From Plant Resources of South-East Asia No 2: Edible fruits and nuts, PROSEA Foundation
by R. E. Coronel
Taxon
Tamarindus indica L.
Protologue
Sp. Pl.: 34 (1753).
Family
LEGUMINOSAE
Chromosome Numbers
2n = 24
Synonyms
Tamarindus occidentalis Gaertn. (1791), Tamarindus officinalis Hook. (1851).
Vernacular Names
Tamarind,
Indian tamarind (En). Tamarinier (Fr). Indonesia: asam, asam jawa,
tambaring. Malaysia: asam jawa. Philippines: sampalok (Tagalog),
kalamagi (Bisaya), salomagi (Ilokano). Burma: magyee, majee-pen.
Cambodia: 'âm'pül, ampil, khoua me. Laos: khaam, mak kham. Thailand:
makham (general), bakham (northern), somkham (peninsular). Vietnam: me,
trai me.
Origin and Geographic Distribution
The
origin of tamarind is unknown. It is generally believed that it is
indigenous to the drier savannas of tropical Africa, but it certainly
naturalized long ago in tropical Asia. Tamarind is now cultivated in
all tropical countries, even on a plantation scale in India, and it is
economically important all over South-East Asia.
Uses
The green fruits and flowers
may be used for souring soupy dishes of fish and meat. The ripe fruit
of the sweet type is usually eaten fresh, whereas the fruits of sour
types are made into juice, jam, syrup and candy. Tamarind seeds are
also edible after soaking in water and boiling to remove the seed-coat.
Flour from the seed may be made into cake and bread. Roasted seeds are
claimed to be superior to groundnuts in flavour. The seed oil — which
resembles linseed oil — is suitable for making paint and varnish.
The
bark is astringent and tonic and its ash may be given internally as a
digestive. Incorporated into lotions or poultices, the bark may be used
to relieve sores, ulcers, boils and rashes. It may also be administered
as a decoction against asthma and amenorrhea and as a febrifuge. Young
leaves may be used in fomentation for rheumatism, applied to sores and
wounds, or administered as a poultice for inflammation of joints to
reduce swelling and relieve pain. A sweetened decoction of leaves is
good against cough and fever. Filtered hot juice of young leaves and a
poultice of the flowers are used for conjunctivitis. The pulp may be
used as an acid refrigerant, a mild laxative and also to treat scurvy.
Powdered seeds may be given to cure dysentery and diarrhoea.
Production and International Trade
Although
production should be substantial, statistical records do not usually
specify tamarind. The crop in India — the largest producer — was
250,000 t in 1964 and India also exports several thousand tonnes per
year,
mainly of seed and seed powder, but also some pulp. Export statistics
in Thailand for the early 1980s range from 11,000 to 21,000 t of dried
pods. In India, Thailand, Central America (Mexico: 4,400 ha) and Brazil
the crop is to some extent grown in orchards; elsewhere production
comes only from trees along roads, in field borders and in home gardens.
Properties
Ripe fruits
have 40—50% edible pulp which contains per 100 g: water 17.8—35.8 g,
protein 2—3 g, fat 0.6 g, carbohydrates 41.1—61.4 g, fibre 2.9 g, ash
2.6—3.9 g, calcium 34—94 mg, phosphorus 34—78 mg, iron 0.2—0.9 mg,
thiamine 0.33 mg, riboflavin 0.1 mg, niacin 1.0 mg and vitamin C 44 mg.
Fresh seeds contain 13% water, 20% protein, 5.5% fat, 59% carbohydrates
and 2.4% ash. The acidity is caused by tartaric acid, which on ripening
does not disappear but is matched more or less by increasing sugar
levels. Hence tamarind is said to be simultaneously the most acid and
the most sweet fruit.
