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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    Understanding the role of oat ß-glucan in oat-based dough systems
    Londono, D.M. ; Gilissen, L.J.W.J. ; Visser, R.G.F. ; Smulders, M.J.M. ; Hamer, R.J. - \ 2015
    Journal of Cereal Science 62 (2015). - ISSN 0733-5210 - p. 1 - 7.
    rheological properties - celiac-disease - bread quality - pentosans - diet - formulations - yeast
    B-glucan is one of the components that differentiate oats from other cereals and that contribute to the health-related value of oats. However, so far oats cannot easily be applied in bread-like products without loss of product quality. Here we have studied how the content and viscosity of oat ß-glucan affect the technological properties of oat dough in both a gluten-free and a gluten-containing system. In both systems, increasing the ß-glucan concentration resulted in an increase of dough stiffness and in a reduction of dough extensibility. ¿-glucan negatively impacted the elastic properties that additional wheat gluten conferred to oat dough. This effect was smaller for medium-viscosity ß-glucan than for high-viscosity ß-glucan. Interestingly, dough made from low ß-glucan flour (
    The effect of particle size of wheat bran fractions on bread quality – Evidence for fibre–protein interactions
    Noort, M.W.J. ; Haaster, D.J. van; Hemery, Y. ; Schols, H.A. ; Hamer, R.J. - \ 2010
    Journal of Cereal Science 52 (2010)1. - ISSN 0733-5210 - p. 59 - 64.
    water unextractable solids - loaf volume - phenolic-acid - brown bread - breadmaking - pentosans - phytate - layers - grain
    The nature of the adverse effects of wheat bran fractions on bread-making quality was studied. Two fractions of bran, representing different tissue layers and having different compositions, were used. The particle size of the bran fractions was varied by various milling techniques. All fractions were added to white flour and water addition was adjusted to obtain dough with a constant consistency. Both dough-mixing properties and bread-making quality were affected by the addition of bran. The negative influence was enhanced when bran particle size was reduced. The effects on bread quality are strongly correlated to negative effects of bran on gluten network formation. The results show that fibre–gluten interactions are the main cause for the negative effects of fibres, rather than dilution of gluten, piercing of gas cells or particles disturbing the gluten network. Two possible explanations for the enhancement of the adverse effects when reducing the particle size of bran fractions are discussed: 1) increased interaction surface 2) liberation of reactive components due to cell breakage.
    Surface Layer Properties of Dough Liquor Components: Are They Key Parameters in Gas Retention in Bread Dough?
    Primo Martin, C. ; Hamer, R.J. ; Jongh, H.H.J. de - \ 2006
    Food Biophysics 1 (2006)2. - ISSN 1557-1858 - p. 83 - 93.
    interfacial rheological properties - wheat-flour - competitive adsorption - aqueous phases - protein - pentosans - stability
    Gas cell stability during bread making is controlled by both surface and bulk properties. This paper is focused on studying the surface properties of the water-soluble phase of the dough, the dough liquor (with and without lipids), as well as the composition of the air/water interface. Using infrared reflection measurements, we showed that in lipid-poor liquor, proteins are the dominant species present at the air/water interface. With complete liquor (including the lipids), a mixed interface of protein and lipids is obtained. However, the presence of lipids in the surface layer did not significantly affect the surface pressure. We also added enzymes to the flour to evaluate in what way the surface-active properties of the liquor components can be affected. These results were compared to the effect of adding a surfactant [diacetyl tartaric esters of mono- and diglycerides (DATEM)]. Biobake 10804, a xylanase that increased the arabinoxylan content of the dough liquor, decreased the surface pressure and increased the dilational modulus in lipid-poor liquor. This effect was not observed with the liquor including the lipids. Lipopan 50 BG, a 1,3-specific lipase, increased the surface pressure of the liquor that included the lipids. Lipopan F BG, which converts polar lipids to their lyso form, strongly increased the surface pressure not only in the lipid-containing liquor but also in the lipid-poor liquor. DATEM, as expected, increased the surface pressure while strongly decreasing the dilational modulus. Results of these studies were used to help explain changes in loaf volume observed in a series of baking tests, using the same enzymes and additives. This led to the conclusion that the effect of surface-active components alone cannot account for the larger loaf volumes observed. Clearly, both the effect of bulk and interfacial rheological properties should be considered together when explaining gas cell stability.
    Horseradish peroxidase-catalyzed cross-linking of feruloylated arabinoxylans with ß-casein
    Boeriu, C.G. ; Oudgenoeg, G. ; Spekking, W.T.J. ; Berendsen, L.B.J.M. ; Vancon, L. ; Boumans, H. ; Gruppen, H. ; Berkel, W.J.H. van; Laane, N.C.M. ; Voragen, A.G.J. - \ 2004
    Journal of Agricultural and Food Chemistry 52 (2004)21. - ISSN 0021-8561 - p. 6633 - 6639.
    ferulic acid - fungal laccase - proteins - polysaccharides - conjugation - pentosans - bran
    Heterologous conjugates of wheat arabinoxylan and beta-casein were prepared via enzymatic cross-linking, using sequential addition of the arabinoxylan to a mixture of beta-casein, peroxidase, and hydrogen peroxide. The maximal formation of adducts between the beta-casein and the feruloylated arabinoxylan was reached at a protein-to-arabinoxylan ratio of 10:1, in combination with a molar ratio hydrogen peroxide to substrate of 2:1 and a molar protein-to-enzyme ratio between 10(2) and 10(4). The protein-arabinoxylan adducts were separated from the arabinoxylan homopolymers by size exclusion and anion exchange chromatography. The molar ratio protein:arabinoxylan in the purified conjugates varied between 0.1 and 5.6. This is the first report on the large-scale enzymatic preparation of heterologous protein-arabinoxylan conjugates.
    Effect of water unextractable solids on gluten formation and properties: mechanistic consideration.
    Wang, M. ; Hamer, R.J. ; Vliet, T. van; Gruppen, H. ; Marseille, H. ; Weegels, P.L. - \ 2003
    Journal of Cereal Science 37 (2003)1. - ISSN 0733-5210 - p. 55 - 64.
    non-starch polysaccharides - wheat-flour - pentosans - fractions - quality - protein - bread - dough - peroxidase - separation
    A miniaturised set-up for gluten-starch separation was used to systematically study the effect of water unextractable solids (WUS) on the formation and properties of gluten. The results showed that WUS not only have a negative effect on gluten yield, but also affect gluten and glutenin macropolymer (GMP) composition and rheological properties. The negative effect of WUS on gluten yield could be compensated for to a large extent, but not completely, by increasing mixing time and mixing water. Adding xylanase can effectively counteract the effect of WUS. On the basis of these results we hypothesize that WUS interfere with gluten formation in both a direct and an indirect way. WUS interfere indirectly by competing for water and thus changing conditions for gluten development. This effect can be corrected for by the combination of adding more 0·2% NaCl solution during dough mixing and a longer mixing time. The particulate nature of WUS requires that the direct effect occurs through an interaction between WUS particles and gluten particles. Both effects of WUS can be counteracted through the use of xylanase.
    Effect of pentosans on gluten formation and properties.
    Wang, M. - \ 2003
    Wageningen University. Promotor(en): Rob Hamer, co-promotor(en): Ton van Vliet. - Wageningen : WU - ISBN 9789058088284 - 190
    tarwegluten - pentosanen - opbrengsten - reologische eigenschappen - formatie - wheat gluten - pentosans - yields - rheological properties - formation

