Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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Visual scores or subcutaneous fat thickness measurements, which is better for designing a 3D vision-technology body condition assessment method
Bokkers, Eddie ; Leijdekkers, Elles ; Song, X. ; Tol, J.J.P. van der - \ 2018
In: AgEng Conference 2018: New engineering concepts for a valued agriculture. - - p. 62 - 62.
Assessing body condition (BC) of dairy cows is a way to collect information about their fat reserves, which is essential for effective feeding management. 3D vision-technology might offer the opportunity to automatically and frequently assess BC. Daily monitoring provides a short feedback-loop of changes in fat reserves. Hence, feedings strategies can be optimized which is beneficial from an economic (lower costs), environmental (lower emissions) and animal welfare (lower disease incidences) perspective. This study aimed to determine whether visual scores or subcutaneous fat thickness measurement is better to design
a system using 3D vision-technology to predict BC scores. Cows (n=46) ranging in BC score on a 5-point-scale from 1 (lean) to 5 (fat) were preselected on four farms. For eight body parts,
BC scores (1-5) given by two observers independently via visual observation and subcutaneous fat thicknesses (mm) measured by ultrasound were related with corresponding 3D variables. The three methodologies were conducted twice on two consecutive days. Only two body parts, i.e. sacral ligament and line between spinous process and tips of short ribs could be assessed by all three
methodologies (ultrasound was limiting). The inter- and intra-observer agreement (kappa) for visual observation ranged from 0.52 to 0.71 and 0.50 to 0.69 for the two body parts respectively. Correlation coefficients between days for the two body parts were 0.72 and 0.88 for subcutaneous fat thickness and 0.91 and 0.96 for 3D vision variables. Furthermore, 3D vision variables
of the two body parts correlated better with visual observations (range 0.79-0.88) than with subcutaneous fat thickness (range 0.55-0.69). Despite the high precision of the ultrasound device, this method appeared labour intensive and only delivered useful information for two body parts. Instead visual observations were made on all eight body parts and showed better potential for predictive BC models using 3D vision variables.
Identification of novel isomeric pectic oligosaccharides using hydrophilic interaction chromatography coupled to traveling-wave ion mobility mass spectrometry
Leijdekkers, A.G.M. ; Huang, J.H. ; Bakx, E.J. ; Gruppen, H. ; Schols, H.A. - \ 2015
Carbohydrate Research : an international journal 404 (2015). - ISSN 0008-6215 - p. 1 - 8.
interaction liquid-chromatography - fluorescent labels - galacturonic acid - cell walls - separation
Separation and characterization of complex mixtures of pectic oligosaccharides still remains challenging and often requires the use of multiple analytical techniques, especially when isomeric structures are present. In this work, it is demonstrated that the coupling of hydrophilic interaction chromatography (HILIC) to traveling-wave ion mobility mass spectrometry (TWIMMS) enabled the simultaneous separation and characterization of complex mixtures of various isomeric pectic oligosaccharides. Labeling of oligosaccharides with 3-aminoquinoline (3-AQ) improved MS-ionization efficiency of the oligosaccharides and reduced the complexity of the product ion mass spectra, without losing resolution of the HILIC separation. In addition, labeling enabled quantification of oligosaccharides on molar basis using in-line fluorescence detection. Isomeric structures were distinguished using TWIMMS. The 3-AQ-HILIC–TWIMMS method was used to characterize a series of isomeric sugar beet rhamnogalacturonan I derived oligosaccharides carrying a glucuronic acid substituent. Thereby, some novel structural features were identified for the first time: glucuronic acid was attached to O-3 or to O-2 of galacturonic acid residues and a single galacturonic acid residue within an oligomer could contain both an acetyl group and a glucuronic acid substituent.
Characterization of sugar beet pulp derived oligosaccharides
Leijdekkers, M. - \ 2015
Wageningen University. Promotor(en): Harry Gruppen; Henk Schols. - Wageningen : Wageningen University - ISBN 9789462572430 - 162
suikerbieten - bietenpulp - oligosacchariden - versuikering - bioraffinage - voer - fermentatie - sugarbeet - beet pulp - oligosaccharides - saccharification - biorefinery - feeds - fermentation

Abstract

This thesis aimed at characterizing complex mixtures of sugar beet pulp derived oligosaccharides, in order to be able to monitor and optimize the enzymatic saccharification of sugar beet pulp.

