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.

    We have a manual that explains all the features 

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Tourism innovation by hundling practices : a genealogy of the 'Zeelandpas' destination card
Derriks, T. ; Duim, V.R. van der; Peters, K.B.M. - \ 2019
In: Theories of Practice in Tourism / James, Laura, Ren, Carina, Halkier, Henrik, Oxxon : Routledge - ISBN 9781138061705 - p. 115 - 132.
Effect of fermentation on content, molecule weight distribution and viscosity of β-glucans in oat sourdough
Lu, Jun ; Shan, Lingke ; Xie, Yiting ; Min, Fangfang ; Gao, Jinyan ; Guo, Laichun ; Ren, Changzhong ; Yuan, Juanli ; Gilissen, Luud ; Chen, Hongbing - \ 2018
International Journal of Food Science and Technology (2018). - ISSN 0950-5423
Fermentation - Lactobacillus plantarum - Oat β-glucan - Sourdough - Viscosity

This study investigated the effect of fermentation on the physicochemical properties of β-glucans in oat sourdough. Sourdoughs were produced from oat using homo-fermentative lactic acid bacteria, Lactobacillus plantarum 22134. The contents of total β-glucan and soluble β-glucan, the molecular weight (MW) of β-glucan and the viscosity of the extracted β-glucans were determined at 0, 4, 8, 10 and 12 h of fermentation. The total β-glucan content decreased from 4.89% to 4.23% after 12 h of fermentation. The soluble β-glucan concentration increased from 1.89% to 2.18% and then decreased to 1.97% after 8 h of fermentation. The content of β-glucans with MW > 105 decreased from 0 to 4 h of fermentation, followed by an increase and then a decrease after 8 h. The oat sourdough fermented for 8 h had high viscosity, which could be more beneficial for health and bread texture quality, especially for gluten-free breads. International Journal of Food Science and Technology

Haiti technical cold chain dry run : applying distributed ledger technology to connect Haitian mango and avocado producers toforeign markets
Oostewechel, Rene ; Régis, Yves-Laurent ; Brouwers, Jan ; Vogels, Jan ; Smeenk, Anton ; Ren, Xin-Ying - \ 2018
Wageningen : Wageningen Food & Biobased Research (Wageningen Food & Biobased Research report 1838) - ISBN 9789463434706 - 33
This report provides the technical results of a dry run transporting mangoes and avocados from Haiti to the US, Canada and The Netherlands. For both fruits, temperature has been registered from the moment of harvest till arrival at all destinations. Also logistical data related to the planning and preparation of the test, time needed for each step, and quality of fruits has been analysed. After the introduction chapter, technical data are provided for both mango and avocado in the next two chapters, with a concluding last chapter afterwards that provides overall analysis, lessons learned and recommendations. Use of the QR codes has allowed a transparent and digital process where all chain partners have open access to all information. The report presents a block chain test at limited level and actual implementation and scaling of block chain procedures might still need refinement like the longer ripening and/or storage before retail distribution.
The intelligent delivery systems for bioactive compounds in foods : Physicochemical and physiological conditions, absorption mechanisms, obstacles and responsive strategies
Chai, Jingjing ; Jiang, Ping ; Wang, Pengjie ; Jiang, Yumeng ; Li, Dan ; Bao, Weier ; Liu, Bingxue ; Liu, Bin ; Zhao, Liyun ; Norde, Willem ; Yuan, Qipeng ; Ren, Fazheng ; Li, Yuan - \ 2018
Trends in Food Science and Technology 78 (2018). - ISSN 0924-2244 - p. 144 - 154.
Bioaccessibility - Bioactive compounds - Bioavailability - Delivery barriers - Encapsulation - Intelligent delivery systems

Background: Bioactive natural compounds have received considerable attention due to their health benefits, including anti-oxidant, anti-cancer, anti-diabetes and cardiovascular disease-preventing functions. However, the stability of these sensitive compounds can be influenced by unfavourable environmental conditions during processing and storage. In addition, delivery of bioactive compounds via the oral route is restricted by various physiological barriers, including a harsh pH, gastrointestinal enzymes, the mucus layer, and the epithelium. Intelligent delivery systems are a promising method to protect bioactive molecules from degradation and improve their bioavailability. Scope and approach: We have demonstrated the physicochemical and physiological GI conditions. The structural composition of the epithelium and transport mechanisms of bioactives and nanoparticles across the intestinal epithelium were discussed. The effects of enhanced aqueous solubility, stability, bioaccessibility and bioavailability after encapsulation were illustrated. Furthermore, novel intelligent carriers that are responsive to the oral route, pH, enzymes and cell receptors were also discussed. Key findings and conclusions: This comprehensive multidisciplinary review provides useful guidelines for the application of bioactive compounds in the food industry. Intelligent carrier systems are designed to improve the low solubility, poor stability and low permeability of the gastrointestinal tract, and they have the potential to improve oral bioavailability.

