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Manuel A. Coimbra - One of the best experts on this subject based on the ideXlab platform.
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Structural ripening-related changes of the arabinan-rich pectic polysaccharides from Olive Pulp cell walls.
Journal of agricultural and food chemistry, 2007Co-Authors: Susana M. Cardoso, José Alexandre Ferreira, Isabel Mafra, And Artur M. S. Silva, Manuel A. CoimbraAbstract:In this study, the structural features and ripening-related changes that occur in the arabinan-rich pectic polysaccharides highly enmeshed in the cellulosic matrix of the Olive Pulp fruit were evaluated. These pectic polysaccharides, obtained from two consecutive harvests at green, cherry, and black ripening stages, account for 11-19% of the total pectic polysaccharides found in the Olive Pulp cell walls and were previously shown to occur as calcium chelating dimers. On the basis of the 13C NMR, (1H, 13C) gHSQC, 2D COSYPR, and (1H,13C) gHMBC carbon and proton resonances of the variously linked arabinosyl residues, we propose a tentative structure. This structure is particularly characterized by T-beta-Araf (1-->5)-linked to (1-->3,5)-Araf residues and by the occurrence of branched and linear blocks in the arabinan backbone. Methylation analysis showed that these pectic polysaccharides of black Olives have more arabinan side chains, which were shorter (less (1-->5)-Araf), highly branched (more (1-->3,5)-Araf), and with shorter side chains (fewer (1-->3)-Araf) than those of green and cherry Olives. Quantitative 13C NMR data indicated that these modifications involved the disappearance of the characteristic terminally linked beta-Araf residue of the arabinans. This odd feature can be used as a diagnostic tool in the evaluation of the stage of ripening of this fruit, as well as a marker for the presence of Olive Pulp in matrices containing pectic polysaccharides samples.
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The combined effects of black oxidising table Olive process and ripening on the cell wall polysaccharides of Olive Pulp
Carbohydrate Polymers, 2007Co-Authors: Isabel Mafra, António S. Barros, Manuel A. CoimbraAbstract:Olive fruits harvested at cherry and black stages of ripening were processed according the table Olive black oxidising processing and sampled after the three main steps: storage in brine, lye treatment and thermal treatment (final product). The results show that the storage in brine contributed positively to the stabilisation of cell wall polysaccharides of Olive Pulp as the amounts of main polysaccharides practically were maintained in both stages of ripening. The lye treatment introduced degradation of cell walls due to the generalised loss of pectic and hemicellulosic polysaccharides and cellulose, caused by the breakage of ester and hydrogen bonds. On the other hand, the lye treatment introduced shifts in the solubilisation of polysaccharides rendering them more difficult to extract by alkali solutions and enabling their retention in the cellulosic residue, which should contribute positively to cell wall firmness. The thermal treatment introduced degradation of cellulose and increased the solubilisation of polysaccharides with a higher extent in the black Olives. This work showed that the differences on the cell wall polysaccharides between stages of ripening are magnified after processing and allowed to conclude that the stage of ripening of Olive fruits is determinant for obtaining a final product with adequate texture properties for table Olive consumption.
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Identification of oleuropein oligomers in Olive Pulp and pomace
Journal of the Science of Food and Agriculture, 2006Co-Authors: Susana M. Cardoso, Sylvain Guyot, Nathalie Marnet, José A. Lopes-da-silva, Catherine M.g.c. Renard, Artur M. S. Silva, Manuel A. CoimbraAbstract:Analysis of a purified fraction from acetone extracts of Olive Pulp and pomace by electrospray ionisation tandem mass spectrometry (ESI-MSn) showed the presence of oleuropein oligomers, whose occurrence has not been reported previously in the literature. The main ionic species (m/z 1613) in the ESI-MS spectrum was an oleuropein trimer containing three linkages through the hydroxytyrosol backbone. In both samples, oleuropein dimers (m/z 1075), trimers comprising two hydroxytyrosol linkages (m/z 1615), tetramers (m/z 2153) and pentamers (m/z 2691) were also detected by MS. The occurrence of oleuropein oligomers was also observed by nuclear magnetic resonance (NMR). 13C, 13C distortionless enhancement by polarisation transfer DEPT 90, 13C DEPT 135, gHSQC (heteronuclear single quantum coherence) and gHMBC (heteronuclear multiple bond coherence) spectra showed all carbon and proton resonances of oleuropein with the exception of the low-mobility and asymmetric signals of the aromatic rings. Since mature Olives were used in this study, it is possible that the disappearance of oleuropein that has been described to occur with the Olive fruit maturation, could be associated with the formation of phenolic oligomers together with lower-molecular-weight compounds resulting from its degradation. Copyright © 2006 Society of Chemical Industry