Description
A
large evergreen tree, up to 30 m tall, bole usually 1—2 m long, up to 2
m diameter, crown densely foliated, widely spreading, rounded; bark
rough, fissured, greyish-brown. Leaves alternate, stipulate, petiolate,
paripinnately compound; petiole up to 1.5 cm long, leaving a prominent
scar after falling; blade suboblong in outline, up to 13 cm x 5 cm,
with 8—16 pairs of leaflets; leaflets narrowly oblong, 1—3.5 cm x 0.5—1
cm, entire, oblique and rounded at base, rounded to slightly emarginate
at apex. Inflorescences lax lateral and terminal racemes, up to 13 cm
long; flowers ca. 3 cm long, fragrant; sepals 4, unequal, up to 1.5 cm
long; petals 5, the posterior and lateral ones large and showy, cream
coloured with brown-red veins, the 2 anterior ones much reduced,
linear, white; stamens 3; pistil 1, up to 18-ovuled. Fruit a
subcylindrical, straight or curved, indehiscent pod with rounded ends,
up to 14 cm x 4 cm, up to 10-seeded, often irregularly constricted
between the seeds; exocarp crustaceous, greyish or more usually scurfy
brown, with some strong fibrous threads inside; mesocarp thick-syrupy,
blackish-brown; endocarp thin, leathery. Seeds irregularly shaped,
flattened rhomboid, up to 18 mm long, very hard, brown.
Growth and Development
The
seeds remain viable for many months and germinate within 2 weeks after
sowing. Growth is generally slow, seedling height increasing by about
60 cm annually. The juvenile phase lasts 4—5 years or longer. At higher
latitudes shoots grow mainly in spring, flower throughout the summer
and pods ripen in the spring, the period from flowering to harvest
being quite long (about 8 months until full maturity). Very little is
known about the growth rhythm in the tropics. In the monsoon climate of
East Java the tree changes its leaves towards the end of the dry season
(some trees in September, others in October—November). Some trees may
be nearly leafless for a while, but normally they remain foliated. More
or less incidental shoot growth continues through the rainy season
(November—April) into the dry season, but in July—August the trees are
virtually quiescent. Flowers emerge on the new shoots that mark the
leaf change, but some trees flower later, even as late as February when
the shoots have long matured. The fruit ripens mainly in June—September.
In
Thailand the fruiting season is December—February, in the Philippines
from May to December with a peak in August—October. The flowers produce
nectar and are probably pollinated by insects; self-pollination results
in seeded pods.
Other Botanical Information
Tamarindus L. is a monospecific genus. In the past a distinction was made between tamarinds from the West and the East Indies:
— West Indies: Tamarindus occidentalis: pod up to 3 times longer than wide, containing 1—4 seeds;
— East Indies: Tamarindus indica: pod up to 6 times or more longer than wide, containing 6—12 seeds.
There
are several tamarind cultivars, differing mainly in colour and
sweetness of the flesh. In Thailand named cultivars of the sweet type
(makahm wahn) are grown in orchards, e.g. 'Muen Chong', 'Nazi Zad', 'Si
Chompoo'. 'Manila Sweet' is a cultivar of the Philippines.
Ecology
Tamarind
grows well over a wide range of soil and climatic conditions. It is
found in places with sandy to clay soils, at low to medium altitudes
(up to 1000 m, sometimes to 1500 m), where rainfall is evenly
distributed or where the dry season is long and very pronounced. Its
extensive root system contributes to its resistance to drought and
strong winds. In the wet tropics (rainfall > 4000 mm) the tree does
not flower, and wet conditions during the final stages of fruit
development are detrimental. Young trees are killed by the slightest
frost, but older trees seem more cold-resistant than mango, avocado and
lime trees.
Propagation and planting
Tamarind
may be propagated by seeds and by marcotting, grafting and budding.
Seedlings are big enough to be planted out in the field in a year or
less, but they do not come true to type. Outstanding mother trees are
propagated asexually. Shield and patch budding and cleft grafting are
fast and reliable methods and at present used in large-scale
propagation in the Philippines, the best time being the cool and dry
months of November to January. Budded or grafted trees are planted in
the field at the onset of the rainy season (May to June in the
Philippines) at a spacing of 8—10 m.
