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Broersen, K. (author), Elshof, M. (author), de Groot, J. (author), Voragen, A.G.J. (author), Hamer, R.J. (author), de Jongh, H.H.J. (author), TNO Kwaliteit van Leven (author)A large number of proteins are glycosylated, either in vivo or as a result of industrial processing. Even though the effect of glycosylation on the aggregation of proteins has been studied extensively in the past, some reports show that the aggregation process is accelerated, whereas others found that the process is inhibited by glycosylation....article 2007
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TNO Kwaliteit van Leven (author), de Jongh, H.H.J. (author)Introduction * Proteins and their functional groups * Protein aggregation and network formation * Interface stabilization by proteins * Application of protein functionality * References. © 2007 Woodhead Publishing Limited. All rights reserved.bookPart 2007
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Wierenga, P.A. (author), Egmond, M.R. (author), Voragen, A.G.J. (author), de Jongh, H.H.J. (author), TNO Kwaliteit van Leven (author)Unfolding of proteins has often been mentioned as an important factor during the adsorption process at air-water interfaces and in the increase of surface pressure at later stages of the adsorption process. This work focuses on the question whether the folding state of the adsorbed protein depends on the rate of adsorption to the interface,...article 2006
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Primo-Martín, C. (author), Hamer, R.J. (author), de Jongh, H.H.J. (author), TNO Kwaliteit van Leven (author)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...article 2006
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Broersen, K. (author), van Teeffelen, A.M.M. (author), Vries, A. (author), Voragen, A.G.J. (author), Hamer, R.J. (author), de Jongh, H.H.J. (author), TNO Kwaliteit van Leven (author)The aim of this work is to evaluate the impact of sulfhydryl groups on ovalbumin aggregation and gelation. Ovalbumin was chemically modified to add sulfhydryl groups in various degrees. The rate of aggregation was not affected by the introduction of sulfhydryl groups, and disulfide bond formation was preceded by physical interactions. Hence,...article 2006
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Ganzevles, R.A. (author), Zinoviadou, K. (author), van Vliet, T. (author), Stuart, M.A.C. (author), de Jongh, H.H.J. (author), TNO Kwaliteit van Leven (author)There is a large interest in mixed protein/polysaccharide layers at air-water and oil-water interfaces because of their ability to stabilize foams and emulsions. Mixed protein/polysaccharide adsorbed layers at air-water interfaces can be prepared either by adsorption of soluble protein/ polysaccharide complexes or by sequential adsorption of...article 2006
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Wierenga, P.A. (author), Kosters, H. (author), Egmond, M.R. (author), Voragen, A.G.J. (author), de Jongh, H.H.J. (author), TNO Kwaliteit van Leven (author)The stability of adsorbed protein layers against deformation has in literature been attributed to the formation of a continuous gel-like network. This hypothesis is mostly based on measurements of the increase of the surface shear elasticity with time. For several proteins this increase has been attributed to the formation of intermolecular...article 2006
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Ganzevles, R.A. (author), Cohen Stuart, M.A. (author), Vliet, T.v. (author), de Jongh, H.H.J. (author), TNO Kwaliteit van Leven (author)In order to understand foaming behaviour of mixed protein/anionic polysaccharide solutions, we investigated the effect of β-lactoglobulin/pectin interaction in the bulk on β-lactoglobulin adsorption to the air-water interface. Adsorption kinetics were evaluated by following surface pressure development in time of several pure protein solutions...article 2006
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de Jongh, H.H.J. (author), Wierenga, P.A. (author), TNO Kwaliteit van Leven (author)There is an ongoing debate about whether a protein surface film at an air-water interface can be regarded as a gelled layer. There is literature reporting that such films show macroscopic fracture behavior and a rheology comparable to three-dimensional protein bulk-networks. If this is the case, a complete description of the formation of...article 2006
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Kudryashova, E.V. (author), Visser, A.J.W.G. (author), de Jongh, H.H.J. (author), TNO Kwaliteit van Leven (author)In this study the relation between the ability of protein self-association and the surface properties at air-water interfaces is investigated using a combination of spectroscopic techniques. Three forms of chicken egg ovalbumin were obtained with different self-associating behavior: native ovalbumin, heat-treated ovalbumin-being a cluster of 12...article 2005
