Correlation of Fatty Acid Structure With Preferential Order of Urea Complex Formation

Iverson, John L; Weik, Robert W

doi:10.1093/jaoac/50.5.1111

Cited by 4 publications

(6 citation statements)

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“…The resulting solution was concentrated, and the samples were fractionated with urea (butter, suet, goat's milk fat, human milk fat) or subjected to Ag + -HPLC (goat's milk fat), or both, and analyzed by GC/MS in the SIM mode. Urea fractionation was used for the enrichment of methyl-branched fatty acids in favor of long straight-chain fatty acids . For this purpose, 100 μg of fatty acid methyl esters (FAME) was dissolved in 10 mL of methanol.…”

Section: Methodsmentioning

confidence: 99%

Enantioselective Determination of Anteiso Fatty Acids in Food Samples

2007

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Anteiso fatty acids (aFAs)-long-chain carboxylic acids with a methyl branch on the (n - 2)-carbon-are among the most simple fatty acids that are chiral. The most frequently occurring aFAs in food are 12-methyltetradecanoic acid (a15:0) and 14-methylhexadecanoic acid (a17:0), structures where the asymmetric carbon is more than 10 carbons separated from the polar head group. Previously, only enantioseparation of 4-methyl-substituted carboxylic fatty acids has been reported by gas chromatography. Here we present the first direct partial enantioresolution of synthesized racemic a15:0-a17:0 on a capillary column coated with 50% heptakis(6-O-tert-butyldimethylsilyl-2,3-di-O-methyl)-beta-cyclodextrin diluted in OV1701. Synthesized (S)-(+)-enantiomers were used to demonstrate that the elution order was (R)- prior to (S)-enantiomers. Using this system, food samples (butter, goat's milk fat, suet, human milk, seal oil, cod liver oil) known to contain aFAs were analyzed. Prior to the enantioselective gas chromatography, unsaturated fatty acids were preseparated by urea complexation, silver ion high performance liquid chromatography (Ag+-HPLC), or both from food samples. The fractions of the food samples enriched with methyl-branched fatty acids were then analyzed by GC/MS in the SIM mode. The measurements confirmed that the (S)-enantiomer of a15:0 (ee >96%), a16:0, and a17:0 (ee >90%, respectively) dominated in all samples. While the (R)-enantiomers could not be identified in samples from ruminants and human milk, their presence could be established in cod liver and seal oil (ee <86%).

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Section: Methodsmentioning

confidence: 99%

Enantioselective Determination of Anteiso Fatty Acids in Food Samples

2007

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“…The simple and effective technique for obtaining polyunsaturated fatty acids (PUFA) concentrates in the form of free fatty acids (FFA) is urea complex fractionation. This is a well-established technique for the elimination of saturated and monounsaturated fatty acids [6,7]. Initially the triacylglycerols (TAG) of the oil are split into their constituent fatty acids by alkaline hydrolysis using alcoholic KOH or NaOH and these FFA are then mixed with an ethanol solution of urea for complex formation.…”

Section: Introductionmentioning

confidence: 99%

Optimizing Conditions for the Purification of Linoleic Acid from Sunflower Oil by Urea Complex Fractionation

Ding

Wang

et al. 2008

J Americ Oil Chem Soc

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The separation and purification of linoleic acid (LA) from sunflower seed oil by urea complex fractionation was studied. Crystallization reaction conditions of urea inclusion were optimized using the response surface method, and the optimal model was developed. Using the linear weighting method of the fitting model for optimization, the optimal balance between the purity and the recovery of LA was obtained. Under optimal conditions, the purity of LA was 87.8%, and the recovery was 83.4% at a urea-to-fatty acids ratio (w/w) of 0.94, 95% ethanol-tourea (v/w) of 5.00, a crystallization temperature of 18.0°C, and a crystallization time of 5.0 h. Verification results revealed that the predicted values from these models were reasonably close to the experimentally observed values.

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“…The affinity of FA and esters with urea decreases when unsaturated bonds are present in the chain. Thus, SFA and MUFA are first precipitated from the solution while PUFA remain in solution (Iverson & Weik, 1967;Strocchi & Bonaga, 1975). The parameters governing the crystallization have been extensively studied as the urea adductability values (binding properties between urea and FA) (Iverson & Weik, 1967), the stability constants and the heats of formation of crystals (Schlenk, 1954;Swern, 1964).…”

Section: Urea Crystallizationmentioning

confidence: 99%

“…Thus, SFA and MUFA are first precipitated from the solution while PUFA remain in solution (Iverson & Weik, 1967;Strocchi & Bonaga, 1975). The parameters governing the crystallization have been extensively studied as the urea adductability values (binding properties between urea and FA) (Iverson & Weik, 1967), the stability constants and the heats of formation of crystals (Schlenk, 1954;Swern, 1964). To form complexes, the urea concentration should be near saturation; the fractionation is greatly influenced by urea:FA ratio and temperature can be adjusted according to the desired concentration of FA.…”

Section: Urea Crystallizationmentioning

confidence: 99%

Algal Derived Functional Lipids and their Role in Promoting Health

Terme

Chénais

Fournière

et al. 2021

Recent Advances in Micro and Macroalgal Processing

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Algae are organisms with an enormous biodiversity and contain manifold fatty acid molecular structures and ratios. This chapter presents information about the structure and distribution of fatty acids in algae whether microalgae or macroalgae. The parameters affecting lipid and fatty acid contents as well as distribution are also discussed. Methods for isolation and purification of fatty acids from algae to obtain highly pure fatty acid or fatty acid fractions with good overall yields are presented. Algal fatty acids are known as sources of bioactive compounds for health promotion and wellness. Lipid fractions and fatty acids act as actives or additives for cosmeceutical applications. For health promotion, preventive effects of n-3 polyunsaturated fatty acids on cardiovascular disease, metabolic syndrome and cancer are discussed. The role of n-3 fatty acids in cancer therapy and antiviral activities of lipids are also exposed. Furthermore, potential commercial application domains and concepts are discussed in this chapter.

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Correlation of Fatty Acid Structure With Preferential Order of Urea Complex Formation

Cited by 4 publications

References 0 publications

Enantioselective Determination of Anteiso Fatty Acids in Food Samples

Enantioselective Determination of Anteiso Fatty Acids in Food Samples

Optimizing Conditions for the Purification of Linoleic Acid from Sunflower Oil by Urea Complex Fractionation

Algal Derived Functional Lipids and their Role in Promoting Health

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