    Keywords: pentosans, gluten yield, gluten properties, glutenin macropolymer

    The gluten protein polymeric network plays a pivotal role in determining the end-use quality of wheat in many food products. The properties of this polymeric network are strongly affected by wheat flour composition (protein, starch and pentosans etc.), ingredients (i.e. salt, fat), processing aids (i.e. enzymes) and process parameters (mixing time, mixing water, temperature). Although the content of pentosans, usually divided into water unextractable solids (WUS) and water extractable pentosans (WEP) in wheat flour is low (1-2%w/w), these polymers play an important role in gluten formation and properties. Unravelling the underlying relationships and understanding the effect of pentosans on gluten network formation is, therefore, of extreme importance. The aim of this thesis is to clarify the mechanism of action of pentosans on gluten formation and properties. The study was greatly facilitated by the use of a miniaturized set-up for gluten-starch separation. This allowed us to systematically study the effect of pentosans on gluten formation and properties gluten.

     

    The results show that both WUS and WEP affect gluten yield, composition and properties in a similar fashion. Pretreatment of WUS and WEP with xylanase did not remove the negative effect on gluten yield, but addition of xylanase or ferulic acid (FA) during gluten extraction did. Added pentosans hinder gluten agglomeration even if they are only present during the dough dilution phase. This is only partly related to a viscosity effect. FA related interactions are more important here. Both act on the ability of glutenin macropolymer (GMP) particles to form gluten, affecting both gluten yield and gluten rheological properties. We propose that pentosans interfere with gluten formation in both an indirect and a direct way. The indirect effect is related to water availability. The direct effect is related to an interaction between pentosans and gluten in which FA plays an important role.

    The interference of WUS or WEP with gluten formation caused an incomplete aggregation of gluten protein, which was reflected in a larger average GMP particle size and a smaller tendency of these particles to aggregate. If xylanase or FA were added, aggregation was more complete, which was reflected in a smaller average GMP particle size and a larger tendency of these particles to aggregate. Now, also smaller GMP particles were recovered. The same trend was found with three wheat cultivars of very different qualities. Based on our results, we propose a possible explanation for the effect of pentosans on gluten formation and properties. Both a physical effect and a chemical effect are involved. The physical effect is related to viscosity and likely also depletion attraction between protein particles. The chemical effect is related to FA and 'controls' the tendency of the particles to aggregate and hence also gluten yield. In our explanation pentosans do not so much affect the growth of these particles directly after mixing, but hinder the further agglomeration of especially smaller particles to end up in the gluten. The partial agglomeration of GMP particles will result in turn in GMP with a different GMP particle size distribution and hence in gluten with changed rheological properties.

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