Hydrophilic interaction chromatography with on-line evaporative light scattering detection and multidimensional mass spectrometry (HILIC-ELSD-MSn) was developed as a versatile technique for the characterization of a wide range of neutral and acidic plant cell wall derived oligosaccharides. It was shown that the separation capacity of HILIC for acidic oligosaccharides outperforms other techniques. HILIC-MSn enabled efficient sequence elucidation of oligosaccharides in complex mixtures.

The enzymatic saccharification of sugar beet pulp was optimized to release the maximum amounts of monomeric galacturonic acid and arabinose with limited concomitant degradation of cellulose, using conditions that are feasible for industrial upscaling. The oligosaccharides that were obtained after hydrolysis were characterized, thereby enabling recognition of enzyme activities additionally needed for the full degradation of recalcitrant oligosaccharides.

The in vitro fermentation characteristics of sugar beet pectic oligosaccharides (SBPOS) were studied using human and pig fecal inocula. The fate of the different classes of SBPOS, the production of short-chain fatty acids and the changes in human fecal bacterial populations during in vitro fermentation were described. Several modifications in the microbiota composition that are potentially beneficial to host health were observed.

HILIC was also coupled to traveling-wave ion mobility mass spectrometry to enable the simultaneous separation and characterization of complex mixtures of various isomeric pectic oligosaccharides. The developed method was used to characterize isomeric sugar beet rhamnogalacturonan I derived oligosaccharides carrying a glucuronic acid substituent, thereby identifying novel structural features of sugar beet pectin.

