3.4.2. Titratable acidity and pH
The effect of coating on titratable acidity and pH of tomatoes is
given in Fig. 3b and c, respectively. There was slight increase in the
acidity of the tomatoes till 4th day of storage that may be attributed
to the period of maturation prior to ripening of the tomatoes.
Thereafter, there was gradual decline in the acidity of the coated
and the uncoated tomatoes which can be attributed to the increase
in ethylene production and respiration rate during the advent of
ripening. Similar pattern of change in titratable acidity was also
reported by Oz and Ulukanli (2011). Retaining of titratable acidity
was also reported by Atress, El-Mogy, Aboul-Anean, and Alsanius
(2010). Acidity loss was highest in the control samples followed by
the S/G samples. S/G/L/A samples showing a higher drop in acidity
for the initial 12 days of storage than the S/G/L samples, maintained
an almost constant acidity from 12th to 16th day resulting in
a higher titratable acidity than S/G/L samples on the 20th day. This
indicates the retention of the titratable acidity by the film at least
till the 16th day of storage that subsequently slowed down ethylene
production and ripening.