Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

    Current refinement(s):

    Records 1 - 10 / 10

    • help
    • print

      Print search results

    • export

      Export search results

    Check title to add to marked list
    Effects of salt on the expansion of starchy snacks: a multiscale analysis
    Sman, R.G.M. van der; Broeze, J. - \ 2014
    Food & Function 5 (2014)12. - ISSN 2042-6496 - p. 3076 - 3082.
    glass-transition - sodium-chloride - aqueous-solutions - mass-transfer - sucrose - extrusion - potato - water - trehalose - mixtures
    We investigate the effect of salt on the expansion of starchy snacks during frying by means of a multiscale simulation model. This model has been developed earlier for starchy snacks without salt. The simulation results are analysed by means of the supplemented state diagram. We have found that the optimal expansion for salty snacks occurs under the same conditions as for snacks without salt. This occurs at the moisture content where the 4 bar boiling line intersects the critical isoviscosity line of 1 MPa s. Salt is shown to influence both the boiling line and the critical isoviscosity line, via a change of the glass transition. The optimal moisture content for salty snacks is lower than that of unsalted snacks. We view our findings as important for reformulations of starchy snacks with lower salt levels. Furthermore, the presented tools of the multiscale simulations and supplemented state diagram can generally be used for reformulation problems in structured foods.
    Inactivation of Lactobacillus plantarum WCFS1 during spray drying and storage assessed with complementary viability determination methods
    Perdana, J.A. ; Besten, H.M.W. den; Aryani, D.C. ; Kutahya, O. ; Fox, M.B. ; Kleerebezem, M. ; Boom, R.M. ; Schutyser, M.A.I. - \ 2014
    Food Research International 64 (2014). - ISSN 0963-9969 - p. 212 - 217.
    differential scanning calorimetry - naturally-occurring osmolytes - bacillus-cereus - population heterogeneity - listeria-monocytogenes - thermal inactivation - growth-parameters - stress-response - trehalose - proteins
    Survival of Lactobacillus plantarum WCFS1 spray-dried and stored under different conditions was investigated using complementary methods. One method involved a cell membrane integrity viability-based determination, the other assessed cell growth behavior in a liquid medium by means of detection time or by conventional plating. Survival decreased below 95% when spray drying was carried out at higher outlet spray drying temperatures (Tout N 70 °C). However, the membrane integrity method provided higher residual viability values compared to the detection time and conventional plating. This suggests that loss of viability may be due to a combination of damage to intracellular components and cell membrane. Also during storage viability based on growth behavior declined faster and was more temperature dependent compared to the viability as determined by the membrane integritymethod. Also here additional damage to intracellular components is expected responsible to loss of viability. Major conclusion is that one should not only rely on a cell-membrane integrity based method to assess survival during spray drying and storage of bacteria. Previous studies that did so most probably underestimated viability as critical damage to intracellular components was not assessed.
    Yeasts preservation: alternatives for lyophilisation
    Nyanga, L.K. ; Nout, M.J.R. ; Smid, E.J. ; Boekhout, T. ; Zwietering, M.H. - \ 2012
    World Journal of Microbiology and Biotechnology 28 (2012)11. - ISSN 0959-3993 - p. 3239 - 3244.
    ziziphus-mauritiana - starter cultures - trehalose - viability - fermentation - survival - efficacy - zimbabwe - storage - fruits
    The aim of the study was to compare the effect of two low-cost, low technology traditional methods for drying starter cultures with standard lyophilisation. Lyophilised yeast cultures and yeast cultures preserved in dry rice cakes and dry plant fibre strands were examined for viable cell counts during 6 months storage at 4 and 25 °C. None of the yeast cultures showed a significant loss in viable cell count during 6 months of storage at 4 °C upon lyophilisation and preservation in dry rice cakes. During storage at 25 °C in the dark, yeast cultures preserved in dry rice cakes, and lyophilised cultures of Saccharomyces cerevisiae and Issatchenkia orientalis showed no significant loss of viable cells up to 4 months of storage. Yeast cultures preserved in dry plant fibre strands had the greatest loss of viable count during the 6 months of storage at 25 °C. Preservation of yeasts cultures in dry rice cakes provided better survival during storage at 4 °C than lyophilisation. The current study demonstrated that traditional methods can be useful and effective for starter culture preservation in small-scale, low-tech applications.
    A rapid, sensitive and cost-efficient assay to estimate viability of potato cyst nematodes
    Elsen, S.J.J. van den; Ave, M. ; Schoenmakers, N. ; Landeweert, R. ; Bakker, J. ; Helder, J. - \ 2012
    Phytopathology 102 (2012)2. - ISSN 0031-949X - p. 140 - 146.
