Modifications of Atlantic salmon by-product oil for obtaining different ω-3 polyunsaturated fatty acids concentrates: An approach to comparative analysis

Abstract

Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) rich 2-monoacylglycerols (2-MAG), omega-3 polyunsaturated free fatty acids (ω-3 PUFFAs) concentrate, and PUFA enriched acylglycerols were prepared from salmon frame bone oil (SFBO) by enzymatic alcoholysis, urea complexation, and enzymatic esterification, respectively. The yields of 2-MAG, ω-3 PUFFAs concentrate, and PUFA enriched acylglycerols were 40.25, 16.52, and 15.65%, respectively. ω-3 PUFFAs concentrate and PUFA enriched acylglycerols showed darker red color than SFBO and 2-MAG due to aggregation of astaxanthin pigment in ω-3 PUFFAs concentrate during urea complexation. The viscosity and specific gravity of SFBO and PUFA enriched acylglycerols showed similar values whereas 2-MAG and ω-3 PUFFAs showed significantly (p < 0.05) lower values. Stability parameters like acid value, peroxide value, free fatty acid value, and p-anisidine value of SFBO and ω-3 PUFAs concentrates were within acceptable limits except extreme high acid value and free fatty acid value of ω-3 PUFFAs concentrate. Thermogravimetric analysis showed similar and higher thermal stability of SFBO and PUFA enriched acylglycerols than 2-MAG and ω-3 PUFFAs concentrate. The ω-3 PUFAs content in 2-MAG, ω-3 PUFFAs concentrate, and PUFA enriched acylglycerols was increased to 20.81, 52.96, and 51.74% respectively from 13.54% in SFBO. ω-3 PUFFAs concentrate and PUFA enriched acylglycerols showed higher DPPH and ABTS radical scavenging activity than SFBO and 2-MAG. The results obtained from this study suggest the production of PUFA enriched acylglycerols rich in ω-3 PUFAs supplements from fish oil for human and pet animals.

Keywords: 2-MAG; Comparative analysis; PUFA enriched acylglycerols; Salmon frame bone oil; ω-3 PUFFAs concentrate.

Fig. 1

Standard curve used for the determination of astaxanthin content.

Fig. 2

TLC analysis of SFBO and ω-3 PUFAs concentrates.

Fig. 3

Yield of different ω-3 PUFAs concentrates. Values are the mean of 3 determinations. Different letters with the bar indicate significant differences (p < 0.05).

Fig. 4

The pattern of the thermal degradation of SFBO and different ω-3 PUFAs concentrates.

Fig. 5

Antioxidant activity of SFBO and different ω-3 PUFAs concentrates (a) DPPH radical scavenging activity (b) ABTS⁺ inhibition activity.