Mango - Crop Post-Harvest: Science and Technology - page 122

in delayed ripening of fruit. There are some contradictory
reports on the usefulness of Ca treatment in extending the
shelf life and on the penetration patterns and distribution of
Ca in different parts of fruit. Yuen et al . (1993) found that
the ripening in 'Kensington' mangoes can be delayed by
12 and 8 days at 20°C when they were either pressure
(115 kPa for 2 min) or vacuum infiltrated (−32 kPa), respec-
tively, with CaCl 2 solution (2-8%). However, Joyce et al .
(2001) did not obtain any extension in shelf life of four
cultivars viz., 'Kensington', 'Sensation, 'Irwin' and
'Palmer' when these were vacuum infiltrated (−33 kPa)
with 4% (w/v) CaCl 2 which was in contrast to findings of
Tirmazi and Wills (1981), Mootoo (1991) and Yuen et al .
(1993). They observed that Ca level in flesh tissue was not
affected by vacuum infiltration into any of the cultivars
harvested at different maturities. Calcium concentration of
4g Ca 2+ /L should be considered the upper limit as higher
concentration may lead to skin injury (Shorter & Joyce
1998; Tirmazi & Wills 1981). Fruit infiltrated with the
optimum dose at very low partial pressures (−66 and
−99 kPa) exhibited injuries which included exacerbated
lenticel blackening and anaerobic off-odour and lacked
respiratory climacteric and normal ripening (Shorter &
Joyce 1998). Calcium uptake was not influenced by the
maturity factor in mango (Joyce et al . 2001) as in some
other temperate fruits. Most of the applied Ca 2+ remained
localised in the skin and outer flesh of fruit and hardly
penetrated into the inner mesocarp and caused skin injury
(Joyce et al . 2001). However, Ca uptake can be improved
by the use of some surfactants like Tween-80 (0.01%)
before dipping in CaCl 2 solution (Singh et al . 2000). The
combination of post-harvest Ca treatment along with wax-
ing (Bringas-Taddei et al . 2005) and MAP (Singh et al .
2000; Yuen et al . 1993) have also shown synergistic effects
on post-harvest life, firmness and quality of mangoes. It is
still inconclusive from the literature whether it would be
beneficial to adopt post-harvest treatment of calcium as
there a risk of skin injury coupled with limited benefit of
delayed fruit ripening.

ascorbic acid content, and reduced amylase and peroxidase
activity during ripening (Khader 1988). Similarly, pre-
harvest application of GA 3 also influenced the post-harvest
ripening behaviour of mango fruit (Khader 1991). The post-
harvest dip treatment of 'Alphonso' mango with cycocel,
alar and menadione bisulphite at 500 ppm significantly
retarded ripening process (Krishnamurthy & Gopalakrishna
Rao 1982). The application of polyamines as a pre-storage
treatment significantly affected mango fruit quality
parameters. Dipping of 'Kensington Pride' mangoes in
0.01mM spermine solution for 6 min prior to storage at 13°C
for three or four weeks resulted in retarded fruit softening
during storage while putrescine (1mM) was effective in
maintaining higher fruit firmness and ascorbic acid in ripe
fruits (Malik & Singh 2005; Malik et al . 2003).

POST-HARVEST DISORDERS

Chilling injury
Mango fruit is highly chilling sensitive and cannot be
stored below 13°C (Chaplin et al . 1991; Kane et al . 1982;
Malik & Singh 2005; Medlicott et al . 1986b; O'Hare &
Prasad 1993). The severity of chilling injury (CI) depends
upon the storage temperature, duration of exposure,
maturation stage, cultivar and pre-storage conditions
(Medlicott et al . 1990a; Mohammed & Brecht 2002; Nair
et al . 2004a, 2004b; Phakawatmongkol et al . 2004; Wang
1993). The fruit at pre-climacteric stage were more
susceptible to CI than at post-climacteric (Cheema et al .
1950; Medlicott et al . 1990a; Mohammed & Brecht 2002).
The symptoms of CI in mango include pitting or sunken
lesions, skin discolouration, lenticel spotting, flesh brown-
ing, uneven ripening, reduction in carotenoid development,
insipid flavour and increased susceptibility to decay
(Chaplin et al . 1991; Chhatpar et al . 1971; Han et al . 2006;
Kane et al . 1982; Medlicott et al . 1990b; Mohammed &
Brecht 2002; Nair & Singh 2003; Nair et al . 2004b; Pesis
et al . 2000; Phakawatmongkol et al . 2004). Most of the CI
symptoms appear only after the fruit are transferred to
ambient conditions for ripening. The increased tolerance to
chilling in chilling-sensitive tissues or delayed develop-
ment of chilling injury symptoms would lead to the
possibility of storing these commodities at lower tempera-
tures with a minimum rate of deterioration in quality (Nair
& Singh 2003). Chilling-induced damage to cell
membranes disrupts a cascade of metabolic reactions in
mango including ethylene production, causes increased
respiration, interference in energy production, accumula-
tion of toxic compounds such as ethanol and acetaldehyde,

Plant growth regulators and other chemicals
The use of plant growth regulators both as pre-harvest and
post-harvest treatments has been studied in mango and found
successful in delaying ripening and maintaining quality
during storage and ripening. Post-harvest treatment with
gibberellic acid (GA 3 ) at 200 ppm has been found highly
effective in retarding ripening of 'Mallika', 'Alphonso' and
'Kesar' mangoes (Khader 1988; Krishnamurthy &
Gopalakrishna Rao 1982; Parmar & Chundawat 1988). GA 3
treatment retarded the total loss in weight, chlorophyll and