Papaya - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 296

by saturated water vapor at 44.4 ◦ C until the center of the
fruit reaches that temperature and then held for 8.5 hours;
or exposed to forced hot-air treatment: 2 hours at 43 ◦ C

lesion size and anthracnose disease. Nevertheless, UV-C
irradiation doses used by Cia et al. (2007) were not able to
reduce occurrence and caused fruit browning. Forced hotair
treatment at low relative humidity was effective in reducing
decay development and even CI (Perez-Carrillo and Yahia,
2004).

+

2 hours at 45 ◦ C 2 hours at 46.5 ◦ C 2 hours at 49 ◦ C + +

(UCD, 2010).
Yahia et al. (1992) proposed to use low O 2 atmospheres
( < 0.4%) as a quarantine insect control treatment in papaya,
for periods < 3daysat20 ◦ C without the risk of significant
fruit injury.

Postharvest treatments to increase shelf life
For extending the postharvest shelf life and improving
quality of papaya fruit, 1-MCP (1-methylcyclopropene)
has been used as a tool (Hofman et al., 2001; Jacomino
et al., 2002). Papaya fruit treated with 1-MCP when more
than 25% ripe had a delay in softening and shelf life that
have commercial utility (Manenoi et al., 2007). Moreover,
if treated before, than 25% yellowing did not ripen com-
pletely. The application of 1-MCP was effective in delaying
the process of ripening of papaya fruits, being even more
efficient when associated with initial maturation stages (de
Souza et al., 2009). Nevertheless, Fabi et al. (2007) sug-
gested that 1-MCP can decrease the quality of 'Golden'
papaya treated fruit and that even the use of ethylene for
triggering or inducing homogeneous ripening can result
in lower quality when compared to that of fruit allowed
to ripen naturally. Therefore the cultivar and the maturity
stage before 1-MCP application affect overall quality.
The introduction of potassium permanganate sachets
in low-density polyethylene (LDPE) bags was effective
in maintaining the fruit at the preclimacteric stage over
25 days of storage and did not interfere with normal ripen-
ing after bag removal (Silva et al., 2009).
Postharvest dipping of papaya fruit either in Gibberellic
acid or CaCl 2 preserved the fruit, extending the shelf life
up to 9 days without any decline in fruit quality (Rajkumar
and Manivannan, 2007).

Storage technologies
Fruit harvested and placed to ripen at the recommended har-
vest stage (1/4) will ripen to 3/5 yellow coloration within
4-6 days under ambient tropical conditions (25 ◦ -28 ◦ C) or
up to 3 weeks at lower temperatures (10 ◦ -12 ◦ C) (Paull
et al., 1997). The storage life is significantly reduced when
papaya is harvested at more advanced stages of ripen-
ing. The optimal storage temperature for fully ripe fruit is
about 2.2 ◦ C.
Importers require fruit at specific stages of ripeness, nor-
mally between 3/5 and 3/4 yellow color but depend on the
importer, the market, and the time of year. The maximum
and minimum color stages on departure from the packing
house, the length of the shipment period, and the tempera-
ture in the importing country should be taken into account
so that the fruit reaches the target market in the correct
maturity stage. Thus for air, shipment color stages can vary
from 1/4 to 1/2, and the selections are generally more rigid
during the summer months due to the rapid rates of ripen-
ing on arrival in importing countries. Fruit exported too
green (less than 20% yellow color) will fail to ripen ade-
quately when temperatures in importing countries are low,
particularly in winter months.
Sea shipment of papaya is possible when fruits are
shipped at the optimum harvest maturity (one or two yellow
streaks). Shipments should be made at 10 ◦ -12 ◦ C and 85%
to 95% relative humidity in refrigerated holds or reefer con-
tainers. Postharvest disease control is critical with sea ship-
ment, particularly anthracnose and Phytophthora. Color de-
velopment during sea shipment usually increases from 10%
to 40% during 10 days at 12 ◦ C and will develop further dur-
ing the customs, clearance, and delivery period on arrival.
The latest Codex Alimentarius standard for papaya,
amended in 2005, included standards regarding quality,
size, uniformity, packaging, labeling, contaminants, and
hygiene (Codex, 2005). For trade and export fresh papaya,
many aspects need to be closely monitored and considered:
marketing of the products that are in demand; access to right
distribution channels, consumption patterns, and trends in
the country; and compliance with different standards in

Disinfestation procedures for fruit flies
The damage caused by fruit flies includes small surface
blemishes, destruction of the edible flesh, and spoilage from
decay. Fruit for export to those countries with quarantine
barriers must be harvested and packed in strict compliance
with quarantine regulations to be certified for shipment. As
a result of the cancellation of ethylene dibromide (EDB) in
1984 as a postharvest fumigant, heat treatments and irradi-
ation are used to achieve fruit fly disinfestation (Akamine
and Arisumi, 1953; Couey et al., 1984; Paull, 1990; Arm-
strong, 1994). The approved heat treatments for papaya are
hot water, vapor heat, and forced hot air.
Thus bins or pallets should be submerged for 30 minutes
at 42 ◦ C, followed within 3 min by a 49 ◦ C dip for 20 min;
exposed to vapor heat in which fruit temperature is raised