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Dimeric calcium complexes of arabinan-rich pectic polysaccharides from Olea europaea L. cell walls
Carbohydrate Polymers, 2006Co-Authors: José Alexandre Ferreira, Isabel Mafra, M. Rosário Soares, Dmitry V. Evtuguin, Manuel A. CoimbraAbstract:Abstract The study carried out in this work concerns the pectic polysaccharides of Olive cell walls as present in Olive Pulp and that remained entrapped in the cellulosic residue after sequential extraction of the cell wall material (CWM) with imidazole, carbonate and KOH aqueous solutions. These polymers, obtained after neutralisation and dialysis of an aqueous suspension of the residue (sn-CR fraction), extracted with 4 M KOH, were arabinan-rich pectic polysaccharides. They accounted for 11–19% of the total pectic polysaccharides found in the Olive Pulp cell walls of fruits collected in two years and in three stages of ripening (green, cherry and black). The analysis by powder X-ray diffraction highlighted the existence, in all sn-CR fractions, of crystalline phases related with the presence of calcium-pectic polysaccharide complexes (CPPC) occurring in an amorphous carbohydrate network. The relative crystallinity of the CPPC varied linearly with the Ca 2+ /GalA molar ratio until a maximum of 0.57. Size-exclusion chromatography showed that sn-CR fractions possessed a bimodal molecular weight distribution. The lower molecular weight fraction of sn-CR ( M w = 70–135 kDa) was independent on the ripening stage of Olive fruit, whereas the higher molecular weight fraction showed values of 1.1, 0.6–0.9 and 0.5–0.7 MDa, respectively, for green, cherry and black Olives. Treatment of the sn-CR pectic polysaccharides with a 2 M imidazole solution disrupted the CPPC crystalline network showing the loss of low molecular weight galacturonan-rich material during dialysis (12–14 kDa cut off) and the decrease of molecular weight of the polymers to roughly half. These results allowed to infer the presence of oligogalacturonides held within cell walls by calcium ions and that the pectic polysaccharides of sn-CR fraction occurred in Olive Pulp cell walls as calcium bridged macrodimers.
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characterisation of phenolic extracts from Olive Pulp and Olive pomace by electrospray mass spectrometry
Journal of the Science of Food and Agriculture, 2005Co-Authors: Susana M. Cardoso, Sylvain Guyot, Nathalie Marnet, Catherine M.g.c. Renard, Jose A Lopesdasilva, Manuel A. CoimbraAbstract:Methanol extracts of Olive pomace (two-phase Olive oil extraction) and Olive Pulp were analysed by reverse phase HPLC and the eluted fractions were characterised by electrospray ionisation mass spectrometry. This technique allowed the identification of some common phenolic compounds, namely, verbascoside, rutin, caffeoyl-quinic acid, luteolin-4-glucoside and 11-methyl-oleoside. Hydroxytyrosol-1 � - β-glucoside, luteolin-7-rutinoside and oleoside were also detected. Moreover, this technique enabled the identification, for the first time in Olea europaea tissues, of two oleoside derivatives, 6 � -β-glucopyranosyl- oleoside and 6 � -β-rhamnopyranosyl-oleoside, and of 10-hydroxy-oleuropein. Also, an oleuropein glucoside that had previously been identified in Olive leaves was now detected in Olive fruit, both in Olive Pulp and Olive pomace. With the exception of oleoside and oleuropein, the majority of phenolic compounds were found to occur in equivalent amounts in Olive Pulp and Olive pomace. Oleoside was the main phenolic compound in Olive Pulp (31.6mgg −1 ) but was reduced to 3.6mgg −1 in Olive pomace, and oleuropein (2.7mgg −1 in the Pulp) almost disappeared (<0.1mgg −1 in the pomace). Both these phenolic compounds were degraded during the Olive oil extraction process. 2004 Society of Chemical Industry
Ana Reis - One of the best experts on this subject based on the ideXlab platform.
