Agriculture Reference
In-Depth Information
Table 11.6
Effect of Post-harvest 1-MCP Treatment on Strawberry Fruit Quality.
Cultivar
Concentration (nl/l)
Duration
Storage condition
Effects
Reference
—
500
—
5 or 20°C
⇑ post-harvest decay, quality
Ku
et al
. 1999
Pajaro
2000
18 h
20°C
⇓ respiration, loss in firmness,
colour changes; ⇑ ethylene
production,
Tian
et al
. 2000
Everest
100 and 250
2 h
3d at 20°C in
dark at
> 95RH%
⇓ post-harvest decay (
Rhizopus
stolonifer
), ethylene
production, loss in firmness
Jiang
et al
. 2001
500 and 1000
as above
⇑ post-harvest decay
(
R. stolonifer
), PAL activity,
anthocyanins; ⇓ total phenolics
NS
10-1000
24
0 or 5°C
⇑ post-harvest decay; ⇓ ethylene
production, calyx deterioration
Bower et al. 2003
by Trainotti
et al
. (2005) argued that ethylene may have a
role in strawberry ripening as different ethylene receptors
showed increased expression during development.
Despite the wealth of evidence that supports the view
that ethylene may have a role in postharvest storage of
strawberry, work has shown that total removal of ethyl-
ene from a hermetically sealed environment using a
newly developed and highly efficacious palladium-
promoted ethylene scavenger had some benefit (Terry
et al
. 2007a). Even though ethylene was removed using
the Pd-promoted material the effects on postharvest
strawberry fruit quality and storage life were small. A
similar conclusion was given by Bower
et al
. (2003) who
concluded that despite some beneficial effects neither the
removal of ethylene or treatment with 1-MCP were likely
to be cost-effective methods of extending the storage life
of strawberries (cv. not stated). Again, these results mir-
ror those reported by many other authors that the effects
of ethylene are not well defined for strawberry and may
be affected by cultivar, maturity, disease, storage temper-
ature and even tissue type (Jiang
et al
. 2001; Bower
et al
.
2003; Iannetta
et al
. 2006).
Knee
et al
. 1977; Abeles & Takeda 1990; Rosli
et al
.
2004). However, other authors have argued that the
amount of cellulose remains relatively constant during
strawberry fruit ripening (Koh & Melton, 2002). Reports
have implicated that strawberry fruit softening is
governed, in part, by de-polymerisation of strawberry
xyloglucans by
endo
-glucanase (Harpster
et al
. 1998;
Trainotti
et al
. 1999; Wooley
et al
. 2001). Cleavage of
xyloglucan linkages due to
endo
-glucanase may result in
pectin solubilisation (Koh & Melton 2002). Similarly,
progression from white stage to red stage in raspberry
fruit coincides with a dramatic reduction in pectin
(Stewart
et al
. 2001). Cell wall disassembly events in
raspberry, blueberry and boysenberry (Vicente
et al
.
2007a, 2007b, 2007c) have been described in detail.
Jiménez Bermúdez
et al
. (2002) demonstrated that
strawberry fruit firmness could be maintained by
engineering plants which incorporated an antisense
sequence of a strawberry pectate lyase gene. Data from
strawberry cultivars with differing fruit firmness suggest
that strawberry fruit softening is principally related to
pectin solubilisation (Woodward 1972; Knee
et al
. 1997)
and also to a lesser extent de-polymerisation (Rosli
et al
.
2004) in the apparent absence of polygalacturonases (PG)
(Koh & Melton, 2002). The role of PG in strawberry fruit
ripening remains controversial. Despite different endo- or
exo-PG activity being partially characterised (Nogata
et al
. 1993), pectin solubilisation occurs in the presence
of very low PG activity. It remains unclear that all
developmentally regulated PGs found in strawberry
function in cell wall degradation during ripening.
Firmness
Strawberries soften greatly during ripening, however, the
biochemical basis of cell wall degradation in strawberry
has not been fully established. The general consensus is
that softening results from a degradation of the middle
lamella between cortical parenchyma cells (Abeles &
Takeda 1990). Hemicellulose and cellulose degradation
may also contribute to softening (Barnes & Patchett 1976;
