Supercritical CO₂/ethanol extraction of astaxanthin from blue crab (Callinectes sapidus) shell waste

Astaxanthin (AX) is the major naturally occurring carotenoid pigment in marine crustaceans and the flesh of salmonids. These organisms are unable to synthesize AX de novo and when farmed commercially, require it in their feed. The high cost of synthetic AX has promoted research into new natural sources of the pigment, such as crustacean wastes. In this work, AX from demineralized crab (Callinectes sapidus) shell waste was extracted with a mixture of supercritical CO₂ and ethanol as a cosolvent. The effect of total solids load, pressure and temperature was assessed by response surface methodology (RSM). Extracted AX was determined by HPLC. The experimental data were fitted to a second order model whereby the conditions for maximum extraction yield were defined (≥ 34 MPa, 45C and solids load of 25 g). Pressure and solids load were the most important factors affecting AX extraction yields.