LAUSR

Abstract The effects of operating conditions and Z-isomer content of astaxanthin on coprecipitate formation of polyvinylpyrrolidone (PVP) and astaxanthin by solution-enhanced dispersion by supercritical fluids (SEDS) process were investigated. Using this process, nano-sized (100–200 nm) and water-soluble PVP/astaxanthin inclusion complex was successfully prepared. As the operating pressure increased from 8 to 15 MPa at a constant temperature, astaxanthin content in the coprecipitates decreased, and increasing the operating temperature from 40 to 60 °C at a constant pressure, the particle size and the astaxanthin content increased. Increasing the PVP ratio for astaxanthin in the range of 5:1 to 20:1, the particle size decreased and when 10:1 of the ratio, the astaxanthin content in the coprecipitates was the highest (60 °C, 10 MPa). Additionally, as the Z-isomer content of astaxanthin increased, the astaxanthin content decreased slightly. However, the coprecipitates rich in astaxanthin Z-isomers, which have higher bioavailability and antioxidant capacity, were obtained.