From the book
Fruits of Warm Climates
by Julia F. Morton
Naranjilla
Solanum quitoense Lam.
Solanum angulatum Lam.
SOLANACEAE
An intriguing and highly appealing member of the nightshade family, Solanaceae, the naranjilla, Solanum quitoense Lam. (syn. S. angulatum
Lam.), acquired its Spanish name, meaning "little orange" because it is
round, and is bright-orange when fully ripe. In Ecuador it is called
naranjilla de Quito, or nuqui; in Peru, naranjita de Quito. The Incas
called it lulum. In Mexico, it is lulun; in Colombia, lulo, naranjilla
or toronja. Variety septentrionale Schultes & Cuatr. is called lulo
de castilla, lulo de perro, or lulo morado.
Plate LXIII: NARANJILLA, Solanum quitoense
Description
The
naranjilla plant is a spreading, herbaceous shrub to 8 ft (2.5 m) high
with thick stems that become somewhat woody with age; spiny in the
wild, spineless in cultivated plants. The alternate leaves are
oblong-ovate, to 2 ft (60 cm) long and 18 in (45 cm) wide, soft and
woolly. There may be few or many spines on petioles, midrib and lateral
veins, above and below, or the leaves may be completely spineless.
Young leaves, young stems and petioles are coated with richly purple
stellate hairs. Hairs on other parts may appear simple. Borne in short
axillary clusters of as many as 10, the fragrant flowers, about 1 1/5
in (3 cm) wide, have 5 petals, white on the upper surface, purple hairy
beneath, and 5 prominent yellow stamens. The unopened buds are likewise
covered with purple hairs. A brown, hairy coat protects the fruit until
it is fully ripe, when the hairs can be easily rubbed off, showing the
bright-orange, smooth, leathery, fairly thick peel. The fruit, crowned
with the persistent, 5-pointed calyx, is round or round-ovate, to 2 1/2
in (6.25 cm) across and contains 4 compartments separated by membranous
partitions and filled with translucent green or yellowish, very juicy,
slightly acid to acid, pulp of delicious flavor which has been likened
to pineapple-and-lemon. There are numerous pale-buff seeds, thin, flat,
hard and 1/8 in (3 mm) in diameter.
Origin and
Distribution
The
usually spineless naranjilla is believed to be indigenous and most
abundant in Peru, Ecuador and southern Colombia. The forms found in the
rest of Colombia and in the central and northern Andes of Venezuela and
interior mountain ranges of Costa Rica may vary from partly to very
spiny. Some botanists have suggested that these spiny forms belong to
the botanical variety septentrionale.
In Ecuador, 90% of commercial naranjilla cultivation is in a 15-mile
area in the valley and adjacent hillsides of the Pastaza River, a
tributary of the Amazon.
Seeds were first sent to the United
States Department of Agriculture from Colombia in 1913; from Ecuador in
1914 and 1916. Many other introductions were made but the resulting
plantings in California, Florida and northern greenhouses flourished
only briefly, some set fruit, and all died. Trial plantings were made
in the Philippines about 1922. The exhibition of fruits and 1,500
gallons of freshly made juice of Ecuadorian naranjillas at the New York
World's Fair in 1939 roused a great deal of interest. In February,
1948, 20 naranjilla plants were set out in a field at the University of
Florida's Agricultural Research and Education Center in Homestead,
Florida. They flourished and were beginning to fruit when nearly all
were destroyed by hurricanes. Dr. Milton Cobin tried grafting the
naranjilla on the so-called "potato tree", Solanum macranthum
Dunal of Brazil, hoping to give it wind-resistance. The grafted plants
were set out in 1949 and fruited well. Seeds of acid and sweet strains
were obtained from the United States Department of Agriculture in 1950.
Some of the resulting plants were grafted onto S. macranthum
and did well; others, set out on their own roots, became severely
infested with rootknot nematodes and died. In 1951, the naranjilla was
grafted onto S. erianthum D.
Don but the plants were dwarfed by this rootstock and short-lived. A
number of fruit fanciers took up the growing of grafted naranjilla
plants in home gardens. Interest was aroused in Caribbean
horticulturists and other visitors to the Homestead station. In the
early 1950's, plantings were made in Puerto Rico, Jamaica, Panama,
Hawaii and Queensland, and in the Meseta Central of Costa Rica where
one of several growers set out 70,000 plants of the local wild variety
which bears a larger fruit than the non-spiny South American type.
