However, good antioxidant activity and tinctorial power are
depended on the storage stability of astaxanthin. Figs. 3 and 4 show
the storage stabilities of astaxanthin and the complex at 4 ◦C and
25 ◦C respectively. It can be found that the absorbance of astaxanthin
and the complex reduced slowly within test periods. The
stability of the complex was higher than that of native astaxanthin.
After 28 days test, 6.09% of native astaxanthin decomposed,
meanwhile, 4.59% of astaxanthin in the complex lost, at 4 ◦C. When
stored at 25 ◦C, 8.58% of native astaxanthin and 7.20% of astaxanthin
in the complex decomposed, respectively. The data is slightly
higher than that of 4 ◦C. Overall, both native and astaxanthin in the
Fig. 3. Storage stability of astaxanthin (a) and astaxanthin/HPCD (b) complex at 4 ◦C.
complex showed high stability under storage condition. This result
was agreed with former report (Rao, Sarada, & Ravishankar, 2007).
Complexation was helpful to improve stability of astaxanthin under
storage condition.