From the book
Fruits of Warm Climates
by Julia F. Morton
Passionfruit
Passiflora
edulis Sims
PASSIFLORACEAE
Of the estimated 500 species of Passiflora, in the family
Passifloraceae, only one, P. edulis Sims, has the exclusive designation
of passionfruit, without qualification. Within this species, there are
two distinct forms, the standard purple, and the yellow, distinguished
as P. edulis f. flavicarpa Deg., and differing not only in color but in
certain other features as will be noted further on.
General names for both in Spanish are granadilla, parcha, parchita,
parchita maracuyá, or ceibey (Cuba); in Portuguese, maracuja peroba; in
French, grenadille, or couzou. The purple form may be called purple,
red, or black granadilla, or, in Hawaii, lilikoi; in Jamaica, mountain
sweet cup; in Thailand, linmangkon. The yellow form is widely known as
yellow passionfruit; is called yellow lilikoi in Hawaii; golden
passionfruit in Australia; parcha amarilla in Venezuela.
Fig. 91: Purple passionfruit (Passiflora
edulis) is subtropical, important in some countries, while
the more tropical yellow passionfruit excels in others. Both yield
delicious juice.
Description
The passionfruit vine is a shallow-rooted, woody, perennial, climbing
by means of tendrils. The alternate, evergreen leaves, deeply 3-lobed
when mature, are finely toothed, 3 to 8 in (7.5-20 cm) long, deep-green
and glossy above, paler and dull beneath, and, like the young stems and
tendrils, tinged with red or purple, especially in the yellow form. A
single, fragrant flower, 2 to 3 in (5-7.5 cm) wide, is borne at each
node on the new growth. The bloom, clasped by 3 large, green, leaflike
bracts, consists of 5 greenish-white sepals, 5 white petals, a
fringelike corona of straight, white-tipped rays, rich purple at the
base, also 5 stamens with large anthers, the ovary, and triple-branched
style forming a prominent central structure. The flower of the yellow
is the more showy, with more intense color. The nearly round or ovoid
fruit, 1 1/2 to 3 in (4-7.5 cm) wide, has a tough rind, smooth, waxy,
ranging in hue from dark-purple with faint, fine white specks, to
light-yellow or pumpkin-color. It is 1/8 in (3 mm) thick, adhering to a
1/4 in (6 mm) layer of white pith. Within is a cavity more or less
filled with an aromatic mass of double-walled, membranous sacs filled
with orange-colored, pulpy juice and as many as 250 small, hard,
dark-brown or black, pitted seeds. The flavor is appealing, musky,
guava-like, subacid to acid.
Origin and
Distribution
The purple passionfruit is native from southern Brazil through Paraguay
to northern Argentina. It has been stated that the yellow form is of
unknown origin, or perhaps native to the Amazon region of Brazil, or is
a hybrid between P. edulis and P. ligularis (q.v.). Cytological studies
have not borne out the hybrid theory. Speculation as to Australian
origin arose through the introduction of seeds from that country into
Hawaii and the mainland United States by E.N. Reasoner in 1923. Seeds
of a yellow-fruited form were sent from Argentina to the United States
Department of Agriculture in 1915 (S.P.I. No. 40852) with the
explanation that the vine was grown at the Guemes Agricultural
Experiment Station from seeds taken from fruits purchased in Covent
Garden, London. Some now think the yellow is a chance mutant that
occurred in Australia. However, E.P. Killip, in 1938, described P.
edulis in its natural range as having purple or yellow fruits.
Brazil has long had a well-established passionfruit industry with
large-scale juice extraction plants. The purple passionfruit is there
preferred for consuming fresh; the yellow for juice processing and the
making of preserves.
In Australia, the purple passionfruit was flourishing and partially
naturalized in coastal areas of Queensland before 1900. Its
cultivation, especially on abandoned banana plantations, attained great
importance and the crop was considered relatively disease-free and
easily managed. Then, about 1943, a widespread invasion of Fusarium
wilt killed the vines and forced the undertaking of research to find
fungus-resistant substitutes. It was discovered that the neglected
yellow passionfruit is both wilt-and nematode-resistant and does not
sucker from the roots. It was adopted as a rootstock and plants
propagated by grafting were soon made available to planters in
Queensland and northern New South Wales.
The Australian taste is strongly prejudiced in favor of the purple
passionfruit and growers have been reluctant to relinquish it
altogether. Only in the last few decades have they begun to adopt
hybrids of the purple and yellow which have shown some ability to
withstand the serious virus disease called "woodiness".
New Zealand, in the early 1930's, had a small but thriving purple
passionfruit industry in Auckland Province but in a few years the
disease-susceptibility of this type brought about its decline. Good
local marketing and export prospects have brought about a revival of
efforts to control infestations and increase acreage, mostly in the Bay
of Plenty region. Today, fruits and juice are exported. A profitable
purple passionfruit industry has developed also in New Guinea.
