Guava - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 198

physiological damage. In the first case, the pathogens infect
the fruit while it is still in the field and remain latent until the
fruit is ripe, when physiological and biochemical changes
will enable their renewed growth. Conversely, in the lat-
ter case, the contamination by pathogens can occur after
harvesting, usually owing to skin damage during handling
(Barkai-Golan, 2001).
For guava, over 90 pathogens of the fruit have been re-
ported, besides 42 of the foliage, 18 of the twigs, and 18
of the roots. Moreover, 17 fungi were isolated from the
washed surface of the fruits, which are responsible for var-
ious diseases such as pre- and postharvest fruit rots (dry
rots, wet rots, soft rots, sour rots, brown rots, ripe rots, scab,
ring rots, pink rots, and waxy fruit rots), canker, wilt, die
back, defoliation, twig drying, leaf spot, leaf blight, an-
thracnose, red rust, sooty mould, rust, seedling blight, and
damping off (Misra, 2004). For the fruit in particular, the
main pathogens responsible for the quiescent infections that
lead to postharvest losses are Colletotrichum gloeospori-
oides and C. acutatum (anthracnose), Puccinia psidii Wint
(guava rust), Mucor hiemalis (mucor rot), and Guignardia
psidii (black spot). Conversely, during postharvest manipu-
lation, infection of the fruits is usually due to fungi, which
is generally caused by the genus Rhizopus and Pestalotia
(Barkai-Golan, 2001; Martins et al., 2007).
To reduce losses due to fruit diseases, regular sanitation
practices are essential from the orchard to the packing-
house. The use of of fungicides and pesticides in the form
of sprays or dips, such as Bordeaux mixture, benomyl, and
copper oxychloride, have been reported as controlling prac-
tices for diseases that cause infections of guava fruits (Jun-
queira et al., 2001; Misra, 2004), although local legislation
should be considered for regulating their use.

range for guava storage depends on the variety and ripen-
ing degree considered (Gonzaga-Neto et al., 1999; Sidhu,
2006; Kader, 2009). Mature-green guavas are more chill
sensitive than fully ripe fruit. In the first case, the guava
should be stored from 8 ◦ to 10 ◦ C, while fully ripe fruits
may be kept for up to a week at 5 ◦ C without exhibiting
signs of chilling injury (Kader, 2009).
Besides refrigeration, several other techniques have
been studied to preserve the quality of guava and minimize
postharvest losses such as irradiation, modified atmo-
sphere packaging, calcium dips, heat treatment, edible
coatings, and the use of a vegetable regulator such as
1-methylcyclopropene (1-MCP). However, the economic
availability of these techniques as well as the sensory
quality of the final product must be considered for their
use (Basseto, 2002).
Ionizing radiation extends the shelf life of fruits mainly
due to its property of inactivating pathogens (Niemira,
2003). This technique is used in many countries as a phy-
tosanitary treatment against a number of insect pests. Be-
sides the microbiological aspect, it has also been observed
that radiation may delay the ripening of guava (Ahmad
et al., 1972; Singh and Pal, 2009). Singh and Pal (2009)
observed that the use of ionizing radiation treatment on
guava cultivars 'Lucknow-49' and 'Allahabad Safeda' sup-
pressed the respiration and ethylene production rates, re-
tarding fruit ripening during storage and consequently de-
laying the physical and biochemical changes associated
with ripening such as firmness, titratable acidity, soluble
solids, and vitamin C during storage.
Modified atmosphere packaging (MAP) involves the
alteration of the atmosphere surrounding the product by re-
ducing the O 2 and increasing the CO 2 content (Villanueva
et al., 2005). The use of a coextruded polyolefin film
maintained good sensory characteristics of cv. 'Kumagai'
guava for 28 days under refrigerated storage (Jacomino
et al., 2001), while up to 6 weeks of shelf life was achieved
for the cultivar 'Pedro Sato' with the use of MAP in
Cryovac packaging under refrigeration at 8 ◦ C (Yamashita
and Benassi, 2000). In the latter case, the authors also
stated that such packaging was efficient in reducing loss of
mass and fungal attack.
Calcium dips alone or in combination with heat treat-
ment have been used in the postharvest treatment of guava
to reduce pathological deterioration and to extend the shelf
life. Solutions of calcium salts such as lactate, chloride,
and nitrate (0.5-3.5%) have been used for this purpose
(Chandra et al., 1999; Gonzaga-Neto et al., 1999; Botelho
et al., 2002). Werner et al. (2009) related that guava
immersed in solutions of 1% calcium chloride for 15 min
maintained their quality for 12 days at 22 ◦ C, showing lower

Storage and postharvest technologies
The use of low temperatures is still one of the most
common practices for increasing the shelf life of guava.
Generally, low temperatures and high relative humidity
decrease guava fruit transpiration and, consequently, its
weight loss, which are closely related to fruit senescence
and deterioration (Sigrist, 1988). Moreover, the decrease
in mass not only leads to quantitative losses but also to
deterioration in the appearance (shrinkage and wrinkling)
and textural properties (softening, loss of freshness, and
juiciness) (Kader, 2002).
However, it must be considered that guava, like most
tropical fruits, is highly chill sensitive. Various authors
have observed that guava stored from 5 ◦ to 10 ◦ C and 85-
95% of relative humidity can be preserved for 2-5 weeks
(Salunkhe and Desai, 1984; Gonzaga-Neto et al., 1999;
Barkai-Golan, 2001). However, a more precise temperature