Pomegranate - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 521

together. These unwanted media must be removed on the
packing line since they decrease the shelf life and value of
the minimally produced products. To overcome this prob-
lem, a computer-based machine capable of detecting and
removing unwanted materials and sorting the arils by color
has been developed (Blasco et al., 2009). This machine
may be used commercially to sort minimally processed ar-
ils. On the other hand, a novel method that enables opening
the fruit without cutting, extracting the arils with mini-
mum damage, separating arils from the extraneous materi-
als, and providing clean arils to the package line has been
invented, patented, and implemented commercially in Is-
rael (Schmilovitch et al., 2009).

velopment (Gil et al., 1996b). Furthermore, semiperme-
able packages may be used for pomegranate aril (Chilean
'Wonderful') storage at 4 ◦ C for 14 days, with good physic-
ochemical and microbiological quality (Sep ulveda et al.,
2000).

Microbiological issues and food safety aspects
Many countries demand that minimally or fresh-cut pro-
duce not carry more than 7 log CFU/g aerobic bacteria.
Consequently, minimally processed arils should be kept at
0 ◦ -5 ◦ C to maintain their microbial safety below the 7 log
CFU/g aerobic level.

Quality attributes: physical, chemical, sensory
Since pomegranates are rich in both organic acids and phe-
nolic compounds, their contribution to sensory attributes is
closely followed during and after processing. In pigmented
products like pomegranate, the discoloration generated by
oxidation of phenolic compounds catalyzed by pheonolases
and peroxidases causes an additional problem (Babic et al.,
2006). As the color of pomegranate arils is one the most im-
portant quality attributes, their stability must be conserved
(Gil et al., 1995). Dip/washing in antibrowning or antiox-
idant solutions might be therefore useful to preserve arils'
characteristic attractive color.

Pretreatments and sanitizer use
To avoid or delay microbial development, washing mini-
mally processed produce with chlorine solutions is widely
accepted and used, with the concentration of chlorine
mostly limited to 300 ppm (Schilimme, 1995). Wash-

ing arils with chlorine (100 mg/kg) followed by ascorbic
acid (5 g/liter) and citric acid (5 g/liter) dip may be used to
extend the shelf life of arils (Gil et al., 1996b). The UV-C
radiation, however, may not be used as a pretreatment for
prolonging the shelf life since L opez-Rubira et al. (2005)
reported that UV-C at 0.56, 1.13, 2.27, 4.54, and 13.62
kJ/m 2 had no significant effect on the shelf life of 'Mollar
de Elche' fruit stored under MAP at 5 ◦ C.
Arils, similar to whole fruit, have a relatively low rate of
respiration and ethylene production. Minimally processed
fruitmaybestoredupto14daysat7 ◦ C without com-
promising too much quality loss (Kader, 2006). During
the aril extracting process, some arils are damaged, thus
making them susceptible to decay. Therefore minimizing
physical damage to arils is a critical factor in this process.
To extend shelf life of minimally processed arils, several
postharvest applications, such as MAP (Gil et al., 1996a;
Sep ulveda et al., 2000), CA storage (Holcroft et al., 1998),
antioxidants (Gil et al., 1996a; Sep ulveda et al., 2000), or
honey coating (Ergun and Ergun, 2009), have been put into
practice. Gil et al. (1996b) reported that pomegranate arils
packaged in polypropylene films should be stored at 0 ◦ -1 ◦ C
to get optimum shelf life.

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PROCESSING AND PROCESSED PRODUCTS
Pomegranate is physically divided into different tissues,
each of which can be processed into value-added products.
The rind represents 28-30% of the fruit and is rich in tannins
and other beneficial polyphenols; white segments, connec-
tive tissues with a porous structure, represent about 10% of
the fruit, while internal membranes represent about 1-2%;
and arils about 60% of the fruit (Borgese and Massini,
2007). These portions, however, can vary depending on
cultivar, soil, plant nutrition, and climate.
Pomegranates, mostly unpeeled, may be crushed for
juice, concentrated juice, and syrup or may be used for
making jelly or other products (Artes and Tomas-Barberan,
2000). Arils may be employed for making cake and dessert.
Pomegranates, especially sour types, may be processed into
vinegar, as well as citric acid. Dried and ground fruit is also
used as spice in some parts of Asia. In northern India, arils
are dried in the sun for 10 to 15 days and then sold as a
spice (Morton, 1987).
No specific grading, washing, and cutting procedures ex-
ist for pomegranate fruit, but extracting arils with the mini-
mum physical damage and sorting arils by color and defects
on the packaging or processing line is very important for
the quality of processed products.

Packaging of minimally processed products
MAP is one of the successful methods of prolonging the
shelf life of arils (Gil et al., 1996a, 1996b). Under the
MAP, where the initial atmosphere was actively modified
to 20 mL/liter O 2 and 0 ml/liter CO 2 , minimally processed
pomegranate arils (cv. Mollar, Spain) may be stored up
to 7 days at 1 ◦ C without fungal growth or off-flavor de-