In
1962, a commercial plantation owned by Frederic Zeuner, proprietor of
Cia Procesadora de Naranjilla Ltda, of San José, covered 1,200 acres
(511 ha) and a $55,000 factory was built to process the fruits. The
pulp was being shipped to the United States in No. 10 cans. It was
blended with apple or pineapple juice, put up in small cans and frozen
for retail sale. In 1966, I was advised by the U.S. Agricultural
Attaché in San José that this pilot effort failed because the canned
product was not properly processed and had a metallic taste, also
because of the collapse of the canners' contracts with farmers.
Production of a better product with proper cooling and storage
continued on a local scale. In 1963, the naranjilla was a relatively
new crop in Guatemala and there was an experimental plantation and
others that were semi-commercial.
The naranjilla is much admired
as an ornamental foliage plant in northern conservatories but it will
not fruit in temperate latitudes.
Varieties
The botanical variety septentrionale
already referred to is found in Valle, Cundinamarca, Magdalena,
Santanderes and Tolima, in central and northern Colombia, and also in
Ecuador and Venezuela. It is said to differ from the typical form, var.
quitoense, of Ecuador, Peru
and southern Colombia, only in having spines on the stem, branches,
petioles, and principal veins of the leaves.
There is a sweet, but not very juicy strain around the Andean town of Baza, about 50 miles (80 km) east of Quito, Ecuador.
A
wild, spiny form in Costa Rica, called berenjena de olor ("fragrant
eggplant"), has woodier stem and branches and unusually large fruits to
2 1/2 in (6.25 cm) in diameter.
The fruit of seedling plants
shows much variation. However, there seems to be little or no effort to
select and name superior cultivars.
Climate
In Colombia, the
naranjilla flourishes in humid regions at elevations between 3,600 and
7,900 ft (1,600 and 2,400 m) where the annual rainfall is about 60 in
(150 cm). Precipitation up to 120 in (250 cm) is tolerable if well
distributed throughout the year. In Panama, the naranjilla has made
good growth at altitudes from 4,000 to 6,000 ft (1,200-1,800 m). It is
grown in southern Florida at near sea-level. The best plantations in
Ecuador are between 5,000 and 6,000 ft (1,500-1,800 m), where the mean
temperature is 62.6º to 66.2º F (17º-19º C). The naranjilla cannot
tolerate temperatures over 85º F (29.4º C). It is not adapted to full
sun but favors semi-shade.
Soil
The plant does best in a rich, organic soil; also grows well on poor,
stony ground, and on scarified limestone. It must have good drainage.
In Latin America, naranjillas are planted on virgin soil in tracts
where the large trees have been felled and the undergrowth burned off.
The remaining trees provide semi-shade and wind protection.
Propagation
The naranjilla
can be propagated by air-layering or by cuttings of mature wood. In
Latin America, it is commonly grown from seeds which must first be
spread out in the shade to ferment slightly to eliminate the mucilage,
then washed, air-dried, and dusted with fungicide. There are about
140,000 seeds to the pound (.5 kg); 9,000 to the ounce (28 g).
Seedlings are raised in nurseries by the same methods appropriate for
tomato seedlings, and are ready for transplanting in 2 to 3 months.
In Florida, the naranjilla is easily cleft-grafted onto S. macranthum
seedlings that have grown 2 ft (60 cm) tall and have been cut back to 1
ft (30 cm) from the ground, then split down the center for a distance
of 1 to 2 in (2.5-5 cm). Selected scions 2 to 3 in (5-7.5 cm) long are
inserted in the slit and tightly bound in place. It takes 2 to 3 weeks
for the scion to fully unite with the stock. The plants are not set out
until the scion has grown about 2 ft (30 cm). Other grafting
methods–saddle, side, and whip–have also been successful.
Trials on tree tomato (Cyphomandra betacea Sendt.) seemed promising in 1952. In tropical Africa, the naranjilla has done well on the nematode-resistant relative, S. torvum Sw.
