Low density supercritical fluids precipitation of 9-cis and all trans-β-carotenes enriched particulates from Dunaliella salina

• Ultrasonic extraction (UE), column fractionation (CF), supercritical anti-solvent (SAS) were adopted.
• Effects of operation parameters on purification of cis-9 and trans-β-carotenes were discussed.
• Several experimental designs for the SAS process were evaluated.

In this study, supercritical anti-solvent (SAS) pulverization coupled with reverse phase elution chromatography was employed to isolate 9-cis and trans-β-carotenes from Dunaliella salina. Total concentration of 9-cis (134.7 mg/g) and trans-β-carotene (204.2 mg/g) was increased from 338.9 mg/g of the ultrasonic extract to 859.7 mg/g (338.9 for 9-cis and 520.8 for trans) of the elution fraction. The SAS pulverization of the collected fraction further produced submicron-sized particulates containing 932.1 mg/g (355.6 for 9-cis and 576.5 for trans) of total β-carotenes with a recovery of 86.3% (83.9% for cis and 87.8% for trans). Effects of two SAS operational conditions on the purity, recovery of total β-carotenes, mean size and morphology of the precipitates were obtained from an experimentally designed method. Generation of micronized particulates enriched with 9-cis and trans-β-carotenes by low-density SAS was proved to be feasible and environmental benign.