Postharvest Handling of Passion Fruit
Postharvest
handling operations for marketing passion fruit are relatively simple,
although careful control is needed in the critical areas of harvesting
at the correct maturity, minimizing mechanical damage, and maintaining
appropriate temperature. Passion fruit can be stored for up to four weeks
but are susceptible to water loss, mechanical damage, and subsequent disease
development.
Export
Criteria
Passion fruit
for export need to be uniformly graded by size and color; the skin should
not be excessively wrinkled or pitted or show collapsed areas. Fruit should
also be juicy and sweet. Round fruit are normally preferred to oval fruit.
Varieties
The most
popular passion fruit is the purple type (Passiflora edulis Sims.), although
the yellow type (Passiflora edulis Sims. F. flavicarpa Degner.) is acceptable
in some markets. The yellow passion fruit has a more vigorous vine, and
the fruit is normally larger than the purple. However, the purple fruit
is less acidic, has a better aroma and flavor, and normally has a higher
juice content. The purple fruit has black seeds, and the yellow fruit
has brown seeds. There are several commercial cultivars, some of which
show resistance to disease and pests occurring during production. These
include the following:
| Cultivar |
Color Fruit |
Country of Origin |
| Waimanalso (four strains) strains |
Purple |
Hawaii |
| Lacey; Purple-Gold |
Purple |
Australia/td>
|
| Ouropretano; Peroba |
Purple |
Brazil |
| Mirim; Guassu |
Yellow |
Brazil |
| Hawaiiana |
Yellow |
Colombia |
The yellow and purple varieties are species of the subgenus Grenadilla;
there are more than 60 other Passiflora species with edible fruits.
Harvest
Maturity
 Many producers of passion
fruit used for processing harvest following naturally occurring abscission,
and the fruit are collected from the ground. The time between flowering
and abscission varies between the purple and yellow forms, and the production
conditions from 50 to 100 days.
For fresh-fruit exports,
harvesting must take place before abscission occurs naturally. The color
stage at harvest depends on the storage time, but if harvested too young,
the fruit have poor flavor. Passion fruit begin accumulating soluble solids
and organic acids 14 days before natural abscission; color changes may begin
7 to 21 days before abscission. As a result, to obtain maximum flavor and
storage life, growers should harvest fruit from the vine with a minimum
of 50 percent color and an optimum of 75 percent purple or yellow color.
Green fruit or fruit with limited color should not be harvested because
they may not ripen unless ethylene treatment is given, or they will ripen
with poor flavor and color. The passion fruit is a climacteric fruit, and
there is a direct relationship between age at harvest and the speed and
timing of ripening.
Harvesting 
Harvesting is normally
carried out 6 to 9 months after transplanting, with full bearing achieved
after 18 months. The timing depends on the transplanting techniques and
the production conditions. There are two to three crops annually; the main
harvest takes place during summer, with smaller crops following, but limited
quantities of fruit are available for harvest throughout the year.
As mentioned, abscissed
fruit can be collected from the ground, but they should be used for export
only if they show the required coloration and quality, and if harvesting
is carried out two to three times a week. Fallen fruit rapidly lose 10 to
20 percent of their fresh weight because of water loss. For the fresh-fruit
market, it is preferable that fruit be harvested directly from the vine
with 50 to 75 percent coloration (yellow or purple); such fruit have a longer
storage life and are less likely to spoil. Harvesters should use secateurs
or a sharp knife, leaving up to 3 centimeters of stem intact, to help prevent
water loss and fungal development. The fruit should not be pulled from the
plant or the stem cut too close to the fruit.
After harvest, fruit
should be carefully placed into shallow plastic field crates lined with
foam, which prevents bruising. To prevent heat damage, harvesters should
leave crates in the shade before transporting them to the packing facility.
Fruit harvested in wet conditions and stored in unventilated crates or sacks
rapidly spoil. Water loss can be prevented if the time between harvesting
and packing is kept to a minimum. All fruit showing signs of disease, insect
damage, or overripeness should be left in the field and not transported
or mixed with export-quality fruit. Damaged fruit should be collected and
processed separately; separation will prevent cross infection and contamination,
and it will improve efficiency in the packhouse.
Packhouse
Operations
Packhouse facilities
and operations can range from basic wash tanks and grading tables to highly
sophisticated systems featuring automated washing and size grading. Although
pre-grading is carried out in the field, outgrading is required at the packhouse
to remove fruit that do not meet specifications, particularly those that
have fresh mechanical damage.
Fruit are removed from
the field crates and placed directly into water tanks. They are wiped with
a clean, damp cloth, separated by size, and Chlorinated water can be used
in tanks and washing systems (100 parts per million), but postharvest fungicide
treatments for disease control are not normally used.
Grading
After fruit
are cleaned, they are rechecked before they are separated into groups
for packing by count. This classification is based on diameter, ranging
between 50 and 80 millimeters. Classification may also be made by color,
for example 50 percent color or 75 percent color. Separate grading tables
for each size classification are used to increase packing efficiency:
packers then focus on packing and do not have to search for fruit of similar
sizes.
Packing
Only fruit in the same
size category and stage of ripeness should be packed in the same carton.
Product uniformity is essential. Passion fruit are normally packed in single-layer
cartons or tray packs with 24 to 48 fruit per tray. Some markets sell double-layer
4-kilogram cartons with 46 to 48 fruit. Specialty markets prefer cartons
weighing as much as 7 kilograms, with fruit packed in several layers.
Mechanically graded
passion fruit are placed into trays that fit inside packing cartons. In
the trays, each fruit occupies a single cell that protects it from other
fruit and mechanical damage. If fruit are placed directly into the carton,
they should be packed with the stem in a uniform position‹for example, with
the stem below the fruit in the line next to it, or with the stem above
the preceding fruit.
