Purification of Fish Oils and Production of Protein Powders with EPA and DHA Enriched Fish Oils

Abstract

Eicosapentaenoic (EPA) and docosahexaenoic (DHA) in marine oils are known to provide health benefits. However, marine oils are accompanied by saturated fatty acids. By enriching fish oils with EPA and DHA the beneficial effect of fish oils can be increased while limiting the detrimental effect of the saturated fatty acids. Fish oils need to be purified before consumption. A number of methods have been used for extracting and purifying EPA and DHA enriched fish oils; however, thermal degradation and oxidation of polyunsaturated fatty acids (PUFAs) often occurs as a result of exposure to high temperatures, solvents and adverse conditions during processing. Therefore, it is important to develop a combined purification and enrichment method for EPA and DHA that minimizes the degradation and oxidation of PUFAs. A process which produces a dry powder microencapsulated fish oil enriched with EPA and DHA enclosed in a protein and peptide coating may suffice and result in higher market value and extended shelf life. Menhaden (MO) and salmon (SO) oils were used to develop the process. MO and SO were hydrolyzed by lipase at enzyme concentrations of 250, 500, 2500 U/g oil and 50, 250, 1250 U/g oil, respectively, for up to 24h. The enzyme was subsequently inactivated and removed using centrifugal force. The fish oils enriched with EPA and DHA were purified using adsorption technology. The purified oils enriched with EPA and DHA were microencapsulated with protein and peptides. The lipase hydrolysis kinetics of MO and SO were well fitted with the Michealis-Menten model. Total EPA and DHA fractions increased from 21.1% to 38.9% for MO at 2500 U/g oil and from 20.1% to 32.8% for SO at 1250 U /g after 6 h of hydrolyzation. The adsorption process reduced impurities in fish oil enriched with EPA and DHA. Microencapsulated MO and SO enriched with EPA and DHA powders contained all the essential amino acids. This study demonstrated a method to enrich fish oils with EPA and DHA and to purify the oils enriched with EPA and DHA. In addition, the study demonstrated the microencapsulation of fish oils enriched with EPA and DHA with a protein and peptide wall material.