The quantitative distribution of 23 classes of acyl lipids was determined in the germ, aleurone, starch and endosperm non-starch fractions of Atou (Soft English), Flinor (Hard English), Waldron (US Hard Red Spring) and Edmore (US Amber Durum) wheats. All four wheats had similar proportions (dry basis) of pericarp (6.8-8.6 %), germ (2.5-3.0 %), starchy endosperm (78.7-84.5 %) and starch (59.3-67.5 %), and similar quantities of acyl lipids in the whole kernels (2.8-3.2 :{), germ (25.7-30.5 %). starch (0.8-1.2%) and endosperm non-starch fractions (0.8-1.1 %). Flinor, Waldron and Edmore had 7.3-10% aleurone containing 8.7-10.6 %lipids, but Atou appeared to have a n abnormally low aleurone weight (4.0%) and a correspondingly high lipid content (19.4%). Pericarp acyl lipids were studied only in Atou, where they comprised 1.3 o, { of the dry weight and 3.8 7; of the total acyl lipids in the whole kernel. Lipids in the germ and aleurone consisted of triglycerides (60.3-79.3 %), other nonpolar lipids (5.6-12.0%) and phospholipids (13.6-17.9%). Starch lipids were almost exclusively lysophospholipids (89.4-94.4 %). Greater variation was found in the endosperm non-starch lipids which consisted of triglycerides (1 3.7-34.1 $.' ,), other nonpolar lipids (33.248.5 : Q, glycolipids (18.6-38.3 %) and phospholipids (21.9-35.3 7;).Edmore had the highest levels of triglycerides and non-polar lipids, and the lowest levels of glycolipids (as expected in a tetraploid wheat). Atouresembled Edmore in its low levels of steryl esters and glycolipids, but it also had least phospholipids.
Methods are described for the extraction and quantification of total lipids in cereal grains and other similar tissues, and for the determination of all the major classes of acyl lipid found in these extracts. Total lipids, obtained by direct solvent extraction or after acid hydrolysis, are quantified as fatty acid methyl esters (FAME) by gas chromatography (g.c.), using heptadecanoate (17 : 0) as internal standard. Individual lipid classes are separated by thin-layer chromatography; non-polar lipids and glycolipids are measured as FAME by g.c., while phospholipids are determined from phosphorus distribution. Crude lipid extracts are used to avoid losses during purification, and methanolysis of lipid classes is always performed without extracting the lipids from silica gel in order to minimise autoxidation, handling losses and contamination. Corrections are described for minor losses during experimental procedures, and factors are given for conversion of weights of FAME or phosphorus into weights of original lipid. In the authors' laboratory the precision of routine determinations (variations expressed as percentage of mean values) are usually well within the limits: total lipids, 1.5 %; major lipid classes, 1.5 %; minor lipid classes, 5 %.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.