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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    FeedOmics, an approach to evaluate the functional properties of protein containing feed ingredients
    Kar, Soumya K. - \ 2017
    Wageningen University. Promotor(en): M.A. Smits; J.M. Wells, co-promotor(en): A.J.M. Jansman; D. Schokker. - Wageningen : Wageningen University - ISBN 9789463434461 - 254
    compound feeds - ingredients - protein sources - proteins - functional properties - metabolism - feed formulation - protein digestion - proteomics - digestive tract - nutrition physiology - animal nutrition - livestock feeding - mengvoer - ingrediënten - eiwitbronnen - eiwitten - functionele eigenschappen - metabolisme - voersamenstelling - eiwitvertering - eiwitexpressieanalyse - spijsverteringskanaal - voedingsfysiologie - diervoeding - veevoeding

    This thesis presents FeedOmics approach as a toolkit, to evaluate (novel) protein containing feed ingredients of different origin considering both their nutritional and functional value in terms of their capacity to support or modify nutrient supply, the animal’s physiology, tissue development and functioning. Such knowledge may contribute to introduce novel and/or alternative protein containing feed ingredients in the diet of livestock, thus creating a sustainable food supply for growing human population.

    Correlating composition and functionality of soy protein hydrolysates used in animal cell cultures
    Gupta, A.J. - \ 2015
    Wageningen University. Promotor(en): Harry Gruppen, co-promotor(en): Peter Wierenga; J.W. Boots. - Wageningen : Wageningen University - ISBN 9789462573208 - 127
    sojaeiwit - eiwithydrolysaten - functionele eigenschappen - warmtebehandeling - celculturen - chemische samenstelling - metabolomica - soya protein - protein hydrolysates - functional properties - heat treatment - cell cultures - chemical composition - metabolomics

    Abstract

    Soy protein hydrolysates are often supplemented to chemically defined (CD) media in cell cultures, but there is little understanding of the effect of their composition on their functionality (viable cell density, total immunoglobulin (IgG), and specific IgG production). To identify the key parameters (e.g. compound classes) that determine their functionality, hydrolysates were prepared from different starting materials (meal, concentrates, and isolate) and from soybean meal that was heated for different time periods. The functionality of these hydrolysates were compared to those of industrial hydrolysates. From the comparison, it was shown that the variation in industrial and experimental processes of hydrolysate production induced larger variation in the functionality than the variation in starting materials. Moreover, it was observed that the correlations between the functionality and compositional parameters observed in one experiment were absent in the other experiments. During the study, it became apparent that the variations in other factors, like CD media and temperature during culturing also resulted in variation in functionality. The extent of variations in the functionality due to variation in CD media and temperature during culturing was equivalent to the variation caused by varying the hydrolysate composition. The functionality data of the different experiments were fitted with a model that described the relation between specific IgG production and viable cell density. Using the model, the maximum achievable total IgG production could be calculated for a culture condition. This information can provide directions for further optimization of hydrolysates to maximize total IgG production.

    Mesoscale structure and techno-functional properties of enzymatically cross-linked a-lactalbumin nanoparticles
    Dhayal, S.K. - \ 2015
    Wageningen University. Promotor(en): Harry Gruppen, co-promotor(en): Peter Wierenga. - Wageningen : Wageningen University - ISBN 9789462572812 - 152
    enzymatische cross-linking - eiwitten - nanotechnologie - deeltjes - functionele eigenschappen - polymerisatie - peroxidase - enzymatic cross-linking - proteins - nanotechnology - particles - functional properties - polymerization - peroxidase

