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.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Physiologically based in silico modelling to examine DNA adduct formation by different food-borne a,ß-unsaturated aldehydes at realistic low dietary exposure levels
    Kiwamoto, R. - \ 2015
    Wageningen University. Promotor(en): Ivonne Rietjens, co-promotor(en): Ans Punt. - Wageningen : Wageningen University - ISBN 9789462572843 - 200
    aldehyden - dna - ontgifting - voedseladditieven - aromatische stoffen - genotoxiciteit - carcinogenen - modellen - wiskundige modellen - fysiologie - simulatiemodellen - toxicologie - aldehydes - dna - detoxification - food additives - flavourings - genotoxicity - carcinogens - models - mathematical models - physiology - simulation models - toxicology

    Abstract (R.Kiwamoto ISBN 978-94-6257-284-3)

    Various α,β-unsaturated aldehydes are present in fruits, vegetables, spices, or processed products containing these items as natural constituents or as added food flavouring agents. Because of the α,β-unsaturated aldehyde moiety the β carbon in the molecule becomes electron deficient and the aldehydes react with electron rich molecules including DNA via Michael addition. The formation of DNA adducts raises a concern for genotoxicity, although formation of DNA adducts may not be significant at low doses relevant for dietary exposure in vivo because of adequate detoxification. This thesis therefore aimed at determining dose-dependent detoxification and DNA adduct formation of food-borne α,β-unsaturated aldehydes by using a physiologically based in silico modelling approach in order to contribute to the safety assessment of these aldehydes used as food flavourings instead of performing animal experiments.

    Physiologically based in silico models were developed for 18 α,β-unsaturated aldehydes. The model outcomes indicated that the DNA adduct formation by the 18 α,β-unsaturated aldehydes as food flavourings is negligible and does not raise a safety concern at their levels of intake resulting from their use as food flavourings. The application of QSAR models strongly accelerated the development process of the PBK/D models of the group of 18 compounds. Also, it was illustrated that physiologically based in silico models provide a very useful and powerful tool to facilitate a group evaluation and read-across for food-borne DNA reactive agents. PBK/D models developed for the group of compounds supported read-across from cinnamaldehyde which is known not to be genotoxic or carcinogenic in vivo to other aldehydes, by allowing comparison of dose-dependent DNA adduct formations. Altogether this thesis presented physiologically based in silico modelling as an approach to test relevance of positive in vitro genotoxicity results by DNA reactive compounds in vivo without using animal experiments.

    Formation of Amino Acid Derived Cheese Flavour Compounds
    Smit, B.A. - \ 2004
    Wageningen University. Promotor(en): J.T.M. Wouters; Gerrit Smit, co-promotor(en): W.J.M. Engels. - Wageningen : S.n. - ISBN 9789058089960 - 127
    geurstoffen en smaakstoffen - aldehyden - kazen - melkzuurbacteriën - aminozuren - aroma - fermentatieproducten - flavour compounds - aldehydes - cheeses - lactic acid bacteria - amino acids - aroma - fermentation products
    Lactic acid bacteria (LAB), among them Lactococcus lactis, are often used for the fermentation of milk into various products, such as cheeses. For their growth and maintenance LAB metabolise milk sugar, protein and fat into various low molecular compounds, which sometimes have strong flavour characteristics. This thesis focuses on the production of one class of these compounds as a model system: aldehydes, in particular the key-flavour compounds 3-methylbutanal and 2-methyl propanal, which are enzymatically derived from the amino acids leucine and valine. Comparing several strains belonging not only to the genus Lactococcus , but also to the genera Lactobacillus , Streptococcus , Leuconostoc , Bifidobacterium , Propionibacterium , Brevibacterium , Corynebacterium and Arthrobacter with regard to various enzyme activities involved in the conversion pathway of leucine to 3-methylbutanal, revealed a large variation between and within species. In particular,a-keto acid decarboxylase activity, leading to 3-methylbutanal was identified as a rate-limiting step in this pathway.

    Identification of thea-keto acid decarboxylase gene was obtained by screening of mutant libraries of the decarboxylase-positive strain L. lactis B1157 with a newly developed method for high throughput analysis (HTS) of volatiles, present in the headspace of miniaturised fermentations. The gene had a very high homology with a (most probably) truncated gene in the genome of L. lactis IL1403 annotated as ipd . The molecular weight of the TPP dependant enzyme was 60.9 kDa, its estimated pI is 5.03. The enzyme activity was hardly affected by high salinity and activity was found to be optimal at pH=6.3. Moreover, of all potential substrates tested, the activity towards branched-chaina-keto acids was the highest, for which reason it is proposed to be annotated as BcKAD (branched-chain keto acid decarboxylase).

