4. Conclusions
In this study, the storage stability and antioxidant activity of astaxanthin/HPCD complex were evaluated. Both native astaxanthin and the complex showed high stability under storage condition at 4 ◦C and 25 ◦C. Complexation improved the stability of astaxanthin under storage conditions. Both astaxanthin and astaxanthin/HPCD complex had high antioxidant activity in vitro. Compared with ascorbic acid, the reducing power and DPPH radical scavenging activity of astaxanthin were lower in the water due to the poor solubility and self-assembly; the complex was stronger at low concentration for solubility enhancing effect of HPCD. However, the activity decreased at high concentration for the difficult release of astaxanthin in the complex. Astaxanthin and the complex were about dozens of higher than ascorbic acid in the hydroxyl radical scavenging activity, and the complex was a little lower than native astaxanthin. In summary, complexation with HPCD could affectthe antioxidant activity of astaxanthin;it should be improved at low concentration aqueous solution, but hindered at high due to the controlled-release effect. Moredetailedstudies areunderway in our laboratory to understand the storage stability and antioxidant potential of astaxanthin/HPCD complex in the food system.