Fruiting, Harvesting and Post-Harvest 153
for shipment, only the first indication of yellow is permissible. Technically fruits
are harvested at colour break of 1/4 yellow for export or at 1/2–3/4 yellow for local
markets, depending on cultivars, ripening characteristics and season. Those fruits
harvested before this stage could fail to show complete ripening, while those har-
vested later could be more susceptible to damage and bruising during handling (Paull
1993a,b). Less mature fruits are lower in sugar and ripen poorly (Kader 2006). Fruit
ripening in papaya cultivars varies widely in terms of softening, skin colour changes
and shelf-life (Zhang and Paull 1990; Thumdee et al. 2007). At fruit maturity, latex
of fruits becomes watery and T.S.S at harvest should be minimum 8° Brix. Hawaii
specifies a minimum total soluble solid of 11.5% and fruit showing at least 6% sur-
face colouration at the blossom end region with proper fruit size (Quinta and Paull
1993). The fruit is size-graded, treated with hot vapours of ethylene bromide to kill
fruit fly, wrapped in newspapers and packed in boxes before shipping. Such wrapped
fruits will ripen and turn completely yellow in colour at room temperature within
2–4 days. The fruit should be harvested with a 20-mm portion of stem attached and
must be packed carefully in a single layer in a carry box with the stem-end resting
on the bottom. The bottom of the carry box should be covered with paper wool or
other noncontaminant material, which will absorb latex. Latex should, therefore, be
allowed to drain from the stem-end onto the paper wool where it will be absorbed.
Care should be taken not to have any latex dripping onto the fruit during harvesting
(DAIS 2009). The papayas must be packed in a way that ensures they are sufficiently
protected for export purposes. Packing material used inside the carton must be new,
clean and must be shaped in such a manner that it cannot cause any damage to either
the inside or outside of the fruit. The usage of materials, such as papers and stick-
ers with company details on them, is permitted provided that no toxic inks, dyes, or
glues have been used. The packaging must be free of all other materials.
Packaging provides protection from physical damage during storage, transporta-
tion and marketing (Irtwange 2006). Azene et al. (2011) reported on the effects of
different packaging materials and storage environment on post-harvest quality of
papaya fruit. There are variety of packages, packaging materials and inserts avail-
able. Nowadays, produce is transported and sold in an enormous way of packages
constructed of wood, fibre board, jute, or plastics. An important supplement to proper
temperature and relative humidity management is the use of modified atmosphere
(MA) (Azene et al. 2011). Modified atmosphere packaging (MAP) of fresh produce
relies on modification of the atmosphere inside the package, achieved by the natural
interplay between two processes, the respiration of the product and transfer of gases
through the package, which leads to an atmosphere richer in CO 2 and poorer in O 2.
This atmosphere can potentially reduce the respiration rate, ethylene sensitivity and
production, decay and oxidation and hence delays ripening and senescence (Kader
and Rolle 2004). MAP also relates to packages and film box liners with specific
properties that offer a measure of control over the composition of the atmosphere
around the produce (Irtwange 2006). The principal plastic materials for MAP that
can be used with fruits and vegetables include polybutylene, low-density polyeth-
ylene (LDPE), high-density polyethylene (HDPE), PP, PVC, polystyrene, ionomer,
pliofilm and polyvinylidine chloride (Schlimme and Rooney 1994). The permeabil-
ity of films to gases (including water vapour) varies with the type of material from