Extraction of astaxanthin from engineered Camelina sativa seed using ethanol-modified supercritical carbon dioxide

Natural astaxanthin, a high-value carotenoid that is currently extracted mainly from marine organisms, was extracted from engineered camelina seed using ethanol-modified supercritical carbon dioxide (SC-CO₂) for the first time, and compared with hexane and accelerated solvent extraction using hexane and ethanol. Response surface methodology (RSM) based on central composite rotatable design was employed to investigate the effect of pressure (30–45 MPa), temperature (40–60 °C), and ethanol concentration (10–35%, w/w). RSM-optimized conditions (41.6 MPa, 36.6 °C and 42.0% ethanol concentration) predicted the astaxanthin concentration as 437 μg/g oil, whereas the actual concentration was 421 ± 14 μg/g oil. Astaxanthin concentration in accelerated solvent extracted oil was significantly lower than that in ethanol-modified SC-CO₂- and hexane-extracted oils (P < 0.05). Oils extracted with ethanol-modified SC-CO₂ had the highest antioxidant activity. Results indicated that ethanol-modified SC-CO₂ extraction method can be successfully used as a green method to extract astaxanthin from high oil feedstocks.