Mango Production, Postharvest Physiology and Storage - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 258

skin can subsequently become a site for secondary infec-
tions, which further decreases the storage life of the fruit.
The amount of sap exuded by a fruit varies with maturity
(the less mature the fruit, the more sap it will exude), time
of day (there is a greater sap flow early in the morning than
later during the day), and cultivar (Srivastava, 1998).
However, varieties vary in their susceptibility to sap in-
jury. Export cultivars like 'Tommy Atkins,' 'Haden,' 'Kent,'
'Keitt,' 'Kensington,' and 'Alphonso' are reported to be
prone to sapburn (Cunha et al., 1993; O'Hare and Prasad,
1993). The oil (alkenyl resorcinol) fraction of sap is re-
sponsible for skin injury whenever it comes in contact with
and enters the mango skin via the lenticels. Injury could
be largely eliminated by desapping mango fruit immersed
in a solution of 1% (w/v) calcium hydroxide (O'Hare
and Prasad, 1993), as ionization and subsequent disper-
sion of the oil fraction occur under alkaline conditions
(pH

weevil, fruit fly, spongy tissue, and so on, in some vari-
eties of mangoes, which need to be detected before making
consignment for export.
Several mango postharvest handling techniques have
been developed for controlling disease and insects and
for protection against injury during packaging and storage
(Johnson et al., 1997; Pinto et al., 2004). Good handling
practices during harvesting can minimize mechanical dam-
age and reduce subsequent wastage due to microbial attack
(Wills et al., 1998).

Postharvest disease management
Susceptibility of mango fruit to postharvest diseases in-
creases after harvest, during ripening, and over prolonged
storage as a result of physiological changes in the fruit,
favoring pathogen development (Eckert et al., 1996). The
major postharvest diseases that cause considerable losses
in all mango producing areas of the world are anthrac-
nose caused by Colletotrichum gloeosporioides (Penzig)
and stem-end rot caused by Botryosphaeria spp. (Swart
et al., 2002). The disease occurs as quiescent infections on
immature fruit, and the damage it incites is more important
in the postharvest period (Dodd et al., 1997). Management
of these diseases relies primarily on the application of pre-
harvest fungicidal sprays (Ploetz and Prakash, 1997) and
postharvest hot water dips either alone or in combination
with chemicals (Johnson et al., 1997; Dodd et al., 1997;
Swart et al., 2002). These practices have proven relatively
effective in protecting the crop against pre- and posthar-
vest pathogen infection and in extending the storage life
of mango fruit during overseas shipment. However, precise
control of temperature and time is critical, as fruit can be
easily damaged by overexposure to heat.
Hot water dips incorporating chemicals such as prochlo-
raz (Johnson et al., 1995) are effective in controlling
postharvest anthracnose and stem-end rot diseases. Some
antagonistic micro-organisms (bacteria, fungi, and yeast)
isolated from mango were also found to be effective as
potential biological agents for the control of anthracnose
on harvested mango fruits (Kefialew and Ayalew, 2008).
'Keitt' mango fruits treated with biocontrol agent ( Bacil-
lus licheniformis ) applied in hot water (45 ◦ C), followed
by a quarter strength prochloraz dip, showed reduced
anthracnose and stem-end rot incidence both at 10 ◦ and
20 ◦ C (Govender et al., 2005).
Prusky et al. (2006) suggested a combination of acid
solutions, alone or in the presence of reduced prochlo-
raz concentrations, for the control of postharvest diseases
that alkalinize the host environment. Application of a com-
bination of hot water spraying and brushing (HWB) for

12.5). Bonding may then occur between the ion-
ized fraction of the sap and divalent calcium ions to form
a membrane-like polymer on the surface of the solution.
Brown et al. (1986) reported that 1% alum (aluminum
potassium sulfate) solution, which coagulated sap during
the dipping treatment, was the most effective in controlling
sapburn.
Lim and Kuppelweiser (1992) showed that dipping man-
goes in DC Tron oil at 100-1,000 μ l/liter for up to 60 sec
gave excellent protection against sapburn injury in com-
parison to similar dosages of Ethoken, Agral 60, Croplife,
Codacide and 1% Chlorsan or calcium hydroxide. Fruits
treated with DC Tron ripened and colored normally with
no off-flavors or reduction in quality.
Holmes and Ledger (1992) has demonstrated that mango
sapburn can be reduced by a number of methods: (1) us-
ing detergent dips and sprays prior to de-stemming, (2)
destemming under water using lime, and (3) picking with-
out stems onto a harvesting aid and dipping or spraying
detergent onto the fruit immediately. The harvesting aid
proved to be the most effective, lowering the levels of sap-
burn down to 15.9%. Cleaning latex from the fruit is also
recommended, using a solution of 0.5-5% CaCO 3 .

∼

Postharvest losses, causes, and remedies
The postharvest losses in mangoes have been estimated
to be in the range of 25-40% from harvesting until they
reach consumers. Mango fruits are climacteric in nature
and ripen quickly after harvest. Disease susceptibility, sen-
sitivity to low storage temperatures, and perishability due
to ripening and softening are serious causes of postharvest
losses in mango, limiting its handling, storage, and trans-
port potential. The other internal defects reported are stone