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- Visschers, R.W. (author), de Jongh, H.H.J. (author), TNO Kwaliteit van Leven (author) article 2005
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Wierenga, P.A. (author), Meinders, M.B.J. (author), Egmond, M.R. (author), Voragen, A.G.J. (author), de Jongh, H.H.J. (author), TNO Kwaliteit van Leven (author)In this study a set of chemically engineered variants of ovalbumin was produced to study the effects of electrostatic charge on the adsorption kinetics and resulting surface pressure at the air-water interface. The modification itself was based on the coupling of succinic anhydride to lysine residues on the protein surface. After purification of...article 2005
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Koppelman, S.J. (author), Nieuwenhuizen, W.F. (author), Gaspari, M. (author), Knippels, L.M.J. (author), Penninks, A.H. (author), Knol, E.F. (author), Hefle, S.L. (author), de Jongh, H.H.J. (author), TNO Kwaliteit van Leven (author)The high resistance of Brazil nut 2S albumin, previously identified as an allergen, against proteolysis by pepsin was examined in this work. Although the denaturation temperature of this protein exceeds the 110 °C at neutral pH, at low pH a fully reversible thermal denaturation was observed at ∼82 °C. The poor digestibility of the protein by...article 2005
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van Teeffelen, A.M.M. (author), Meinders, M.B.J. (author), de Jongh, H.H.J. (author), TNO Kwaliteit van Leven (author)Information on changes in heat capacity (ΔCp) of proteins upon unfolding is used frequently in literature to understand possible follow-up reactions of protein denaturation, like their aggregation propensity. This thermodynamic property is intrinsic to the protein's architecture and unfolding and should be independent of the approach used to...article 2005
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van Teeffelen, A.M.M. (author), Broersen, K. (author), de Jongh, H.H.J. (author), TNO Kwaliteit van Leven (author)Chemical glycosylation of proteins occurs in vivo spontaneously, especially under stress conditions, and has been linked in a number of cases to diseases related to protein denaturation and aggregation. It is the aim of this work to study the origin of the change in thermodynamic properties due to glucosylation of the folded β-lactoglobulin A....article 2005
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Broersen, K. (author), Voragen, A.G.J. (author), Hamer, R.J. (author), de Jongh, H.H.J. (author), TNO Voeding (author)In this article we show how various degrees of glycosylation can be used to control the thermal stability of proteins. The primary amines of β-lactoglobulin were glycosylated with glucose or fructose within a range of non-denaturing reaction parameters. The modified fractions were characterized and analyzed for structural stability and...article 2004
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de Jongh, H.H.J. (author), Kosters, H.A. (author), Kudryashova, E. (author), Meinders, M.B.J. (author), Trofimova, D. (author), Wierenga, P.A. (author), TNO Voeding (author)Using a variety of spectroscopic techniques, a number of molecular functionalities have been studied in relation to the adsorption process of proteins to air-water interfaces. While ellipsometry and drop tensiometry are used to derive information on adsorbed amount and exerted surface pressure, external reflection circular dichroism, infrared,...article 2004
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Trofimova, D. (author), de Jongh, H.H.J. (author), TNO Voeding (author)Maillard products of β-lactoglobulin (βLg) and fructose oligosaccharide (FOS) were obtained in different degrees of modification depending on incubation time and pH. By use of a variety of biochemical and spectroscopic tools, it was demonstrated that the modification at limited degrees does not significantly affect the secondary, tertiary, and...article 2004
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Kosters, H.A. (author), Broersen, K. (author), de Groot, J. (author), Simons, J.W.F.A. (author), Wierenga, P. (author), de Jongh, H.H.J. (author), TNO Voeding (author)Processing of ovalbumin may result in proteins that differ more than 23°C in denaturation temperature while the structural fold is not significantly affected. This is achieved by 1) conversion of positive residues into negative ones (succinylation); 2) elimination of negative charges (methylation); 3) reducing the proteins hydrophobic exposure ...article 2003
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Kosters, H.A. (author), de Jongh, H.H.J. (author), TNO Voeding (author)A number of relevant properties of Woodward's reagent K have been determined, such as the stability of the reactant and the optimal reaction conditions of the reactant with protein carboxylates. A Woodward's reagent K stock solution was stable at 4°C for prolonged time, whereas upon storage at 22°C, almost 20% of the reactive compound was lost...article 2003