In Vitro fermentability of sugar beet pulp derived oligosaccharides using human and pig fecal inocula
Leijdekkers, A.G.M. ; Aguirre, M. ; Venema, K. ; Bosch, G. ; Gruppen, H. ; Schols, H.A. - \ 2014
Journal of Agricultural and Food Chemistry 62 (2014)5. - ISSN 0021-8561 - p. 1079 - 1087.
irritable-bowel-syndrome - pectic-oligosaccharides - arabino-oligosaccharides - ulcerative-colitis - large-intestine - fermentation - microbiota - butyrate - bacteria - profiles
The in vitro fermentation characteristics of different classes of sugar beet pectic oligosaccharides (SBPOS) were studied using human and pig fecal inocula. The SBPOS consisted mainly of partially acetylated rhamnogalacturonan-oligosaccharides and partially methyl esterified/acetylated homogalacturonan-oligosaccharides. Some SBPOS contained an unsaturated galacturonic acid residue at their non-reducing end. It was shown that SBPOS could be completely fermented by human and pig fecal microbiota, thereby producing butyrate, yet mainly acetate and propionate as metabolites. The degradation of SBPOS by pig fecal microbiota was different and much slower compared to human fecal microbiota. In general, rhamnogalacturonan-oligosaccharides were slower degraded than homogalacturonan32 oligosaccharides. Acetylation of rhamnogalacturonan-oligosaccharides lowered the degradation rate by pig fecal microbiota, but not by human fecal microbiota. No classic bifidogenic effect was shown for SBPOS using human fecal inoculum. However, several other potentially interesting modifications in the microbiota composition that can be associated with host health were observed, which are discussed.
Enzymatic saccharification of sugar beet pulp for the production of galacturonic acid and arabinose; a study on the impact of the formation of recalcitrant oligosaccharides
Leijdekkers, A.G.M. ; Bink, J.P.M. ; Geutjes, S. ; Schols, H.A. ; Gruppen, H. - \ 2013
Bioresource Technology 128 (2013). - ISSN 0960-8524 - p. 518 - 525.
rhamnogalacturonan regions - ethanol-production - pectin - fermentation - hydrolysis - polysaccharides - pretreatment - cellulose - enzymes
Enzymatic saccharification of sugar beet pulp was optimized on kg-scale to release the maximum amounts of monomeric galacturonic acid and arabinose with limited concomitant degradation of cellulose, using conditions that are feasible for industrial upscaling. A selected mixture of pectinases released 79% of the galacturonic acid and 82% of the arabinose as monomers from sugar beet pulp while simultaneously degrading only 17% of the cellulose. The recalcitrant structures that were obtained after hydrolysis were characterized using mass spectrometry. The most abundant structures had an average degree of polymerization of 4–5. They were identified as partially acetylated rhamnogalacturonan-oligosaccharides, mostly containing a terminal galacturonosyl residue on both reducing and non-reducing end, partially methyl esterified/acetylated homogalacturonan-oligosaccharides, mostly containing methyl and acetyl esters at contiguous galacturonosyl residues and arabinan-oligosaccharides, hypothesized to be mainly branched. It could be concluded that especially rhamnogalacturonan-galacturonohydrolase, arabinofuranosidase and pectin acetylesterase are lacking for further degradation of recalcitrant oligosaccharides
Combined HILIC-ELSD/ESI-MSn enables the separation, identification and quantification of sugar beet pectin derived oligomers
Remoroza, C.A. ; Cord-Landwehr, S. ; Leijdekkers, A.G.M. ; Moerschbacher, B.M. ; Schols, H.A. ; Gruppen, H. - \ 2012
Carbohydrate Polymers 90 (2012)1. - ISSN 0144-8617 - p. 41 - 48.
performance liquid-chromatography - aspergillus-niger - mass-spectrometry - acetyl groups - acid - methyl - oligogalacturonides - lyase - esterification - degradation
The combined action of endo-polygalacturonase (endo-PGII), pectin lyase (PL), pectin methyl esterase (fungal PME) and RG-I degrading enzymes enabled the extended degradation of methylesterified and acetylated sugar beet pectins (SBPs). The released oligomers were separated, identified and quantified using hydrophilic interaction liquid chromatography (HILIC) with online electrospray ionization ion trap mass spectrometry (ESI-IT-MSn) and evaporative light scattering detection (ELSD). By MSn, the structures of galacturonic acid (GalA) oligomers having an acetyl group in the O-2 and/or O-3 positions eluting from the HILIC column were elucidated. The presence of methylesterified and/or acetylated galacturonic acid units within an oligomer reduced the interaction with the HILIC column significantly compared to the unsubstituted GalA oligomers. The HILIC column enables a good separation of most oligomers present in the digest. The use of ELSD to quantify oligogalacturonides was validated using pure GalA standards and the signal was found to be independent of the chemical structure of the oligomer being detected. The combination of chromatographic and enzymatic strategies enables to distinguish SBPs having different methylesters and acetyl group distribution.
Characterizing plant cell wall derived oligosaccharides using hydrophilic interaction chromatography with mass spectrometry detection
Leijdekkers, A.G.M. ; Sanders, M.G. ; Schols, H.A. ; Gruppen, H. - \ 2011
Journal of Chromatography. A, Including electrophoresis and other separation methods 1218 (2011)51. - ISSN 0021-9673 - p. 9227 - 9235.
anion-exchange chromatography - assisted laser-desorption - sugar-beet - acidic oligosaccharides - graphitic carbon - polar compounds - performance - separation - pectins - oligomers
Analysis of complex mixtures of plant cell wall derived oligosaccharides is still challenging and multiple analytical techniques are often required for separation and characterization of these mixtures. In this work it is demonstrated that hydrophilic interaction chromatography coupled with evaporative light scattering and mass spectrometry detection (HILIC–ELSD–MSn) is a valuable tool for identification of a wide range of neutral and acidic cell wall derived oligosaccharides. The separation potential for acidic oligosaccharides observed with HILIC is much better compared to other existing techniques, like capillary electrophoresis, reversed phase and porous-graphitized carbon chromatography. Important structural information, such as presence of methyl esters and acetyl groups, is retained during analysis. Separation of acidic oligosaccharides with equal charge yet with different degrees of polymerization can be obtained. The efficient coupling of HILIC with ELSD and MSn-detection enables characterization and quantification of many different oligosaccharide structures present in complex mixtures. This makes HILIC–ELSD–MSn a versatile and powerful additional technique in plant cell wall analysis.
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