    ethidium-bromide monoazide - globodera-rostochiensis - living nematodes - quantification - dead - anhydrobiosis - trehalose - samples - dye
    Potato cyst nematodes (PCN) are quarantine organisms, and they belong to the economically most relevant pathogens of potato worldwide. Methodologies to assess the viability of their cysts which can contain 200-500 eggs protected by the hardened cuticle of a dead female, are either time and labor intensive, or lack robustness. We present a robust and cost-efficient viability assay based on loss of membrane integrity upon death. This assay uses trehalose, a disaccharide present at a high concentration in the perivitelline fluid of PCN eggs, as a viability marker. Although this assay can detect a single viable egg, the limit of detection for regular field samples was higher, ~ ten viable eggs, due to background signals produced by other soil components. On the basis of thirty non-viable PCN samples from The Netherlands, a threshold level was defined (¿Atrehalose= 0.0094) below which the presence of more than ten viable eggs is highly unlikely (true for ~ 99.7% of the observations). This assay can easily be combined with a subsequent DNA-based species determination. As the presence of trehalose is a general phenomenon among cyst nematodes, this method can probably be used for, e.g., soybean, sugar beet and cereal cyst nematodes as well
    Protection of in-vitro grown Arabidopsis seedlings against abiotic stresses
    Klerk, G.J.M. de; Pumisutapon, P. - \ 2008
    Plant Cell, Tissue and Organ Culture: an international journal on in vitro culture of higher plants 95 (2008)2. - ISSN 0167-6857 - p. 149 - 154.
    plants - tolerance - thermotolerance - trehalose - proteins - drought - biosynthesis - accumulation - performance - expression
    Severe abiotic stresses may cause permanent damage leading to death. In Arabidopsis seedlings germinating in vitro, we examined whether stress-related damage could be reduced by addition of protective low-molecular-weight compounds (trehalose and putrescine), addition of a specific signal molecule (acetylsalicylic acid), culture in the dark before and/or after the stress, and hardening mild-stress pretreatments. All four tested protective procedures increased survival after exposure to drought, warm air, warm water or salinity, often from ca. 15% in the control to ca. 85% in the treated seedlings. These protective measures may be usable to reduce the negative effects of abiotic stresses related to tissue culture.
    Eenvoudige remedies voor stress bij weefselkweekplantjes
    Klerk, G.J.M. de - \ 2007
    Onder Glas 8 (2007)4. - p. 24 - 25.
    vermeerderingsmateriaal - weefselkweek - zaailingen - droogte - stress - genetische modificatie - beschermingsmiddelen - trehalose - immunisatie - proeven - glastuinbouw - propagation materials - tissue culture - seedlings - drought - stress - genetic engineering - protectants - trehalose - immunization - trials - greenhouse horticulture
    Als planten in de natuur onder stress staan, bijvoorbeeld door droogte, beschermen ze kwetsbare componenten door speciefieke stoffen, 'protectants', in grote hoeveelheden aan te maken. Deze manier van bescherming is ook bij weefselkweek te gebruiken. Telers kunnen planten voorbehandelen met milde stress. Daardoor kunnen ze daarna een zware stress doorstaan. Onderzoek met de modelplant Arabidopsis en met lelie, roos en appel geeft uitstekende resultaten. De methoden zijn eenvoudig. Op basis van deze resultaten kan de tuinbouw allerlei toepassingen ontwikkelen
    Cryopreservation of boar semen: equilibrium freezing in the cryomicroscope and in straws
    Woelders, H. ; Matthijs, A. ; Zuidberg, C.A. ; Chaveiro, A. - \ 2005
    Theriogenology 63 (2005)2. - ISSN 0093-691X - p. 383 - 395.
    0.5 ml straws - acrosomal integrity - spermatozoa frozen - cooling rate - injury - cells - hypothesis - trehalose - viability - motility
    Supercooling causes very abrupt temperature and osmotic changes and can thus lead to freezing damage. Supercooling can be prevented by seeding, using a sample volume and geometry that allows rapid spreading of the ice throughout the sample. In a split-sample comparison of such samples on the cooling stage of a cryomicroscope and seeded at ¿5 and ¿15 °C, respectively, the percentages of membrane-intact sperm and sperm with acrosomes with a `normal apical ridge¿ (NAR) were 72.5 ± 3.8 and 75.8 ± 2.0 versus 46.3 ± 4.8 and 36.0 ± 3.7 (means ± S.E.M., n = 4). In ejaculates of 15 unselected AI boars, after seeding at ¿5 °C, the post-thaw % live and % NAR were 66.3 ± 10.4 and 74.8 ± 7.5, respectively. Our present research is aimed at translating these findings to freezing in straws and at a high sperm concentration. We have designed a novel type of freezing apparatus for controlled-rate freezing of straws, in which supercooling can be effectively prevented in the entire straw. In a split-sample comparison of semen frozen in straws at a sperm concentration of 1.5 × 109 cells/ml with nine ejaculates from eight unselected AI boars, we found 54.8 ± 1.9% versus 40.7 ± 1.7% (means ± S.E.M.) membrane-intact sperm for the new apparatus and a conventional freezing apparatus, respectively. With bull semen (eight ejaculates from six bulls), we obtained 67.3 ± 3.0% versus 59.3 ± 2.9% (means ± S.E.M.) membrane-intact sperm for the new apparatus and conventional freezing, respectively. Additionally, the temperature curve after ice nucleation is of great importance. We have developed a model that allows us to predict that optimal cryopreservation requires a non-linear cooling curve in which the cooling rate varies as a function of subzero temperature
