Supercritical CO2 extraction of lipids and astaxanthin from Atlantic shrimp by-products with static co-solvents: Process optimization and mathematical modeling studies

Shrimp processing by-products are a source of valuable biomaterials/bioactive materials (such as lipids and astaxanthin). Extraction of these compounds could not only decrease environmental impacts associated with shrimp harvesting but also result in economic benefits. This work investigates the caonditions for supercritical extraction combined with co-solvents for the extraction of lipids and astaxanthin from Atlantic shrimp by-products ( Pandalus borealis ). Extraction conditions (pressure, carbon dioxide flow, and temperature) impact lipid and astaxanthin yields and compositions. A model was developed to describe the SC-CO 2 extraction rates of lipids/astaxanthin using the Goto et al. model. In experiments using only CO 2 , the highest lipid yield was extracted at 50 °C and 30 MPa and the maximum astaxanthin yield and total carotenoid content at 60 °C and 32 MPa. Lipid/astaxanthin recovery increased with an increase in pressure; however, the impact of temperature was more complex. Overall extraction rates of lipid/astaxanthin were controlled by the strong solid–solute interaction. Pure SC-CO 2 extract had high percentages of neutral lipids but low phospholipids. In co-solvent experiments (using ethanol, 40:60 vol% hexane/acetone, fish oil, or sunflower oil), polar organic co-solvents showed higher lipid/astaxanthin yield and phospholipids/saturated fatty acid concentrations in the extract relative to pure SC-CO 2 extract. There was a corresponding decrease in monounsaturated and polyunsaturated fatty acid concentrations in the extract. Sunflower oil as a co-solvent showed higher astaxanthin, sterol, and free fatty acid concentrations compared to the fish oil extract. • Shrimp processing by-product is a rich but underutilized source of astaxanthin. • Fish oil as a solvent in extract rich in triacylglycerols, n-6 fatty acids and astaxanthin. • Drying increases astaxanthin in fish oil extracts but impact lipid compositions. • Fish oil:waste ratio increases the ASX yield.