3.6. Effect of cutting styles on the antioxidant enzymes activity in
fresh-cut pitaya fruit
To understand the effect of cutting styles on the antioxidase
system, the activities of SOD, CAT, APX and GR were determined on
the whole pitaya fruit and fresh-cut tissues during storage (Fig. 6).
The SOD activity of whole pitaya fruit showed a slow increase
through storage time, while fresh-cut processing induced a much
higher increase of SOD at the first 2 d of storage and a slight decrease then. During the whole storage time, the quarter-slice
showed the highest SOD activity enhancement, followed by halfslice and slice (p < 0.05, Fig. 6A).
For the whole pitaya fruit, CAT activity showed a similar
variation compared to that of SOD. Cutting styles had no obvious
effect on CAT activity during the first day, but after then, the three
kind of fresh-cut tissues showed higher enzyme activity compared
with the control (p < 0.05, Fig. 6B).
APX activity had no significant change for whole pitaya fruit
during the storage, while fresh-cut processing caused a decrease in
APX activity at the first day and an increase later on. For the freshcut tissues, the APX activity declined with the increase of
wounding intensity (p < 0.05, Fig. 6C).
No remarkable change of GR activity was observed in whole
pitaya fruit. Fresh-cut processing significantly induced an increase
of GR at the first 2 d of storage and this effect was enhanced with
the increase of wounding intensity (p < 0.05, Fig. 6D).