From Plant
Resources of South-East Asia No 2: Edible fruits and nuts, PROSEA
Foundation
by Sri Setyati Harjadi
Taxon
Malpighia glabra L.
Protologue
Sp. Pl.: 425 (1753).
Family
MALPIGHIACEAE
Chromosome
Numbers
2n = 40
Synonyms
Malpighia punicifolia L. (1762).
Vernacular
Names
Acerola, West Indian cherry, Barbados cherry (En). Cerise-antillaise (Fr). Thailand: choeri (Bangkok), Vietnam: so'ri.
Origin and
Geographic Distribution
The
acerola is native to the Lesser Antilles and from northern South
America to southern Texas in the United States. It has been introduced
into other parts of the tropics and subtropics. In South-East Asia it
is only sporadically grown.
Uses
The sour fruits are eaten
fresh, but more often preserved with sugar, e.g. in the form of jam.
Juice is used commercially to enrich other fruit juices low in vitamin
C. The bark has been used for tanning. The wood, which is hard and
heavy, can be used for small utensils. The fruits are considered
beneficial against liver problems, diarrhoea, dysentery, coughs and
colds.
Production and International Trade
Although
acerola was promoted commercially in the 1950s as a rich natural source
of vitamin C, it is now only important in Puerto Rico. Canned juice and
frozen fruit are exported to the United States, where they are used to
enrich fruit preserves and are marketed as baby foods.
Properties
The edible pulp
represents about half of the fruit weight and contains per 100 g: water
82—91 g, protein 0.7—1.8 g, fat 0.1—0.2 g, carbohydrates 7—14 g, fibre
0.6—1.2 g, ash 0.8 g. The energy value is 247 kJ per 100 g. The fruit —
particularly when immature — is one of the richest sources of vitamin
C, containing up to 4.7 g per 100 g edible portion.
Botany
Shrub or small
evergreen tree, 2—3(—6) m tall, with spreading, more or less drooping
branches on a short trunk. Leaves opposite, ovate to
elliptic-lanceolate, 2—8 cm x 1—4 cm, entire or undulating, dark green
and glossy above, petiole short. Inflorescences sessile or
short-peduncled axillary cymes with 3—5 flowers; flowers bisexual, 1—2
cm in diameter, pinkish to reddish; calyx with 6—10 large sessile
glands; petals 5, fringed, slender-clawed; stamens 10, filaments united
below. Fruit a bright-red, juicy drupe, depressed-ovoid, 1—3 cm in
diameter and weighing 3—5 g, usually in pairs or threes, obscurely
3-lobed; skin thin, flesh soft, orange, acid to subacid. Seeds 3,
triangular, ridged.
The germination rate of the seed is low (5—50%).
Trees start to produce well 3—4 years after planting and continue for
15 years. In Puerto Rico flowering appeared to be independent of the
daylength and several cropping periods are possible per year,
especially with alternating dry and rainy periods. The flowers are
pollinated by insects; honey bees substantially improve fruit set.
Self- and cross-incompatibility have been reported. Fruits ripen
completely 3—4 weeks after flowering. In Puerto Rico the large-fruited
(up to 20 g/fruit) selection B-15 is most important. In Florida,
'Florida Sweet' is a high-yielding cultivar.
A distinction is sometimes made in nomenclature between wild and cultivated (improved) plants, the latter being called Malpighia punicifolia L. It is now, however, generally accepted that both taxa belong to Malpighia glabra. Malpighia coccigera L. and Malpighia urens L. are incidentally cultivated in South-East Asia for the same purposes as Malpighia glabra.
Ecology
Acerola can be grown
almost anywhere in the tropics and warm subtropics. Young plants are
killed by frost, but mature trees survive brief exposure to —2°C. The
plants tolerate long periods of drought and do not stand waterlogging.
The soil should preferably be rich, deep and well drained, with a pH
above 5.5. On calcareous soils the plants require additional
micronutrients, on acid soils addition of lime is required.
Agronomy
Fully developed
seeds should be used for planting. Acerola may also be propagated
vegetatively by cuttings, budding or grafting. The recommended spacing
is 3—4 m on the square, or in double rows, e.g. (4 + 2) m x 3 m. NPK
fertilization twice a year and application of organic material are
recommended for Puerto Rico. Bearing will be enhanced if mature plants
are judiciously pruned after the main crop, followed by a top dressing.
Acerola is very susceptible to the root-knot nematode Meloidogyne incognita var. acrita. It can be controlled by soil fumigation, mulching and regular irrigation.
Fruits
for home consumption are picked when fully ripe. For processing fruits
are harvested when they turn from yellow to red. Picking is carried out
every 1—3 days as there is continuous fruiting over long periods.
Individual trees may produce 15—30 kg of fruits per year, whereas
yields per hectare per year may vary considerably: (10—)15—25(—65) t.
Mature fruits bruise easily and are very perishable. Storage up to 3
days at 7°C is possible. Half-ripe acerolas can be kept for a few more
days, but if longer storage is necessary the fruit must be frozen and
kept at —12°C.
Genetic Resources and Breeding
Germplasm
collections are available at the Subtropical Horticultural Research
Unit USDA, Miami, Florida, United States and the Department of
Horticulture, College of Agricultural Sciences, University of Puerto
Rico, Mayaguez.
Prospects
The acerola is a
suitable fruit for home gardens. The plants have ornamental value and
are very suitable for backyards and places where children play (to eat
the fruits and to climb the trees) and for hedges.
Literature
Ostendorf, F.W., 1963. The West Indian cherry. Tropical Abstracts 18(3): 145—150.
Moscoso, C.G., 1956. West Indian cherry — richest known source of natural vitamin C. Economic Botany 10: 280—294.
Ledin, R.B., 1958. The Barbados or West Indian cherry. Florida Agricultural Experimental Station Bulletin 594: 1—28.
Yamane, G.M. & Nakasone, H.Y., 1961. Pollination and fruit set studies of acerola (Malpighia glabra L.) in Hawaii. Proceedings American Society for Horticultural Science 78: 141—148.
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