Compound formation in binary fatty-acid mixtures

1955 ◽  
Vol 233 (1193) ◽  
pp. 195-202 ◽  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
High Resolution ◽  
Compound Formation ◽  
X Ray ◽  
Fatty Acid Mixtures

Long crystal spacings d 1 and short spacings d 2 and d 3 of C 12 –C 14 , C 14 –C 16 and C 16 –C 18 fatty - acid mixtures have been determined using a high resolution X -ray diffractometer in an attempt to elucidate the question of compound formation in these mixtures. Both d 1 and d 3 spacings showed significant changes in relation to the composition of the mixtures whereas d 2 spacings remained practically unchanged. The changes in d 1 and d 3 spacings are interpreted as denoting limited intersolubility of the component fatty acids and partial compound formation. Numerical correlation found between the above changes seems to indicate a shortening of the distance between alternate carbon atoms of the higher melting component in mixtures containing 30 to 70 mol. percent of this component.

scholarly journals High-resolution neutron and X-ray diffraction room-temperature studies of an H-FABP–oleic acid complex: study of the internal water cluster and ligand binding by a transferred multipolar electron-density distribution

IUCrJ ◽  
2016 ◽  
Vol 3 (2) ◽  
pp. 115-126 ◽  
Author(s):  
E. I. Howard ◽  
B. Guillot ◽  
M. P. Blakeley ◽  
M. Haertlein ◽  
M. Moulin ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Fatty Acid ◽  
High Resolution ◽  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Room Temperature ◽  
Water Molecules ◽  
X Ray

Crystal diffraction data of heart fatty acid binding protein (H-FABP) in complex with oleic acid were measured at room temperature with high-resolution X-ray and neutron protein crystallography (0.98 and 1.90 Å resolution, respectively). These data provided very detailed information about the cluster of water molecules and the bound oleic acid in the H-FABP large internal cavity. The jointly refined X-ray/neutron structure of H-FABP was complemented by a transferred multipolar electron-density distribution using the parameters of the ELMAMII library. The resulting electron density allowed a precise determination of the electrostatic potential in the fatty acid (FA) binding pocket. Bader's quantum theory of atoms in molecules was then used to study interactions involving the internal water molecules, the FA and the protein. This approach showed H...H contacts of the FA with highly conserved hydrophobic residues known to play a role in the stabilization of long-chain FAs in the binding cavity. The determination of water hydrogen (deuterium) positions allowed the analysis of the orientation and electrostatic properties of the water molecules in the very ordered cluster. As a result, a significant alignment of the permanent dipoles of the water molecules with the protein electrostatic field was observed. This can be related to the dielectric properties of hydration layers around proteins, where the shielding of electrostatic interactions depends directly on the rotational degrees of freedom of the water molecules in the interface.

IV.—An X-ray Examination of Saturated Dicarboxylic Acids and Amides of the Fatty Acid Series

1929 ◽  
Vol 48 ◽  
pp. 20-27 ◽  
Author(s):  
Edward Henderson
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Malonic Acid ◽  
Dicarboxylic Acids ◽  
X Rays ◽  
X Ray ◽  
Fatty Acid Amides

SummarySeveral additional members of the series of normal saturated dicarboxylic acids have been investigated by X-rays, and the results are in agreement with the conclusions arrived at in an earlier paper. In the series of mono- and di-alkyl malonic acids, successive reflection planes are separated by the length of one molecule. The series of fatty acid amides closely resembles that of the fatty acids themselves. The cleavage planes are separated by the length of two molecules oriented in opposite directions.My thanks are due to Mr N. K. Adam for the specimens of mono- and dioctadecyl malonic acid, and to Sir James Walker for his advice and helpful criticism.

scholarly journals Streamlined Methods for the Resolution and Quantification of Fatty Acids Including Trans Fatty Acid Isomers in Food Products by Gas Chromatography

