Macbride) or with 'mowra butter' obtained from seed of Madhuca longifolia (Koenig) Mcbride, the resulting blend has properties similar to cocoa butter but is somewhat harder and more suitable for hot climates. Kokam butter has also been modified by lipase-catalyzed ester interchange to produce an interesterified fat that is similar to cocoa butter in solid fat content and melting temperature. The sweet and sour dried rind of the fruit of Garcinia indica used as a condiment contains 10—30% (—)hydroxy-citric acid (HCA), the source of its sour taste. The acid may have a regulatory effect on obesity and appetite. Garcinol, one of the components of the fruit rind of Garcinia indica, has anti-oxidative and anti-glycation activities, possibly accounting for positive results in treating age-related diseases such as diabetes. Fat-soluble yellow pigments such as cyanidin-3-sambudioside and cyanidin-3-glucoside have also been identified in the fruit rind. The seed cake remaining after oil extraction has 70% digestible nutrients, including 9—17% crude protein and 4% crude fibre.
Tamal fat from Garcinia morella is brownish-yellow. The fatty acids are mainly stearic acid (46%) and oleic acid (50%). Its melting point is only 33°C and its consistency is more plastic than kokam butter, not breaking with a sharp crack at ambient temperatures. All parts of Garcinia morella contain gamboge, a red-yellow or brown-orange, odourless, tasteless or slightly acidic resin, with a smooth, uniform conchoidal fracture. Gamboge forms a yellow emulsion with water and a clear, dark orange one with weak ammonia. It can be dissolved by adding alcohol and water and this solution can be transformed into solid form by adding acid. Commercial gamboge has the following characteristics: specific gravity 1.22, acid value 65—90, ester value 45—65, saponification value 125—145, ash content 1% and water content 3—5%. One constituent of gamboge is gamboge acid which has shown anticancer activity in experiments. The pericarp, stem bark and leaves of Garcinia morella show antibacterial activity against Staphylococcus aureus and this action is primarily attributed to the yellow pigment morellin.

Dioecious evergreen trees. Trunk straight, tapering to the top of the conical crown. Branches arranged in alternating pairs, arising from the trunk at an acute angle, later becoming horizontal or pendent. In the forest branches are restricted to the upper part of the trunk, remnants of lower branches persist for a long time as woody knobs. White or yellow, thick, sticky latex is present in all parts. Leaves decussate, successive pairs at maturity in one plane by torsion of the twigs, the petiole with a basal foveola. Flowers axillary, polygamous-dioecious, regular, sepals and petals 4—5; male flowers with various numbers of stamens, filaments connate into one central column or into 4—5 bundles, pistil rudimentary or lacking; female flowers usually larger than male ones, usually solitary, staminodes with filaments connate into a ring at the base or into 4—5 short bundles; ovary 2—12-celled with 1 ovule per cell, style short or absent, stigma peltate, 2—12-lobed or incised, usually papillate. Fruit a berry with 1—12 seeds. Seeds large, usually enveloped in a juicy arillode; embryo a solid mass representing the hypocotyl, cotyledons absent.
— Garcinia indica. Tree 10(—15) m tall, trunk blackish, usually buttressed. Leaves red when young, turning shiny dark green above and pale beneath; petiole 5—12 mm long; blade lanceolate or ovate-oblong, 6.5—11 cm x 1.5—5 cm, apex acuminate. Flowers solitary or in fascicles, unisexual per tree, small, 4—8 mm in diameter, white; bracts scale-like, caducous; sepals 4, ovate-rotundate, 3—5 mm long, the outer two smaller than the inner ones, thick, fleshy, yellowish to pink-orange; petals 4, 5—6 mm long, thick; male flowers with 10—20 stamens joined into a central column; female flower on pedicel 3 mm long, staminodes 1—3 mm long, ovary subglobose, 4—8-locular, stigma sessile. Fruit a globose berry, 2.5—4 cm in diameter, dark purple to pink when ripe, surrounded by persistent sepals. Seeds 5—8 per fruit, compressed.
— Garcinia morella. Tree, up to 20 m tall; trunk diameter 50 cm but usually much smaller, glabrous in all parts. Inner bark up to 1 cm thick, white to pale yellow, containing plenty of brilliant yellow, sticky latex. Leaves coriaceous, entire; petiole up to 2 cm long, foveola conspicuous with prominent margins; blade obovate to oblanceolate, 9—24 cm x 5—10 cm, base tapering, apex usually obscurely acuminate, lateral veins on lower surface prominent, parallel, 8—14 mm apart, in 7—8 pairs. Flowers subsessile, solitary (female) or 2—3 together (male), per tree unisexual; sepals 4, 5 mm long; petals 4, elliptical, 5—8 mm long, fleshy, white to pink; stamens in male flowers in a monadelphous central column with free red anthers; female flowers with sessile peltate stigma, base of ovary surrounded by about 15 free staminodes. Fruit a globose berry, up to 3.5 cm in diameter, at base surrounded by the persistent sepals, at apex crowned by the flat tuberculate stigma, smooth, yellowish; exocarp thin; fruit pulp edible, acid-sweet, containing 2—3 seeds. Seed kidney-shaped, laterally compressed.