    Abstract

    The aim of this thesis is to understand the connection between molecular, meso and macroscales of enzymatically cross-linked proteins. It was hypothesised that the techno-functional properties at macroscale, such as bulk rheology and foam stability, are affected by the structure of nanoparticles at mesoscale. The approach was to make α-lactalbumin (α-LA) nanoparticles by using two different enzymes, horseradish peroxidase (HRP) or microbial transglutaminase (mTG), to produce an open and compact mesoscale structure, respectively. In addition to the control over the mesoscale structure, the size of the nanoparticles can be independently controlled by varying the dosage of hydrogen peroxide in the case of HRP and by thermal inactivation in the case of mTG. The other important parameters determining the size are protein concentration and ionic strength. The size (radius of gyration) range that could be achieved by varying the above mentioned control parameters is 20 – 200 nm. The polydispersed nanoparticles were separated by asymmetrical flow field flow fractionation (AF4) and characterised inline with multi angle light scattering (MALS). Polymerization of apo α-LA with HRP and mTG proceeds in a step growth way i.e. first monomers react to form oligomers and the oligomers are cross-linked to form polymers (nanoparticles). Extensive cross-linking of α-LA with HRP gives rise to not only di-tyrosine cross-links, but also tri–octa tyrosine cross-links, which was hitherto unknown. The two different mesoscale structures result in gels of different storage moduli. The storage modulus of gels made by concentrating the α-LA/mTG nanoparticles was around ten times higher than that made with open nanoparticles. The half-life time (t0.5) of the foam made with α-LA nanoparticles was two to six times higher than that of the monomeric α-LA. The higher foam-stability of the α-LA nanoparticles as compared to the monomeric α-LA is due to their higher thickness of the interfacial layer and thin films. In conclusion, it is shown that the techno-functional properties of α-LA are directly correlated to the size and meso-scale structures of the nanoparticles and enzymatic cross-linking is an effective way to control them.

    Physico-chemical and techno-functional properties of proteins isolated from the green microalgae Tetraselmis sp.
    Schwenzfeier, A. - \ 2013
    Wageningen University. Promotor(en): Harry Gruppen, co-promotor(en): Peter Wierenga; Michel Eppink. - S.l. : s.n. - ISBN 9789461734532 - 132
    algen - eiwitten - functionele eigenschappen - schuimen - emulgeren - emulsies - algae - proteins - functional properties - foaming - emulsifying - emulsions

    In this thesis, the mild isolation of an algae soluble protein isolate (ASPI) and the characterisation of its techno-functional properties are described. The ASPI was isolated from the green microalgae Tetraselmis sp. by beadmilling and subsequent anion exchange adsorption. The isolate obtained contained 59 ± 7% (w/w) protein and 20 ± 6% (w/w) carbohydrates, the latter composed for approximately one fourth of uronic acids (4.8 ± 0.4% [w/w]). In the pH range 5.5 – 6.5, in which currently used legumin seed protein isolates (e.g. soy) show low solubility, ASPI retained high solubility independent of ionic strength. In the soluble pH range, the foam stability of ASPI is superior to the foam stabilities of whey protein isolate (WPI) and egg white albumin (EWA). At pH 7, ASPI stabilized foams are 1.7 times more stable than WPI stabilized foams. Further fractionation of APSI results in foams even 3 times more stable than WPI stabilized foams. In addition, emulsions stabilised with ASPI are stable against droplet aggregation around pH 5 at low ionic strength, while emulsions stabilised by WPI are not stable at this pH. The stability of ASPI emulsions at this pH is attributed to the co-adsorption of the charged polysaccharide fraction present in ASPI. The role of the charged polysaccharides on stabilisation of the emulsions was confirmed by fractionating ASPI into protein-rich and charged polysaccharide-rich fractions. The combination of charged polysaccharides and proteins in ASPI results in good techno-functional properties that are between that of pure proteins and that of the naturally occurring protein-polysaccharide hybrid gum arabic (GA). It is concluded that ASPI represents an attractive substitute for currently used high-value food protein isolates. Due to the combination of the positive interfacial properties of its protein fraction with the broad pH stability of its charged polysaccharide fraction, ASPI possesses the positive attributes of two types of techno-functional ingredients.

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