In Hawaii, seeds of the purple passionfruit, brought from Australia,
were first planted in 1880 and the vine came to be popular in home
gardens. It quickly became naturalized in the lower forests and, by
1930, could be found wild on all the islands of the Hawaiian chain. In
the 1940's, a Mr. Haley attempted to market canned passionfruit juice
in a small way but the product was unsatisfactory and his effort was
terminated by World War II. A processor on Kauai produced a concentrate
in glass jars and this project, though small, proved successful. In
1951, when Hawaiian passionfruit plantings totalled less than 5 acres
(2 ha), the University of Hawai'i chose this fruit as the most promising
crop for development and undertook to create an industry based on
quick-frozen passionfruit juice concentrate. From among Mr. Haley's
vines, choice strains of yellow passionfruit were selected. These gave
four times the yield of the purple passionfruit and had a higher juice
content. By 1958, 1,200 acres (486 ha) were devoted to yellow
passionfruit production and the industry was firmly established on a
satisfactory economic level.
Commercial culture of purple passionfruit was begun in Kenya in 1933
and was expanded in 1960, when the crop was also introduced into Uganda
for commercial production. In both countries, the large plantations
were devastated several times by easily-spread diseases and pests. It
became necessary to abandon them in favor of small and isolated
plantings which could be better protected.
South Africa in 1947 produced 2,000 tons of purple passionfruit for
domestic consumption. Production was doubled by 1950. In 1965,
passionfruit plantations were initiated over large areas of the
Transvaal to meet the market demand and apparently there have been no
serious setbacks as yet, from disease or other causes.
India, for many years, has enjoyed a moderate harvest of purple
passionfruit in the Nilgiris in the south and in various parts of
northern India. In many areas, the vine has run wild. The yellow form
was unknown in India until just a few decades ago when it was
introduced from Ceylon and proved well adapted to low elevations around
Madras and Kerala.
It was quickly approved as having a more pronounced flavor than the
purple and producing within a year of planting heavier and more regular
crops.
The purple passionfruit was introduced into Israel from Australia early
in the 20th Century and is commonly grown in home gardens all around
the coastal plain, with small quantities being supplied to processing
factories.
Passionfruit vines are found wild and cultivated to some extent in many
other parts of the Old World–including the highlands of Java, Sumatra,
Malaya, Western Samoa, Norfolk Islands, Cook Islands, Solomon Islands,
Guam, the Philippines, the Ivory Coast, Zimbabwe and Taiwan. From
several of these sources, considerable quantities of yellow
passionfruit juice and pulp are exported to Australia, causing some
protests from Queensland growers. The yellow passionfruit was
introduced into Fiji from Hawaii in 1950, was distributed to farmers in
1960 and became the basis of a small juice-processing industry. Fiji
has exported to Australia, New Zealand, and Canada as well as to nearby
islands.
In South America, interest in yellow passionfruit culture intensified
in Colombia and Venezuela in the mid-1950's and in Surinam in 1975. In
Colombia, there are commercial plantations mainly in the Cauca Valley.
YELLOW PASSIONFRUIT, Passiflora
edulis var. flavicarpa
Since the introduction of the yellow
passionfruit from Brazil into Venezuela in 1954, it has achieved
industrial status and national popularity. Much effort is being devoted
to improving the yield to better meet the demand for the extracted
juice, passionfruit ice cream, and other appealing products such as
bottled passionfruit-and-rum cocktail.
The purple passionfruit was naturalized in the Blue Mountains of
Jamaica by 1913, and both the purple and the yellow are planted to some
extent in Puerto Rico.
Various species of Passiflora have reached the United States Plant
Introduction Station (now the Subtropical Horticulture Research Unit)
in Miami, Florida, in the routine course of plant accession. Some vines
were known to exist and bear fruit year after year here and there in
the southern and central areas of the state since 1887 or earlier. In
1953, I requested seeds of good strains of the purple and yellow forms
from the Queensland Department of Agriculture and Stock and gave seeds
to experimenters. In 1955, one yellow-fruited vine from these seeds was
flourishing at Pinecrest and, from the reports of hunters camping
beyond that locality, it appears that bird-transported seeds have
produced fruiting vines in outlying Everglades hammocks. In 1957, a
very fruitful specimen was thriving at the home of Benjamin Blumberg in
Coconut Grove, and an escape was bearing unusually large fruits in the
treetops of a natural hammock a few miles away.
At this time, the purple passionfruit was being grown successfully by a
homeowner further north, at Land O'Lakes, Pasco County, and the seeds
were advertised for sale. There were small plantations of purple
passionfruit in San Diego County, California, the fruits being sold on
the fresh fruit market and also processed for juice. However, there was
little interest in developing either form as a crop in the United
States. At the University of Florida's Subtropical Experiment Station
in Homestead, Florida, limited trials with the purple and yellow forms
resulted in words of discouragement, the purple vine in particular
having proved so susceptible to disease. Certain vines at the Plant
Introduction Station had died from Fusarium attack and the survivors
showed poor fruiting performance.