2009 ◽  
Vol 92 (5) ◽  
pp. 1301-1309 ◽  
Author(s):  
Pierre-Alain Golay ◽  
Francesca Giuffrida ◽  
Fabiola Dionisi ◽  
Frédéric Destaillats
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
High Resolution ◽  
Methyl Esters ◽  
Direct Methods ◽  
Food Products ◽  
Response Factors ◽  
Geometrical Isomers ◽  
Cost Constraints ◽  
Wide Range

Abstract To support labeling, claims, and authenticity of food products, industry needs reliable methods for the analysis of fatty acids, including Trans fatty acids (TFA). In finished products, precise quantification of TFA can be problematic due to the occurrence of various positional and geometrical isomers originating from different sources, such as animal fats or processed vegetable oils and fats. The risk of underestimating TFA amounts is particularly high when inappropriate GC conditions are used. Complex sample preparation procedures involving purification of TFA isomers by silver ion chromatography have been well-documented and used for research purposes. However, in the food industry, time and cost constraints do not permit multiple analytical steps; therefore, streamlined methods are necessary. Direct methods include preparation of fatty acid methyl esters directly from food samples without prior extraction. The appropriate resolution is obtained using high-resolution GC with a highly polar 100 m capillary column, and quantification is achieved using experimentally determined response. We found that it is possible to quantify TFA in the range of 0.01 to 5.00 g/100 g of lipids in a wide range of food products. In addition, the use of direct transmethylation, response factors, and high-resolution GC allow accurate quantification of other fatty acids, including polyunsaturated and long-chain polyunsaturated fatty acids.

scholarly journals Probing conformational changes of human serum albumin due to unsaturated fatty acid binding by chemical cross-linking and mass spectrometry

2005 ◽  
Vol 387 (3) ◽  
pp. 695-702 ◽  
Author(s):  
Bill X. HUANG ◽  
Chhabil DASS ◽  
Hee-Yong KIM
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Conformational Changes ◽  
Cross Linking ◽  
X Ray ◽  
Chemical Cross Linking

Mass spectrometry with chemical cross-linking was used to probe the conformational changes of HSA (human serum albumin) in solution on interaction with monounsaturated OA (oleic acid) or polyunsaturated AA (arachidonic acid) or DHA (docosahexaenoic acid). Fatty acid-free or -bound HSA was modified with lysine-specific cross-linkers and digested with trypsin. Cross-linked peptides were analysed by nano-electrospray ionization MS to localize the sites of cross-linking. Our data indicated that a local conformational change involving movement of the side chains of Lys-402 of subdomain IIIA or Lys-541 of subdomain IIIB occurred upon binding of all three fatty acids. Our data also indicated that the side chains of Lys-205 (IIA) and Lys-466 (IIIA) moved closer towards each other upon binding AA or DHA, but not OA, suggesting that the conformations of HSA when bound to mono- and poly-unsaturated fatty acids are distinctively different. While these observations agreed with previous X-ray crystallographic studies, the distances between ε-amino groups of most cross-linked lysine pairs were shorter than the crystal structure predicted, possibly reflecting a discrepancy between the solution and crystal structures. This method can serve as a useful complement to X-ray crystallography, particularly in probing the structure of a protein in solution.

The hygroscopicity and reactivity of fatty acid atmospheric aerosol proxies are affected by nanostructure 

2021 ◽  
Author(s):  
Adam Milsom ◽  
Adam Squires ◽  
Nicholas Terrill ◽  
Andrew Ward ◽  
Christian Pfrang
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Atmospheric Aerosol ◽  
Structural Changes ◽  
Chemical Reactivity ◽  
Structural Parameters ◽  
Raman Microscopy ◽  
X Ray ◽  
Molecular Arrangement ◽  
Surfactant Material

