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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Monitor Voedselverspilling : Update 2009 -2017: Omvang in kilogrammen in Nederland
Soethoudt, J.M. ; Vollebregt, H.M. - \ 2019
Wageningen : Wageningen Food & Biobased Research - 3 p.
Gaat dit veldonderzoek de reeën redden?
Grift, Edgar van der - \ 2019

Ieder jaar worden ruim 6.300 reeën aangereden, een landelijk probleem. Maar over een oplossing zijn de meningen verdeeld. De komen jaren worden twee kansrijke maatregelen in de Achterhoek en in Utrecht getest.

Ieder jaar worden ruim 6.300 reeën aangereden, een landelijk probleem. Maar over een oplossing zijn de meningen verdeeld. De komen jaren worden twee kansrijke maatregelen in de Achterhoek en in Utrecht getest.

Data from: Horizontal and vertical diversity jointly shape food web stability against small and large perturbations
Zhao, Qinghua ; Brink, P.J. van den; Carpentier, Camille ; Wang, Yingying ; Rodríguez Sánchez, P. ; Xu, Chi ; Vollbrecht, Silke ; Gillissen, F. ; Vollebregt, M.E. ; Wang, Shaopeng ; Laender, Frederik De - \ 2019
The biodiversity of food webs is composed of horizontal (i.e. within trophic levels) and vertical diversity (i.e. the number of trophic levels). Understanding their joint effect on stability is a key challenge. Theory mostly considers their individual effects and focuses on small perturbations near equilibrium in hypothetical food webs. Here, we study the joint effects of horizontal and vertical diversity on the stability of hypothetical (modelled) and empirical food webs. In modelled food webs, horizontal and vertical diversity increased and decreased stability, respectively, with a stronger positive effect of producer diversity on stability at higher consumer diversity. Experiments with an empirical plankton food-web, where we manipulated horizontal and vertical diversity and measured stability from species interactions and from resilience against large perturbations, confirmed these predictions. Taken together, our findings highlight the need to conserve horizontal biodiversity at different trophic levels to ensure stability.
Horizontal and vertical diversity jointly shape food web stability against small and large perturbations
Zhao, Qinghua ; Brink, Paul J. Van den; Carpentier, Camille ; Wang, Yingying X.G. ; Rodríguez-Sánchez, Pablo ; Xu, Chi ; Vollbrecht, Silke ; Gillissen, Frits ; Vollebregt, Marlies ; Wang, Shaopeng ; Laender, Frederik De - \ 2019
Ecology Letters 22 (2019)7. - ISSN 1461-023X - p. 1152 - 1162.
Equilibrium - horizontal diversity - large perturbations - small perturbations - stability - vertical diversity

The biodiversity of food webs is composed of horizontal (i.e. within trophic levels) and vertical diversity (i.e. the number of trophic levels). Understanding their joint effect on stability is a key challenge. Theory mostly considers their individual effects and focuses on small perturbations near equilibrium in hypothetical food webs. Here, we study the joint effects of horizontal and vertical diversity on the stability of hypothetical (modelled) and empirical food webs. In modelled food webs, horizontal and vertical diversity increased and decreased stability, respectively, with a stronger positive effect of producer diversity on stability at higher consumer diversity. Experiments with an empirical plankton food web, where we manipulated horizontal and vertical diversity and measured stability from species interactions and from resilience against large perturbations, confirmed these predictions. Taken together, our findings highlight the need to conserve horizontal biodiversity at different trophic levels to ensure stability.

Effects of filler ingredients on the structure and texture of starchy, extruded snacks
Sman, R.G.M. van der; Vollebregt, H.M. ; Meinders, M.B.J. ; Beri, A. - \ 2018
Food Structure 18 (2018). - ISSN 2213-3291 - 13 p.
Crispiness - Expanded snacks - Filler ingredients

Several starchy snacks differing in filler ingredients have been analysed regarding (1) the fate of filler ingredients during processing, and (2) the role of filler ingredients with respect to texture and structure. The structure has been characterized with X-ray tomography, and the texture has been evaluated via acoustic emissions from snack compression using a texture analyzer, which is assumed to be representative for crispiness. Our study shows that one has to distinguish hard and soft fillers. The absence of any filler or the presence of many hard fillers lead to a snack with a hard, coarse and non-crispy texture. However, if a significant amount of soft fillers is used then one attains a fine, and crispy texture.

