Passion Fruit - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 319

the three different conditions. However, during storage, the
juice pasteurized at 85 ◦ C for 27 sec showed the least alter-
ation, while pasteurization at 75 ◦ C for 60 sec had the most
negative effects, especially in color, sweet, characteristic,
and floral aroma and in characteristic flavor. Refrigerated
storage maintained the sensory quality better.
When pasteurized in heat exchangers, the juice should
be immediately cooled to 5 ◦ to 10 ◦ C and packaged. For the
export market, juice and concentrate are packed in double
polyethylene bags in metallic drums of 200 liters, which
are frozen and stored at a temperature of -18 ◦ Corbelow.
Processing of the concentrated juice differs only in the
concentration step. This process needs special considera-
tion due to the presence of starch, which gels during heating,
increasing the viscosity of the juice. For high starch vari-
eties of passion fruit, enzymatic treatment with amylases or
separation of the starch by centrifugation is recommended.
To concentrate passion fruit juice, centrifugal evaporators
have been successfully used in Brazil and Australia. The
main advantage is the short residence time (0.2-1.0 sec),
which minimizes heat damage. The equipment for concen-
trated juice should have an aroma recovery unit. Alterna-
tively, addition of a part of the fresh juice (10%) to the
concentrated juice should be undertaken (cut back). Pas-
sion fruit concentrate can be stored at -18 ◦ C for 6 months,
4 ◦ C for 3 months, and 20 ◦ C for 1 month with good color
and flavor retention and no microbial spoilage.
Passion fruit juice may be quick frozen directly from the
finisher. Preferably, a slush type or scraped surface freezer
should be used to hasten the freezing process, aside from
increasing the freezing capacity of the processing plant.
The juice may also be frozen directly in containers in an air
blast freezer. This product is sold to manufacturers of juice
blends and of other food products with passion fruit as an
ingredient or as a major flavor component.
In Hawaii, the processing of passion fruit juice has long
been highly mechanized, with separation of the gelatinous
pulp from the seed and rind usually accomplished by a cen-
trifugal extractor (Chan, 1993; Chavan and Kadam, 1995).
Ripe fruits are delivered to the processing plant in boxes or
bins and dumped by a lift truck into an agitated wash tank.
The fruits are conveyed on a wire mesh belt and washed
with strong sprays of water to remove soil and dirt. They
are then sorted on a slow-moving conveyor to remove im-
mature, spoiled, and other unfit fruit. A gang of serrated,
rotating, and circular knives slice the rinds open. The sliced
fruit is fed into a perforated basket centrifuge with inclined
walls. A centrifugal force pushes seeds and pulp through
the holes in the basket, while the rinds slide up the sloping
walls and out of the centrifuge into the waste conveyor. A

pulper fitted with a screen separates the seeds from the pulp
and juice. The pulpy juice is then passed through a finisher
fitted with a screen to remove seed and fiber particles. A
typical extractor has a capacity of 1725 kg/hr of passion
fruit with an extraction efficiency of 94%. The main dis-
advantages of this system are that some seeds are cut in
the slicing operation, which necessitates the use of a fine
screen in the finishing operation, and there is a possibility
of extraction of skin flavors.
In Australia, there is appreciable consumption of the
fresh fruit, although the bulk of passion fruit production is
processed into juice, consumed locally as carbonated bev-
erages. The juice is also used as flavoring in ice cream,
confectioneries, and tropical fruit salads. Australian con-
sumers are used to eating and drinking passion fruit prod-
ucts with the seeds still present, the seeds being regarded
as evidence of passion fruit content. Elsewhere, the seeds
must be removed.
Extraction of the juice in Australia is done in several dif-
ferent ways (Chan, 1993). The converging cone extractor is
the most commonly employed extractor. In another method,
a modified apricot-pitting machine and plunger are used.
Since Australian consumers are accustomed to consuming
passion fruit products with the seeds, further processing to
remove the seeds from the pulp is not necessary.

APPLICATION OF EMERGING TECHNOLOGIES
Pasteurization was found to result in major undesirable
changes, which tended to intensify during storage (Sandi
et al., 2003). Thus the effects of the nonthermal high hydro-
static pressure (HHP) processing, as compared to pasteur-
ization, on the sensory characteristics (appearance, aroma,
flavor, mouthfeel, consistency) of yellow passion fruit juice
was investigated by Laboissiere et al. (2007). The passion
fruit pulp was packed in pressure-resistant polyethylene
bags, sealed, and pressurized at 300 MPa for 5 min at
25 ◦ C. HHP yielded a ready-to-drink juice with improved
sensory quality, as compared to commercial pasteurized
juices available in the Brazilian market, having high simi-
larity with the fresh juice.
Microfiltration was reported to be effective in the clari-
fication and stabilization of yellow passion fruit (de Paula
et al., 2004). It was carried out in a tubular membrane sys-
tem with average pore size of 0.3 μm and trans membrane
pressure of 1.5 bar. Enzymatic treatment was done before
microfiltration to enhance process efficiency by reducing
viscosity and pulp content of the juice. The permeate juice
was clear, free from pulp, and had good microbiological
quality.