Microscopic Origins of Shear Jamming for 2D Frictional Grains
Wang, Dong ; Ren, Jie ; Dijksman, Joshua A. ; Zheng, Hu ; Behringer, Robert P. - \ 2018
Physical Review Letters 120 (2018)20. - ISSN 0031-9007

Shear jamming (SJ) occurs for frictional granular materials with packing fractions φ in φS<φ<φJ0, when the material is subject to shear strain γ starting from a force-free state. Here, φJμ is the isotropic jamming point for particles with a friction coefficient μ. SJ states have mechanically stable anisotropic force networks, e.g., force chains. Here, we investigate the origins of SJ by considering small-scale structures - trimers and branches - whose response to shear leads to SJ. Trimers are any three grains where the two outer grains contact a center one. Branches occur where three or more quasilinear force chain segments intersect. Certain trimers respond to shear by compressing and bending; bending is a nonlinear symmetry-breaking process that can push particles in the dilation direction faster than the affine dilation. We identify these structures in physical experiments on systems of two-dimensional frictional discs, and verify their role in SJ. Trimer bending and branch creation both increase Z above Ziso≃3 needed for jamming 2D frictional grains, and grow the strong force network, leading to SJ.

Characterizing granular networks using topological metrics
Dijksman, Joshua A. ; Kovalcinova, Lenka ; Ren, Jie ; Behringer, Robert P. ; Kramar, Miroslav ; Mischaikow, Konstantin ; Kondic, Lou - \ 2018
Physical Review. E, Statistical nonlinear, and soft matter physics 97 (2018)4. - ISSN 2470-0045
We carry out a direct comparison of experimental and numerical realizations of the exact same granular system as it undergoes shear jamming. We adjust the numerical methods used to optimally represent the experimental settings and outcomes up to microscopic contact force dynamics. Measures presented here range from microscopic through mesoscopic to systemwide characteristics of the system. Topological properties of the mesoscopic force networks provide a key link between microscales and macroscales. We report two main findings: (1) The number of particles in the packing that have at least two contacts is a good predictor for the mechanical state of the system, regardless of strain history and packing density. All measures explored in both experiments and numerics, including stress-tensor-derived measures and contact numbers depend in a universal manner on the fraction of nonrattler particles, fNR. (2) The force network topology also tends to show this universality, yet the shape of the master curve depends much more on the details of the numerical simulations. In particular we show that adding force noise to the numerical data set can significantly alter the topological features in the data. We conclude that both fNR and topological metrics are useful measures to consider when quantifying the state of a granular system.
Data-Driven Modeling of Intracellular Auxin Fluxes Indicates a Dominant Role of the ER in Controlling Nuclear Auxin Uptake
Middleton, Alistair M. ; Bosco, Cristina Dal; Chlap, Phillip ; Bensch, Robert ; Harz, Hartmann ; Ren, Fugang ; Bergmann, Stefan ; Wend, Sabrina ; Weber, Wilfried ; Hayashi, Ken Ichiro ; Zurbriggen, Matias D. ; Uhl, Rainer ; Ronneberger, Olaf ; Palme, Klaus ; Fleck, Christian ; Dovzhenko, Alexander - \ 2018
Cell Reports 22 (2018)11. - ISSN 2211-1247 - p. 3044 - 3057.
auxin - auxin flux - auxin sensor - endoplasmic reticulum - fluorescent aux - mathematical modeling - microscopy - nucleus - protoplasts - single cells
In plants, the phytohormone auxin acts as a master regulator of developmental processes and environmental responses. The best characterized process in the auxin regulatory network occurs at the subcellular scale, wherein auxin mediates signal transduction into transcriptional programs by triggering the degradation of Aux/IAA transcriptional repressor proteins in the nucleus. However, whether and how auxin movement between the nucleus and the surrounding compartments is regulated remain elusive. Using a fluorescent auxin analog, we show that its diffusion into the nucleus is restricted. By combining mathematical modeling with time course assays on auxin-mediated nuclear signaling and quantitative phenotyping in single plant cell systems, we show that ER-to-nucleus auxin flux represents a major subcellular pathway to directly control nuclear auxin levels. Our findings propose that the homeostatically regulated auxin pool in the ER and ER-to-nucleus auxin fluxes underpin auxin-mediated downstream responses in plant cells. Middleton et al. study how the plant phytohormone auxin enters the nucleus by using quantitative phenotyping in single plant cell systems and bespoke mathematical models that relate controlled perturbations to experimentally measurable responses. Their findings show that auxin predominantly enters the nucleus via the endoplasmic reticulum.
The evolution of determinate and indeterminate nodules within the Papilionoideae subfamily
Ren, Guiling - \ 2018
University. Promotor(en): Ton Bisseling, co-promotor(en): Rene Geurts. - Wageningen : Wageningen University - ISBN 9789463432306 - 129