    The newly developed method for analysis of volatiles was also applied for monitoring the non-enzymatic conversion of the leucine-derived keto acid to the branched chain aldehyde 2-methylpropanal. 2-Methylpropanal is the aldehyde, which was believed to be a product of the enzymatic conversion of valine. The non-enzymatic reaction proceeded in the presence of manganese ions and oxygen, the products were the aldehyde and either carbon oxides or oxalate. The conversion was maximal at pH 5.5 and pH>8. A range ofa-keto acids were converted under the sameconditions,and keto acids with an electron-pulling side chain had the highest conversion rates.

    The results described in this thesis add to the understanding of the control of flavour formation in fermented products like cheese. The thesis focuses mainly on the existence and relevance of some of the amino acid converting pathways of certain bacterial strains. In addition to this, further research on regulation and/or complementation of these pathways in/by several strains is recommended. The HTS-method also enables the selection of strains from large culture collections for production of certain volatiles and for application of this property in cheese making.

    Qualitätsbestimmung bei Lagerkartoffeln
    Hak, P.S. ; Oosterhaven, J. - \ 1997
    Der Kartoffelbau 48 (1997)11. - ISSN 0022-9156 - p. 418 - 420.
    opslag - chemische samenstelling - planten - chemische analyse - koolhydraten - aldehyden - ketonen - zetmeel - cellulose - kwaliteit - prestatieniveau - fabrieksaardappelen - storage - chemical composition - plants - chemical analysis - carbohydrates - aldehydes - ketones - starch - quality - performance - starch potatoes
    Onderzoek naar oorzaken van veroudering bij het bewaren van fabrieksaardappelen. De balans tussen het zetmeel- en suikergehalte is een indicator voor de kwaliteit van frieten
    Enzymic modification of cellulose - xyloglucan networks : implications for fruit juice processing = Enzymatische modificatie van cellulose - xyloglucaan netwerken
    Vincken, J.P. - \ 1996
    Agricultural University. Promotor(en): A.G.J. Voragen; G. Beldman. - S.l. : Vincken - ISBN 9789054855101 - 159
    appels - malus - koolhydraten - aldehyden - ketonen - zetmeel - cellulose - apples - malus - carbohydrates - aldehydes - ketones - starch - cellulose

    Xyloglucans play an important role in connecting cellulose microfibrils in the primary coli wall of plants, and the resulting cellulose-xyloglucan network is thought to determine the strength of these walls. Xyloglucans were isolated from apple fruit and potato tuber cell wall material by alkaline extraction and their primary structures were determined. Major differences between these two polysaccharides were their degree of backbone branching and the presence of fucosyl and arabinosyl residues.

    The substrate specificity of three ondoglucanases from Trichoderma viride (endol, endolV and endoV) was investigated. The target substrate of endol is cellulose, that of endolV xyloglucan, whereas endoV is the most versatile endoglucanase having the ability of degrading both substrates. EndolV and endoV differ in their mode of action towards potato xyloglucan. Further, strong indications were obtained that xyloglucanase activity is related to a long array of substrate-binding sites.

    The degradation of the cellulose-xyloglucan network in isolated coli wall material from apple fruit involves several glucanase activities. Xyloglucanase activity is important to make cell wall embedded cellulose more accessible to true cellulolytic enzymes such as endol and cellobiohydrolase. Extensive degradation is required because xyloglucan fragments having a backbone of 20 glucosyl residues (five building units) still bind to cellulose surfaces. These results might explain why fungi excrete so many different kinds of endoglucanases.

    When the cell walls of living apple fruit tissue were treated with pectin lyase and a mixture of glucanases from Trichoderma viride (liquefaction), the ease with which the apple tissue disintegrated, seemed to depend on the maturity of the fruit. The disintegration of apple fruit tissue during liquefaction correlates to the level of (ripeningrelated) xyloglucan endotransglycosylase activity in apple fruit. An hypothesis for the synergism of fungal and plant glucanases is put forward. Under certain circumstances (controlled liquefaction) the cellulose-xyloglucan network can be modified in such a way, that a stable cellulose-based cloud is formed in the resulting apple juice. The significance of these observations for juice manufacturing is discussed.

