Effects of high water content and drying pre-treatment on supercritical CO2 extraction from Dunaliella salina microalgae: Experiments and modelling

• Effects of water content on supercritical CO2 extraction from Dunaliella salina microalgae are presented.
• Extraction curves of solutes from sample with relatively high water content were modelled.
• Sovová’s approach was chosen for the modelling.
• Three different kinds of drying were applied in the study.
• The extraction experiments were conducted at different process parameters.

This study investigates the effects due to the water content and to the drying pre-treatment on the extraction kinetics of solutes extracted from Dunaliella salina microalgae by supercritical CO2. The extraction experiments were conducted at pressure range from 20 up to 40 MPa at a temperature of 333 K on crushed samples with water content varying from 5.5 up to 23 wt%. Three drying pre-treatments were applied: air flow drying at 318 K, air flow drying followed by additional microwave treatment and freeze-drying. A water content up to 23 wt% helps to extract a higher content of carotenoids (mainly β-carotene) and does not restrict the extraction process. Sovová’s mathematical model was applied and the parameters were adapted for the description of the extraction curves from samples containing high water content with a deviation between experimental and calculated values comprised between 1.1% and 4.3%.

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