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Positive and negative electrospray ionisation tandem mass spectrometry as a tool for structural characterisation of acid released oligosaccharides from Olive Pulp glucuronoxylans
Carbohydrate research, 2003Co-Authors: Ana Reis, M. Rosário M. Domingues, Pedro Domingues, António J. Ferrer-correia, Manuel A. CoimbraAbstract:Abstract Xylo-oligosaccharides with degrees of polymerisation 5–13, formed by partial acid hydrolysis from an extract representative of Olive Pulp glucuronoxylans (GX), were analysed by electrospray ionisation mass spectrometry (ESI-MS), both in positive and negative modes. The positive spectrum showed the presence of xylo-oligosaccharides in the mass range between m/z 500 and 1500 corresponding to singly [M+Na] + charged ions of neutral (Xyl 7–9 ) and acidic xylo-oligosaccharides (Xyl 5–9 MeGlcA), and doubly [M+2Na] 2+ charged ions of Xyl 9–13 and Xyl 7–11 MeGlcA. Ammonium adducts [M+NH 4 ] + were also observed for Xyl 5–9 MeGlcA. The negative spectra showed the contribution of ions in the mass range between m/z 600 and 1400, ascribed to the deprotonated molecules [M−H] − of Xyl 3–9 MeGlcA. Tandem mass spectrometry (MS/MS) of the major ions observed in the MS spectra was performed. The MS/MS spectra of the [M+Na] + adducts showed the loss of MeGlcA residues as the major fragmentation pathway and glycosidic fragment ions of Xyl n and Xyl n MeGlcA structures. The MS/MS spectra of the [M+NH 4 ] + adducts suggests the occurrence of isomers of Xyl 5–9 MeGlcA oligosaccharides with the MeGlcA residue at the reducing end and at the non-reducing end of the molecules, although other structural isomers can also occur. Both glycosidic bond and cross-ring cleavages in the MS/MS spectra of the [M−H] − ion suggest the occurrence of Xyl 3–9 MeGlcA with the substituting group at the reducing end position of the xylose backbone, as the main fragmentation ions. The results obtained by ESI-MS/MS, both in positive and negative modes, of Xyl 7–13 - and Xyl 5–11 MeGlcA, allow to identify fragmentation patterns of the structural isomers with MeGlcA linked to the terminal xylosyl residues of the oligosaccharides. The occurrence of these higher molecular weight oligosaccharides with a low substitution pattern allows to infer a scatter and random distribution of MeGlcA along the xylan backbone of Olive Pulp.
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Structural characterisation by MALDI-MS of Olive xylo-oligosaccharides obtained by partial acid hydrolysis
Carbohydrate Polymers, 2003Co-Authors: Ana Reis, António J. Ferrer-correia, Maria Rosário Domingues, Manuel A. CoimbraAbstract:Abstract Alkali extractable Olive Pulp and Olive seed hull glucuronoxylans were submitted to mild acid hydrolysis originating low molecular weight xylo-oligosaccharides. The xylo-oligosaccharides thus formed were partially separated by size exclusion chromatography (Biogel P6) and several elution fractions were identified by MALDI-MS. The MALDI mass spectra obtained revealed the presence of several xylo-oligosaccharides ions in each fraction between the m / z ranges 500–2500. Based on the sugar and methylation analyses of the glucuronoxylans, the proposed structures are the neutral xylo-oligosaccharides (Xyl n , n =4–18) and acidic xylo-oligosaccharides substituted by glucuronic acid residues (Xyl n GlcA, n =3–16 and Xyl n GlcA 2 , n =2–14), by 4- O -methyl-glucuronic acid residues (Xyl n MeGlcA, n =3–14 and Xyl 2 MeGlcA 2 ) and by both acid residues (Xyl n GlcAMeGlcA, n =4–7). The identification of ions corresponding to long blocks of neutral and acidic oligosaccharides suggested that the acidic residues were irregularly distributed along the xylan backbone in both Olive Pulp and Olive seed hull. In addition, MALDI mass spectra showed that the acidic xylo-oligosaccharides from the Pulp were predominantly constituted by Xyl n MeGlcA oligosaccharides, while the acidic xylo-oligosaccharides from the seed hull were predominantly constituted by Xyl n GlcA and Xyl n GlcA 2 oligosaccharides.
