<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lopes, Marta H.</style></author><author><style face="normal" font="default" size="100%">Gil, Ana M.</style></author><author><style face="normal" font="default" size="100%">Silvestre, Armando J. D.</style></author><author><style face="normal" font="default" size="100%">Neto, Carlos Pascoal</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Composition of Suberin Extracted upon Gradual Alkaline Methanolysis of Quercus suber L. Cork</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Agricultural and Food Chemistry</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Alkaline methanolysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">GC-MS</style></keyword><keyword><style  face="normal" font="default" size="100%">NMR</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber L.</style></keyword><keyword><style  face="normal" font="default" size="100%">suberin</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2000</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2000///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1021/jf9909398</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">48</style></volume><pages><style face="normal" font="default" size="100%">383 - 391</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The monomeric composition of suberin extracts obtained by gradual alkaline methanolysis of Quercus suber cork was determined by gas chromatography?mass spectrometry (GC-MS). Results show that 1-alkanols and alkanoic and α,?-alkanedioic acids are preferentially removed upon mild alkaline conditions, whereas mid-chain-modified ?-hydroxyalkanoic acids are preferentially removed under stronger alkaline conditions. Saturated ?-hydroxyalkanoic acids are found to be abundant in all suberin extracts. These results are consistent with two distinct suberin fractions with different locations in cork cell walls and/or esterification degrees. It is proposed that these fractions correlate with the two main suberin peaks in the solid state 13C NMR spectra of cork and suberin extracts. Quantitative GC-MS analysis showed that suberin monomers comprise ?30% (w/w) of the suberin extracts, the remaining comprising nonvolatile structures with high Mn values, as measured by vapor pressure osmometry. The presence of a large fraction of high molecular weight aliphatic structures in suberin extracts is supported by the corresponding NMR spectra. Keywords: Suberin; cork; Quercus suber L.; GC-MS; NMR; alkaline methanolysis</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><notes><style face="normal" font="default" size="100%">doi: 10.1021/jf9909398doi: 10.1021/jf9909398The following values have no corresponding Zotero field:&lt;br/&gt;publisher: American Chemical Society</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Cordeiro, N.</style></author><author><style face="normal" font="default" size="100%">Belgacem, M. N.</style></author><author><style face="normal" font="default" size="100%">Silvestre, a J.</style></author><author><style face="normal" font="default" size="100%">Pascoal Neto, C.</style></author><author><style face="normal" font="default" size="100%">Gandini, A.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Cork suberin as a new source of chemicals. 1. Isolation and chemical characterization of its composition.</style></title><secondary-title><style face="normal" font="default" size="100%">International journal of biological macromolecules</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Alkaline methanolysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Chemical characterization</style></keyword><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular weight distribution</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber L.</style></keyword><keyword><style  face="normal" font="default" size="100%">suberin</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1998</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1998///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/9585884</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">22</style></volume><pages><style face="normal" font="default" size="100%">71 - 80</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Extractive-free cork from Quercus suber L. was submitted to a solvolysis treatment with methanolic NaOH which yielded 37% (o.d. cork) of suberin. This mixture of compounds was thoroughly characterized by FTIR, 1H- and 13C-NMR, gas chromatography coupled with mass spectrometric (GC-MS) analysis, vapour pressure osmometry (VPO), mass spectrography (MS) and gel permeation chromatography (GPC). After derivatization, the main components of the volatile fraction, representing less than half of the total, were found to be omega-hydroxymonocarboxylates, alpha, omega-dicarboxylates, simple alkanoates and 1-alkanols, all with chain lengths ranging from C16 to C24. A second fraction, with an average molecular weight about three times higher, was detected by VPO, MS and GPC. The presence of this important fraction in cork suberin had not been recognized in earlier studies. Both fractions constitute interesting precursors for the elaboration of new materials.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;accession-num: 9585884</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Cordeiro, N</style></author><author><style face="normal" font="default" size="100%">Belgacem, M N</style></author><author><style face="normal" font="default" size="100%">Silvestre, a J</style></author><author><style face="normal" font="default" size="100%">Pascoal Neto, C</style></author><author><style face="normal" font="default" size="100%">Gandini, A</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Cork suberin as a new source of chemicals. 1. Isolation and chemical characterization of its composition.