Fish Oil: Extraction Methods Affect Omega-3 Quality
Here is how fish oil extraction methods influence the quality of Omega-3 supplements
The quality of fish oil rich in Omega-3 can be improved by using the so-called supercritical carbon dioxide in extraction processes. This was demonstrated in a study published in the Journal of Food Engineering by a group led by Sagrario Beltrán from the University of Burgos (Spain). According to the Spanish researchers, the supercritical fluid extraction (SFE) method allows for the removal of heavy metals that may contaminate the raw material. SFE also reduces the oxidation of Omega-3 during fish oil production.
General trials for better Omega-3
Beltrán and colleagues compared supercritical fluid extraction, which operates in a state between gas and liquid, with traditional extraction methods. The researchers used supercritical carbon dioxide, a fluid requiring a non-oxidizing atmosphere and moderate temperatures, conditions that prevent the oxidation of Omega-3 fatty acids. The three methods compared were:
- cold extraction
- wet extraction
- enzymatic extraction
Four different fish processing by-products were used as raw materials, characterized for their water, protein, fat content, and trace metals. After extraction, the fish oil was analyzed to determine its chemical and organoleptic properties.
Higher quality fish oil
The data showed that extraction with supercritical fluids under moderate conditions (25 MegaPascal pressure and 40°C temperature) reduces the oxidation of fish oil. This technique is especially advantageous when the raw materials are low-fat fish waste and lyophilized materials. Moreover, when starting from hake waste or giant squid liver, SFE is the only method that yields significant oil quantities. Finally, using supercritical carbon dioxide helps limit the extraction of some pollutants, such as certain species of arsenic.
Beltrán and colleagues also emphasized that process efficiency strongly depends on the quality and freshness of the starting material, and in some cases an additional deodorization step is necessary to remove unpleasant odors.
Enriching fish oil with Omega-3
The extraction method used to obtain Omega-3 rich oils determines the final product quality. Specifically, it affects the oxidation of fatty acids, pollutant levels, and organoleptic properties. The authors concluded that supercritical fluid extraction is a valid alternative to physical and chemical refining methods and improves fish oil quality. This improvement is due to preventing lipid oxidation, especially when producing Omega-3 rich fish oil, such as that from salmon. Quality is also increased by a significant reduction in pollutants.
Source
1. Rubio-Rodríguez N, de Diego SM, Beltrán S, Jaime I, Sanz MT, Rovira J, “Supercritical fluid extraction of fish oil from fish by-products: A comparison with other extraction methods”, J Food Eng, 2012 Mar;109(2):238-248
