Determination and Structural Elucidation of Triacylglycerols in Krill Oil by Chromatographic Techniques

Abstract

The content of triacylglycerols (TAG) in krill oil is generally omitted from the labels of commercial supplements and unacknowledged in studies aimed at proving its health benefits. The present study demonstrates that TAG compounds, in addition to phospholipids and lysophospholipids, are an important lipid class in pure krill oil. The fatty acid composition of TAG molecules from krill oil and their distribution on the backbone of TAG structures were determined by gas chromatography and liquid chromatography tandem mass spectrometric, respectively. The content of omega 3 polyunsaturated fatty acids (n-3 PUFA) was similar to those reported in the literature for fish oil. It was estimated that 21 % of n-3 PUFA were at the sn-2 position of TAG structures. To our knowledge, this is the first determination and structural characterization of TAG in pure krill oil supplements.

Comprehensive Study of the Lipid Classes of Krill Oil by Fractionation and Identification of Triacylglycerols, Diacylglycerols, and Phospholipid Molecular Species by Using UPLC/QToF-MS

“…Nevertheless, stearic acid (18:0) was at similar values in the three fractions. These results are in agreement with the results showed by Araujo et al (2014) in which the 14:0 represented 17.5 % in TAG fraction and only 4.2 % in PL while 16:0 was contained in 25.0 % in this latter fraction against 18.9 % in TAG. The MUFA content decreased as the polarity of the fraction increased, and hence, F1, F2, and F3 had contents of 35, 28, and 17 %, respectively.…”

“…Likewise, the value of 0.14 obtained for the omega-6/omega-3 ratio in this study was in the same range as those reported previously in other studies by Ju et al (2009) and Kassis et al (2012). The same happened for the EPA/DHA ratio of 2.9:1, which was in agreement with the value reported for the KO manufacturer of 2.5:1 and Ju et al (2009) with 2.8:1 and somewhat higher than the value reported by Kolakowska et al (1994) and Araujo et al (2014) of 2:1 in comparable samples.…”

“…Ju and Harvey (2004), Ulven et al (2011), andAraujo et al (2014) reported contents of 33, 34, and 38.1 % for SFA; 25, 28, and 24.0 % for MUFA; and 38, 42, and 37.9 % for PUFA, respectively. Hence, our results for these variables are consistent with these existing studies.…”

Opportunities to enhance alternative sources of long-chainn-3 fatty acids within the diet

“…Krill contain LC n-3 PUFA mainly as phospholipids (38) but also as TAG (31) . E. superba contains the highest concentration of EPA and DHA compared to other krill species (39) .…”

Plackett-Burman Design and Fragmentation Studies to Assist the Comparison of Techniques used to Extract Phospholipids Prior to Regiospecific Characterization by Liquid Chromatography Mass Spectrometry

“…For example, krill oil usually contains different lipid classes, including phospholipids, triacylglycerols, free fatty acids and cholesterol (Araujo et al, 2014) to the extent that an effective extraction protocol is required prior to the analysis of phospholipids by LCMS n to prevent interference from other lipid classes, ensure data quality and improve the accuracy of the identification and quantification steps.…”