Dr. Robert Knight and Harold F. Winters of the United States Department
of Agriculture prepared two reports on the pollination of the yellow
passionfruit and the problems affecting yield. They expressed a dim
view of economical juice production and the need for extensive field
studies. They offered plant material to anyone qualified to undertake
such work. The Minute Maid Company established a test plot of the
yellow form at Indiantown in 1965. They found the fruit entirely
satisfactory for processing but abandoned the project 2 years later,
stating: "The yields are not as large as in more tropical areas where
the plant remains productive all year round. Our plants went out of
production during the winter season. During the windy spring months of
March and April, the vines are badly damaged and no flowers are set
until sometime in May. We also found that the passionfruit were
expensive to harvest. The fruit has to fall on the ground and sometimes
it gets hung up in the vines. There is a continual collection of small
quantities of fruit throughout the [bearing] year * Special equipment
is needed to obtain the juice from the fruit without bits of the calyx
showing up as objectionable black specks. This equipment is costly and
can only be justified when a large volume of fruit is being processed."
In 1965, the Laboratorie de Recherche des Produits Nestlé, Vevey,
Switzerland, placed the passionfruit among the three
insufficiently-known tropical fruits having the greatest potential for
nectar processing for the European market. It is obvious, then, that in
spite of the handicaps of passionfruit culture, the crop offers
revenue-earning opportunities for developing countries with low labor
costs.
YELLOW PASSIONFRUIT, Passiflora
edulis var. flavicarpa
Varieties
The yellow form has a more vigorous vine and generally larger fruit
than the purple, but the pulp of the purple is less acid, richer in
aroma and flavor, and has a higher proportion of juice-35-38%. The
purple form has black seeds, the yellow, brown seeds.
The following are some of the older cultivars as well as some of the
more recent:
'Australian Purple',
or 'Nelly Kelly'–a purple selection of mild, sweet flavor, grown in
Australia and Hawaii.
'Common Purple'–the
form growing naturalized in Hawaii; thick-skinned, with small seed
cavity, but of fine flavor and low acidity.
'Kapoho Selection'–a
cross of 'Sevcik' and other yellow strains in Hawaii. A heavy bearer of
large fruits but subject to brown rot; many fruits contain little or no
pulp and the juice has the off-flavor of 'Sevcik' though not as
pronounced.
'Pratt Hybrid'–apparently
a natural cross between the 'Common Purple' and a yellow strain;
subject to rot, but juice is of fine color and flavor, low in acid.
'Sevcik Selection'–a
golden form of the yellow selected in Hawaii; a heavy bearer, but
subject to brown rot and the juice has a peculiar woody flavor.
'University Round
Selection'–Hawaiian crosses of 'Waimanalo' and 'Yee'–fruit
smaller than 'Yee'; not as attractive but yields 10% more juice of very
good flavor.
'University Selection No.
B-74'–a Hawaiian hybrid between 'Pratt' and 'C-77',
usually yellow, occasionally with red tinges; resembles 'Waimanalo';
has good juice yield and very good flavor.
'Waimanalo Selection'–consists
of 4 strains: 'C-54', 'C-77', 'C-80', of similar size, shape, color and
very good flavor, and 'C-39' as pollinator.
'Yee Selection'–yellow,
round, very attractive, highly disease-resistant, but fruit has thick
rind and low yield of juice which is of very good flavor.
What may be a great improvement over any of the above is the cultivar
known as 'Noel's Special'. It is a yellow passionfruit selected in 1968
from open-pollinated seedlings of a vine discovered at an abandoned
farm on Hilo, Hawaii, by Noel Fujimoto in the early 1950's. The fruit
is round, averages 3.17 oz (90 g); the cavity is filled with
dark-orange pulp yielding 43 to 56% bright-orange, richly flavored
juice. The vine is vigorous, begins to bear in one year, and is
tolerant to brown spot. It produces 88% marketable fruit in a season–a
higher proportion than any other cultivar.
In 1967, two purple X yellow hybrids–'3-1' and '3-26', developed at the
Redlands Horticulture Research Station, Queensland, had nearly replaced
the purple passionfruit in commercial plantations on the coast of
southern Queensland and New South Wales. They have a longer fruiting
season than the purple, are high-yielding, with high pulp content, keep
very well, and meet with little market resistance. Australian breeders
continued to strive for a type that would have the needed
characteristics and reproduce true from seed. Hybrid '23-E' followed.
By 1981, hybrid '3-1' had succumbed to a new, more virulent strain of
"woodiness" virus and had to be abandoned. Other popular hybrids are
'Lacey' and 'Purple-gold'.
In early 1980, several purple passionfruit hybrids, all
insect-pollinated, were introduced into the island of Niue, as possible
substitutes for the yellow form cultivated commercially there for
export since 1955, with the view of eliminating the labor of
hand-pollination required by the yellow for top production. However,
the hybrids are more susceptible to mealybug infestation.
One New Zealand grower has exported purple passionfruits to the United
States under the trade name of 'Bali
Hai'.
Commercial cultivars of the purple form in Brazil include 'Ouropretano', 'Muico', 'Peroba', and 'Pintado'; of the
yellow form, 'Mirim'
or 'Redondo',
and 'Guassu'
or 'Grande'.
In the Cauca Valley of Colombia, the best-performing yellow
passionfruit is the 'Hawaiiana'.
Venezuelan growers favor the 'Hawaiiana', 'Brasilera amarilla', and the
purple-fruited 'Brasilera rosada'.
A highly promising hybrid, 'M-21471A' has been developed by Dr. R.J.
