The color response value X at the beginning and end are
not corresponded to the storage temperature and time. It is
only determined by the percentage of enzyme in the TTI.
The color change processes of the four time–temperature
indicators were similar. With the hydrolysis of starch, the
color of the clathrate changes from dark blue to colorless.
Since the amylase was from Bacillus subtilis, which was pale
yellow, the final color of the clathrate was pale yellow,
either. Furthermore, the more content of the enzyme, the
more deep the end color of TTI was. Fig. 1 exhibited the
color change process of TTI #3 at 25 C.