Enrichment of β-carotene from palm oil using supercritical carbon dioxide pretreatment-solvent extraction technique

- A two-step method was developed to enrich beta-carotene from 10 g/100 g beta-carotene concentrate.
- Supercritical CO2 extraction was an effective way to remove impurities like oil and wax fraction.
- Solvent extraction further boosted the pretreated beta-carotene concentrate from 16.5 g/100 g to 58.7 g/100 g.
- Extraction and purification mechanisms by supercritical CO2 and solvent extraction were explained.

Enriching natural 10 g/100 g β-carotene concentrate further is both meaningful and challenging issue. In this paper, a two-step technique has been reported to boost the concentration of natural β-carotene. Supercritical carbon dioxide (SC-CO2) was utilized to preconcentrate 10 g/100 g β-carotene made from crude palm oil followed with a solvent extraction. In the first step, the β-carotene concentration was preconcentrated to 16.7 g/100 g from 10 g/100 g when pretreating conditions were as follows: extraction temperature 60 °C, extraction pressure 20 MPa, extraction time 3 h, and CO2 flow rate 22 kg/h, In the second step, the β-carotene was boosted to 58.7 g/100 g from 16.7 g/100 g when the ratio of the preconcentrated sample and n-hexane solvent was 4:200 (g:mL), and the processing temperature was −5 °C. This is attributed to that SC-CO2 was able selectively to remove the impurities such as oil fraction. Removing impurities enable further purification of the beta-carotene with hexane extraction. The pretreatment of removing oil fraction using supercritical (SC-CO2) plays a vital role in the enrichment of β-carotene from 10 g/100 g β-carotene concentrates to higher content.