Submitted to: Cereal Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/11/2010
Publication Date: 9/1/2010
Citation: Doehlert, D.C., Moreau, R.A., Welti, R., Roth, M.R., Mcmullen, M.S. 2010. Polar lipids from oat kernels. Cereal Chemistry. 87(5):467-474. Interpretive Summary: Polar lipids include phospholipids and glycolipids, and are commonly referred to as lecithin as a food ingredient. These have important potential commercial applications such as emulsifiers in baked goods, or as carriers of fat soluble drugs in the pharmaceutical industry. Oats appear to be one of the richest sources of polar lipids of any plant source yet analyzed by scientists. In this report, we show polar lipid concentrations in 18 different oat varieties. Glycolipids are particularly abundant in oats and contain diverse forms, called estolides, not found in any other organisms analyzed by scientists. Thus, oats represent a particularly rich source of polar lipids for potential application in food or pharmaceutical products.
Technical Abstract: Oat (Avena sativa L.) kernels appear to contain much higher polar lipid concentrations than other plant tissues. We have extracted, identified, and quantified polar lipids from 18 oat genotypes grown in replicated plots in three environments in order to determine genotypic or environmental variation in these lipids. Validation experiments indicated a solid phase silica gel extraction step elution provided excellent and clean separation of extracted lipids into neutral lipid, glycolipid and phospholipid fractions. Analysis of phospholipids by HPLC (normal phase, diol column) indicated phosphatidylethanolamine, phosphatidylcholine, phosphatidic acid, phosphatidylglycerol, phosphatidylinositol and lyso- forms, but very little genotypic or environmental variation. Di, tri and tetragalactosyl-diacylglycerols were quantified in the glycolipids, along with their mono-, di-, and tri-acyl estolides. Most of these exhibited significant genotypic variation. Molecular species analysis of the glycolipids in the ’Morton’ cultivar by direct infusion electrospray ionization tandem mass spectrometry confirmed the enormous diversity of galactosyl-lipids in oats. Analyses indicated total lipid of about 8.3% (dry weight basis), of which about 10% was phospholipid and 11% was glycolipids. These results indicate that oats are a rich source of polar lipids and contain an extremely rich diversity of galactosyl-lipids.