Table 2.

Extraction of omega-3 (EPA and DHA)-enriched fish oils from marine side streams using SFE.

Side Stream	Source	SFE Conditions	Outcomes	Ref.
Caviar and viscera	Carp (Cyprinus carpio L.)	Temperature: 40, 50, and 60 °C Pressure: 200, 300, 350, and 400 bar CO2 flow: 0.194 kg/h Extraction time: 180 min	High yields (>50 g/100 g) in viscera, which are similar to those obtained with conventional methods	[51]
Head	Thunnus tonggol	Temperature: 65 °C Pressure: 40 MPa CO2 flow with ethanol: 3 mL/min Extraction time: 2 h	Co-solvent allowed to extract omega-3 after oil fractionations	[46]
Head, shells and tails	Northern shrimp (Pandalus borealis Kreyer)	Temperature: 40 °C Pressure: 35 MPa CO2 flow: 3–5 L/min Extraction time: 90 min	Lower yields (137 mg oil/g) than those obtained with solvent extraction. Higher fatty acid (795 mg/g), EPA (7.8%), and DHA (8%) contents	[49]
Heads and tails	Sardine	Temperature: 75 °C Pressure: 300 bar CO2 flow: 2.5 mL/min Extraction time: 45 min	Increased extraction yields: DHA (59%) and EPA (28%)	[47]
Liver	Rock lobsters (Jasus edwardsii)	Temperature: 50 °C Pressure: 35 MPa Continuous CO2 flow: 0.434 kg/h Extraction time: 4 h	Enrichment in PUFAs (DHA, EPA) vs. Soxhlet extraction Reduction of toxic heavy metals	[50]
Off-cuts	Hake (Merluccius capensis– Merluccius paradoxus) Orange roughy (Hoplostethus atlanticus) Salmon (Salmo salar)	Temperature: 313 K Pressure: 25 MPa CO2 flow: 880 kg/m3	Increased fish oil stability Reduction of impurities Co-extraction of some endogenous volatile compounds	[48]
Liver	Jumbo squid (Dosidicus gigas)
Skins, scales and bones	Bigeye tuna (Thunnus obesus)	Temperature: 40 °C Pressure: 25 MPa CO2 flow: 10 kg/h	Recovery of 85.6, 83.2, and 87.7% of oil from skins, scales, and bones. EPA + DHA contents of 26.7–28.3%	[45]