Using eutectic solvents for extracting astaxanthin from dry biomass of Xanthophyllomyces dendrorhous pretreated by pulsed electric fields

The healthy properties of astaxanthin (AST) together with the growing interest in products of natural origin have motivated the development of sustainable extraction procedures from biomass. For this, it is essential to establish mechanisms that allow overcoming the barrier of the cell envelopes as well as the substitution of the conventional solvents. This work is focused on the evaluation of pulse electric fields (PEFs) as a fresh biomass pretreatment to enhance the efficacy of eutectic mixtures (ESs) as eco-friendly solvents for extracting AST from the freeze-dried yeast Xanthophyllomyces dendrorhous. The results showed a positive effect on the extraction efficiency of the pulse treatment and subsequent incubation stage. The thymol/salol system was the best solvent and the most favorable composition, temperature and extraction time were calculated. The efficiency reached 79% in the PEF-treated cells after incubation. The antioxidant capacity of AST in the eutectic mixture was determined and an IC50 value of 0.02 μg/mL was obtained. A synergistic effect between AST and thymol was observed. The main conclusion of the work is that consecutively using PEFs as an electroporation technique and ESs as solvents allows us to obtain a high extraction efficiency of AST from dry yeast.