    The life and death of sponge cells
    Sipkema, D. ; Snijders, A.P.L. ; Schroën, C.G.P.H. ; Osinga, R. ; Wijffels, R.H. - \ 2004
    Biotechnology and Bioengineering 85 (2004)3. - ISSN 0006-3592 - p. 239 - 247.
    marine natural-products - in-vitro - growth-inhibition - primary culture - ammonium ion - heat-stress - trehalose - sea - identification - cytotoxicity
    Cell viability is an essential touchstone in the study of the effect of medium components on cell physiology. We developed a flow-cytometric assay to determine sponge-cell viability, based on the combined use of fluorescein diacetate (FDA) and propidium iodide (PI). Cell fluorescence measurements based on incubation of cells with FDA or PI resulted in a useful and reproducible estimate of the viability of primary sponge-cell cultures. We studied the effects of temperature, ammonium, and the fungicide amphotericin B on the viability of a primary-cell culture from the marine sponge Suberites domuncula using the aforementioned flow-cytometric assay. S. domuncula cells die rapidly at a temperature of greater than or equal to22degreesC, but they are insensitive to ammonium concentrations of up to 25 mM. Amphotericin B, which is frequently used in sponge-cell culture media, was found to be toxic to S. domuncula cells. (C) 2004 Wiley Periodicals, Inc.
    Assessment of compatible solutes to overcome salinity stress in thermophilic (55 oC) methanol-fed sulfate reducing granular sludges
    Vallero, M.V.G. ; Lettinga, G. ; Lens, P.N.L. - \ 2003
    Water Science and Technology 48 (2003)6. - ISSN 0273-1223 - p. 195 - 202.
    anaërobe behandeling - afvalwaterbehandeling - methanol - reductie - natriumchloride - sulfaten - rioolafvalwater - slib - anaerobic treatment - waste water treatment - methanol - reduction - sodium chloride - sulfates - sewage effluent - sludges - glycine betaine - growing-cells - accumulation - degradation - adaptation - trehalose - glutamate - reactor
    High NaCl concentrations (25 g.L-1) considerably decreased the methanol depletion rates for sludges harvested from two lab-scale sulfate reducing UASB reactors. In addition, 25 gNaCl.L-1 strongly affected the fate of methanol degradation, with clear increase in the acetate production at the expense of sulfide and methane production. The addition of different osmoprotectants, viz. glutamate, betaine, ectoine, choline, a mixture of compatible solutes and K+ and Mg2+, slightly increased methanol depletion rates for UASB reactors sludges. However, the acceleration in the methanol uptake rate favored the homoacetogenic bacteria, as the methanol breakdown was steered to the formation of acetate without increasing sulfate reduction and methane production rates. Thus, the compatible solutes used in this work were not effective as osmoprotectants to alleviate the acute NaCl toxicity on sulfate reducing granular sludges developed in methanol degrading thermophilic (55°C) UASB reactors
    High NaCl concentrations (25 g(.)L(-1)) considerably decreased the methanol depletion rates for sludges harvested from two lab-scale sulfate reducing UASB reactors. In addition, 25 gNaCl.L-1 strongly affected the fate of methanol degradation, with clear increase in the acetate production at the expense of sulfide and,methane production. The addition of different osmoprotectants, viz. glutmate, betaine, ectoine, choline, a mixture of compatible solutes and K+ and Mg2+, slightly increased methanol depletion rates for UASB reactors sludges. However, the acceleration in the methanol uptake rate favored the homoacetogenic bacteria, as the methanol breakdown was steered to the formation of acetate without increasing sulfate reduction and methane production rates. Thus, the compatible solutes used in this work were not effective as osmoprotectants to alleviate the acute NaCl toxicity on sulfate reducing granular sludges developed in methanol degrading thermophilic (55degreesC) UASB reactors.
    Source-sink relations in transgenic tobacco with modified trehalose metabolism : a comparative labelling study with the stable isotopes 13C and 15N of wildtype and five transgenic types
    Visser, A.J.C. de; Leeuwen, P.H. van; Pot, C.S. - \ 1999
    Wageningen : AB-DLO (Note / Agricultural Research Department, Research Institute for Agrobiology and Soil Fertility 179) - 32
    plantengroeiregulatoren - genetische modificatie - nicotiana - trehalose - vloeistoffen (liquids) - sapstroom - distributie - plant growth regulators - genetic engineering - liquids - sap flow - distribution
    Check title to add to marked list

    Show 20 50 100 records per page

     
    Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.