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Structural characterisation of underivatised Olive Pulp xylo‐oligosaccharides by mass spectrometry using matrix‐assisted laser desorption/ionisation and electrospray ionisation
Rapid communications in mass spectrometry : RCM, 2002Co-Authors: Ana Reis, Manuel A. Coimbra, Pedro Domingues, António J. Ferrer-correia, M. Rosário M. DominguesAbstract:Purified Olive Pulp glucuronoxylans, with a Xyl/GlcA ratio of 7:1, were subjected to mild acid hydrolysis and the mixture of oligosaccharides obtained was fractionated by size exclusion chromatography. One elution fraction representative of low molecular weight oligosaccharides was analysed by mass spectrometry using matrix-assisted laser desorption/ionisation (MALDI) and electrospray ionisation (ESI) as ionisation methods, in the positive mode. Both types of spectra showed cationised molecules [M + Na]+ of xylo-oligosaccharides in a range below m/z 1000. The xylo-oligosaccharide structures identified were series of neutral oligosaccharides of xylose (Xyln, n = 3–7), of acidic oligosaccharides substituted by one glucuronic acid (XylnGlcA, n = 3–5) and by two glucuronic acid residues (XylnGlcA2, n = 2 and 3), and also of acidic oligosaccharides substituted with one 4-O-methylglucuronic acid residue (XylnmeGlcA, n = 2–4). The proposed structures were confirmed by tandem mass (MS/MS) spectra obtained using collision induced dissociation of the molecular ions. Fragmentation of cationised adducts of neutral Xyln yielded C- and A-type fragments, while ammonium adducts mainly yielded B-type fragments. The fragmentation of the sodium adducts of acidic oligosaccharides (XylnmeGlcA, XylnGlcA) resulted in the loss of the substituting residue (GlcA or meGlcA) as the predominant fragment, while the corresponding ammonium adducts yielded B-type fragments. Copyright © 2002 John Wiley & Sons, Ltd.
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structural characterisation of underivatised Olive Pulp xylo oligosaccharides by mass spectrometry using matrix assisted laser desorption ionisation and electrospray ionisation
Rapid Communications in Mass Spectrometry, 2002Co-Authors: Ana Reis, Manuel A. Coimbra, Pedro Domingues, A J Ferrercorreia, Rosario M M DominguesAbstract:Purified Olive Pulp glucuronoxylans, with a Xyl/GlcA ratio of 7:1, were subjected to mild acid hydrolysis and the mixture of oligosaccharides obtained was fractionated by size exclusion chromatography. One elution fraction representative of low molecular weight oligosaccharides was analysed by mass spectrometry using matrix-assisted laser desorption/ionisation (MALDI) and electrospray ionisation (ESI) as ionisation methods, in the positive mode. Both types of spectra showed cationised molecules [M + Na]+ of xylo-oligosaccharides in a range below m/z 1000. The xylo-oligosaccharide structures identified were series of neutral oligosaccharides of xylose (Xyln, n = 3–7), of acidic oligosaccharides substituted by one glucuronic acid (XylnGlcA, n = 3–5) and by two glucuronic acid residues (XylnGlcA2, n = 2 and 3), and also of acidic oligosaccharides substituted with one 4-O-methylglucuronic acid residue (XylnmeGlcA, n = 2–4). The proposed structures were confirmed by tandem mass (MS/MS) spectra obtained using collision induced dissociation of the molecular ions. Fragmentation of cationised adducts of neutral Xyln yielded C- and A-type fragments, while ammonium adducts mainly yielded B-type fragments. The fragmentation of the sodium adducts of acidic oligosaccharides (XylnmeGlcA, XylnGlcA) resulted in the loss of the substituting residue (GlcA or meGlcA) as the predominant fragment, while the corresponding ammonium adducts yielded B-type fragments. Copyright © 2002 John Wiley & Sons, Ltd.
Pedro Domingues - One of the best experts on this subject based on the ideXlab platform.
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lipidomic profiling of the Olive olea europaea l fruit towards its valorisation as a functional food in depth identification of triacylglycerols and polar lipids in portuguese Olives
Molecules, 2019Co-Authors: Eliana Alves, Rosario M M Domingues, Tânia Melo, Madalena P Barros, Pedro DominguesAbstract:Olives (Olea europaea L.) are classic ingredients in the Mediterranean diet with well-known health benefits, but their lipid composition has not been fully addressed. In this work, we characterised triacylglycerol (TAG) and polar lipid profiles of the Olive Pulp while using a complementary methodological approach that was based on solid-phase extraction to recover the neutral lipid (NL) and the polar lipid-rich fractions. The TAG profile was analysed in the NL-fraction by C30 reversed-phase liquid chromatography (LC) and the polar lipid profile by normal-phase hydrophilic interaction liquid chromatography (HILIC), with both being coupled to electrospray ionization-mass spectrometry (ESI-MS) and ESI-MS/MS. This approach identified 71 TAG ions that were attributed to more than 350 molecular species, with fatty acyl chain lengths from C11:0 to C26:0, including different polyunsaturated acyl chains. The polar lipids included 107 molecular species that belonged to 11 lipid classes that comprised phospholipids, glyceroglycolipids, glycosphingolipids, and betaine lipids. In addition to polyunsaturated fatty acids, some of the phospholipids, glycolipids, and glycosphingolipids that were identified in the Olive Pulp have been described as biologically active molecules. Lipidomic phenotyping of the Olive Pulp has led to the discovery of compounds that will allow for a better assessment of its nutritional value and new applications of bioactive lipid components in this functional food.