Knight at the United States Department of Agriculture's Subtropical
Horticulture Research Station, Miami. The fruit is maroon, weighs about
3 oz (85 g); is close to the purple parent in quality; is
self-compatible and resists soil-borne diseases like its yellow parent.
F1 hybrids may be reddish-purple with more conspicuous white dots than
on the purple parent, and sometimes there is a tinge of yellow in the
background. F2 hybrids show three variations of purple and are
difficult to distinguish from the purple parent.
Fig. 92: Flowers of the purple passionfruit are fragrant and lovely,
though those of the yellow are richer in color.
Pollination
Yellow passionfruit flowers are perfect but self-sterile. In controlled
pollination studies at the College of Agriculture of Jaboticabal, Sao
Paulo, Brazil, it was found that the yellow passionfruit has three
types of flowers according to the curvature of the style: TC (totally
curved), PC (partially curved), and SC (upright-styled). TC flowers are
most prevalent.
Carpenter bees (Xylocopa megaxylocopa frontalis and X. neoxylocopa)
efficiently pollinated TC and PC flowers. Honey bees (Apis mellifera
adansonii) were much less efficient. Wind is ineffective because of the
heaviness and stickiness of the pollen. SC flowers have fertile pollen
but do not set fruit. To assure the presence of carpenter bees, it is
wise to have decaying logs among the vines to provide nesting places.
Carpenter bees will not work the flowers if the nectary is wet. If rain
occurs in 1 1/2 hrs after pollination, there will be no fruit set, but
if 2 hrs pass before rain falls, it will have no detrimental effect. In
the absence of carpenter bees in Fiji, farmers cross-pollinate by hand,
treating 600 flowers an hour, with 70% fruit set and 60% of fruit
reaching maturity.
The purple form blooms in spring and early summer (July-November) in
Queensland and again for a shorter period in fall and early winter
(February-April). In Florida, blooming occurs from mid-March through
April. The flowers open early in the morning (about dawn) and close
before noon, and are self-compatible. The yellow form has one flowering
season in Queensland (October-June). In Florida, blooming has occurred
from mid-April to mid-November. The flowers open around noon and close
about 9 to 10 PM and are self-incompatible.
In crossing the yellow and purple forms, it is necessary to
use the purple as the seed parent because the flowers of the yellow are
not receptive to the pollen of the purple, and an early-blooming yellow
must be utilized in order to have a sufficient overlapping period for
pollen transfer. Dr. R.J. Knight has suggested lengthening the overlap
by exposing the yellow to artificial light for 6 weeks before the
normal flowering season. However, despite the seasonal and hourly
differences, natural hybrids between the two forms occur in South
Africa, Queensland and in Hawaii. Growers of purple passionfruit in
South Africa are warned not to take seed from any vine in proximity to
a planting of yellow passionfruit, otherwise the seedlings are apt to
produce hybrid fruit of inferior quality.
In some areas, trellis-grown vines of the yellow passionfruit require
hand-pollination to assist fruit set. In the home garden, at least two
vines of different parentage should be planted and allowed to
intertwine for cross-pollination.
Climate
The purple passionfruit is subtropical. It grows and produces well
between altitudes of 2,000 and 4,000 ft (650-1,300 m) in India. In
Java, it grows well in lowlands but will flower and fruit only above
3,200 ft (1,000 m). In west-central Florida, at 28º N latitude and
slightly above sea-level, 3-year-old vines have survived freezing
temperatures with the lower 3 ft (.9 m) of the stems wrapped in
fiberglass 4 in (10 cm) thick. The upper parts suffered cold injury,
were cut back, the vines were heavily fertilized, recovered rapidly and
fruited heavily the second summer thereafter.
The yellow passionfruit is tropical or near-tropical. In Western Samoa,
it is grown from near sea-level up to an elevation of 2,000 ft (600 m).
Both forms need protection from wind. Generally, annual rainfall should
be at least 35 in (90 cm), but in the Northern Transvaal, in South
Africa, there is reduced transpiration because of high atmospheric
humidity and commercial culture is carried on with precipitation of
only 24 in (60 cm). It is reported that annual rainfall in
passionfruit-growing areas of India ranges between 40 and 100 in
(100-250 cm).
Soil
Passionfruit vines are grown on many soil types but light to heavy
sandy loams, of medium texture are most suitable, and pH should be from
6.5 to 7.5. If the soil is too acid, lime must be applied. Good
drainage is essential to minimize the incidence of collar rot.
Propagation
Passionfruit vines are usually grown from seeds. With the yellow form,
seedling variation provides cross-pollination and helps overcome the
problem of self-sterility. Some say that the fruits should be stored
for a week or two to allow them to shrivel and become perfectly ripe
before seeds are extracted. If planted soon after removal from the
fruit, seeds will germinate in 2 to 3 weeks. Cleaned and stored seeds
have a lower and slower rate of germination. Sprouting may be hastened
by allowing the pulp to ferment for a few days before separating the
seeds, or by chipping the seeds or rubbing them with fine sandpaper.