Culture
Naranjilla plants
should be set 6 to 8 ft (1.8-2.4 m) apart each way, which provides
1,250 plants per acre (3,000/ha). Colombians transplant young seedlings
from the nursery bed into polyethylene bags containing 5 1/2 lbs. (2.5
kg) of soil, keep them in semi-shade, give them ½ oz (14 g) of
super-phosphate and frequent irrigation. When 14 in (35 cm) high, they
are set out in holes enriched with 8.8 lbs (4 kg) of organic compost,
breaking the plastic bag as they place the plant in the hole. In Latin
America, generally, the naranjilla is planted out in the afternoon of a
cloudy day at the beginning of the rainy season. The planting hole is
12 x 12 x 12 in (30 x 30 x 30 cm) and a circle at least 3 ft (1 m) in
diameter is kept free of weeds. The plant is a heavy feeder and growth
is rapid if fertilizer is given once a month, though most plantations
are given no such nutritional care. A 12-12-20 mixture of NPK at the
rate of 3 oz (85 g) per plant every 2 months has been recommended. In
the coffee zone of Caldas, Colombia, where the soil is organically rich
but low in phosphorus, the addition of urea, superphosphate and
potassium sulphate, has been found to double productivity.
Seedlings
flower 4 to 5 months after transplanting. Fruiting begins 10 to 12
months from seed and is continuous for 3 years in Panama. When the
plants reach 4 years of age, productivity declines and they begin to
die. In Costa Rica, they are said to bear until 4 to 7 years old.
Grafted plants begin to bear about 1 year from planting in the field.
In Florida, they continue fruiting for 2 years, then they die back and
are replaced by young ones. Watering is essential in dry periods.
Harvesting and Yield
Though
everbearing in its natural habitat, the naranjilla fruits mainly in the
winter in Florida; rarely, or very lightly, in the summer. For eating
out-of-hand, the fruits are picked fully ripe, at which stage the calyx
naturally separates from the fruit, leaving a circular depression. In
the field, workers remove the hairs by stooping down and rubbing the
fruit in dry grass. For marketing, the fruits must be picked when
half-colored to avoid falling and bruising and to assure they are firm
enough to withstand handling and packing. They are individually cleaned
with a dry cloth and then packed in wooden boxes holding 400
fruits–about 70 lbs (32 kg).
In large-scale processing
operations, there are mechanized devices for inspection and grading of
fruits, washing off the hairy coat, drying, and removing the peduncle
and calyx. For underripe fruits with firmly adhering hairs, the machine
must be equipped with brushes. Because of the continuous bearing,
fruits must be collected every 7 to 10 days. In Ecuador, long trains of
mules and burros make weekly trips with sacks and boxes of naranjillas
down the trails to central market places.
A healthy plant bears
100 to 150 fruits a year. A good annual yield is 135 fruits–20 lbs (9
kg)–per plant. This results in 25,000 lbs (10,417 kg) per acre, 60,000
lbs (27,273 kg) per hectare.
Keeping Quality
Fully
ripe naranjillas soften and ferment very quickly. Fruit picked when
half colored will remain in good condition at ordinary temperatures for
8 days. They can be stored for 1 or 2 months at 45°-50° F (7.22°-10° C)
and relative humidity of 70 to 80%.
Pests and
Diseases
The chief enemies of the naranjilla are the rootknot nematodes (Meloidogyne
sp.) and grafting on nematode-resistant rootstock is essential to fruit
production in southern Florida. In the Chinchiná coffee-growing region
of Caldas, Colombia, nematicide-treatment of the soil each time it is
invaded is considered too expensive, and the plants can therefore be
kept in production only one year before they succumb to nematode
damage. Nematodes are causing a drop in naranjilla production in
various parts of the country and Dr. Charles Heiser of Indiana
University is studying the possibility of hybridization with
nematode-resistant wild relatives in order to save the industry.
Measures to reduce nematode populations in Guatemalan fields include
discarding nursery seedlings and adult plants that show typical
symptoms (chlorosis, dwarfing, rachitic appearance), mulching, or
frequent plowing during hot, dry spells. In Panama, the main stem and
branches, and sometimes even the fruits, of mature plants are attacked
by the cochinilla blanca (white, or West Indian, peach scale, Pseudaulacaspis pentagona).
