Principe de l’HPAEC-PAD appliquée à l’analyse d’oligo- et poly-saccharides

Scientific conference (2008)

Les saccharides sont de loin la famille de macromolécules avec la plus grande diversité mais avec néanmoins la présence de structures proches. Il est donc essentiel de disposer d'une méthode très ... [more ▼]

Les saccharides sont de loin la famille de macromolécules avec la plus grande diversité mais avec néanmoins la présence de structures proches. Il est donc essentiel de disposer d'une méthode très sélective de séparation et de détection. L'HPAEC-PAD permet à la fois une séparation fine des saccharides et une détection très sensible (< µmol) [less ▲]

Rapport 3 projet FIRST DEI IMOBIOSE

Report (2007)

Le projet FIRST DEI IMOBIOSE est financé par la région wallonne et en partenariat avec la société Meurens Natural. Ce projet a pour but de produire des sirops d’isomaltooligosaccharides prébiotiques à ... [more ▼]

Le projet FIRST DEI IMOBIOSE est financé par la région wallonne et en partenariat avec la société Meurens Natural. Ce projet a pour but de produire des sirops d’isomaltooligosaccharides prébiotiques à partir de sirops de céréales et ce dans le respect du cahier des charges biologique, mais également de les caractériser d’un point de vue de leur composition et de leurs effets sur la santé. [less ▲]

Mood Food

Conference (2007)

Mood-food can be understood as a nutrition substance, which is able to influence the good disposition of a person. Regulation is made by Neurotransmitters such as endorphins, serotonin, norepinephine and ... [more ▼]

Mood-food can be understood as a nutrition substance, which is able to influence the good disposition of a person. Regulation is made by Neurotransmitters such as endorphins, serotonin, norepinephine and dopamine, made from amino acids through chemical pathways requiring vitamins and minerals as cofactors. [less ▲]

Stratégie pour l’analyse qualitative et quantitative de sirops de céréales enrichis par voie enzymatique en isomaltooligosaccharides

Master of advanced studies dissertation (2007)

Les Isomaltooligosaccharides (IMO) sont constitués de monomères de glucose liés par au moins une liaison α-1-6 (IMO classique), ou dans une moindre proportion α -1-3 (famille nigero-) ou α -1-2 (famille ... [more ▼]

Les Isomaltooligosaccharides (IMO) sont constitués de monomères de glucose liés par au moins une liaison α-1-6 (IMO classique), ou dans une moindre proportion α -1-3 (famille nigero-) ou α -1-2 (famille koji-). Ils sont produits par voie enzymatique à partir d’amidon de céréales hydrolysé. Un mélange très complexe est obtenu avec des molécules caractérisées à la fois par leur valeur de DP (de 2 à ~15), le type de liaisons en présence ainsi que la proportion et la position de chaque type de liaison (seules α -1-6 ou en combinaison). Le défi de cette étude est de trouver une méthode qualitative et quantitative pour caractériser ces sirops. Trois différentes méthodes ont été testées à l’aide de trois différents types de détecteur et comparées selon des critères de sélectivité, sensibilité, robustesse, applicabilité et de la faisabilité de l’analyse quantitative L’HPLC-RID (Refractive Index Detector) utilisée avec une colonne Prevail Carbohydrate (Alltech), adaptée aux sucres de DP variables, s’est révélée être peu sélective du fait de l’obligation de travailler en conditions isocratiques. L’HPLC-ELSD (Evaporating Light Scattering Detector) permettant de travailler en gradient d’élution, une très bonne séparation des différents DP est obtenue sur la même colonne ainsi qu’une séparation des différents DP2 et une amélioration de la sensibilité. L’analyse quantitative reste plus délicate du fait de la zone relativement limitée de linéarité. La Chromatographie à Echange d’Anion et à Haute performance couplée à la Détection à Amperometrie Pulsée (HPAEC-PAD), une séparation hautement sélective et une détection très sensible. Elle est une des seules méthode capable de séparer des molécules homologues ayant comme seules différences leur DP ou de leur type et la séquence de leurs liaisons. L’analyse quantitative a fait l’objet d’une étude approfondie, les facteur de réponses étant dépendant de la structure, du DP et du type de liaisons des oligosaccharides. [less ▲]

On the understanding of the physical changes in inulin powder as a function of water activity.

Poster (2006, December)

Qualitative and quantitative analysis of crop syrup containing enzymatically produced isomaltooligosaccharides.

Poster (2006, October)

Strategy for the qualitative and quantitative analysis of crop syrup containing enzymatically produced Isomaltooligosaccharides known as emerging prebiotics.