Towards a safe and sustainable poultry production chain
Berghout, Jacqueline ; Roland, Wibke ; Vollebregt, Martijntje ; Koene, Miriam ; Jong, Ingrid de - \ 2018
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research report 1126) - 79
Climate reddening increases the chance of critical transitions
Bolt, Bregje van der; Nes, Egbert H. van; Bathiany, Sebastian ; Vollebregt, Marlies E. ; Scheffer, Marten - \ 2018
Nature Climate Change 8 (2018)6. - ISSN 1758-678X - p. 478 - 484.
Climate change research often focuses on trends in the mean and variance. However, analyses of palaeoclimatic and contemporary dynamics reveal that climate memory - as measured for instance by temporal autocorrelation - may also change substantially over time. Here, we show that elevated temporal autocorrelation in climatic variables should be expected to increase the chance of critical transitions in climate-sensitive systems with tipping points. We demonstrate that this prediction is consistent with evidence from forests, coral reefs, poverty traps, violent conflict and ice sheet instability. In each example, the duration of anomalous dry or warm events elevates chances of invoking a critical transition. Understanding the effects of climate variability thus requires research not only on variance, but also on climate memory.
In-situ Single Mode Dielectric Measurements of microwaveable snack pellets
Esveld, Erik ; Bows, John ; Vollebregt, Martijntje ; Sman, Ruud van der - \ 2018
Journal of Food Engineering 231 (2018). - ISSN 0260-8774 - p. 109 - 122.
Dielectric properties - Expansion - Microwave - Starch

The dielectric properties of starch based snack pellets have been measured in situ during microwave heating and expansion. The microwave setup consists of a single mode shorted waveguide, equipped with a six-port impedance analyser which measures the absorbed power and complex reflection coefficient during heating. The pellet is suspended in the electric field maximum, with an optic temperature sensor inserted in the centre. The dielectric properties of the pellet during heating and after expansion are obtained via an inverse mapping of the recorded reflection coefficient to dielectric properties, which are pre-computed via finite elements simulations. Experiments show that the dielectric properties of the starch pellets change significantly during heating, expansion and subsequent drying. The dielectric properties increase with increasing temperature up to the moment that the pellet starts expanding. Subsequently, the power absorption shows a sudden decline, which is mainly due to the sudden change in porosity. Addition of salt (2.5%) to the starch pellet composition results in a slight decrease of the dielectric constant and loss factor, as it apparently lowers the effective mobility of the dipoles. The dielectric properties as function of temperature and moisture content were fitted with a polynomial model. The strong effect of porosity for the dielectric properties of the expanded snack is well predicted with the effective medium mixing rule.

From highly specialised to generally available modelling of shear induced particle migration for flow segregation based separation technology
Drijer, I. ; Laar, T. van de; Vollebregt, H.M. ; Schroën, C.G.P.H. - \ 2018
Separation and Purification Technology 192 (2018). - ISSN 1383-5866 - p. 99 - 109.
Computational fluid dynamics - Concentrated suspensions - Constant flux - Flow segregation - Particle migration - Shear induced diffusion

Shear induced diffusion can be used to induce particle migration in flow, and this may be a lead to novel separation technology. Under specific conditions, depending on, amongst others, the ratio between channel height and particle diameter, larger particles preferentially move to the centre of a channel. It has been demonstrated earlier that separation and fractionation can be facilitated by this, leading to lower energy and water demand, and prevention of particle accumulation on sieves that have pores that are much larger than the particles. This situation is very different from regular (cross-flow) membrane filtration, in which particles are retained by the pores, and accumulate in various layers. Unfortunately, the underlying mechanisms of particle migration are not that well understood, and contradicting results are reported in literature. There is clearly a need for a unifying approach that can be used by many; therefore, we developed a CFD computer model that can readily be used, unlike the rather inaccessible computer models that are mostly reported in literature. We focus on particle–particle interactions of monodisperse suspensions in flow, for which we added momentum terms to the general momentum equation. We found amongst others that due to shear induced diffusion the particle volume fraction will be 1.7 times higher at the centre of the channel compared to the channel wall for a bulk particle volume fraction of 50%. Our results describe the experimental results, obtained under similar ideal conditions, to a high level of detail. Our findings are also in reasonable agreement with other modelling and experimental studies from literature, and the discrepancies are most probably due to non-ideal behaviour in the experiments and different approaches used in the models. The big advantage of using this software is that the model can be adapted readily by researchers not specifically trained in modelling or programming, but even more importantly, particle migration can now be used as a starting point in separation design since parameter and geometry studies will take less effort using this software.