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Lipidomic Profiling of the Olive (Olea europaea L.) Fruit towards Its Valorisation as a Functional Food: In-Depth Identification of Triacylglycerols and Polar Lipids in Portuguese Olives.
Molecules (Basel Switzerland), 2019Co-Authors: Eliana Alves, M. Rosário M. Domingues, Tânia Melo, Madalena P Barros, Pedro DominguesAbstract:Olives (Olea europaea L.) are classic ingredients in the Mediterranean diet with well-known health benefits, but their lipid composition has not been fully addressed. In this work, we characterised triacylglycerol (TAG) and polar lipid profiles of the Olive Pulp while using a complementary methodological approach that was based on solid-phase extraction to recover the neutral lipid (NL) and the polar lipid-rich fractions. The TAG profile was analysed in the NL-fraction by C30 reversed-phase liquid chromatography (LC) and the polar lipid profile by normal-phase hydrophilic interaction liquid chromatography (HILIC), with both being coupled to electrospray ionization-mass spectrometry (ESI-MS) and ESI-MS/MS. This approach identified 71 TAG ions that were attributed to more than 350 molecular species, with fatty acyl chain lengths from C11:0 to C26:0, including different polyunsaturated acyl chains. The polar lipids included 107 molecular species that belonged to 11 lipid classes that comprised phospholipids, glyceroglycolipids, glycosphingolipids, and betaine lipids. In addition to polyunsaturated fatty acids, some of the phospholipids, glycolipids, and glycosphingolipids that were identified in the Olive Pulp have been described as biologically active molecules. Lipidomic phenotyping of the Olive Pulp has led to the discovery of compounds that will allow for a better assessment of its nutritional value and new applications of bioactive lipid components in this functional food.
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Positive and negative electrospray ionisation tandem mass spectrometry as a tool for structural characterisation of acid released oligosaccharides from Olive Pulp glucuronoxylans
Carbohydrate research, 2003Co-Authors: Ana Reis, M. Rosário M. Domingues, Pedro Domingues, António J. Ferrer-correia, Manuel A. CoimbraAbstract:Abstract Xylo-oligosaccharides with degrees of polymerisation 5–13, formed by partial acid hydrolysis from an extract representative of Olive Pulp glucuronoxylans (GX), were analysed by electrospray ionisation mass spectrometry (ESI-MS), both in positive and negative modes. The positive spectrum showed the presence of xylo-oligosaccharides in the mass range between m/z 500 and 1500 corresponding to singly [M+Na] + charged ions of neutral (Xyl 7–9 ) and acidic xylo-oligosaccharides (Xyl 5–9 MeGlcA), and doubly [M+2Na] 2+ charged ions of Xyl 9–13 and Xyl 7–11 MeGlcA. Ammonium adducts [M+NH 4 ] + were also observed for Xyl 5–9 MeGlcA. The negative spectra showed the contribution of ions in the mass range between m/z 600 and 1400, ascribed to the deprotonated molecules [M−H] − of Xyl 3–9 MeGlcA. Tandem mass spectrometry (MS/MS) of the major ions observed in the MS spectra was performed. The MS/MS spectra of the [M+Na] + adducts showed the loss of MeGlcA residues as the major fragmentation pathway and glycosidic fragment ions of Xyl n and Xyl n MeGlcA structures. The MS/MS spectra of the [M+NH 4 ] + adducts suggests the occurrence of isomers of Xyl 5–9 MeGlcA oligosaccharides with the MeGlcA residue at the reducing end and at the non-reducing end of the molecules, although other structural isomers can also occur. Both glycosidic bond and cross-ring cleavages in the MS/MS spectra of the [M−H] − ion suggest the occurrence of Xyl 3–9 MeGlcA with the substituting group at the reducing end position of the xylose backbone, as the main fragmentation ions. The results obtained by ESI-MS/MS, both in positive and negative modes, of Xyl 7–13 - and Xyl 5–11 MeGlcA, allow to identify fragmentation patterns of the structural isomers with MeGlcA linked to the terminal xylosyl residues of the oligosaccharides. The occurrence of these higher molecular weight oligosaccharides with a low substitution pattern allows to infer a scatter and random distribution of MeGlcA along the xylan backbone of Olive Pulp.
