Reactions of Ozone with Fatty Acid Monolayers: A Model System for Disruption of Lipid Molecular Assemblies by Ozone

1979 ◽  
Vol 34 (5) ◽  
pp. 346-349 ◽  
Author(s):  
E. V. SriSankar ◽  
L. K. Patterson
Keyword(s):  
Fatty Acid ◽  
Model System ◽  
Molecular Assemblies

scholarly journals Inhibition of Stigmasterol Oxidation by Antioxidants in Purified Sunflower Oil

2004 ◽  
Vol 87 (2) ◽  
pp. 499-504 ◽  
Author(s):  
Magdalena Rudzińska ◽  
Józef Korczak ◽  
Anna Gramza ◽  
Erwin Wąsowicz ◽  
Paresh C Dutta
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Peroxide Value ◽  
Sunflower Oil ◽  
Model System ◽  
Oxidation Products ◽  
Butylated Hydroxytoluene ◽  
Rosemary Extract ◽  
Peroxide Values ◽  
Ethanolic Extracts

Abstract A study was conducted to analyze the effect of the antioxidants butylated hydroxytoluene, α-tocopherol, ethanolic extracts of rosemary, and green tea on stigmasterol resistance against degradation and formation of its oxidation products in purified triacylglycerols (TAG) from sunflower oil. The content of stigmasterol and its oxidation products 7α-and 7β-hydroxy, α-and β-epoxy, triol, and 7-ketostigmasterol were determined during incubation at 60°C for 3, 6, and 9 days. In addition, peroxide value and fatty acid composition were also determined in the samples. Correlation between the levels of the accumulated stigmasterol oxides and peroxide value of the TAG with antioxidants during incubation was significant only for rosemary extract (R = 0.6799, p < 0.05). The lack of correlation precludes the use of peroxide values to determine the level of sterol oxidation products in the used model system. Correlation between stigmasterol content and the level of stigmasterol oxides was significant for all samples (R = 0.8874, p < 0.05). The total increase of the stigmasterol oxidation products was the lowest in samples with α-tocopherol, but the content of stigmasterol-triol increased the most in this sample. In all the analyzed samples, α-epoxy-stigmasterol was formed in the highest amounts among the analyzed stigmasterol oxidation products.

scholarly journals Drosophila melanogasteras a model system to study long-chain fatty acid amide metabolism

FEBS Letters ◽  
2014 ◽  
Vol 588 (9) ◽  
pp. 1596-1602 ◽  
Author(s):  
Kristen A. Jeffries ◽  
Daniel R. Dempsey ◽  
Anita L. Behari ◽  
Ryan L. Anderson ◽  
David J. Merkler
Keyword(s):  
Fatty Acid ◽  
Acid Amide ◽  
Model System ◽  
Chain Fatty Acid ◽  
Long Chain Fatty Acid ◽  
Long Chain ◽  
Fatty Acid Amide

scholarly journals The Effect of Selected Synbiotics on Microbial Composition and Short-Chain Fatty Acid Production in a Model System of the Human Colon

PLoS ONE ◽  
2012 ◽  
Vol 7 (10) ◽  
pp. e47212 ◽  
Author(s):  
Gabriella C. van Zanten ◽  
Anne Knudsen ◽  
Henna Röytiö ◽  
Sofia Forssten ◽  
Mark Lawther ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Acid Production ◽  
Short Chain Fatty Acid ◽  
Human Colon ◽  
Model System ◽  
Chain Fatty Acid ◽  
Short Chain ◽  
Microbial Composition ◽  
Fatty Acid Production

scholarly journals The enzymic and non-enzymic degradation of colneleic acid, an unsaturated fatty acid ether intermediate in the lipoxygenase pathway of linoleic acid oxidation in potato (Solanum tuberosum) tubers

1974 ◽  
Vol 138 (1) ◽  
pp. 23-31 ◽  
Author(s):  
T. Galliard ◽  
D. A. Wardale ◽  
J. A. Matthew
Keyword(s):  
Fatty Acid ◽  
Linoleic Acid ◽  
Model System ◽  
Butylated Hydroxytoluene ◽  
Acid Oxidation ◽  
Reaction Products ◽  
Lipoxygenase Pathway ◽  
Iron Protein ◽  
Linoleic Acid Oxidation ◽  
Low Concentrations