High-pressure processing combined with heat for fruit and vegetable preservation
Matser, Ariette ; Vollebregt, Martijntje - \ 2017
In: High Pressure Processing of Fruit and Vegetable Products CRC Press - ISBN 9781498739023 - p. 135 - 145.

In addition to chilled HP pasteurized products, there is a need for ambient stable fruit and vegetable products of high quality that can be stored at ambient temperatures for longer times. Alternative sterilization methods resulting in high quality products can therefore be interesting. Moreover, these technologies can contribute to the reduction of food waste from fruit and vegetable products, as fruit and vegetable products are one of categories of products which are spilled due to short shelf life. High pressure processing at elevated temperature could be an interesting option for production of ambient stable products with fruit and vegetables. Various processes are being developed that show that it is indeed possible to inactivate all the micro-organisms, including spores, and enzymes resulting in a stable product at ambient storage conditions. The research summarized in this chapter, showed the impact on texture, color, flavor and nutrients in fruit and vegetables. At the moment, this process is still under investigation and not applied in industry. To bring high pressure sterilization a step forward to implementation, it is crucial that good examples are being developed of complex food products with high added value.

Monitor Voedselverspilling : Update 2009-2016
Soethoudt, J.M. ; Vollebregt, H.M. - \ 2017
Wageningen : Wageningen University & Research (Wageningen Food & Biobased Research, Rapport 1822) - 3 p.
consumers - food chains - food wastes
Monitor voedselverspilling : update 2009-2014
Soethoudt, Han ; Vollebregt, Martijntje ; Burgh, Marianne van der - \ 2016
Wageningen : Wageningen UR - Food & Biobased Research (Food & Biobased Research rapport 1703) - 31
voedselverspilling - monitoring - voedselproducten - consumentengedrag - verliezen - voedselafval - food wastage - food products - consumer behaviour - losses - food wastes
IAFP's European Symposium on Food Safety, Athens, Greece, 11-13 May 2016
Banach, Jen - \ 2016
Banach JL, Van Overbeek L, Vollebregt M, Nierop Groot M, Van der Zouwen P, Van Kekem K, Berendsen L, Van der Fels-Klerx HJ. 2016. Efficacy of aqueous chlorine dioxide on Escherichia coli inactivation during fresh-cut “Lollo rossa” (Lactuca sativa) washing at the pilot scale.
Monitor voedselverspilling : zelfmonitoring pilots
Soethoudt, Han ; Vollebregt, Martijntje ; Burgh, Marianne van der - \ 2016
Wageningen : Wageningen UR - Food & Biobased Research (Food & Biobased Research rapport 1702) - 28
voedselverspilling - reststromen - monitoring - voedselproducten - consumentengedrag - verliezen - voedselafval - food wastage - residual streams - food products - consumer behaviour - losses - food wastes
Microbiologische gevaren in de pluimveevleesketen : Een literatuurstudie met additionele informatie van stakeholders
Bokhorst-van de Veen, Hermien van; Hazeleger, Wilma ; Nierop Groot, Masja ; Vollebregt, Martijntje ; Zwietering, Marcel - \ 2015
Wageningen : Wageningen UR Food & Biobased Research (Rapport / Wageningen UR Food & Biobased Research 1567) - ISBN 9789462575165 - 76
Data from: Positive shrub-tree interactions facilitate woody encroachment in boreal peatlands
Holmgren, M. ; Lin, C.Y. ; Murillo, J.E. ; Nieuwenhuis, A. ; Penninkhof, J.M. ; Sanders, N. ; Bart, T. van; Veen, H. van; Vasander, H. ; Vollebregt, M.E. ; Limpens, J. - \ 2015
boreal forests - climate change - competition - critical transition - ecosystem shift - peatbog - positive interactions - resilience - tree seedling establishment
Boreal ecosystems are warming roughly twice as fast as the global average, resulting in woody expansion that could further speed up the climate warming. Boreal peatbogs are waterlogged systems that store more than 30% of the global soil carbon. Facilitative effects of shrubs and trees on the establishment of new individuals could increase tree cover with profound consequences for the structure and functioning of boreal peatbogs, carbon sequestration and climate. We conducted two field experiments in boreal peatbogs to assess the mechanisms that explain tree seedling recruitment and to estimate the strength of positive feedbacks between shrubs and trees. We planted seeds and seedlings of Pinus sylvestris in microsites with contrasting water-tables and woody cover and manipulated both shrub canopy and root competition. We monitored seedling emergence, growth and survival for up to four growing seasons and assessed how seedling responses related to abiotic and biotic conditions. We found that tree recruitment is more successful in drier topographical microsites with deeper water-tables. On these hummocks, shrubs have both positive and negative effects on tree seedling establishment. Shrub cover improved tree seedling condition, growth and survival during the warmest growing season. In turn, higher tree basal area correlates positively with soil nutrient availability, shrub biomass and abundance of tree juveniles. Synthesis. Our results suggest that shrubs facilitate tree colonization of peatbogs which further increases shrub growth. These facilitative effects seem to be stronger under warmer conditions suggesting that a higher frequency of warmer and dry summers may lead to stronger positive interactions between shrubs and trees that could eventually facilitate a shift from moss to tree-dominated systems.
Hurdle technology to improve organoleptic aspects of broccoli in pressure-assisted thermal sterilisation (PATS)
Vollebregt, Martijntje - \ 2015
Comparison of first principles model of beer microfiltration to experiments via systematic parameter identification
Sman, R.G.M. van der; Willigenburg, G. van; Vollebregt, H.M. ; Eisner, V. ; Mepschen, A. - \ 2015
Journal of Membrane Science 484 (2015). - ISSN 0376-7388 - p. 64 - 79.
Beer - Fouling - Microfiltration - Shear-induced diffusion

