Enzymatic oil extraction and positional analysis of ω-3 fatty acids in Nile perch and salmon heads

The use of commercial proteases, bromelain and Protex 30L for oil extraction/recovery of polyunsaturated fatty acids (PUFA) from Nile perch and salmon heads was evaluated. Four phases were obtained after hydrolysis, oily phase, emulsion, aqueous phase and sludge. An increase in water content during the hydrolysis resulted in a decrease in oil yield. Maximum oil yield was obtained when hydrolysis was performed with Protex 30L at 55 °C, without pH adjustment or water addition. An oil yield of 11.2% and 15.7% of wet weight was obtained from Nile perch and salmon heads, respectively, compared to 13.8% and 17.6%, respectively obtained using solvent extraction. Fatty acid distribution analysis showed 50% of palmitic acid was in sn-2 position in Nile perch triglycerides (TAG), while only 16% of this fatty acid was in sn-2 position in salmon oil TAG.