Solid-state (2)H NMR and MD simulations of positional isomers of a monounsaturated phospholipid membrane: structural implications of double bond location.

The impact that the position of double bonds has upon the properties of membranes is investigated using solid-state (2)H NMR and MD simulations to compare positional isomers of 1-palmitoyl-2-octadecenoylphosphatidylcholine (16:0-18:1PC) bilayers that are otherwise identical apart from the location of a single cis double bond at the Delta(6), Delta(9), Delta(12), or Delta(15) position in the 18:1 sn-2 chain. Moment analysis of (2)H NMR spectra recorded for isomers perdeuterated in the 16:0 sn-1 chain reveals that average order parameters S(CD) change by more than 35% and that the temperature for chain melting T(m) varies by 40 degrees C. At equal temperature, the S(CD) values exhibit a minimum, as do T(m) values, when the double bond is in the middle of the 18:1 sn-2 chain and increase as it is shifted toward each end.

A practical guide to the isolation, analysis and identification of conjugated linoleic acid.

Natural and synthetic conjugated linoleic acids (CLA) are reputed to have therapeutic properties that are specific to particular geometrical and positional isomers. Analysis of these has presented unique problems that have brought forward distinctive solutions, especially the use of gas chromatography-mass spectrometry and silver-ion high-performance liquid chromatography. In the analysis of CLA present at low levels in tissue samples, it is sometimes necessary to use concentration methods.

Preparation of spread oils meeting U.S. Food and Drug Administration Labeling requirements for trans fatty acids via pressure-controlled hydrogenation.

On July 11, 2003, the U.S. Food and Drug Administration (FDA) announced final regulations for trans fatty acid (TFA) labeling.

Triacylglycerol structure and composition of hydrogenated soybean oil margarine and shortening basestocks.

The composition and structures of triacylglycerols (TAG) in a commercially prepared hydrogenated soybean oil margarine basestock [iodine value (IV) 65, 39.7% trans fatty acids] were determined by high-performance liquid chromatography (HPLC) in tandem with atmospheric pressure chemical ionization (APCI) mass spectrometry (MS). The basestock was separated by preparative HPLC into four fractions.

Sex pheromone biosynthesis in the pine caterpillar moth, Dendrolimus punctatus (Lepidoptera: Lasiocampidae): pathways leading to Z5-monoene and 5,7-conjugated diene components.

Biosynthesis of the sex pheromone components (Z)-5-dodecenol and (Z,E)-5,7-dodecadienol in Dendrolimus punctatus was studied by topical application of deuterium-labeled fatty acids to pheromone glands and subsequent analysis of fatty acyl groups and pheromone components by gas chromatography-mass spectrometry. Our studies suggest that both (Z)-5-dodecenol and (Z,E)-5,7-dodecadienol can be biosynthetically derived from chain elongation of palmitate to stearate in the gland, and its subsequent Delta11 desaturation to produce (Z)-11-octadecenoate. After three cycles of 2-carbon chain-shortening, the pheromone glands produce (Z)-5-dodecenoate, which is then converted to (Z)-5-dodecenol by reduction.

Synthesis and analysis of symmetrical and nonsymmetrical disaturated/monounsaturated triacylglycerols.

Symmetrical disaturated triacylglycerols of the structure SUS, where S is stearic acid (18:0) and U is an unsaturated fatty acid, either oleic (O; 9cis-18:1), linoleic (L; 9cis,12cis-18:2), or linolenic (Ln; 9cis,12cis,15cis-18:3), are important components providing functionality to interesterified fat blends and structurally modified oils. Nonsymmetrical triacylglycerols of the structure SSU can significantly change melting point and solid fat content profiles. To characterize the physical properties of pure and symmetrical and nonsymmetrical triacylglycerol mixtures, the same reaction sequence has been used to prepare multigram quantities of triacylglycerols SUS and SSU.