Agriculture Reference
In-Depth Information
Table 6.2
Continued
Maturity Index
Cultivar
Description
Country
Reference
4. Starch content
Tommy Atkins
Brazil
Rocha
et al
. 2001
5.
Starch: acidity ratio
Langra
≥ 4.0
India
Teotia
et al
. 1968
6. Phenolics
-
-
India
Lakshminarayana, 1980
E.
Nondestructive methods
Acoustic resonance
spectroscopy
Neelum
India
Raju
et al
. 2006
Near-infrared (NIR)
spectroscopy
-
-
Japan
Saranwong
et al
. 2003
Ultrasonic waves
-
-
Israel
Mizrach
et al
. 1999
so the extremely high temperatures prevailing in some
regions may limit the use of heat units as maturity indices.
Specific gravity as a maturity index is also widely acknowl-
edged in mango. In mature mango, the specific gravity is
equal to or more than 1.0 (Kapse & Katrodia 1997).
However, in some cultivars specific gravity may reach 1.0
before the fruit is completely mature (Lam
et al
. 1982;
Obasi 2004). As the maturation progresses, there is a constant
increase in total solids, dry matter and decrease in titratable
acidity and phenolics (Lakshminarayana 1980; Rocha
et al
.
2001; Teaotia
et al
. 1968). The use of chemical attributes
such as SSC, acidity, SSC: acidity ratio, phenolics and
starch content has limited application because the changes
in these parameters during the later phase of maturation
(near harvest) are little (Del Mundo
et al
. 1984; Lam
et al
.
1982; Mendoza
et al
. 1972). The development of some non-
destructive techniques like acoustic resonance spectroscopy
(Raju
et al
. 2006), near-infrared spectroscopy (Saranwong
et al
. 2003) and ultrasonic waves (Mizrach
et al
. 1999) in
evaluation of maturity status is still in nascent stage. These
methods are also based on the dry matter and starch content
in fruit. It is difficult to reach any consensus on a single
maturity index for a particular cultivar. Therefore, the use of
multiple maturity indices to determine harvest maturity
may be more appropriate.
aim at minimizing the rate of respiration of fruit to the
lowest possible level without any anaerobiosis and also to
reduce the biosynthesis and action of ethylene. The rise in
the rates of respiration and ethylene production during
ripening symbolises normal ripening behaviour of mango
fruit. The absence of such an upsurge in the respiration and
ethylene production is generally associated with uneven
ripening leading to inferior quality of ripe fruit. The
respiratory patterns of mango are influenced by several
factors such as cultivar, harvest maturity, ethylene, post-
harvest handling conditions such as storage temperature
and atmosphere, disease incidence, heat treatments (Cua &
Lizada 1990; Esguerra & Lizada 1990; Lalel
et al
. 2005;
Mitcham & McDonald 1993; Nair & Singh 2003; Nair
et al
. 2004b). 'Kensington' mangoes harvested at mature
green stage showed a respiratory peak on day 3 of ripening
at 21°C with a concomitant increase in the ethylene pro-
duction on the same day (Lalel
et al
. 2003f). Interestingly,
the cyanide (CN) insensitive respiration pathway operates
in mango fruit during ripening (Considine
et al
. 2001;
Cruz-Hernandez & Gomez-Lim 1995; Kumar
et al
. 1990).
As a consequence of CN pathway operation, there is a
drastic increase in the internal fruit temperature from 29°C
to 38.9°C during ripening (Kumar
et al
. 1990). The CN
respiration contributes 80% of the total respiration during
the climacteric phase of fruit ripening (Kumar
et al
. 1990).
The alternative oxidase (Aox) responsible for CN insensi-
tive respiration during ripening of mango is differentially
expressed (Cruz-Hernandez & Gomez-Lim 1995). The
accumulation pattern of cytochrome proteins during
ripening suggested their role in facilitating the climacteric
burst of respiration and that the alternative oxidase (Aox)
and uncoupling proteins (Ucp) may play a role in post-
climacteric senescent processes. Both messages and
CHANGES DURING RIPENING
Respiration and ethylene
Mango is a climacteric fruit and exhibits a burst in the
respiratory activity and ethylene production during normal
course of ripening (Akamine & Goo 1973; Biale & Young
1981; Mattoo & Modi 1969). The post-harvest techniques