Soaking, often recommended, has not proved helpful. Seeds are planted
1/2 in (1.25 cm) deep in beds, and seedlings may be transplanted when
10 in (25 cm) high. If taller–up to 3 ft (.9 in)–the tops should be cut
back and the plants heavily watered.
Some growers prefer layers or cuttings of matured wood with 3 to 4
nodes. Cuttings should be well rooted and ready for setting out in 90
days. Rooting may be hastened by hormone treatment. Grafting is an
important means of perpetuating hybrids and reducing nematode damage
and diseases by utilizing the resistant yellow passionfruit rootstock.
If seeds are available in the early spring, seedlings for rootstocks
can be raised 4 in (10 cm) apart in rows 24 in (60 cm) apart and the
grafted plants will be ready to set out in late summer. If seeds cannot
be obtained until late summer, the seedlings are raised and grafted in
pots and set out in the spring. Scions from healthy young vines are
preferred to those from mature plants. The diameter of the selected
scion should match that of the rootstock. Either a cleft graft, whip
graft, or side-wedge graft may be made.
If approach-grafting is to be done, a row of potted scions must be
placed close alongside the row of rootstocks so that the union can be
made at about 3/4 of the height of the plant.
Culture
Root-pruning should precede transplanting of seedlings by 2 weeks.
Transplanting is best done on a cool, overcast day. The soil should be
prepared and enriched organically a month in advance if possible.
Grafted vines must be planted with the union well above ground, not
covered by soil or mulch, otherwise the disease resistance will be
lost. Mounding of the rows greatly facilitates fruit collection.
In plantations, the vines are set at various distances, but studies in
Venezuela indicate that highest yields in yellow passionfruit are
obtained when the vines are set 10 ft (3 m) apart each way. In South
Africa, purple passionfruit vines are set 8 ft (2 1/2 m) apart in cool
areas, and 12 to 15 ft (3 1/2-4 1/2 m) apart in warm areas. Spacing of
purple passionfruit in Kenya has been 10 ft (3 m) between vines and 6
ft (1.8 m) between rows. Recent 3-year trials of 4 ft (1.2 m) between
rows, with light pruning the 2nd and 3rd years, resulted in the highest
yield (50% of the crop being home the first year). But it is recognized
that such close planting can lead to disease problems and replanting
after the 3rd year.
Commercially, vines are trained to strongly-supported wire trellises at
least 7 ft (2.13 m) high. However, for the benefit of the homeowner, it
should be pointed out that the yellow passionfruit is more productive
and less subject to pests and diseases if allowed to climb a tall tree.
After a vine of either the yellow or purple passionfruit attains 2
years of age, pruning once a year will stimulate new growth and
consequently more flower and fruit production. The average life of a
plantation in Fiji is only 3 years. Judicious pruning of lateral
branches after fruiting aids in disease control and can extend
plantation life to 5 or 6 years. In South Africa, at elevations between
4,000 and 4,800 ft (1,200-1,460 m), plantations are kept in full
production for as long as 8 years.
Regular watering will keep a vine flowering and fruiting almost
continuously. Least flowers develop during the winter season due to
short day length. Water requirement is high when fruits are approaching
maturity. If soil is dry, fruits may shrivel and fall prematurely.
Fertilizer (10-5-20 NPK) should be applied at the rate of 3 lbs (1.36
kg) per plant 4 times a year, under normal conditions. In India, trials
of purple passionfruit on red sandy loam with a pH of 6.5 and high
organic content, the optimum fertilizer treatment was found to be 290
lbs (132 kg) N and 69 1/2 lbs (31.6 kg) P per ha per year.
French horticulturists have reported that, in plantations on the Ivory
Coast, annual supplements of 8 oz (220 g) urea and 7 1/2 oz (210 g)
potassium sulfate per plant per year of age will have a highly
favorable effect on production. It is said that 32 to 36 oz (900-1,000
g) of nitrogen are required to produce 66 lbs (30 kg) of fruits, but
excessive nitrogen will cause premature fruit drop. Passionfruit vines
should always be watched for deficiencies, particularly in potassium
and calcium, and of less importance, magnesium.
The passionfruit vine, especially the yellow, is fast-growing and will
begin to bear in 1 to 3 years. Ripening occurs 70 to 80 days after
pollination. Injuries to the base of the vine, which allow entrance of
disease organisms, can be avoided by hand-weeding or the application of
herbicides around the main stems. These practices will also protect the
shallow root system. In Surinam, good weed control under trellises has
been achieved by covering the soil with black plastic.
Seasons and
Harvesting
The different flowering seasons of the purple and yellow passionfruits
have been mentioned under "Pollination". In some areas, as in India,
the vines bear throughout the year but peak periods are, first, August
to December, and, second, March to May. At the latter time, the fruits
are somewhat smaller, with less juice. In Hawaii, passionfruits mature
from June through January, with heaviest crops in July and August and
October and November. With variations according to cultivar, and with
commercial cultivation both above and below the Equator, there need
never be a shortage of raw material for processing.
Ripe fruits fall to the ground and will roll in between mounded rows.
