Role of Cuticles in Produce Quality and Preservation 43
that the fruit developed cuticular cracks in response to the low oxygen and high
relative humidity in the storage atmosphere. These cuticular cracks could improve
air exchange between the atmosphere and oxygen-depleted tissue in the apple.
Veraverbeke et al. [89,131] also observed that the cuticle structure changed when
the fruits were moved from the controlled atmosphere storage to a place with normal
oxygen levels. The small cuticular cracks filled in and the epicuticular wax layer on
the cuticle surface became smooth. The results indicate that the cuticle is a dynamic
structure that can be altered and modified by the plant to better adapt to its environment.
2.8.5.3 Tomato
Cherry tomato is a soft textured produce that can develop cuticle or skin cracks due
to rainfall or poor irrigation practices [132–134]. Once skin cracks develop, the
tomato can no longer be marketed because the cracked site becomes desiccated and
infected with fungi [132]. Swelling and cracking susceptibility is greater in the
morning when the tomato is fully hydrated [132]. In one study, Lichter et al. [132]
reported that fruit thinning and deleafing also increased cracking susceptibility [135].
However, in another study, Emmons and Scott [133] found no relationship between
pruning fruits and leaves and the incidence of cracking. Instead, they found that
cracking potential decreased when the whole plant experienced environmental stress
under hot and dry field conditions [133].
The growth rate or tomato size had no influence on cracking susceptibility [134].
On the other hand, the tomato’s developmental stage had a significant effect on
susceptibility to cracking. Mature-green fruits were the most susceptible, and the
severity of the cracking increased the most between the mature-green and breaker
stages [133]. Also, the fruit with a thicker skin, cuticle, and epidermis had a lower
incidence of cracking [134].
Lichter et al. [132] used water immersion treatments to study cracking in cherry
tomatoes. They found that adding calcium to the immersion solution reduced the
incidence of cracking. In contrast, adding a chelating agent to the solution increased
cracking [132]. The authors concluded that, similar to cherry fruit, the pectin fraction
of the cuticle and epidermal cell wall plays an important role in determining the
cracking potential of tomatoes.
2.8.5.4 Other Produce
Fruit cracking has also been shown to occur in other produce as well
(99,134,111,136,137). Iwanami [138] reported that shallow, concentric cracks
occurred during the late stage of fruit development in the cuticle of persimmons
(Diospyros kaki Thumb.). These cracks occurred in roughly 50% of the cultivars of
Japanese origin and promoted water loss. In another study, Yamada et al. [139] found
that cracking susceptibility was largely genetic and constituted one of the properties
considered by breeding programs when evaluating new persimmon cultivars. In most
produce, moisture loss and desiccation adversely affected quality. However, in Jap-
anese persimmon cultivars, fruit that had cuticular cracks remained high in quality
and had higher soluble solids content than fruit without cuticular cracks. Apparently,