We selected the legume Indigofera argentea for our research. It was collected in the desert of Jizan in Saudi Arabia. We selected this species for two reasons. It is well adapted to heat and drought and therefore it has the potential to study, in the future, mechanisms that confer tolerance to these abiotic stresses. Further, Indigofera represents an early branching lineage within the indigoferoid/milletioid clade. Therefore, Indigofera is a key genus in studying the evolution of nodulation within the Papilionoideae subfamily.

In Chapter 1, a general introduction is given on nitrogen fixing symbiosis of legumes and rhizobia. In this introduction, we focus on the process of nodule initiation and organogenesis. Two main nodule types, determinate and indeterminate nodule, are introduced based on the knowledge of the few well-studied legumes species. Further, terminal differentiation of rhizobia that is induced by NCR peptides of the host is introduced.

In Chapter 2, we characterized the desert legume I. argentea and developed a platform by which future studies on mechanisms controlling abiotic stress become available. We developed an Agrobacterium rhizogenes-mediated root transformation procedure and did a de novo transcriptome assembly using RNA of various organs.

In Chapter 3, about 60 rhizobium strains have been isolated from nodulated I. argentea plants that were collected in the desert. The strains were characterized by 16S sequencing and their nodulation abilities were studied. One of the efficient nodulating Bradyrhizobium strains was selected for further studies.

In Chapter 4, nodule development of Indigofera and Tephrosia species was analysed and described in detail. Species from both genera have an indeterminate growth. However, it was shown that this is not due to a meristem that is formed at the primordium stage, which is the basis of indeterminate growth of IRLC species like Medicago. The indeterminate growth was shown to be due to secondary clusters of dividing infected cells that were formed from nodule parenchyma cells. Therefore, it evolved independently from the indeterminate growth from IRLC species which is controlled by a persistent meristem composed of non-infected cells.

In Chapter 5, it is shown that bacteroids from I. argentea nodules are markedly enlarged as described for IRLC (e.g. Medicago) and Aeschynomene species. This increase in size was correlated with endoreduplication and terminal differentiation. Further, it was shown that in nodules of I. argentea 4 NCR genes are expressed. Therefore it is probable that these terminal differentiation is controlled by the NCR peptides and this evolved independently in the IRLC clade, Aeschynomene and Indigofera.

In Chapter 6, I discuss my results and put them in a broader perspective. I summarize and discuss the determinate and indeterminate nodule evolution in the Papilionoideae subfamily.

We have shown in Chapter 4 that Indigofera and Tephrosia species have a nodule development that is very similar to that of determinate nodules and their indeterminate growth is due to the formation of secondary clusters of dividing cells. Species from other clades of the Papilionoideae subfamily were analyzed. Based on these analyses, I conclude that the ancestor of the Papilionoideae subfamily formed determinate nodules that had the ability to form secondary clusters of dividing cells. Further, NCR-triggered bacteroid evolution in the Papilionoideae subfamily is discussed.

