Enhancing the stability of astaxanthin by encapsulation in poly (l-lactic acid) microspheres using a supercritical anti-solvent process

•Astaxanthin was successfully encapsulated into PLLA matrix via a SAS process.•Key process variables affecting particle microstructures were investigated.•The optimal particles were uniform microspheres with 91.5% encapsulation efficiency.•The storage stability of astaxanthin could be greatly enhanced when loaded by PLLA.