Structural Characterisation by ESI-MS of Feruloylated Arabino-oligosaccharides Synthesised by Chemoenzymatic Esterification

The chemoenzymatic synthesis of feruloylated arabino-oligosaccharides has neen achieved, using a feruloyl esterase type C from Sporotrichum themophile (StFaeC). The structure of the feruloyl products was comfirmed by ESI-MS

Functional Region Identification in Proteins by Accumulative-Quantitative Peptide Mapping Using RP-HPLC-MS

A new method was developed to identify regions in proteins from which peptides are derived with specific functional properties. This method is applicable for systems in which peptides of a hydrolyzed protein possess specific functional properties, but are too large to be sequenced directly and/or the peptide mixture is too complex to purify and characterize each peptide individually. In the present work, aggregating peptides obtained by proteolytic hydrolysis of soy glycinin were used as a case study. The aggregating peptides are isolated and subsequently further degraded with trypsin to result in peptides with a mas

Onderzoek naar de wetenschap- en techniekactiviteiten van sCoolscience : 12 ontwerpprincipes

In dit rapport wordt verslag gedaan van deze literatuurstudie met als doel een theoretische fundering te bieden voor de regionale activiteiten van sCoolscience. De centrale vraag van de literatuurstudie is: Op basis van welke theoretische principes, inclusief design principes, kunnen de regionale activiteiten van sCoolscience gefundeerd worden? Om de centrale vraag te kunnen beantwoorden, wordt in het theoretisch kader eerst ingegaan op verschillende definities rond science/(natuur)wetenschap en techniek/technology. Daarbinnen wordt onderscheid gemaakt in kennis en vaardigheden. Vervolgens wordt het begrip attitude gedefinieerd. Omdat sCoolscience opbrengsten van leerlingen in kennis, vaardigheden en attitude wil vaststellen, wordt daarna ingegaan opbrengstgericht werken. Ook worden beïnvloedende factoren op kennis, vaardigheden en attitude van leerlingen ten aanzien van wetenschap en techniek besproken. Door rekening te houden met deze factoren kan sCoolscience haar activiteiten zo vormgeven dat zo hoog mogelijke leer- en attitude-opbrengsten bij leerlingen worden bereikt. Om sCoolscience van praktische adviezen te voorzien zijn tot slot bij deze beïnvloedende factoren design principes opgesteld. De opgestelde design principes bestaan uit richtlijnen om rekening te houden met leerling gerelateerde kenmerken (sekseverschillen en de ervaringen en achtergrond van leerlingen) en school gerelateerde kenmerken (de kwaliteit van het onderwijs door de leraar, de tijdsduur en hoeveelheid lessen wetenschap en techniek, praktische activiteiten, en het beeld van wetenschap- en techniekonderwijs op school). Met behulp van de opgestelde design principes kan sCoolscience haar huidige activiteiten verbeteren en nieuwe activiteiten ontwikkelen

Cell wall polysaccharides in black currants and bilberries-characterisation in berries, juice, and press cake

Cell wall polysaccharides from black currants and bilberries were characterised in three approaches. First, compositions of skin, pulp, and seeds show the distribution of polysaccharides over these tissues. A sequential extraction of cell wall material with different aqueous extractants informs about the extractability of the different polysaccharides, viz. pectins, hemicellulose, and cellulose. Finally, by isolation of cell wall polysaccharides from juice and press cakes obtained by the conventional juice manufacturing. The polysaccharide distribution was followed during juice processing. The main difference between bilberries and black currants is the dominant sugar residue in seeds: mannose for black currants and xylose for bilberries. Most of the hemicellulolytic sugars and cellulose can be found back in the press cake. The sugar composition of the press cake is similar to the composition of the residue after sequential extraction. Black currants contain more pectic sugars than bilberries. Consequently, a commercial enzyme used during processing releases more pectic material into the juic

Characterisation of 3-aminoquinoline-derivatised isomeric oligogalacturonic acid by travelling-wave ion mobility mass spectrometry

RATIONALE Mass spectrometry has become a useful technique for elucidating the chemical structures of oligosaccharides. The combined use of chromatography and mass spectrometry for the separation and identification of oligosaccharides has shown much progress in recent years. However, no powerful method has yet been developed to quickly identify isomeric oligosaccharides in complex mixtures. METHODS A rapid travelling-wave ion mobility mass spectrometry (TWIMS-MS) method was developed for the identification of various isomeric oligogalacturonic acids in mixtures and determined their structures, using 3-aminoquinoline (3-AQ) as a labelling agent. RESULTS TWIMS successfully distinguished isomeric oligogalacturonic acids of various degrees of polymerisation (DPs) and levels of methyl-esterification. After derivatisation by 3-AQ, isomeric oligosaccharides of galacturonic acid, with the DP ranging from 2 to 9 and the number of methyl esters ranging from 1 to 5, were identified by 3-AQ-TWIMS-MS. The isomeric oligosaccharides with varying sites of methyl ester substitution were identified by the post-fragmentation mode of TWIMS using 3-AQ labelling to obtain simplified mass spectra. CONCLUSIONS Using the 3-AQ-TWIMS-MS method, the precise distribution of methyl esters within the pectin molecule and isomeric oligogalacturonic acids after enzyme degradation was determined. Simplified product ion mass spectra and precise analysis of the isomers were achieved by labelling 3-AQ at the reducing end of the oligosaccharides. Series of methyl-esterified galacturonic acid oligomers have predictable drift times, depending on the precise position of the methyl ester