Examinando por Autor "Povedano, Isabel"

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    Effects of high pressure on unsaturated fatty acids
    (Taylor & Francis, 2014-09-24) Povedano, Isabel; Guignon, Berenguere; Rodríguez Montoro, Óscar; Sanz, Pedro Dimas; Taravillo Corralo, Mercedes; García Baonza, Mercedes
    The objective of this study is to investigate the effects of high pressure processing on the molecular structure of some unsaturated fatty acids. Samples of elaidic acid, linoleic acid, ZE and EE conjugated linoleic acid are treated at 293 or 333 K at pressures up to 700 MPa. It is observed that the adiabatic heat generated from compression is able to bring the sample temperature above 373 K after 700 MPa. These relatively extreme conditions are of great interest for food sterilization, but they may induce undesirable change in fatty acid quality characteristics. To check for structural changes, Raman spectra of the samples are analysed after treatments. The comparison with Raman spectra of samples kept at atmospheric pressure shows that pressure induces some conformational changes at the hydrocarbon skeleton in solid samples, while the liquid ones remain unchanged. No cis/trans isomerization occurs, but gauche conformers are likely to be present.
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    Ítem
    Pressure as driving force in the formation of Fossil Resins: Pressure Induced Changes in trans-Communic Acid studied by Raman Spectroscopy
    (IOP PUBLISHING, 2017-01-01) Rodríguez Montoro, Óscar; Taravillo Corralo, Mercedes; Povedano, Isabel; Tortajada Pérez, José; García Baonza, Valentín
    The main purpose of this study is to provide spectroscopic evidence of possible chemical pathways in the formation of fossil resins under high pressure conditions. In this work, we have studied trans-communic acid (majority precursor compound in resinites) under high pressure conditions by using a sapphire anvil cell. Raman spectra were measured at atmospheric pressure up to 8 GPa (at room temperature). Slight changes were observed in the spectra. Furthermore, the recovered sample after pressure release was analyzed by FTIR. Our results are not conclusive about a possible chemical pathway of polymerization induced by pressure.