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Structural characterisation of underivatised Olive Pulp xylo‐oligosaccharides by mass spectrometry using matrix‐assisted laser desorption/ionisation and electrospray ionisation
Rapid communications in mass spectrometry : RCM, 2002Co-Authors: Ana Reis, Manuel A. Coimbra, Pedro Domingues, António J. Ferrer-correia, M. Rosário M. DominguesAbstract:Purified Olive Pulp glucuronoxylans, with a Xyl/GlcA ratio of 7:1, were subjected to mild acid hydrolysis and the mixture of oligosaccharides obtained was fractionated by size exclusion chromatography. One elution fraction representative of low molecular weight oligosaccharides was analysed by mass spectrometry using matrix-assisted laser desorption/ionisation (MALDI) and electrospray ionisation (ESI) as ionisation methods, in the positive mode. Both types of spectra showed cationised molecules [M + Na]+ of xylo-oligosaccharides in a range below m/z 1000. The xylo-oligosaccharide structures identified were series of neutral oligosaccharides of xylose (Xyln, n = 3–7), of acidic oligosaccharides substituted by one glucuronic acid (XylnGlcA, n = 3–5) and by two glucuronic acid residues (XylnGlcA2, n = 2 and 3), and also of acidic oligosaccharides substituted with one 4-O-methylglucuronic acid residue (XylnmeGlcA, n = 2–4). The proposed structures were confirmed by tandem mass (MS/MS) spectra obtained using collision induced dissociation of the molecular ions. Fragmentation of cationised adducts of neutral Xyln yielded C- and A-type fragments, while ammonium adducts mainly yielded B-type fragments. The fragmentation of the sodium adducts of acidic oligosaccharides (XylnmeGlcA, XylnGlcA) resulted in the loss of the substituting residue (GlcA or meGlcA) as the predominant fragment, while the corresponding ammonium adducts yielded B-type fragments. Copyright © 2002 John Wiley & Sons, Ltd.
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structural characterisation of underivatised Olive Pulp xylo oligosaccharides by mass spectrometry using matrix assisted laser desorption ionisation and electrospray ionisation
Rapid Communications in Mass Spectrometry, 2002Co-Authors: Ana Reis, Manuel A. Coimbra, Pedro Domingues, A J Ferrercorreia, Rosario M M DominguesAbstract:Purified Olive Pulp glucuronoxylans, with a Xyl/GlcA ratio of 7:1, were subjected to mild acid hydrolysis and the mixture of oligosaccharides obtained was fractionated by size exclusion chromatography. One elution fraction representative of low molecular weight oligosaccharides was analysed by mass spectrometry using matrix-assisted laser desorption/ionisation (MALDI) and electrospray ionisation (ESI) as ionisation methods, in the positive mode. Both types of spectra showed cationised molecules [M + Na]+ of xylo-oligosaccharides in a range below m/z 1000. The xylo-oligosaccharide structures identified were series of neutral oligosaccharides of xylose (Xyln, n = 3–7), of acidic oligosaccharides substituted by one glucuronic acid (XylnGlcA, n = 3–5) and by two glucuronic acid residues (XylnGlcA2, n = 2 and 3), and also of acidic oligosaccharides substituted with one 4-O-methylglucuronic acid residue (XylnmeGlcA, n = 2–4). The proposed structures were confirmed by tandem mass (MS/MS) spectra obtained using collision induced dissociation of the molecular ions. Fragmentation of cationised adducts of neutral Xyln yielded C- and A-type fragments, while ammonium adducts mainly yielded B-type fragments. The fragmentation of the sodium adducts of acidic oligosaccharides (XylnmeGlcA, XylnGlcA) resulted in the loss of the substituting residue (GlcA or meGlcA) as the predominant fragment, while the corresponding ammonium adducts yielded B-type fragments. Copyright © 2002 John Wiley & Sons, Ltd.
M. Rosário M. Domingues - One of the best experts on this subject based on the ideXlab platform.
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Lipidomic Profiling of the Olive (Olea europaea L.) Fruit towards Its Valorisation as a Functional Food: In-Depth Identification of Triacylglycerols and Polar Lipids in Portuguese Olives.