</style></title><secondary-title><style face="normal" font="default" size="100%">International journal of biological macromolecules</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Alkaline methanolysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Chemical characterization</style></keyword><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular weight distribution</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber L.</style></keyword><keyword><style  face="normal" font="default" size="100%">suberin</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1998</style></year></dates><volume><style face="normal" font="default" size="100%">22</style></volume><pages><style face="normal" font="default" size="100%">71-80</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Extractive-free cork from Quercus suber L. was submitted to a solvolysis treatment with methanolic NaOH which yielded 37% (o.d. cork) of suberin. This mixture of compounds was thoroughly characterized by FTIR, 1H- and 13C-NMR, gas chromatography coupled with mass spectrometric (GC-MS) analysis, vapour pressure osmometry (VPO), mass spectrography (MS) and gel permeation chromatography (GPC). After derivatization, the main components of the volatile fraction, representing less than half of the total, were found to be omega-hydroxymonocarboxylates, alpha, omega-dicarboxylates, simple alkanoates and 1-alkanols, all with chain lengths ranging from C16 to C24. A second fraction, with an average molecular weight about three times higher, was detected by VPO, MS and GPC. The presence of this important fraction in cork suberin had not been recognized in earlier studies. Both fractions constitute interesting precursors for the elaboration of new materials.</style></abstract><accession-num><style face="normal" font="default" size="100%">9585884</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Cordeiro, N</style></author><author><style face="normal" font="default" size="100%">Belgacem, N M</style></author><author><style face="normal" font="default" size="100%">Gandini, A</style></author><author><style face="normal" font="default" size="100%">Neto, C P</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Cork suberin as a new source of chemicals: 2. Crystallinity, thermal and rheological properties</style></title><secondary-title><style face="normal" font="default" size="100%">Bioresource technology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Alkaline methanolysis</style></keyword><keyword><style  face="normal" font="default" size="100%">cork of Quercus suber L.</style></keyword><keyword><style  face="normal" font="default" size="100%">crystallinity</style></keyword><keyword><style  face="normal" font="default" size="100%">Density</style></keyword><keyword><style  face="normal" font="default" size="100%">rheological properties</style></keyword><keyword><style  face="normal" font="default" size="100%">suberin</style></keyword><keyword><style  face="normal" font="default" size="100%">thermal characterization</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1998</style></year></dates><volume><style face="normal" font="default" size="100%">63</style></volume><pages><style face="normal" font="default" size="100%">153-158</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Suberin samples, obtained by alkaline methanolysis from cork (Quercus suber L.), were submitted to various physical characterizations; DSC, TGA, optical microscopy, density and rheological properties. A sub- stantial proportion of these oligomers possessed a microcrystalline character with a melting range between 0 and 50°C. The amorphous part was liquid at room temperature and did not display a detectable glass transition upon cooling because of its wide molecular weight distribution. The viscous behaviour of suberin at room temperature was both plastic and thixotropic because of the structuring role of the micro- crystals</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Cordeiro, N.</style></author><author><style face="normal" font="default" size="100%">Belgacem, N. M.</style></author><author><style face="normal" font="default" size="100%">Gandini, A.</style></author><author><style face="normal" font="default" size="100%">Neto, C. P.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Cork suberin as a new source of chemicals: 2. Crystallinity, thermal and rheological properties</style></title><secondary-title><style face="normal" font="default" size="100%">Bioresource technology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Alkaline methanolysis</style></keyword><keyword><style  face="normal" font="default" size="100%">cork of Quercus suber L.</style></keyword><keyword><style  face="normal" font="default" size="100%">crystallinity</style></keyword><keyword><style  face="normal" font="default" size="100%">Density</style></keyword><keyword><style  face="normal" font="default" size="100%">rheological properties</style></keyword><keyword><style  face="normal" font="default" size="100%">suberin</style></keyword><keyword><style  face="normal" font="default" size="100%">thermal characterization</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1998</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1998///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.sciencedirect.com/science/article/pii/S0960852497000734</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">63</style></volume><pages><style face="normal" font="default" size="100%">153 - 158</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Suberin samples, obtained by alkaline methanolysis from cork (Quercus suber L.), were submitted to various physical characterizations; DSC, TGA, optical microscopy, density and rheological properties. A sub- stantial proportion of these oligomers possessed a microcrystalline character with a melting range between 0 and 50°C. The amorphous part was liquid at room temperature and did not display a detectable glass transition upon cooling because of its wide molecular weight distribution. The viscous behaviour of suberin at room temperature was both plastic and thixotropic because of the structuring role of the micro- crystals</style></abstract></record></records></xml>