Production of all trans-beta-carotene by using impinging flow of supercritical carbon dioxide anti-solvent pulverization

► Beta-carotene particles were formed using supercritical anti-solvent (SAS) pulverization. ► Trans-beta-carotene was recovered using reverse phase column chromatography. ► Operation conditions of SAS were revealed by an experimental design. This work investigated column elution chromatography coupled with supercritical anti-solvent precipitation to produce carotenoid rich microsized particulates from microalgal Dunaliella salina species. The extract contained carotenoids ranging from 61.3mg/gsalina to 72.5mg/gsalina using ultrasonic stirred ethyl ether or tetrahydrofuran (THF) extraction. When 10L of ethyl alcohol was employed to elute the THF extract, purity of trans-β-carotene is 823.6mg/g with a recovery of 86.2%. It was found that the supercritical anti-solvent of THF solution at 160bar and 318K produced powdered particulates with a purity of carotenoids above 90%. Subsequently, a central composite response surface design method was used to design supercritical anti-solvent precipitation of carotenoid-rich THF solution. This was accomplished by increasing the pressure from 140bar to 180bar and the time from 40min to 60min at a feed flow rate of 0.2mL/min. A CO2 flow rate of 15L/min and a temperature of 318K were also used to determine the effects on purity and recovery of trans-β-carotene. The combined process produced micronized precipitates with a mean particle size ranging from 3.5μm to 19μm and the purity of trans-β-carotene attained was 926.8mg/g with a recovery of 54%.