Banana - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 136

of the plant and the thermal profile of the distribution sys-
tem. The temperature lowering is a traditional process of
conservation of the fresh product and remains essential in
the case of fresh-cut fruits. Beyond 10 ◦ C, it is impossible
to maintain within a film the viable conditions for the prod-
uct: the risks of exacerbated microbial developments are
combined with a too high respiratory activity, accelerating
the tissue senescence.
Del Nobile et al. (2007) conducted investigations by
packing fresh processed banana with two different com-
mercial films: a laminated PE/aluminum/PET film and a
coextruded polyolefin film. The packages were stored at
5 ◦ C. The package headspace composition was monitored
in terms of O 2 and CO 2 concentration over 4-12 days of
storage in different types of films. The optimized film thick-
ness was estimated at 55 μm for banana preservation in such
conditions.

on fresh-cut surfaces was visually and quantitatively evalu-
ated by observing changes of “L” values and by evaluating
temporal changes in color spectra with the experimental
variables: oxalic acid concentration and storage time.
The effectiveness of pineapple juice for enzymatic
browning inhibition was evaluated by Chaisakdanugull
et al. (2007) on the cut surface of banana slices. After
storage of banana slices at 15 ◦ C for 3 days, pineapple juice
implied browning inhibition to a similar extent to 8 mM
ascorbic acid but to a lesser extent than 4 mM sodium
metabisulfite. Fractionation of pineapple juice by a solid-
phase C18 cartridge revealed that the directly eluted frac-
tion (DE fraction) has fully inhibited banana polyphenol
oxidase (PPO) when compared to the control. Further iden-
tification of the DE fraction by fractionation suggested that
malic acid and citric acid play an important role in the
enzymatic browning inhibition of banana PPO.

Biochemical alterations
The cutting of the plants involves the rupture of many
cellular walls. This trauma causes a release of enzymes,
which allows reactions normally not occurring in healthy
and intact tissues. New advances in extending the shelf life
of fresh-cut fruits were reviewed by Soliva-Fortuny and
Martin-Belloso (2003).

Physical treatment to prevent browning
The potential benefit of edible coatings for processed or
lightly processed fruits is to stabilize the product and
thereby extend product shelf life. Coatings reduce mois-
ture loss, restrict oxygen entrance, lower respiration, de-
lay ethylene production, seal in flavor volatiles, and carry
additives that retard discoloration and microbial growth.
(Baldwin et al., 1995; Guilbert and Biquet, 1996). Bico
et al. (2009) investigated the effects of chemical dip and/or
carrageenan coating and/or controlled atmosphere (CA) on
quality of fresh-cut banana. Banana slices were dipped for
3 min in a solution containing 1% calcium chloride, 0.75%
ascorbic acid, and 0.75% cysteine and/or combined with a
carrageenan coating and/or combined with CA of 3% O 2
and 10% CO 2 . Dipping combined with CA treatment pre-
vented weight loss and PPO activity rise during the 5 days
of storage. Color, firmness, pH, titratable acidity, total solu-
ble solids, and total phenolic content presented the smallest
variations. Microbial analysis showed that minimally pro-
cessed bananas were within the acceptable limits during
5 days of storage at 5 ◦ C.
The UV radiation induced changes in the antioxidant ca-
pacity of fresh-cut tropical fruits. The effect of ultraviolet
(UV-C) treatment on total phenol, flavonoid, and vitamin C
content of fresh-cut banana 'Pisang Mas' was investigated.
The fresh-cut fruits were exposed to UV-C for 0, 10, 20,
and 30 min. Total phenol and flavonoid contents of banana
increased significantly with the time of exposure. UV-C
treatment induced a decrease in the vitamin C content of
the fruits. Industrial UV irradiation of fresh-cut fruits leads
to an increase in antioxidants, polyphenols, and flavonoids.
Hence, apart from the application of UV for microbial

Chemical treatment to prevent browning
Galeazzi and Sgarbieri (1981) showed that the most ef-
fective inhibitor of banana polyphenoloxidase (PPO) was
ascorbic acid, followed by cysteine and then sodium
metabisulfite. Kahn (1985) demonstrated that L-cysteine
at about 0.4 mM gave full inhibition and could be safely
added to food during banana processing for preventing un-
desirable enzymatic browning. Moline et al. (1999) tested
different combinations of antioxidants in banana slices re-
garding their ability to prevent browning. They found that
combinations of citric acid and N-acetylcysteine provided
the best protection against browning during a storage pe-
riod of 7 days. Danyen et al. (2009) studied the interaction
between ascorbic acid and CaCl 2 in minimizing browning
of fresh-cut green banana slices. Dwarf Cavendish banana
slices were treated with antibrowning agents, packed at
55% vacuum level, and stored at 10 ◦ C. The interaction be-
tween ascorbic acid and CaCl 2 was significant for lightness
and redness; however, these color parameters were mainly
driven by the main effect of ascorbic acid. Browning and
loss of firmness were promoted when 4% CaCl 2 was used
and minimized when 2% ascorbic acid was added. Relative
antibrowning potential of oxalic acid on banana slices was
investigated by Yoruk et al. (2004). Degree of browning