3.3. Effect of pre-treatment and freezing on mango characteristics
Changes of the partially ripe (day 2) and ripe (day 3) mango
characteristics resulting from the pre-treatment and freezing processes are illustrated in Fig. 6. The L*, a* and b* values of the
ripe mango (R) at every step were lower than those of the partially
ripe mango (VI) (Fig. 6a). The lower values of the ripe mango corresponded
to its darker yellow/orange color (Fig. 7).It was observed
that immersion in citric/acetic acid and calcium chloride solution
(CC) affected the partially ripe and ripe mango colors in the same
manner: that is, lower values of L* and b*, meaning darker and less
yellow. The L* and b* values of the ripe mango were more reduced
than those of the partially ripe mango. The a* value changed
insignificantly. The vacuum infusion step caused a further reduction
of the L*, a* and b* values of the partially ripe mango,
meaning darker and less red yellow. Freezing/thawing processes
increased the color changes of both ripe and partially ripe mangoes.
Their L* values were reduced; that of the ripe mango was much
lower than that of the partially ripe mango. Their a* values were
not affected. The b* value of the ripe mango was unchanged, while
that of the partially ripe mango increased. This implies that the
partially ripe mango became a more intense yellow color