Packaging
Single-layer, one-piece,
self-locking or two-piece, fully telescopic fiberboard cartons are preferred.
Plastic cells with specific counts inside the cartons can also be used.
Suggested external carton dimensions are 39.5 by 29.5 by 9.0 centimeters.
Ventilation holes are required for horizontal air movement if the fruit
are going into a cold room for cooling. If sea shipment is used, the carton
should also have vents for vertical ventilation.
Labeling requirements
vary by importing country and buyer. Labels may contain the following information:
€ Exporter and importer;
€ Country of origin;
€ Contents, variety, net weight; and
€ Grade, count, size, and ripeness at packing.
Storage and Transportation
Passion fruit can lose
up to 25 percent of their original weight during storage and transportation,
particularly if conditions are not optimum (that is, if fruit are exposed
to high temperature, low humidity, and high air movements). Passion fruit
benefit from rapid precooling after harvesting and packing. The sooner optimum
storage temperatures are achieved, the longer quality can be maintained
and water loss reduced. Forced-air precooling is the most suitable method,
although cold-room cooling is acceptable if box ventilation and stacking
are properly done.
Optimum storage conditions
are 7oC with 85 to 95 percent relative humidity. Passion fruit produce high
levels of ethylene and are sensitive to ethylene; therefore, care should
be taken to ventilate properly when passion fruit are stored with other
produce, particularly those sensitive to ethylene. Storage at temperatures
below 7oC causes internal discoloration and development of diseases, diminishes
flavors, and increases water loss. Passion fruit are normally transported
to market by aircraft, although some exporters ship by sea if the market
requires high volume and transport time is less than 14 days.
Published research suggests
storing passion fruit in modified atmosphere‹where temperature and the levels
of oxygen and carbon dioxide are controlled through use of plastic bags,
wax coatings, and fungicide treatments‹may extend storage life and prevent
water loss. This practice, however, is rarely used by commercial exporters
from developing countries because they lack the technology.
Potential
Postharvest Losses
Mechanical
Damage: Using inappropriate harvesting tools, dropping fruit into
crates, overfilling crates, and allowing stems to rub together or fruit
to move during field transport result in punctures, scars, and bruises.
During storage and ripening, these damaged areas promote rapid water loss
and serve as an entry point for fungal infection.
Pathological
Factors: The most serious disease in passion fruit is brown spot caused
by the fungus Alternaria passiflorae; other diseases include Penicillium
expansum, Aspergillus niger, Fusarium oxysporium, and Rhizopus nigricans.
Infections normally originate in the field and become apparent with mechanical
injury, chilling injury, high temperature, or other factors that cause
fruit stress. Stress factors and disease are minimized by good production
control, careful handling, and hygienic operations.
Low Temperatures:
Storage below 7oC for prolonged periods results in internal discoloration,
pitting, and high water loss. Damage, particularly increased disease incidence,
becomes noticeable when the fruit are transferred from low to high temperatures.
Summary
Specifications for Passion Fruit Exports
| Varieties: |
Purple
and yellow types |
| Characteristics: |
Fruit should be round, fresh, glossy, uniform, and
50 to 75 percent purple or yellow. No shriveling or pitting is allowed
on export; limited, healed scars are allowed. No browning or discoloration
is permitted.
|
| Sizes: |
Fruit
are separated and packed according to size, resulting in different
counts per carton. The following fruit diameter ranges are guides
applicable to both purple and yellow varieties packed to 3.5 kilograms.
€
Small: 48 count ‹ 50-millimeter diameter
€
Medium: 36 count ‹ 65-millimeter diameter
€
Large: 24 count ‹ 80-millimeter diameter
A
10-millimeter variation above or below the specific diameter is
acceptable.
|
| Condition: |
€
No wounds from harvesting or handling should be present, including
punctures, scratches, and bruises.
€
Limited healed scars are acceptable, but should make up less
than 5 percent of the total surface, or less than 10 millimeters
long and 2 millimeters wide.
€
No fruit above the required color stage for shipment, maximum
75 percent color, is allowed.
€
No signs of shriveling should be present at shipment.
€
The stem should be intact.
€
No sooty mold or residual flower parts should be found on fruit.
|
| Market
Requirements: |
€
Most markets require the purple variety, although the yellow
variety is acceptable to some buyers.
€
Round fruit are normally preferred to oval fruit.
€
Uniformity in size and condition is essential for market acceptability.
|
Sources of Technical
Information< Arjona, H. E. and F. B. Matta. 1991. Postharvest quality of
passion fruit as influenced by harvest time and ethylene treatment. HortScience
26: 1297-1298.
Arjona, H. E., F. B.
Matta, and J. O. Garner Jr. 1992. Temperatures and storage affect quality
of yellow passion fruit. HortScience 27: 809-810.
Janick, J. and J. E.
Simon (eds). 1993. New Crops. New York: John Wiley & Sons, Inc., pp. 480-483.
Lippmann, D. 1978. Cultivation
of Passiflora edulis S. Germany: GTZ.
Morton, J. F. 1987.
Fruits of warm climates. Passifloraceae. Winterville, N.C.: Creative Resource
Systems, pp. 320-331. Nagy, S. and P. E. Shaw. 1980. Tropical and subtropical
fruits, composition, properties, and uses. Westport, Connecticut: AVI Publishing
Inc., pp. 300-315.
Pocasangre Enamorado,
H. E., F. L. Finger, R. S. Barros, and R. Puschmann. 1995. Development and
ripening of yellow passion fruit. Journal of Horticultural Science 70 (4):
573-576.
|
