Preparation and characterization of sn-2 polyunsaturated fatty acids-rich monoacylglycerols from menhaden oil and DHA-single cell oil

Abstract

Monoacylglycerols (MAGs) with polyunsaturated fatty acids (PUFAs) at the sn-2 position exhibit excellent health benefits, especially in the development of brain functions, and are suggested materials for the production of functional foods. sn-2 PUFA-MAGs, therefore, were prepared from menhaden oil rich in eicosapentaenoic acid and single cell oil rich in docosahexaenoic acid in the present study. The optimal alcoholysis reaction was catalyzed by mixed lipases of Lipozyme TL IM and Lipozyme 435 in the ratio of 60:40 at 45 °C and 4 h, followed by purification through a liquid-liquid extraction using 85% ethanol and hexane, and further concentrated by acetonitrile fractionation. A systematic method for the identification and confirmation of the purified products using electrospray ionization high-resolution accurate-mass tandem mass spectroscopy and 1D and 2D nuclear magnetic resonance were then established in the present study. The final products, i.e., sn-2 PUFA-MAGs, contained 69.3–71.5 g/100g of 2-MAGs, of which, PUFAs varied from 60.2 to 61.6 g/100g. This MAGs can potentially be used as precursors in the production of functional lipids for health purposes.