They do not attract flies or ants but should be collected daily to
avoid spoilage from soil organisms. In South Africa, they are subject
to sunburn damage on the ground and, for that reason, are picked from
the vines 2 or 3 times a week in the summertime before they are fully
ripe, that is, when they are light-purple. At this stage, they will
reach the fresh fruit market before they wrinkle. In winter, only one
picking per week is necessary. For juice processing, the fruit is
allowed to attain a deep-purple color. In India and Israel the fruits
are always picked from the vine rather than being allowed to fall. It
has been found that fallen fruits are lower in soluble solids, sugar
content, acidity and ascorbic acid content.
The fruits should be collected in lugs or boxes, not in bags which will
cause "sweating". If not sent immediately to processing plants, the
fruits should be spread out on wire racks where there will be good air
circulation.
Yield
Many factors influence the yield of passionfruit vines. In general,
yields of commercial plantations range from 20,000 to 35,000 lbs per
acre (roughly the same number of kg per ha). In Fiji, with hand
pollination, 173 acres (70 ha) will yield 33 tons (30 MT) of fruits.
Hybrids in Australia have raised yields far beyond those obtained with
the purple passionfruit.
On the average, a bushel of passionfruits in Australia weighs 36 lbs
(16 kg); yields 13 1/3 lbs (6 kg) of pulp from which is obtained 1 gal
(3.785 liters)–that is 10.7 lbs (4.5 kg) of juice, and 2.6 lbs (1.18
kg) of seeds. With some strains, the juice yield is much higher.
Storage
Underripe yellow passionfruits can be ripened and stored at 68º F (20º
C) with relative humidity of 85 to 90%. Ripening is too rapid at 86º F
(30º C). Ripe fruits keep for one week at 36º to 45º F (2.22º-7.22º C).
Fruits stored in unperforated, sealed, polyethylene bags at 74º F
(23.1º C), have remained in good condition for 2 weeks. Coating with
paraffin and storing at 41º to 44.6º F (5º to 7º C) and relative
humidity of 85 to 90%, has prevented wrinkling and preserved quality
for 30 days.
Pests and
Diseases
In Hawaii and Australia, infestations of the passion vine mite
(Brevipalpus phoenicis) occur during dry weather in the warm season,
defoliate the younger portions of the vines but not the terminus, and
make brown blemishes on the fruits. The passion vine bug (Leptoglossus
australis) feeds on flowers and young, green fruits in Queensland. The
green vegetable bug, or stinkbug, (Nezara viridula) is a similar but
lesser menace to the plant and young fruits. Both the immature and the
adult stages suck the sap of the growing tips, as do the brown stinkbug
(Boerias maculata), the large black stinkbug (Anoplocnemis sp.) and the
small black stinkbug (Leptoglossus membranaceus).
In Florida, the yellow passionfruit is commonly found to be
superficially punctured by a stinkbug (Chrondrocera laticornis),
affecting only its appearance. Thrips (Thysanoptera sp.) injure and
cause stunting of young seedlings in nurseries. In dry weather, they
also feed on leaves and fruits, leaving them defaced and prone to
shrivel and fall prematurely. In East Africa, injury from the tobacco
white fly (Bemisia tabaci) may lead to galls on the leaves. Leaf
beetles (Haltica sp.) and weevils (Systates spp.) chew the foliage, and
cutworms behead seedlings in nurseries. Two lepidopterous pests, Dione,
or Agraulis, vanillae and Mechanitis variabilis are common in Colombia.
Among scales attacking the vine and petioles, white peach scale
(Pseudaulacaspis pentagona) is most troublesome in Queensland. Not as
prevalent are round purple scale (Chrysomphalus ficus) and granadilla
purple scale (Parasaissetia nigra). These pests may cause dieback of
the entire plant if not controlled. Red scale (Aonidiella aurantii) is
common on mature passion vines in Queensland. Soft brown scale (Coccus
hesperidum) is occasionally troublesome. The passion vine leaf hopper
(Scolypopa australis) requires protective measures. The citrus mealybug
(Planococcus citri) is a major Queensland pest in summer. Spraying,
unfortunately, kills its chief predator, the mealybug ladybird,
Cryptolaemus montrouzieri. The aphids, Aphis gossypii and Myzus
Persicae, transmit the virus which causes "woodiness" (see below).
There has been no report of attack by the Caribbean fruit fly
(Anastrepha suspensa) in Florida, though Anastrepha infestation was on
one occasion observed by Curtis Dowling in Passflora fruits in Costa
Rica. In Brazil, fruit flies of the genus Anastrepha, and in Hawaii the
Oriental fruit fly and the melon fly, deposit eggs in the very young,
tender fruits. In these, the larvae seem able to develop and cause the
immature fruits to shrivel and fall. If fruits are punctured when
nearly mature, the only effect is an external scar. The same is
reported concerning the dominant Queensland fruit fly (Dacus tryoni)
and the less common Mediterranean fruit fly (Ceratitis capitata) in
Australia.
In South Africa, purple passionfruit vines are damaged by several
species of nematodes. The most important, which causes extreme
thickening of the roots, is the root-knot nematode, Meloidogyne
javanica. Others include the spiral nematode (Scutellonema truncatum
and Helicotylenchus sp.), and the lesion nematode (Pratylenchus sp.).
The yellow passionfruit is nematode-resistant.
