Here's how fish oil extraction methods affect the quality of Omega 3 supplements

The quality of Omega 3-richfish oil can be improved by using so-called supercritical carbon dioxide in extraction processes. This was demonstrated in a study published in the Journal of Food Engineering by a group of researchers led by Sagrario Beltrán of the University of Burgos (Spain). According to the Spanish scientists, the supercritical fluid extraction (FSE) method makes it possible to remove heavy metals that can contaminate the starting material. FSE also reduces theoxidation of Omega-3s during the fish oil production process.

General evidence for Omega-3 best

Beltrán and colleagues compared extraction with supercritical fluids, that is, at an intermediate stage between gaseous and liquid, with traditionally used methods. The researchers used supercritical carbon dioxide, a fluid that requires the use of a nonoxidizing atmosphere and moderate temperatures, conditions that preventoxidation of Omega-3 fatty acids. There are 3 techniques by which the comparison was made:

• cold extraction
• wet extraction
• enzymatic extraction

Four different side products of fish processing were used as starting material. Each was characterized as to its water, protein and fat content and for the amount of trace metals present. Following extraction, the fish oil was analyzed to determine its chemical and organoleptic characteristics.

Better quality fish oil

Based on the data collected, the researchers concluded that an extraction with supercritical fluids under moderate conditions, corresponding to a pressure of 25 MegaPascals and a temperature of 40°C, can reduce oxidation offish oil. This technique is particularly advantageous if the starting material is low-fat, freeze-dried fish waste. Also, in the case of starting with hake scraps or giant squid liver, SFE is the only method that allows significant amounts of oil to be obtained. Finally, the use of supercritical carbon dioxide makes it possible to limit the extraction of certain pollutants, such as some arsenic species. 

In any case, Beltrán and colleagues pointed out that the efficiency of the process is highly dependent on the quality and freshness of the starting material, and in some cases an additional step of eliminating unpleasant odors is necessary.

Enrich fish oil with Omega-3s

The extraction process used to obtain Omega-3 rich oils determines the quality of the final product. In particular, fatty acid oxidation, pollutant levels and organoleptic properties depend on it. Thus, the authors of the research concluded that supercritical fluid extraction is a viable alternative to physical and chemical refining procedures that can improve the quality of fish oil. This improvement is due to the prevention of lipid oxidation, especially when a fish oil rich in Omega-3, such as that obtained from salmon, is desired. The increase in quality is also due to the significant reduction of 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