Supercritical CO2 processing of omega-3 polyunsaturated fatty acids – Towards a biorefinery for fish waste valorization

Driven by growing prevalence of chronic diseases and consumer’s health awareness, food supplements and nutraceuticals based on omega-3 polyunsaturated fatty acids (PUFAs) are extensively marketed nowadays. However, commercial omega-3 concentrates still present quality issues related to their purity, bioavailability, and easily-oxidizable nature, compelling the industry to seek for more efficient extraction, concentration and formulation methods. Technologies based on the use of supercritical CO2 (scCO2) are a promising alternative, replacing conventional organic solvents and providing milder conditions and an inert atmosphere, which reduce the risk of oxidation. The present review analyzes the latest advances on the use of scCO2 for processing omega-3 PUFAs, focusing on its application in biorefinery strategies for the valorization of fish by-products. Still, further research on process fundamentals is necessary in order to increase the omega-3 yield and purity while reducing the use of energy and auxiliary materials, especially in the transesterification and concentration steps.panish Agencia Estatal de Investigación [grant number PID2019-539 104950RB-I00 / AEI / 10.13039/501100011033] and the Junta de Castilla y León (JCyL) and the European Regional Development Fund (ERDF) [grant number BU301P18 and BU050P20]