The main diseases of purple passion fruit in Australia are brown spot,
Septoria spot and base rot, Phytophthora blight, Fusarium wilt,
woodiness, and damping-off. Brown spot, caused by Alternaria
passiflorae in warm weather, is a major affliction of the purple
passionfruit also in New Zealand and East Africa. In Hawaii, brown spot
is the leading disease of the yellow passionfruit and A. tenuis was
found to be the dominant species associated with the disease in 1969.
A. macrospora has occasioned severe leaf spot and branch lesions in
India. A similar disease causing spotting and crinkling of leaves and
fruit first appeared in Ceylon in 1970. Septoria spot, from the fungus
Septoria passiflorae, most common in summer and fall, is evidenced by
more numerous and smaller spots than brown spot, on all parts of the
vine and on the fruits, and it is spread by rain, dew and overhead
irrigation. Some believe this fungus to be also the source of base rot,
often induced by injury from mowers or other mechanical equipment.
Phytophthora cinnamoni, the source of collar rot in Fiji, makes it
necessary to replace yellow passionfruit plantings there every 30 to 35
months. P. nicotinae var. parasitica has been linked to fatal blight,
or stem rot, and fruit rot in purple passionfruit vine, but not in the
yellow, in wet periods of summer and fall in Queensland and South
Africa. P. cinnamoni and P. nicotinae are responsible for root rot in
New Zealand and Western Australia, and the latter is identified with
wilt in South Africa and Sarawak, and with damping-off and leaf blight
in both the purple and the yellow passionfruits in India.
Fusarium wilt, arising from the soil-borne fungus, Fusarium oxysporium
f. sp. passiflorae, can be reduced only by grafting the purple, or,
better still, purple-yellow hybrids, onto the Fusarium-resistant yellow
passionfruit rootstock. However, Bedoya et al. have reported that, in
the zones of Palmira, Cerrito and Ginebra of the Cauca Valley of
Colombia, but not in the zone of Unión, collar rot limits the life of
yellow passionfruit plantations to 3 years, and they found, in
inoculation experiments, that Fusarium solani produced the symptoms.
The first signs are chlorosis, necrosis and defoliation; next there is
splitting of the trunk and separation of the bark. The root becomes
progressively discolored and red rays extend to the surface of the soil.
Nectria haematococca, or Hypomyces solani, the ascogenous state of
Fusarium solani, has been determined to be the organism girdling the
collar zone and bringing on sudden wilt of the purple passionfruit vine
in Uganda.
The virus disease, "woodiness", or "bullet", appearing as small
misshapen fruits with thick rind and small pulp cavity, has been the
most serious plague of the purple passionfruit in Australia and East
Africa, but it has little effect on the yellow form. The "woodiness"
virus (PWV) is also the source of tip blight in the coastal districts
of central Queensland. This virus has a wide host range, not only in
the genus Passiflora, but also weedy species in the families
Amaranthaceae, Chenopodiaceae, Cucurbitaceae and Solanaceae.
There are a number of different strains of the "woodiness" virus. For
many years, inoculation of passionfruit vines with mild strains
protected them from further infection, and commercial hybrids
containing small doses of mild strains were released to farmers. But,
in 1978, a new, more virulent, strain of virus appeared and overcame
the "mild strain protection". The New South Wales Passionfruit Growers
Association, in response to this new threat, established, in 1979, a
Passionfruit Scion Accreditation Scheme to "improve the quality of
planting material by field selection and provide scionwood free of the
severe strain of woodiness virus", for a standard fee. Generally, 100
scions can be taken from each accredited vine in a season. By 1981,
16,000 scions had been supplied to commercial growers.
In 1973, two mosaic viruses–PPMV-K and PFMVMY–said to differ from other
reported Passiflora viruses, were found to be prevalent in commercial
plantings of the yellow passionfruit in the Bantung district of
Selangor, Malaya. Damping-off is caused by Rhizoctonia solani and
Pythium spp. in Queensland. Thread blight of yellow passionfruit vine
in Fiji and Western Samoa, seen as patches of black, papery, shredded
leaves with gray to tan layer of merged "threads" beneath, has been
attributed to Rhizoctonia solani (also called Thanatephorus cucumeris).
It may invade the entire vine.
Food Uses
The fruit is of easy preparation. One needs only cut it in half
lengthwise and scoop out the seedy pulp with a spoon. For home use,
Australians do not trouble to remove the seeds but eat the pulp with
cream and sugar or use it in fruit salads or in beverages, seeds and
all. Elsewhere it is usually squeezed through two thicknesses of
cheesecloth or pressed through a strainer to remove the seeds.
Mechanical extractors are, of course, used industrially. The resulting
rich juice, which has been called a natural concentrate, can be
sweetened and diluted with water or other juices (especially orange or
pineapple), to make cold drinks. In South Africa, passionfruit juice is
blended with milk and an alginate; in Australia the pulp is added to
yogurt. After primary juice extraction, some processors employ an
enzymatic process to obtain supplementary "secondary" juice from the
double juice sacs surrounding each seed. The high starch content of the
juice gives it exceptional viscosity. To produce a freeflowing
concentrate, it is desirable to remove the starch by centrifugal
separation in the processing operation.
