Fruit ripening is associated with
important biochemical changes that
modify colour, texture, taste and
other quality traits. The changes of
some physico-chemical characteristics
of Maoluang fruit used in this
study are presented in Table 2. The
values reported are means of tree assays
of each group performed in triplicate.
The colour change of skin was
reflected by the variation of the L*,
a* and b* values determined in
Maoluang fruit. The L* value decreased
with fruit ripening as colour
became deep/dark. The Maoluang
fruit’s skin colour is green at the beginning
of ripening and becomes red
in conjunction with chlorophyll degradation
and anthocyanin accumulation
accumulation.
The a* value variation was used
as an index of redness and greenness.
The a* value increased in the early
fruit ripening stages and then decreased
in the ripe mature stage, as
the violet colour developed Similar
results were reported by Tosun et al.
(2008) and Bureau et al. (2009) for
blackberry and red apricot fruits, respectively.
The b* value variation
was used to express yellowness and
blueness. The b* value was observed
as the Maoluang fruit decreased from
the immature to the over ripe stage
(p < 0.05). It is known that the fruit
weight evolution during fruit maturation
is directly related to the fruit
size. During fruit development and ripening,
fruit weight increased fromabout
0.32 g (immature stage) to 0.68 g (over
ripe stage). Dry matter changes in the
fruit samples decreased (p < 0.05) as the
fruit ripened.
During ripening, a slight and insignificant
increase in the total soluble
solids (TSS) content occurred at
the immature and mature stages. But
at the ripe stage, the change in TSS
was significant (p < 0.05) and the
final TSS content was 18.40% (Tab.
2). The pH is becoming increasingly
recognized for its important contribution
to product quality. This is
especially true about red wine because
it plays a key role in prevention
of microbial spoilage, malolactic
fermentation occurrence and colour
stability of wines. The pH
slightly increased from about 2.20 to
3.95 during fruit development and
ripening. In contrast, the titratable
acidity (TAc) showed a gradual
decrease from about 1.40 to 0.75%.