A number of other pests and diseases affect naranjilla plants in Colombia. Bacterial wilt is a serious problem in Puerto Rico.
Fig. 113: Naranjilla (Solanum quitoense) juice is most prized fresh or preserved, but some is made into wine in Colombia.
Food Uses
Ripe naranjillas,
freed of hairs, may be casually consumed out-of-hand by cutting in half
and squeezing the contents of each half into the mouth. The empty
shells are discarded. The flesh, complete with seeds, may be squeezed
out and added to ice cream mix, made into sauce for native dishes, or
utilized in making pie and various other cooked desserts. The shells
may be stuffed with a mixture of banana and other ingredients and
baked. But the most popular use of the naranjilla is in the form of
juice. For home preparation, the fruits are washed, the hairs are
rubbed off, the fruits cut in half, the pulp squeezed into an electric
blender and processed briefly; then the green juice is strained,
sweetened, and served with ice cubes as a cool, foamy drink. A dozen
fruits will yield 8 oz (227 g) of juice. Commercially, the juice is
extracted mechanically from the cleaned and chopped fruits, strained,
concentrated and canned or put into plastic bags and frozen.
Sherbet
is made in the home by mixing naranjilla juice with corn sirup, sugar,
water, and a little lime juice, partially freezing, then beating to a
froth and freezing. Naranjilla jelly and marmalade are produced on a
small scale in Cali, Colombia.
| Food
Value Per
100 g of Edible Portion* |
| Calories
|
23 |
| Moisture
|
85.8-92.5 g |
| Protein |
0.107-0.6 g |
| Carbohydrates | 5.7 g |
| Fat |
0.1-0.24g
|
| Fiber |
0.3-4.6 g
|
| Ash |
0.61-0.8g
|
| Calcium |
5.9-12.4 mg
|
| Phosphorus |
12.0-43.7 mg
|
| Iron |
0.34-0.64 mg
|
| Carotene |
0.071-0.232 mg (600 I.U.)
|
| Thiamine |
0.04-0.094 mg
|
| Riboflavin | 0.03-0.047 mg | | Niacin | 1.19-1.76 mg | | Ascorbic Acid | 31.2-83.7 mg |
| *According
to analyses of fresh fruits in Colombia and Ecuador. |
|
Toxicity
People with very sensitive skin may find the hairs on the fruits
irritating and should protect the hands when rubbing off the fuzz.
Closely Related
Species
Dr.
Charles Heiser has made a survey of wild relatives of the naranjilla in
the hope that one or more of them may be used in cross-breeding to
incorporate nematode-resistance without adversely affecting the fruit
quality, productivity and other desirable characteristics. He found S. tequileme A. Gray most like S. quitoense.
It is native from central Mexico to central Ecuador, usually between
3,200 and 6,200 ft (1,000-1,900 m) of elevation, and its fruit is
sometimes eaten though its hairy coat is more persistent than that of
the naranjilla. Fertile hybrids of the two species have been achieved.
Among other wild species reported by Heiser as having edible, naranjilla-like fruits: S. pseudolulo
Heiser, of Colombia, with cream-colored flesh and short hairs which are
readily shed. The fruits are gathered and sold by local vendors. This
species, also, has made fertile hybrids with S. quitoense.
S. candidum
occurring in lowland areas from Mexico to northern Peru and called
huevo de gato. The juice is less flavorful than that of the naranjilla
and the hairs do not detach readily.
S. pectinatum Dunal (syn. S. hirsutissimum
Standl.), often a small tree, ranges from Mexico to Venezuela and Peru,
is known variously as lulita, lulo de la tierra fria, toronja, or tumo.
It has juice of fine flavor but is handicapped by persistent hairs and
the fruit reportedly contains alkaloids which may hinder its
exploitation. The spiny plant is a local folk-remedy for hypertension.
The inedible S. hirtum
Vahl., huevo de gato, found wild in Trinidad and Tobago, Yucatan,
Central America, Colombia and Venezuela, is nematode-resistant and
hybrids of this species and S. quitoense
retain this character and have moderately good fruits. Dr. Heiser is
encouraging further efforts at cross-breeding in Colombia and Costa
Rica.
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