In India, Garcinia indica flowers from November to February and fruits from April to May; anthesis is in the early morning from 06.00—08.00 h, anther dehiscence occurs 15—20 minutes before anthesis. Flowering and fruiting of Garcinia morella in southern India is from November to July; fruiting can persist until December. In Indonesia, flowering is in August, fruiting in November. Agamospermy (seed apomixis) is common in Garcinia: many species can produce seed asexually as well as sexually, but the reproductive biology of the genus is still not well-understood. Many wild species flower at night and have a characteristic strong odour.

As long as no taxonomic revision of Garcinia is available, confusion in the literature about correct names and synonyms will continue. Estimates of the total number of species vary between 100 and 400. Garcinia hanburyi Hook.f. (syn. Garcinia morella (Gaertn.) Desr. var. pedicellata Hanbury) is closely related to Garcinia morella and information cannot always be accurately assigned to one of them. Garcinia hanburyi occurs in Thailand and Indo-China and is the major source of gamboge. In Sri Lanka and possibly also in southwestern India, Garcinia echinocarpa Thwaites also has seed rich in fat (60%). The fat is known as 'madol' and can be used in the same way as kokam butter. The tree can easily be recognized because it grows in wet places, always bearing stilt roots. Garcinia is polygamous-dioecious (bisexual, male and female flowers in certain combinations in the same and in different trees) but it is unclear whether Garcinia indica and Garcinia morella also have bisexual flowers.

Garcinia indica prefers a per-humid tropical climate with 6—10 rainy months per year and a total annual rainfall of 2500—5000 mm. It thrives under mean maximum temperatures of 20—30°C, in partial shade, at altitudes up to 800 m, but it also occurs naturally at higher altitudes. Garcinia morella grows both in dry and in humid forest in the tropics and subtropics. Trees in dry zones are often stunted, stiff with divaricate branches and thick nodes and the leaves are less fleshy. It occurs from sea-level up to 1100 m elevation.

Garcinia indica is usually propagated by seed. It can also be propagated vegetatively by softwood grafting. High-yielding cultivars that flower early and are short in stature exist. In India, preferably in October, mature scions (5—6 months old) and rootstock (more than 5 months old) are used. Grafted seedlings can be planted in the field in June—July for optimal establishment and a spacing of 6 m x 6 m is recommended for planting 1-year old grafted kokam.

No information is available on the husbandry of Garcinia indica. Garcinia morella only occurs in the wild.

In Java (Indonesia), sooty moulds (caused by Clypeolum vulgare) and leaf spot disease (caused by Gloeosporium garciniae) have been observed in Garcinia morella. However, no serious diseases or pests are recorded.

No information on fruit collection is available. For the harvest of gamboge, Garcinia morella trees can be tapped when 10 years old by making a spiral incision in the bark and collecting the latex in a small container (e.g. of bamboo).

For Garcinia indica, the kokam butter yield and the number of fruits per tree vary with the cultivar. A maximum yield of nearly 50 kg/tree has been recorded in India. For Garcinia morella, no information on the yield of tamal butter or gamboge is available.

Newly harvested fruits of Garcinia indica are reddish-green and turn full red-purple after about two days. Kokam butter extraction is mostly a cottage industry, where the seeds are crushed, boiled in water and the fat skimmed off. The fat is made into egg-shaped balls and is mostly sold without further cleaning or processing. The normal shelf life of fresh Garcinia indica fruits is about five days. To produce the dried rind, fruits are dried in the sun immediately after harvesting. The fruit is cut in half and the fleshy portion and the seeds are removed. During preparation the rind, which constitutes 50—55% of the fruit, is soaked several times in the juice of the pulp and dried again. About 6—8 days are required for complete drying. The resulting product is the condiment kokam of commerce.

Garcinia indica is included in the list of endangered plants of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), but not enough information is available to specify how seriously it is endangered. Germplasm collections for Garcinia indica or for Garcinia morella are not known to exist.

Some initial selection work on Garcinia indica has been done in India and a clone with high yield, short harvesting period and large fruits with a long shelf life has been selected.

Garcinia indica and Garcinia morella are multi-purpose trees which have not been fully exploited and are poorly known. The use of kokam butter of Garcinia indica as an alternative or additive for cocoa butter deserves research attention in South-East Asia. The pharmaceutical value of both Garciniaspp. also deserves further investigation.

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S. Gopakumar

Gopakumar, S., 2001. Garcinia L.. In: van der Vossen, H.A.M. and Umali, B.E. (Editors): Plant Resources of South-East Asia No 14: Vegetable oils and fats. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea