The black sapote is not, as might be assumed, allied to either the
sapote (Pouteria sapota H.E. Moore & Stearn) or the white
sapote (Casimiroa edulis Llave & Lex.). Instead, it is closely
related to the persimmon in the family Ebenaceae. For many years it
has been widely misidentified as Diospyros ebenaster Retz., a name
confusingly applied also to a strictly wild species of the West
Indies now distinguished as D. revoluta Poir. The presently
accepted binomial for the black sapote is D. digyna Jacq. (syn. D.
obtusifolia Humb. & Bonpl. ex Willd.). In Spanish, it is known
variously as sapote, sapote negro, zapote, zapote negro, zapote
prieto, zapote de mico, matasano (or matazano) de mico, or ebano.
It has been called black persimmon in Hawaii.
Description
The tree is handsome, broad-topped, slow-growing, to 80 ft (25 m)
in height, with furrowed trunk to 30 in (75 cm) in diameter, and
black bark. The evergreen, alternate leaves, elliptic-oblong to
oblong-lanceolate, tapered at both ends or rounded at the base and
bluntly acute at the apex, are leathery, glossy, 4 to 12 in (10-30
cm) long. The flowers, borne singly or in groups of 3 to 7 in the
leaf axils, are tubular, lobed, white, 3/8 to 5/8 in (1-1.6 cm)
wide, with persistent green calyx. Some have both male and female
organs, large calyx lobes and are faintly fragrant; others are
solely male and have a pronounced gardenia-like scent and a few
black specks in the throat of the corolla. The fruit is
bright-green and shiny at first; oblate or nearly round; 2 to 5 in
(5-12.5 cm) wide; with a prominent, 4-lobed, undulate calyx, 1 1/2
to 2 in (4-5 cm) across, clasping the base. On ripening, the
smooth, thin skin becomes olive-green and then rather muddy-green.
Within is a mass of glossy, brown to very dark-brown, almost black,
somewhat jelly-like pulp, soft, sweet and mild in flavor. In the
center, there may be 1 to 10 flat, smooth, brown seeds, 3/4 to 1 in
(2-2.5 cm) long, but the fruits are often seedless.
Origin and Distribution
The black sapote is native along both coasts of Mexico from Jalisco
to Chiapas, Veracruz and Yucatan and in the forested lowlands of
Central America, and it is frequently cultivated throughout this
range. It was apparently carried by the Spaniards to Amboina before
1692, and to the Philippines long before 1776, and eventually
reached Malacca, Mauritius, Hawaii, Brazil, Cuba, Puerto Rico and
the Dominican Republic. In 1919, seeds from Guadalajara, Mexico,
were sent to the Bureau of Plant Industry of the United States
Department of Agriculture; cuttings and seeds were received from
the Isle of Pines, Cuba, in 1915; seeds arrived from Hawaii in 1916
and 1917; others from Oaxaca, Mexico, in 1920. Numerous seedlings
have been grown in southern California but all have been killed by
low temperatures. The tree does very well in southern Florida,
though it has been grown mainly as a curiosity. Outside of its
homeland, the fruit has not achieved any great popularity. In
Mexico, the fruits are regularly marketed.
Varieties
Certain trees tend to bear very large, seedless or nearly seedless
fruits maturing in summer instead of winter as most do, but no
varietal names have been attached to them in Florida.
Climate
The black sapote is not strictly tropical inasmuch as it is hardy
as far north as Palm Beach County, Florida, if protected from frost
during the first few years. Trees that have become well established
have withstood occasional brief exposures to 28 or 30 F (-2.22
or-1.11 C). In Mexico, the tree is cultivated up to elevations of
5,000 or even 6,000 ft (1,500-1,800 m).
Soil
The tree has a broad adaptability as to terrain. In Mexico it grows
naturally in dry forests or on alluvial clay near streams or
lagoons where it is frequently subject to flooding. Nevertheless,
it thrives on moist sandy loam, on well-drained sand or oolitic
limestone with very little top-soil in southern Florida. It is said
to flourish on all the soils of Cuba.
Propagation
The black sapote is usually grown from seeds, which remain viable
for several months in dry storage and germinate in about 30 days
after planting in flats. Vegetative propagation is not commonly
practiced but the tree has been successfully air-layered and also
shield-budded using mature scions.
Culture
Seedlings are best transplanted to pots when about 3 in (7.5 cm)
high and they are set in the field when 1 to 2 years old, at which
time they are 1 to 2 ft (30-60 cm) in height. They should be spaced
at least 40 ft (12 m) apart. Most begin to bear in 5 to 6 years but
some trees may take somewhat longer. The tree is naturally vigorous
and receives little or no cultural attention in Florida though it
has been noted that it benefits from fertilization.
Season
In Mexico, the fruits are common in the markets from August to
January. Most black sapotes in Florida ripen in December, January
or February. Certain trees, especially the large-fruited types,
regularly come into season in June, others in July and August.
Harvesting
It is difficult to detect the slight color change of mature fruits
amid the dense foliage of the black sapote tree. Many black sapotes
ripen, fall and smash on the ground before one has the chance to
pick them, and this is one reason why .the tree is not favored for
landscaping in urban areas. An experienced picker can harvest the
fruits at the green-mature or olive-green stage with a cutting pole
equipped with a cloth sack.
Yield
No yield figures are available but the tree is noted for bearing
well. In 1899, the annual crop in Mexico was valued at $27,000, a
considerable sum at that time.
Keeping Quality
Fruits picked when full-grown but unripe (bright-green) have
ripened in 10 days at room temperature. Therefore it is at this
stage that they must be picked for marketing and shipping. Firm,
olive-green fruits will ripen in 2 to 6 days. Fruits displayed on
markets in Mexico are somewhat shriveled and wrinkled. The black
sapote is very soft when fully ripe. Though it may remain fit for
eating if held for a few days in cold storage, it is too soft to
stand handling.
Food Uses
Unkind writers have employed unflattering phrases in describing the
flesh of the black sapote and have probably hindered its
acceptance. This seems quite unreasonable because the color and
texture of the pulp closely match stewed prunes, to which there
seems to be no aesthetic objection. In the Philippines, the seeded
pulp is served as dessert with a little milk or orange juice poured
over it. The addition of lemon or lime juice makes the pulp
desirable as a filling for pies and other pastry. It is also made
into ice cream. In Mexico, the pulp may be mashed, beaten or passed
through a colander and mixed with orange juice or brandy, and then
served with or without whipped cream. Also, they sometimes mix the
pulp with wine, cinnamon and sugar and serve as dessert. Some
Floridians use an eggbeater to blend the pulp with milk and ground
nutmeg. A foamy, delicious beverage is made by mixing the pulp with
canned pineapple juice in an electric blender. In Central America,
the fermented fruits are made into a liqueur somewhat like brandy.
Food Value Per 100 g of Edible Portion (Flesh)*
Moisture 79.46-83.1 g
Protein 0.62-0.69 g
Carbohydrates 12.85-15.11 g
Fat 0.01 g
Ash 0.37-0.6 g
Calcium 22.0 mg
Phosphorus 23.0 mg
Iron 0.36 mg
Carotene 0.19 mg
Thiamine
Riboflavin 0.03 mg
Niacin 0.20 mg
Ascorbic Acid** 191.7 mg
*According to analyses in Mexico and Guatemala.
**The ascorbic acid content is said to be about twice that of the
average orange.
Toxicity
Unripe black sapotes are very astringent, irritant, caustic and
bitter, and have been used as fish poison in the Philippines.
Other Uses
Wood: The wood is yellowish to deep-yellow with black markings near
the heart of old trunks; compact and suitable for cabinetwork but
little used. Reports of dark wood utilized for furniture are
probably the result of confusion with other species of Diospyros.
Medicinal_Uses
The crushed bark and leaves are applied as a blistering poultice in
the Philippines. In Yucatan, the leaf decoction is employed as an
astringent and is taken internally as a febrifuge. Various
preparations are used against leprosy, ringworm and itching skin
conditions.