A first principles microfiltration model based on shear-induced diffusion is compared to experiments performed on the clarification of beer. After performing an identifiability and sensitivity analysis, the model parameters are estimated using global minimization of the sum of least squares. The model is compared to different series of experiments, where either crossflow or permeate flux is varied. This study is concluded with a parameter study on the scaling of the filtration time with various model parameters. We have found that the filtration time primarily depends on two dimensionless numbers, namely the normalized critical distance for cake layer formation, and the dimensionless time required to plug all pores in the selective layer. We have found that there is an optimal setting of these parameters, rendering a maximal amount of filtrated beer in one cycle.

From sensor output to improved product quality
Hertog, M.L.A.T.M. ; Vollebregt, Martijntje ; Unzueta, I. ; Hoofman, R.J.O.M. ; Lammertyn, J. - \ 2015
Acta Horticulturae 1091 (2015). - ISSN 0567-7572 - p. 165 - 174.
Chain monitoring - Logistics - Quality modeling - Wireless RFID sensor tags

The research conducted in the European PASTEUR project focussed on perishables monitoring through smart tracking of lifetime and quality. The aim was to develop a wireless sensor platform to monitor the environmental conditions of perishable goods in the supply chain between producer and consumer. The sensor platform is based on an intelligent RFID package in which multiple sensor technologies are incorporated. By adding such devices to packaging solutions (crates, containers, boxes, etc.) one can guarantee a product's quality more effectively throughout the whole logistic chain. This project focussed on the low-end (e.g., fruit, vegetables) cold supply chain (cooled transport of goods), which eventually enables item management in the near future. Added intelligence comes from the addition of smart models that analyse the information stream from the sensors. By collecting and studying these data, optimization of logistic flows can be achieved resulting in reduction of food losses and thus preserve the environment. Three types of models are included to help evaluating the logistic cold chains. Statistical control models are implemented to check whether the logistic conditions stay within predefined bounds. Keeping quality models are implemented to provide dynamic information on 'best before dates'. Finally, detailed quality change models are implemented to evaluate the impact of the logistic conditions on specific quality attributes in more details. Together, the three types of models provide instruments for streamlining the logistic activities throughout the cold handling chain increasing efficiency and minimizing losses of e.g., fresh fruits and vegetables.

High-performance inhoudsstoffen vinden hun weg naar de markt
Meer, I.M. van der; Vollebregt, M. - \ 2015
Kennis & Innovatie (2015)3. - p. 2 - 4.
biobased economy - materialen uit biologische grondstoffen - chemicaliën uit biologische grondstoffen - plantextracten - rubber - reststromen - kleurstoffen (dyes) - plantaardige pesticiden - innovaties - biobased materials - biobased chemicals - plant extracts - residual streams - dyes - botanical pesticides - innovations
High-performance inhoudsstoffen uit biomassa ontstijgen de onderzoekslaboratoria en duiken op in proefprojecten met bedrijven en concrete toepassingen in eindproducten. Het tempo waarmee dit gebeurt en de onderliggende markt drivers verschillen per productgebied, zo blijkt uit een rondje langs biobased projecten op het gebied van kleurstoffen, farmaceutische producten/functional foods, gewasbescherming en natuurrubber.
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