Passionfruit juice can be boiled down to a sirup which is used in
making sauce, gelatin desserts, candy, ice cream, sherbet, cake icing,
cake filling, meringue or chiffon pie, cold fruit soup, or in
cocktails. The seeded pulp is made into jelly or is combined with
pineapple or tomato in making jam. The flavor of passionfruit juice is
impaired by heat preservation unless it is done by agitated or "spin"
pasteurization in the can. The frozen juice can be kept without
deterioration for 1 year at 0º F (-17.78º C) and is a very appealing
product. The juice can also be "vacuum-puff" dried or freeze-dried.
Swiss processors have marketed a passionfruit-based soft drink called
"Passaia" for a number of years in Western Europe. Costa Rica produces
a wine sold as "Parchita Seco."
Food
Value Per 100 g of Edible Portion
(Purple passionfruit, pulp and seeds)* |
| Calories |
90 |
| Moisture |
75.1
g |
| Protein |
2.2
g |
| Fat
|
0.7
g |
| Carbohydrates |
21.2
g |
| Fiber |
? |
| Ash
|
0.8g |
| Calcium |
13
mg |
| Phosphorus |
64
mg |
| Iron
|
1.6
mg |
| Sodium |
28
mg |
| Potassium |
348
mg |
| Vitamin
A |
700
I.U. |
| Thiamine |
Trace |
| Riboflavin |
0.13
mg |
| Niacin |
1.5
mg |
| Ascorbic
Acid |
30
mg |
*According to U.S. Dept. Agr., ARS. |
|
The yellow passionfruit has somewhat less ascorbic acid than the purple
but is richer in total acid (mainly citric) and in carotene content. It
is an excellent source of niacin and a good source of riboflavin. Free
amino acids in purple passionfruit juice are: arginine, aspartic acid,
glycine, leucine, lysine, proline, threonine, tyrosine and valine.
Carotenoids in the purple form constitute 1.160%; in the yellow,
0.058%; flavonoids in the purple, 1.060%; in the yellow, 1.000%;
alkaloids in the purple, 0.012%; in the yellow, 0.700% (mainly harman),
and the juice is slightly sedative. Starch content of purple
passionfruit juice is 0.74%; of the yellow, 0.06%.
Toxicity
A cyanogenic glycoside is found in the pulp of passionfruits at all
stages of development, but is highest in very young, unripe fruits and
lowest in fallen, wrinkled fruits, the level in the latter being so low
that it is of no toxicological significance.
Other Uses
Commercial processing of the yellow passionfruit yields 36% juice, 51%
rinds, and 11% seeds.
Rind:
The rinds have a very low pectin content–only 2.4% (14% on a dry weight
basis). Nevertheless, it has been determined in Fiji that extraction of
pectin from the rinds–up to 5 tons (4.5 MT) annually–reduces the
otherwise burdensome problem of waste disposal. The rind residue
contains about 5 to 6% protein and could be used as a filler in poultry
and stock feed. In Brazil, pectin is extracted from the purple form
which has a better quality pectin than that in the yellow. In Hawaii,
the pectin is not extracted. Instead, the rinds are chopped, dried, and
combined with molasses as cattle or pig feed. They can also be
converted into silage.
Seeds:
The seeds yield 23% oil which is similar to sunflower and soybean oil
and accordingly has edible as well as industrial uses. Up to 3,400
gallons (13,000 liters) can be obtained per year in Fiji. The seed meal
contains about 12% protein and 50 to 55% fiber. It has been judged
unsuitable for cattle feed.
Analyses of the fresh rind show: moisture, 78.43-85.24%; crude protein,
2.04-2.84%; fat, 0.05-0.16%; crude starch, 0.75-1.36%; sugars (sucrose,
glucose, fructose), 1.64%; crude fiber, 4.57-7.13%; phosphorus,
0.03-0.06%; silica, 0.01-0.04%; potassium, 0.60-0.78 %; organic acids
(citric and malic), 0.15%; ascorbic acid, 78.3-166.2%. The outer skin
of the purple form contains 1.4 mg per 100 g of the anthocyanin
pigment, pelargonidin 3-diglucoside. There is also some tannin.
The composition of the air-dried seeds is reported as: moisture, 5.4%;
fat, 23.8%; crude fiber, 53.7%; protein, 11.1%; N-free extract, 5.1%;
total ash, 1.84%; ash insoluble in HC1, 0.35%; calcium, 80 mg; iron, 18
mg; phosphorus, 640 mg per 100 g.
The seed oil contains 8.90% saturated fatty acids; 84.09% unsaturated
fatty acids. The fatty acids consist of: palmitic, 6.78%; stearic,
1.76%; arachidic, 0.34%; oleic, 19.0%; linoleic, 59.9%; linolenic, 5.4%.
Medicinal Uses:
There is currently a revival of interest in the pharmaceutical
industry, especially in Europe, in the use of the glycoside,
passiflorine, especially from P. incarnata L., as a sedative or
tranquilizer. Italian chemists have extracted passiflorine from the
air-dried leaves of P. edulis.
In Madeira, the juice of passionfruits is given as a digestive
stimulant and treatment for gastric cancer.
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