Identify stakeholders' understandings of life cycle assessment results on wastewater related issues
Bai, Shunwen ; Zhu, Xueqin ; Wang, Xiuheng ; Ren, Nanqi - \ 2018
Science of the Total Environment 622-623 (2018). - ISSN 0048-9697 - p. 869 - 874.
Conjoint analysis - Life cycle assessment - Stakeholders' preferences - Waste management
To facilitate decision-making processes in waste management, it is important to not only evaluate environmental impacts, but also to measure how stakeholders form opinions and make choices based one valuation results. Life cycle assessments (LCAs) have been widely used to evaluate environmental impacts; however, LCAs cannot be used to measure how people make judgments based on evaluation results. As such, in this study, we combined LCA with conjoint analysis, an economic method that allows individuals to consider all factors and demonstrate their preferences simultaneously. We used this combined method in a case study on wastewater treatment, and obtained two major types of estimation results: (1) the relative importance of each impact category of LCA, and (2) the overall preferences of respondents for each alternative. This study also highlighted some issues regarding the combination of methodologies, such as the selection of impact categories in LCA, the conversion of impact categories into understandable attributes for conjoint analysis, and weaknesses in conjoint analysis that need to be addressed and corrected in future studies.
Co-Creating Tourism Research : Towards Collaborative Ways of Knowing
Ren, Carina ; Jóhannesson, Gunnar Thór ; Duim, V.R. van der - \ 2018
Routledge - ISBN 9781138228191 - 188 p.
Co-creation has become a buzzword in many social science disciplines, in business and in tourism studies. Given the prominence of co-creation, surprisingly little discussion has evolved around its implications for research practices and knowledge production as well as what challenges there are for fulfilling the promise of co-creation in tourism research.
This book aims to contribute to this discussion by addressing how tourism research comes together as a collaborative achievement and by exploring different ways of collaborative knowledge production in tourism research. It is structured to offer, on one hand, an introduction to the ontological basis for collaborative research and, on the other hand, a set of empirical examples of how collaborative knowledge creation can inform tourism design, management, policy and education.
The theoretical accounts and empirical cases of this book display how research collaborations can offer modest, local yet often impactful insights, traces and effects. It therefore will be of value for students, researchers and academics in tourism studies as well as the wider social sciences.
Co-creation of tourism knowledge
Ren, Carina ; Duim, V.R. van der; Jóhannesson, Gunnar Thór - \ 2018
In: Co-Creating Tourism Research / Ren, Carina, Jóhannesson, Gunnar Thór, van der Duim, René, Routledge - ISBN 9781138228191 - p. 1 - 10.
Co-creation has become a buzzword in many social science disciplines and business studies as well as in the field of tourism studies. Everybody is supposed to work together to create ‘more value’, ‘better experiences’ and to enhance knowledge transfer. While no exact or clear-cut definition exists of co-creation, it often refers to ways in which producers and consumers of a particular product or service jointly produce it partly or in whole. In the private sector, it denotes a shift in the organization of production where consumers or users are enabled or encouraged to participate in the making of a product or experience as in the case of tourism. In design studies it has been used in a similar sense to reflect on and work with the relation between designers and end users (Sanders & Stappers, 2008; see also Chapter 6).
Balancing values: co-creation in and out of academia
Duim, V.R. van der; Jóhannesson, Gunnar Thór ; Ren, Carina - \ 2018
In: Co-Creating Tourism Research / Ren, Carina, Jóhannesson, Gunnar Thór, van der Duim, René, Routledge - ISBN 9781138228191 - p. 11 - 23.
Participatory landscape designing for tourism planning: the case of Murter Island, Croatia
Brinkhuijsen, M. ; Ateljevic, I. ; Duim, V.R. van der; Koens, Dion ; Berg, Luuk van den - \ 2018
In: Co-Creating Tourism Research / Ren, Carina, Jóhannesson, Gunnar Thór, van der Duim, René, Routledge - ISBN 9781138228191 - p. 73 - 95.
Towards a collaborative manifesto: configurations of tourism knowledge co-creation
Ren, Carina ; Duim, V.R. van der; Jóhannesson, Gunnar Thór - \ 2018
In: Co-Creating Tourism Research / Ren, Carina, Jóhannesson, Gunnar Thór, van der Duim, René, Routledge - ISBN 9781138228191 - p. 179 - 183.
Li, Chen Yan ; Qiao, Wei ; Xin-Rong, Yan ; Melse, R.W. ; Buisonjé, F.E. de; Dong, Ren Jie - \ 2017
Sichuan Huanjing 36 (2017)4. - ISSN 1001-3644 - p. 55 - 61.
