As shown in Fig. 5A, during cold storage, the pattern of changes
in PODs increased first, and then decreased. POD activity in the control
increased to a peak on the 15th day, and then dropped quickly
for the following day. While fruits treated with chitosan, glucose
or CGC attained the maximums by day 45, which higher than the
peak of controls. When fruits were transferred to 20 ◦C in air for
shelf life, POD activities in all samples decreased sharply.
The changes in SOD activity are shown in Fig. 5B. Under storage
at 0 ◦C, SOD activity in all fruits increased rapidly and reached peaks
on day 15, following to drop at the remainder of time. In the shelf
life, SOD activities in chitosan–glucose complex or chitosan-treated
fruits were higher than that in the control or glucose treatment, in
spite of SOD activities decreased in all samples.