Husbandry
Trees
generally receive minimal care, but in orchards in Thailand's central
delta intensive cropping is practised. This is possible because grafted
trees come into bearing within 3—4 years. Sweet cultivars are planted
and good early crops limit extension growth; presumably the high water
table which prevents deep rooting also helps to dwarf the trees.
Size-control measures include close spacing (about 500 trees per ha)
and pruning to rejuvenate the fruiting wood. The trees are treated in a
similar manner as other fruit crops in the area with respect to
irrigation, manuring and crop protection.
Diseases and Pests
The
trees are hosts to such pests as shothole borers, toy beetles,
leaf-feeding caterpillars, bagworms, mealy bugs and scale insects. In
some seasons, fruit borers may inflict serious damage to maturing
fruits causing a great reduction in marketable yield. Diseases which
have been reported from India include several tree rots and a bacterial
leaf-spot.
Harvesting
In
the Philippines, the fruits of sour types are harvested at 2 stages:
green for flavouring and ripe for processing. Fruits of sweet cultivars
are also harvested at 2 stages: half ripe or 'malasebo' stage and ripe
stage. At the half-ripe stage the skin is easily peeled off; the pulp
is yellowish-green and has the consistency of an apple. At the ripe
stage, the pulp shrinks because of loss of moisture, and changes to
reddish-brown and becomes sticky. If the whole pod is to be marketed,
the fruit should be harvested by clipping to avoid damaging the pods.
Eventually the pods abscise naturally.
Yield
Yield
records are scarce. Up to 170 kg/year of prepared pulp per (large) tree
has been reported from India and Sri Lanka; 80—90 kg is said to be an
average yield. At 100 trees per ha this would mean 8—9 t of prepared
pulp per ha per year. In the Philippines 200—300 kg pods per tree is
considered a good yield. The lack of information on biennial bearing
suggests that bearing is fairly regular.
Handling After Harvest
Green
fruits for cooking, and half-ripe and ripe fruits for fresh consumption
are sold by weight in the markets. Ripe fruits for processing are
peeled, fibre strands are removed, and then they are sold by weight in
plastic containers. The fruit of sweet cultivars commands a much higher
price than the sour fruit.
Genetic Resources
The
greatest diversity of tamarind types is found in the African savannas.
Selected material exhibits tolerance to drought, wind, poor soils,
waterlogging, high pH, low pH and grazing. The Institute of Plant
Breeding in Los Baños, the Philippines, contains a germplasm collection
(46 accessions).
Prospects
The
much-appreciated qualities of the tamarind and its adaptability to
different soils and climates enabled it to conquer the tropics in the
remote past; the tree and its fruit are still highly prized today. It
is, therefore, all the more surprising that so little is known about
tree phenology, floral biology, husbandry, yield and genetic diversity.
The contribution of science to the knowledge which farming communities
have accumulated is minimal; until this situation changes it is
difficult to assess the prospects for the tamarind.
Literature
Carangal,
A.R., Gonzalez, L.G. & Daguman, I.L., 1961. The acid constituents
of some Philippine fruits. The Philippine Agriculturists 44: 514—519.
Coster,
C., 1923. Lauberneuerung und andere periodische Lebensprozesse in dem
trockenen Monsun-Gebiet Ost-Javas. [Leaf change and other periodical
life processes in the dry monsoon area of East Java]. Annales Jardin
Botanique, Buitenzorg 33: 117—189.
Duke, J.A., 1981. Handbook of
legumes of world economic importance. Plenum Press, New York. pp.
228—230. Jansen, P.C.M., 1981. Spices, condiments and medicinal plants
in Ethiopia, their taxonomy and agricultural significance. PUDOC,
Wageningen. pp. 244—256.
Pratt, D.S. & del Rosario, J.I., 1913.
Philippine fruits: their composition and characteristics. Philippine
Journal of Science A8: 59—80.
Soetisna, U. & Hidajat, E., 1977. Pohon asam (Tamarindus indica L.) [Tamarind tree (Tamarindus indica L.)]. Buletin Kebun Raya 3(2): 63—65.
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