Extrusion of Antarctic krill (Euphausia superba) meal and its effect on oil extraction

Summary: Antarctic krill meal as well as mixed krill meal and starches were extruded through a twin-screw extruder. The extrudates were hard and porous agglomerates. The pellets still showed intact structure without obvious disintegration in response to hexane extraction. The oil recovery rates for raw krill meal and the extrudate of single krill meal were 55.08% and 59.08%, respectively. For extrudates, oil recovery rate increased along with the increasing additive amount of starches, with a maximum of 83.13%. Oil extracted from raw krill meal contained 49.30% of triglycerides (TG), 44.16% of phospholipids (PL), 1.45% of free fatty acids (FFA) and 4.69% of cholesterols (CHO). Meanwhile, polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA) and saturated fatty acids (SFA) account for 20.89%, 37.84% and 41.27% of the total fatty acids, respectively. By contrast, oils extracted from extrudates contained more TG but less PL and more SFA but less PUFA.