Molecules (Basel Switzerland), 2019Co-Authors: Eliana Alves, M. Rosário M. Domingues, Tânia Melo, Madalena P Barros, Pedro DominguesAbstract:Olives (Olea europaea L.) are classic ingredients in the Mediterranean diet with well-known health benefits, but their lipid composition has not been fully addressed. In this work, we characterised triacylglycerol (TAG) and polar lipid profiles of the Olive Pulp while using a complementary methodological approach that was based on solid-phase extraction to recover the neutral lipid (NL) and the polar lipid-rich fractions. The TAG profile was analysed in the NL-fraction by C30 reversed-phase liquid chromatography (LC) and the polar lipid profile by normal-phase hydrophilic interaction liquid chromatography (HILIC), with both being coupled to electrospray ionization-mass spectrometry (ESI-MS) and ESI-MS/MS. This approach identified 71 TAG ions that were attributed to more than 350 molecular species, with fatty acyl chain lengths from C11:0 to C26:0, including different polyunsaturated acyl chains. The polar lipids included 107 molecular species that belonged to 11 lipid classes that comprised phospholipids, glyceroglycolipids, glycosphingolipids, and betaine lipids. In addition to polyunsaturated fatty acids, some of the phospholipids, glycolipids, and glycosphingolipids that were identified in the Olive Pulp have been described as biologically active molecules. Lipidomic phenotyping of the Olive Pulp has led to the discovery of compounds that will allow for a better assessment of its nutritional value and new applications of bioactive lipid components in this functional food.
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Positive and negative electrospray ionisation tandem mass spectrometry as a tool for structural characterisation of acid released oligosaccharides from Olive Pulp glucuronoxylans
Carbohydrate research, 2003Co-Authors: Ana Reis, M. Rosário M. Domingues, Pedro Domingues, António J. Ferrer-correia, Manuel A. CoimbraAbstract:Abstract Xylo-oligosaccharides with degrees of polymerisation 5–13, formed by partial acid hydrolysis from an extract representative of Olive Pulp glucuronoxylans (GX), were analysed by electrospray ionisation mass spectrometry (ESI-MS), both in positive and negative modes. The positive spectrum showed the presence of xylo-oligosaccharides in the mass range between m/z 500 and 1500 corresponding to singly [M+Na] + charged ions of neutral (Xyl 7–9 ) and acidic xylo-oligosaccharides (Xyl 5–9 MeGlcA), and doubly [M+2Na] 2+ charged ions of Xyl 9–13 and Xyl 7–11 MeGlcA. Ammonium adducts [M+NH 4 ] + were also observed for Xyl 5–9 MeGlcA. The negative spectra showed the contribution of ions in the mass range between m/z 600 and 1400, ascribed to the deprotonated molecules [M−H] − of Xyl 3–9 MeGlcA. Tandem mass spectrometry (MS/MS) of the major ions observed in the MS spectra was performed. The MS/MS spectra of the [M+Na] + adducts showed the loss of MeGlcA residues as the major fragmentation pathway and glycosidic fragment ions of Xyl n and Xyl n MeGlcA structures. The MS/MS spectra of the [M+NH 4 ] + adducts suggests the occurrence of isomers of Xyl 5–9 MeGlcA oligosaccharides with the MeGlcA residue at the reducing end and at the non-reducing end of the molecules, although other structural isomers can also occur. Both glycosidic bond and cross-ring cleavages in the MS/MS spectra of the [M−H] − ion suggest the occurrence of Xyl 3–9 MeGlcA with the substituting group at the reducing end position of the xylose backbone, as the main fragmentation ions. The results obtained by ESI-MS/MS, both in positive and negative modes, of Xyl 7–13 - and Xyl 5–11 MeGlcA, allow to identify fragmentation patterns of the structural isomers with MeGlcA linked to the terminal xylosyl residues of the oligosaccharides. The occurrence of these higher molecular weight oligosaccharides with a low substitution pattern allows to infer a scatter and random distribution of MeGlcA along the xylan backbone of Olive Pulp.
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Structural characterisation of underivatised Olive Pulp xylo‐oligosaccharides by mass spectrometry using matrix‐assisted laser desorption/ionisation and electrospray ionisation
Rapid communications in mass spectrometry : RCM, 2002Co-Authors: Ana Reis, Manuel A. Coimbra, Pedro Domingues, António J. Ferrer-correia, M. Rosário M. DominguesAbstract:Purified Olive Pulp glucuronoxylans, with a Xyl/GlcA ratio of 7:1, were subjected to mild acid hydrolysis and the mixture of oligosaccharides obtained was fractionated by size exclusion chromatography. One elution fraction representative of low molecular weight oligosaccharides was analysed by mass spectrometry using matrix-assisted laser desorption/ionisation (MALDI) and electrospray ionisation (ESI) as ionisation methods, in the positive mode. Both types of spectra showed cationised molecules [M + Na]+ of xylo-oligosaccharides in a range below m/z 1000. The xylo-oligosaccharide structures identified were series of neutral oligosaccharides of xylose (Xyln, n = 3–7), of acidic oligosaccharides substituted by one glucuronic acid (XylnGlcA, n = 3–5) and by two glucuronic acid residues (XylnGlcA2, n = 2 and 3), and also of acidic oligosaccharides substituted with one 4-O-methylglucuronic acid residue (XylnmeGlcA, n = 2–4). The proposed structures were confirmed by tandem mass (MS/MS) spectra obtained using collision induced dissociation of the molecular ions. Fragmentation of cationised adducts of neutral Xyln yielded C- and A-type fragments, while ammonium adducts mainly yielded B-type fragments. The fragmentation of the sodium adducts of acidic oligosaccharides (XylnmeGlcA, XylnGlcA) resulted in the loss of the substituting residue (GlcA or meGlcA) as the predominant fragment, while the corresponding ammonium adducts yielded B-type fragments. Copyright © 2002 John Wiley & Sons, Ltd.