    Opslag en benutting van niet-structurele koolhydraten in de vegetatieve delen tijdens bloei en zaadvulling bij zaadgewassen : een literatuur-orientatie
    Dijk, W. van - \ 1989
    Wageningen : CABO (CABO-verslag nr. 116) - 41
    aldehyden - koolhydraten - cellulose - distributie - formatie - ketonen - voedingsstoffenreserves - zaadzetting - zaden - zetmeel - aldehydes - carbohydrates - cellulose - distribution - formation - ketones - nutrient reserves - seed set - seeds - starch
    Literatuurstudie naar de bepaling van mono- en disacchariden en polyalcoholen met behulp van instrumentale analysemethoden
    Oostrom, J.J. van; Jong, J. de; Frankhuizen, R. - \ 1989
    Wageningen : RIKILT (Rapport / RIKILT 89.55) - 20
    voedingsmiddelen - voedselproducten - landbouwproducten - voedselkwaliteit - kwaliteitscontroles - derivaten - polyethyleenglycol - glycolen - ethyleenglycol - alcoholen - thiolen - koolhydraten - aldehyden - ketonen - zetmeel - cellulose - analyse - chemie - literatuuroverzichten - analytische scheikunde - foods - food products - agricultural products - food quality - quality controls - derivatives - polyethylene glycol - glycols - ethylene glycol - alcohols - thiols - carbohydrates - aldehydes - ketones - starch - cellulose - analysis - chemistry - literature reviews - analytical chemistry
    Doel van dit onderzoek was het uitvoeren van een literatuurstudie naar de bepalingsmogelijkheden van mono- en disacchariden en polyalcoholen met behulp van instrumentele analysemethoden.
    Hoe bepaal ik suikers in frites- en chipsaardappelen?
    Ludwig, J.W. - \ 1987
    Wageningen : I.B.V.L. (Publikatie / Instituut voor Bewaring en Verwerking van Landbouwprodukten 376)
    aldehyden - koolhydraten - cassave - cellulose - voedselbewaring - voedselkwaliteit - voedingsmiddelen - ketonen - aardappelen - kwaliteitscontroles - wortelgewassen als groente - zetmeel - aldehydes - carbohydrates - cassava - cellulose - food preservation - food quality - foods - ketones - potatoes - quality controls - root vegetables - starch
    De bepaling van reservekoolhydraten in grassen
    Vertregt, N. ; Verhagen, W. - \ 1979
    Wageningen : Centrum voor Agrobiologisch Onderzoek (CABO-verslag / Centrum voor Agrobiologisch Onderzoek no. 23) - 18
    aldehyden - analyse - plantkunde - koolhydraten - cellulose - chemie - ketonen - zetmeel - analytische scheikunde - voedergrassen - aldehydes - analysis - botany - carbohydrates - cellulose - chemistry - ketones - starch - analytical chemistry - fodder grasses
    The determination of sugars in potatoes as studied in a ring - analysis
    Vliet, W.F. van; Mueller, K. - \ 1970
    Wageningen : [s.n.] (Publikatie / Instituut voor bewaring en verwerking van landbouwprodukten no. 218) - 7
    aldehyden - analyse - plantkunde - koolhydraten - cellulose - chemie - ketonen - organische verbindingen - aardappelen - solanum tuberosum - zetmeel - analytische scheikunde - aldehydes - analysis - botany - carbohydrates - cellulose - chemistry - ketones - organic compounds - potatoes - solanum tuberosum - starch - analytical chemistry
    The determination of sugars in potatoes, studied in a ring - analysis
    Vliet, W.F. van - \ 1970
    Wageningen etc. : [s.n.] (Publikatie / Instituut voor bewaring en verwerking van landbouwproducten no. 224) - 2
    aldehyden - analyse - plantkunde - koolhydraten - cellulose - chemie - ketonen - organische verbindingen - aardappelen - solanum tuberosum - zetmeel - analytische scheikunde - aldehydes - analysis - botany - carbohydrates - cellulose - chemistry - ketones - organic compounds - potatoes - solanum tuberosum - starch - analytical chemistry
    De bepaling van pectine in aardappelen
    Schriemer, W. - \ 1961
    Wageningen : [s.n.] (Intern rapport / Instituut voor bewaring en verwerking van landbouwprodukten no. 116) - 19
    aldehyden - koolhydraten - cellulose - ketonen - pectinen - aardappelen - solanum tuberosum - zetmeel - aldehydes - carbohydrates - cellulose - ketones - pectins - potatoes - solanum tuberosum - starch
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