Colneleic acid is an unsaturated ether fatty acid derived from linoleic acid via a lipoxygenase-mediated enzyme pathway. It is degraded (a) by an enzyme in potato tubers which is heat-labile and non-dialysable and (b) by a model system containing catalytic amounts of Fe2+ ions. Both enzyme- and Fe2+-catalysed systems have similar properties with respect to pH optima (pH5.0–5.5), oxygen requirement (0.6–0.7 mol of O2 consumed/mol of ether degraded), inhibitors and reaction products. An unstable product breaks down to C8 and C9 carbonyl fragments. Both systems are inhibited by low concentrations of antioxidants (e.g. 5μm-butylated hydroxytoluene) and some chelating agents (e.g. 5μm-diethyldithio-carbamate). The model system is strongly inhibited by metal ions, particularly Cu2+ and Fe3+, at 20μm. Hydrogen peroxide and haemoproteins do not substitute for the enzyme or Fe2+ ions but the non-haem iron protein, ferredoxin, does catalyse the degradation.

pH dependence of micellar diffusion and dissociation

1980 ◽  
Vol 239 (3) ◽  
pp. G177-G182 ◽  
Author(s):  
Y. F. Shiau ◽  
G. M. Levine
Keyword(s):  
Oleic Acid ◽  
Fatty Acid ◽  
Bile Salt ◽  
Micellar Solution ◽  
Mixed Micelles ◽  
Ph Dependence ◽  
Model System ◽  
Low Ph ◽  
Acid Diffusion ◽  
Monomer Diffusion

A simplified model system was used to examine the effect of pH on the diffusion and dissociation of mixed micelles across an interphase. Diffusion of radioactively labeled taurocholate and oleic acid from a micellar solution into a phosphate buffer of varying pH (5.0-8.0) was measured. The proportion of bile salt and fatty acid as monomers and aggregates in both solutions was determined by ultrafiltration. Results indicate that all of the oleic acid existed as aggregates in the micellar solution, whereas taurocholate was in equilibrium between aggregate and monomer forms. Between pH 5.0 and 7.0, oleic acid and taurocholate diffusion was inversely related to pH and due to the differences in aggregate but not monomer diffusion. Fatty acid diffusion across the interface was always less than taurocholate diffusion, because taurocholate monomers could also diffuse across the interphase. Calculation of the proportion of taurocholate diffusion from aggregate and monomers based on micellar composition was similar to measured values at pH greater than or equal to 6.5, indicating a lack of micelle dissociation. However, at pH less than or equal to 6 measured values for bile salt monomers exceeded calculations, indicating that a low pH microclimate favors dissociation of micelles. A hypothesis is advanced to explain these events occurring in a disequilibrium area adjacent to the epithelial cell membrane.

Raman and Near-Infrared Spectroscopy for Quantification of Fat Composition in a Complex Food Model System

2005 ◽  
Vol 59 (11) ◽  
pp. 1324-1332 ◽  
Author(s):  
N. K. Afseth ◽  
V. H. Segtnan ◽  
B. J. Marquardt ◽  
J. P. Wold
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Polyunsaturated Fatty Acids ◽  
Iodine Value ◽  
Near Infrared ◽  
Model System ◽  
Estimation Errors ◽  
Oil Mixtures ◽  
Food Model

Raman and near-infrared (NIR) spectroscopy have been evaluated for determining fatty acid composition and contents of main constituents in a complex food model system. A model system consisting of 70 different mixtures of protein, water, and oil blends was developed in order to create a rough chemical imitation of typical fish and meat samples, showing variation both in fatty acid composition and in contents of main constituents. The model samples as well as the pure oil mixtures were measured using Raman and NIR techniques. Partial least squares regression was utilized for prediction, and fatty acid features were expressed in terms of the iodine value and as contents of saturated, monounsaturated, and polyunsaturated fatty acids. Raman spectroscopy provided the best results for predicting iodine values of the model samples, giving validated estimation errors accounting for 2.8% of the total iodine value range. Both techniques provided good results for predicting the content of saturated, monounsaturated, and polyunsaturated fatty acids in the model samples, yielding validated estimation errors in the range of 2.4–6.1% of the total range of fatty acid content. Prediction results for determining fatty acid features of the pure oil mixtures were similar for the two techniques. NIR was clearly the best technique for modeling content of main constituents in the model samples.

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