Poster (2006)

Isomaltooligosaccharides (IMOs) are non-digestible oligosaccharides, considered as prebiotics and therefore aim to selectively feed probiotics indigenous to the human colon. Recent data obtained in human ... [more ▼]

Isomaltooligosaccharides (IMOs) are non-digestible oligosaccharides, considered as prebiotics and therefore aim to selectively feed probiotics indigenous to the human colon. Recent data obtained in human subjects, support the involvement of dietary oligosaccharides in physiological processes in the different intestinal cell type and also outside the gastrointestinal tract (e.g. hormone production, lipid and carbohydrate metabolism). IMOs consists of glucose monomers linked by at least one α-1-6, or in a lower proportion α -1-3 (nigerose family) or α -1-2 (kojibiose family) glucosidic linkages. In our case they are produced enzymatically from corn starch. It results in a very complex mixture with molecules characterized at the same time by their DP value (from 2 to ~20), linkages types (α-1-2, 3 or 6) and the proportion and position of each type of linkage (only α -1-6 or combined types). The challenge of this study was to find a qualitative and quantitative method to characterize the syrups. In a subsequent study, every unidentified peak could be determined by NMR or Mass spectrometry. Three different chromatographic methods have been tested and compared over their selectivity, sensibility, robustness, applicability and their quantitative power. The HPLC-RID (Refractive Index Detector) used with a Prevail Carbohydrate column (Alltech), adapted for carbohydrates with a certain value of DP, appear to be poorly selective due to the obligation of working in isocratic conditions. The HPLC-ELSD (Evaporating Light Scattering Detector) used with the same column gave a very good separation upon the DP as the Prevail accepts a wide range of solvant changing and even a separation of the different DP 2 molecules. The sensibility was also improved due to the stability of the baseline. The quantitative analysis is a bit more awkward due to the relatively limited linear portion of the calibration curve. High-performance Anion Exchange Chromatography coupled with Pulsed Amperometric Detection (HPAEC-PAD) appeared to deserve a special mention, since it provides selective separation and sensitive detection. In fact, this technique is the only chromatographic one to separate with effectiveness homologue molecules having a difference only in their DP (up to high DPs) or linkage types. This is due to the separation mode based on the difference in ionic force of the sugars in alkaline conditions (mainly due to the DP and the structure of the molecule). However, during the detection, the electrochemical behavior of carbohydrates can be affected by molecular weight as well as by structural differences giving rise to different response factors; as a consequence, HPAEC-PAD is not generally considered as suitable for quantitative studies of complex mixtures of oligosaccharides. In this work a methodological approach is presented in order to get a quantitative response through a rigorous methodology for our IMOs. It also opens the way to the theoretical determination of the response factor for the homologue molecules in relation with their structure and DP. [less ▲]

STRATEGY FOR THE QUALITATIVE AND QUANTITATIVE ANALYSIS OF CROP SYRUP CONTAINING ISOMALTOOLIGOSACCHARIDES KNOWN AS EMERGING PREBIOTICS

Conference (2006)

Isomaltooligosaccharides (IMOs) are non-digestible oligosaccharides, considered as prebiotics and therefore aim to selectively feed probiotics indigenous to the human colon. Recent data obtained in human ... [more ▼]

Isomaltooligosaccharides (IMOs) are non-digestible oligosaccharides, considered as prebiotics and therefore aim to selectively feed probiotics indigenous to the human colon. Recent data obtained in human subjects, support the involvement of dietary oligosaccharides in physiological processes in the different intestinal cell type and also outside the gastrointestinal tract (e.g. hormone production, lipid and carbohydrate metabolism). IMOs consists of glucose monomers linked by at least one α-1-6, or in a lower proportion α -1-3 (nigerose family) or α -1-2 (kojibiose family) glucosidic linkages. In our case they are produced enzymatically from corn starch. It results in a very complex mixture with molecules characterized at the same time by their DP value (from 2 to ~20), linkages types (α-1-2, 3 or 6) and the proportion and position of each type of linkage (only α -1-6 or combined types). The challenge of this study was to find a qualitative and quantitative method to characterize the syrups. In a subsequent study, every unidentified peak could be determined by NMR or Mass spectrometry. Three different chromatographic methods have been tested and compared over their selectivity, sensibility, robustness, applicability and their quantitative power. The HPLC-RID (Refractive Index Detector) used with a Prevail Carbohydrate column (Alltech), adapted for carbohydrates with a certain value of DP, appear to be poorly selective due to the obligation of working in isocratic conditions. The HPLC-ELSD (Evaporating Light Scattering Detector) used with the same column gave a very good separation upon the DP as the Prevail accepts a wide range of solvant changing and even a separation of the different DP 2 molecules. The sensibility was also improved due to the stability of the baseline. The quantitative analysis is a bit more awkward due to the relatively limited linear portion of the calibration curve. High-performance Anion Exchange Chromatography coupled with Pulsed Amperometric Detection (HPAEC-PAD) appeared to deserve a special mention, since it provides selective separation and sensitive detection. In fact, this technique is the only chromatographic one to separate with effectiveness homologue molecules having a difference only in their DP (up to high DPs) or linkage types. This is due to the separation mode based on the difference in ionic force of the sugars in alkaline conditions (mainly due to the DP and the structure of the molecule). However, during the detection, the electrochemical behavior of carbohydrates can be affected by molecular weight as well as by structural differences giving rise to different response factors; as a consequence, HPAEC-PAD is not generally considered as suitable for quantitative studies of complex mixtures of oligosaccharides. In this work a methodological approach is presented in order to get a quantitative response through a rigorous methodology for our IMOs. It also opens the way to the theoretical determination of the response factor for the homologue molecules in relation with their structure and DP. [less ▲]

Rapport 3 du projet Région Wallonne NANOMEMB

Report (2005)

Projet NANOMEMB financé par la région wallonne, visant le développement d’un modèle membranaire nanobiomimétique à usage pharmacologique

Physiological and bio-functional properties of gum arabic: a notable interest for certain human diseases

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (n.d.)