Agriculture Reference
In-Depth Information
Table 3.1
The Effect of Modified Atmospheres (MA) on Extending the Green-Life of Banana Fruit in
a Number of Studies.
Cultivar
Treatment
Green-life extended by*
Reference
AAA Cavendish, 'Williams'
MA, ambient temperature
7 days
Scott and Roberts (1966)
AAA Cavendish 'Williams'
MA, ambient temperature, C
2
H
4
absorbent
14 days
Scott
et al
. (1970)
AAA Cavendish 'Williams'
MA, cool room, C
2
H
4
absorbent
14 to 30
+
days
Satyan
et al
. (1992)
AAA Cavendish
MA, ambient temperature, C
2
H
4
absorbent
16 to 18
+
days
Jiang
et al
. (1999)
AAB 'Kolikuttu'
MA, cool room, C
2
H
4
absorbent
16 to 18
+
days
Chamara
et al
. (2000)
AAA Cavendish
days Stewart
et al
. (2005)
* The + sign indicates that treatments were stopped before the maximum green-life was determined.
MA, 15°C
13
+
green-life of the control fruit in each paper differs by tenfold.
For example, taking the green-life of fruit at 20°C and 0.1 μL
C
2
H
4
L
−1
in each paper, the green-life of the fruit used by
Inaba and Nakamura (1988) is about 30 h, while that for
Wills
et al
. (1999) is 250 to 300 h, almost 10 times longer.
These large differences in green-life under the same condi-
tions of temperature and exogenous C
2
H
4
reflect, amongst
other things, the differing status, including age, of the fruit
used in the two sets of experiments. So, for transporting fruit
over large distances without refrigeration, but with low exog-
enous C
2
H
4
concentrations, it would be necessary to select
fruit that has an inherently high green-life at harvest. In prac-
tice this is difficult, but experience shows that fruit harvested
at certain times of the year or grown in different locations
can have shortened green-life. There is a need to develop a
method for predicting the green-life of harvested fruit.
The gas 1-methylcyclopropene (1-MCP) blocks ethyl-
ene action (Blankenship and Dole 2000) and could be
expected to extend the green-life of bananas. In commerce,
bananas with a range of maturities are marketed and so
Harris
et al
. (2000) investigated the interaction between
1-MCP application and fruit maturity in cv 'Williams'
(AAA, Cavendish subgroup). They worked on fruit that
varied in diameter from 33 to 42 mm and found a strong
interaction between fruit maturity and 1-MCP application.
The green-life of larger fruit was extended by 1-MCP but
was reduced in thinner fruit. Harris
et al
. (2000) concluded
that this interaction limited commercial application of
1-MCP to extend green-life in cv 'Williams'.
under these conditions by controlling the O
2
and CO
2
concentrations of its atmosphere, and at a low temperature.
Modified atmospheres can be used for bananas where
refrigeration is not available, or is too expensive. In this
case the fruit is sealed in a polyethylene bag and the fruit
'modifies' the surrounding atmosphere over time, depending
on its respiration rate, the volume of gas around the fruit
and the permeability of the enclosing polyethylene bag. In
a modified atmosphere the O
2
concentration falls over time
and the concentration of CO
2
increases as substrate is used
in respiration. Other gases, such as ethylene, may accu-
mulate. When using a controlled or modified atmosphere,
there are two aspects of interest. One is the effect of the
composition of the external atmosphere on the green-life or
shelf life of the fruit. The other aspect is what mechanisms
are involved in the response of the fruit to controlled
or modified atmospheres. We require empirical and
mechanistic knowledge to make progress in managing the
post-harvest behaviour of fruits.
Scott and Roberts (1966) showed that the green-life of
banana fruit could be extended at ambient temperatures,
simply by placing the pre-climacteric fruit in a sealed
polyethylene bag. Adding an absorbent of C
2
H
4
further
increased green-life (Scott
et al
. 1970). Since that time a
number of studies have examined the effect of modified
atmosphere storage on extending the green-life of banana
fruit (Table 3.1).
Oxygen concentrations in fruit tissues
Given the widespread interest in banana storage in mod-
ified atmospheres, especially during transport, to extend
green-life, the implications for gas concentrations within
the fruit tissues and how this impacts quality are very
important. This section concentrates on oxygen and
Modified and controlled atmospheres
Controlled atmosphere storage of temperate fruits was
developed early in the twentieth century (Kidd & West
1927). Temperate fruit can be stored for many months