Rosario M M Domingues - One of the best experts on this subject based on the ideXlab platform.
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lipidomic profiling of the Olive olea europaea l fruit towards its valorisation as a functional food in depth identification of triacylglycerols and polar lipids in portuguese Olives
Molecules, 2019Co-Authors: Eliana Alves, Rosario M M Domingues, Tânia Melo, Madalena P Barros, Pedro DominguesAbstract:Olives (Olea europaea L.) are classic ingredients in the Mediterranean diet with well-known health benefits, but their lipid composition has not been fully addressed. In this work, we characterised triacylglycerol (TAG) and polar lipid profiles of the Olive Pulp while using a complementary methodological approach that was based on solid-phase extraction to recover the neutral lipid (NL) and the polar lipid-rich fractions. The TAG profile was analysed in the NL-fraction by C30 reversed-phase liquid chromatography (LC) and the polar lipid profile by normal-phase hydrophilic interaction liquid chromatography (HILIC), with both being coupled to electrospray ionization-mass spectrometry (ESI-MS) and ESI-MS/MS. This approach identified 71 TAG ions that were attributed to more than 350 molecular species, with fatty acyl chain lengths from C11:0 to C26:0, including different polyunsaturated acyl chains. The polar lipids included 107 molecular species that belonged to 11 lipid classes that comprised phospholipids, glyceroglycolipids, glycosphingolipids, and betaine lipids. In addition to polyunsaturated fatty acids, some of the phospholipids, glycolipids, and glycosphingolipids that were identified in the Olive Pulp have been described as biologically active molecules. Lipidomic phenotyping of the Olive Pulp has led to the discovery of compounds that will allow for a better assessment of its nutritional value and new applications of bioactive lipid components in this functional food.
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structural characterisation of underivatised Olive Pulp xylo oligosaccharides by mass spectrometry using matrix assisted laser desorption ionisation and electrospray ionisation
Rapid Communications in Mass Spectrometry, 2002Co-Authors: Ana Reis, Manuel A. Coimbra, Pedro Domingues, A J Ferrercorreia, Rosario M M DominguesAbstract:Purified Olive Pulp glucuronoxylans, with a Xyl/GlcA ratio of 7:1, were subjected to mild acid hydrolysis and the mixture of oligosaccharides obtained was fractionated by size exclusion chromatography. One elution fraction representative of low molecular weight oligosaccharides was analysed by mass spectrometry using matrix-assisted laser desorption/ionisation (MALDI) and electrospray ionisation (ESI) as ionisation methods, in the positive mode. Both types of spectra showed cationised molecules [M + Na]+ of xylo-oligosaccharides in a range below m/z 1000. The xylo-oligosaccharide structures identified were series of neutral oligosaccharides of xylose (Xyln, n = 3–7), of acidic oligosaccharides substituted by one glucuronic acid (XylnGlcA, n = 3–5) and by two glucuronic acid residues (XylnGlcA2, n = 2 and 3), and also of acidic oligosaccharides substituted with one 4-O-methylglucuronic acid residue (XylnmeGlcA, n = 2–4). The proposed structures were confirmed by tandem mass (MS/MS) spectra obtained using collision induced dissociation of the molecular ions. Fragmentation of cationised adducts of neutral Xyln yielded C- and A-type fragments, while ammonium adducts mainly yielded B-type fragments. The fragmentation of the sodium adducts of acidic oligosaccharides (XylnmeGlcA, XylnGlcA) resulted in the loss of the substituting residue (GlcA or meGlcA) as the predominant fragment, while the corresponding ammonium adducts yielded B-type fragments. Copyright © 2002 John Wiley & Sons, Ltd.
