Inclusion complexes of astaxanthin with hydroxypropyl‐β‐cyclodextrin: Parameters optimization, spectroscopic profiles, and properties

Abstract

Inclusion complexes of astaxanthin with hydroxypropyl‐β‐cyclodextrin (HPCD) were systematically investigated from several aspects of processing optimization by RSM, spectroscopic profiles of UV, FT‐IR, and TG/DTA, and properties of water solubility, storage stability, 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activity, and reducing power. The results showed that the optimal preparation conditions of inclusion complexes were: 500:1 of HPCD/astaxanthin mass ratio, 49.58°C of temperature and 25 mg/mL of HPCD concentration. Under the optimized conditions, inclusion rate of 30.4 ± 1.3% was achieved. Spectroscopic profiles revealed that the hexatomic ring of the astaxanthin molecules was partly included into the HPCD cavities and the starting decomposition temperature of astaxanthin increased by about 50°C due to the protection of HPCD. The storage stability of inclusion complexes was enhanced at the temperatures of 4, 25, 37, and 50°C in dark and light storage conditions. The reducing power and DPPH radical scavenging activities of inclusion complexes were much higher than those of pure astaxanthin, and the inclusion complexes showed good water solubility with high concentration up to 50 mg/mL. In conclusion, the optimized parameters and monitoring procedure by TGA, UV, FT‐IR, and HPLC are useful to conduct the inclusion complexes preparation with good properties, which are helpful for its applications in food and feed industries as an antioxidant additive.Practical applications: (i) The operational parameters of inclusion complexes were optimized and monitored by TGA, UV, FT‐IR, and HPLC, which is useful to conduct the inclusion complexes preparation with good properties; (ii) The properties of inclusion complexes were elucidated such as water solubility, storage stability, DPPH radical scavenging activity, and reducing power, which are helpful for its applications in food and feed industries as an antioxidant additive.Inclusion complexes of astaxanthin with hydroxypropyl‐β‐cyclodextrin (HPCD) were systematically investigated from several aspects of processing optimization by RSM, spectroscopic profiles of UV, FT‐IR, and TG/DTA, and properties of water solubility, storage stability, DPPH radical scavenging activity, and reducing power. The results are useful to conduct the inclusion complexes preparation with good properties and helpful for its applications in food and feed industries as an antioxidant additive.