Postharvest Biology and Technology of Fruits, Vegetables, and Flowers

ENHANCING POSTHARVEST SHELF LIFE AND QUALITY 147
diffusion limitations within the flesh (Hayama et al., 2005). It is probable that the ethylene
receptors are rapidly turned over, which help overcome the 1-MCP effect in the fruit tissue
(Dal Cin et al., 2006). This turnover was not found in apples, which may help explain the
prolonged effect of 1-MCP on apple fruit (Dal Cin et al., 2006).
Ethylene production can be variable in 1-MCP-treated peaches and nectarines (Mathooko
et al., 2001; Fan et al., 2002; Rasori et al., 2002; Liguori et al., 2004; Bregoli et al.,
2005; Girardi et al., 2005). 1-MCP-treated fruits showed a higher level of ethylene production
than untreated fruits (Rasori et al., 2002), and the transcript levels of ACS and ACO
were higher in treated fruit (Bregoli et al., 2005). The respiration rates are also variable
after 1-MCP treatment (Fig. 7.2) (Dong et al., 2001b; Fan et al., 2002; Liguori et al., 2004).
Softening is delayed in 1-MCP-treated fruits, but this effect is not retained during further
storage (Dong et al., 2001b; Mathooko et al., 2001; Liguori et al., 2004). The effect on
soluble solids content is also variable; however, decline in total acidity is slowed in high
acid (Fan et al., 2002; Liguori et al., 2004; Bregoli et al., 2005; Liu et al., 2005), but not in
low-acid cultivars.
7.3.6 Plum
Among stone fruits, plums are much more sensitive to 1-MCP than peaches and nectarines.
Japanese-type plums show either climacteric or suppressed climacteric character. The climacteric
rise in respiration and increase in ethylene production are temporally delayed in
suppressed climacteric fruit during ripening. Ripening of suppressed climacteric cultivars
was inhibited when treated with 1 μL/L 1-MCP unless followed by a subsequent treatment
with propylene (Abdi et al., 1998). When treated with 0.1 μL/L 1-MCP, the fruit eventually
ripened and softened (Dong et al., 2001a).
1-MCP treatment prevented or delayed the climacteric increase in ethylene production
and respiration of plums (Dong et al., 2002; Martinez-Romero et al., 2003; Salvador et al.,
2003; Valero et al., 2003, 2004; Khan and Singh, 2007). In addition, softening and skin
color changes were delayed and weight loss was reduced (Dong et al., 2001a, 2002; Menniti
et al., 2004; Khan and Singh, 2007). Increase in soluble solids content was also affected
(Valero et al., 2004).
Postharvest softening and susceptibility to mechanical injury and pathogens are major
problems that limit shipping and shelf life of plums. The response of plums to 1-MCP is
variable based on cultivar and harvest maturity, but there are reports of large extension of
storage and shelf life of treated fruit due to a decrease in mechanical damage and decay
(Abdi et al., 1998; Martinez-Romero et al., 2003; Khan and Singh, 2007). Moreover, 1-MCP
is more effective in mature fruit showing better organoleptic quality (Salvador et al., 2003;
Valero et al., 2003).
7.3.7 Tomato
Tomato was one of the earliest fruits examined for the effectiveness of 1-MCP by Sisler
et al. (1996). 1-MCP treatment inhibited ethylene production and respiration, fruit softening,
color changes, and decrease in total acidity, but did not change the soluble solids content.
The extent of ripening inhibition in tomato fruit is influenced by 1-MCP concentration, time
of exposure, maturity stage, and cultivar types (Sisler et al., 1996; Hoeberichts et al., 2002;