In recent years, valuable progress has been
made in understanding polyphenoloxidase
and phenolics of apple and apple products.
Many studies have been restricted to model
systems with enzyme acting on a single
phenolic substrate. However, these studies
would provide a better understanding of the
relationship between the extent of browning
and the phenolic composition of fruit.
Fresh-cut apples cause an increase in PPO
activity during storage for 7 days at 4oC. This
increase has been found to be highly
correlated with L value and the browning
index. Changes in color parameters of apple
cubes during storage were found to correlate
quite well with PPO activity (R2 between 0.79
and 1.00), except for CS and AA treatments.
The browning index of apple cubes during
storage was found to correlate well with PPO
activity (R2 > 0.84) in all treatments. No
correlation was found between phenolics and
color parameters (L, a, b, Hue angle, and
chroma value). The predominance of PPO
activity in enzymatic browning seems to be
highly related to the phenolics