<p>Atmospheric aerosol hygroscopicity and reactivity play a significant role in determining aerosol fate, and are affected by composition and other physical properties. Organic aerosol emissions contain fatty acids, along with sugars such as fructose. As surfactants, fatty acids organise into a range of nanostructures (3-D molecular arrangements), dependent on water content and mixture composition. In this study, we were able to demonstrate (and quantify) that the chemical reactivity of this proxy is dependent on its 3-D molecular arrangement. Furthermore, we have determined the effect of each observed nanostructure on hygroscopicity by measuring the swelling of these nanostructures as a function of relative humidity. We did this by coating capillaries with a fatty acid/sugar as a mixture for an urban aerosol, and following structural changes with simultaneous Small-Angle X-ray Scattering (SAXS) and Raman microscopy, at a synchrotron X-ray source. SAXS measured the nano-structural parameters required to follow both the reaction kinetics (ozonolysis) and hygroscopic swelling of each nanostructure. Raman microscopy provided complementary kinetic information and supported these findings. We found that the molecular arrangement of surfactant material has an impact on both the chemical kinetics and hygroscopicity. This has implications for the persistence of particulate matter in the urban environment and surfactant material in the atmosphere.</p>

Transesterification of Kapok Seed Oil (Ceiba pentandra) Using Heterogeneous Catalyst Bimetallic Oxide of Zinc and Copper Supported by γ-Alumina

2020 ◽  
Vol 988 ◽  
pp. 87-94
Author(s):  
Nyoman Puspa Asri ◽  
W.D. Prasetiyo ◽  
A. Kafidhu ◽  
A. Atiqoh ◽  
E.A. Puspitasari ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Zinc Oxide ◽  
Fatty Acid ◽  
Seed Oil ◽  
Acid Methyl Ester ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ceiba Pentandra ◽  
Activity Test ◽  
Acid Methyl

Biodiesel was produced from Kapok seed (Ceiba pentandra) oil (KSO) using heterogeneous bimetallic oxide of copper and zinc supported by γ-alumina. The Alumina-supported copper oxide-zinc oxide (CuO-ZnO γ /- Al2O3) further notated by ACZ was synthesized using precipitation, impregnation and gel methods. It also was characterized using the X-ray diffraction (X-RD), and Brunauwer-Emmett Teller (BET) methods. Before being transesterified, KSO was subjected to pretreatment with the aim of minimizing gum and other impurities and reducing the concentration of free fatty acids. The activity test of ACZ catalyst was done by introducing it through the transesterification process of KSO with methanol. The transesterification process was carried out in a laboratory scale three neck flask. The effect of calcinating temperature (°C), and calcinating time of catalyst (h) on the yield of fatty acid methyl ester (FAME) were studied, respectively. The results revealed that the kapok seed oil was worthy and potentially to transesterified into biodiesel using ACZ catalyst with highest FAME yield of 46.67%.

Effect of inclusion of different forms of dietary fatty acid on the yield and composition of cow's milk

1984 ◽  
Vol 51 (3) ◽  
pp. 387-395 ◽  
Author(s):  
William Banks ◽  
John L. Clapperton ◽  
Anne K. Girdler ◽  
William Steele
Keyword(s):  
Fatty Acids ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Milk Fat ◽  
Control Diet ◽  
Protein Matrix ◽  
Lactating Cows ◽  
Fatty Acid Mixtures ◽  
Long Chain

SummaryIn addition to a control diet, lactating cows were offered saturated fatty acid mixtures in three forms, free acids, free triglycerides and protected triglycerides, i.e. triglyceride encapsulated within a protein matrix which was cross linked by exposure to formaldehyde. Relative to the control diet, all three supplements increased milk yield. However, only the free fatty acids gave rise to increased yields of the three major milk components. The free fat and the protected fat caused significant increases only in the lactose yield. The different effects of the supplements on the yield of milk fat are suggested to be due to the types of long chain acid reaching the mammary gland rather than to any change in rumen activity. Changes in the concentrations of the soluble multivalent ionic constituents of the milks were consistent with this conclusion.

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