Livestock and poultry breeding industry is one of the main industry of rural economy. The rapid development brings environmental pollution problems and now it is the main restricting factor in the construction of new countryside. This paper analyzed the ammonia emission ways under the returning patternand summarized some ammonia reduction measures. Combined with the development of livestock and poultry breeding industry and farmland utilization, this paper summarized that in order to reduce ammonia emission under livestock manure returning pattern, we should feed animals with low protein feed to reduce the generation of N. After solid - liquid separation of livestock waste, store the manure with airtight coverage to reduce the volatilization of ammonia. In the spring, deep tillage with fertilizer application on the land to reduce ammonia emissions. If surface fertilization, the land soil should be turned or ploughed immediately.
Manure nutrient application on a Chinese dairy farm with arable land: A case study based on Dutch experience of equilibrium fertilization
Melse, Roland W. ; Buisonjé, Fridtjof E. de; Qiao, Wei ; Dong, Ren Jie - \ 2017
International Journal of Agricultural and Biological Engineering 10 (2017)4. - ISSN 1934-6344 - p. 182 - 188.
Dairy farm - Dairy manure - Environmental protection - Nutrient application standard - Nutrient balance - Over-fertilization
For a Chinese dairy farm with 2200 milking cows, the annual manure production and manure nutrients (nitrogen and phosphorus) were estimated. Gaseous nitrogen losses from cattle housing with scraped solid floors were based on on-farm measurements. Based on experiences from the Netherlands, nutrient levels in the solid and liquid fractions after slurry separation were estimated. On the basis of assumptions for nutrient losses during covered lagoon storage and land application of the liquid fraction, nitrogen and phosphorous fertilization rates were calculated for the 67 hm 2 of agricultural land that receive the liquid fraction by gravity irrigation. The results show that the application rates of nitrogen and phosphorous significantly exceed the crop needs, which will probably result in losses to soil and water. In order to aim for a balance between nutrient application and crop needs and, as such, reduce environmental harm, the authors recommend to establish application standards for nitrogen and phosphorous on arable land in China and to formulate farm-specific Nutrient Management Plans.
ANT: A decade of interfering with tourism
Duim, V.R. van der; Ren, C. ; Johannesson, G.T. - \ 2017
Annals of Tourism Research 64 (2017). - ISSN 0160-7383 - p. 139 - 149.
actor-network theory, oncology, relational materialism
Ten years ago actor-network theory (ANT) entered this journal. To illustrate how the relational ontology and sensibilities of ANT lend themselves to particular kinds of research, we first interrogate the main controversies as a way to open up and discuss the main premises of ANT. These debates concern the status and agency of objects and non-humans, ANT’s denial of the explanatory power of social structures, and the political implications of ANT. Second we present ANT’s relevance for tourism studies and discuss what ANT ‘does’ in practice. After summarizing a decade of relations between ANT and tourism, we conclude
by tracing three future trajectories of how we have ‘moved away with’ ANT into
new areas of discovery.
Erratum to : Performance evaluation of operational atmospheric correction algorithms over the East China Seas (Chinese Journal of Oceanology and Limnology, (2017), 35, 1, (1-22), 10.1007/s00343-016-5170-6)
He, Shuangyan ; He, Mingxia ; Fischer, Jürgen ; Yuan, Dongliang ; Xu, Peng ; Xu, Tengfei ; Yang, Xianping ; Sokoletsky, Leonid ; Wei, Xiaodao ; Shen, Fang ; Zou, Juhong ; Guo, Maohua ; Cui, Songxue ; Zhou, Wu ; Gao, Dalu ; Jin, Guangzhen ; Lü, Xianqing ; Qiu, Fuwen ; Fang, Wendong ; Pan, Aijun ; Cha, Jing ; Zhang, Shanwu ; Huang, Jiang ; Wang, Tao ; Cheng, Yongzhou ; Chen, Xiaoyan ; Liu, Zhaopu ; Long, Xiaohua ; Hou, Zhishuai ; Wen, Haishen ; Li, Jifang ; He, Feng ; Liu, Qun ; Wang, Jinhuan ; Guan, Biao ; Wang, Qinglong ; Shahjahan, Md ; Kabir, Md Farajul ; Sumon, Kizar Ahmed ; Bhowmik, Lipi Rani ; Rashid, Harunur ; Li, Shu ; Yu, Kefu ; Zhao, Jianxin ; Feng, Yuexing ; Chen, Tianran ; Zhou, Shun ; Ren, Yichao ; Pearce, Christopher M. ; Dong, Shuanglin ; Tian, Xiangli ; Gao, Qinfeng ; Wang, Fang ; Liu, Liming ; Du, Rongbin ; Zhang, Xiaoling ; Dong, Shuanglin ; Sun, Shichun ; Feng, Song ; Lin, Jianing ; Sun, Song ; Zhang, Fang ; Zhang, Zhipeng ; Tang, Xuexi ; Tang, Haitian ; Song, Jingjing ; Zhou, Jian ; Liu, Hongjun ; Wang, Qixiang ; Qian, Kuimei ; Liu, Xia ; Chen, Yuwei ; Sun, Chengjun ; Jiang, Fenghua ; Gao, Wei ; Li, Xiaoyun ; Yu, Yanzhen ; Yin, Xiaofei ; Wang, Yong ; Ding, Haibing ; Sun, Zhongmin ; Wang, Yongqiang ; Yan, Pengcheng ; Guo, Hui ; Yao, Jianting ; Tanaka, Jiro ; Kawai, Hiroshi ; Song, Na ; Chen, Muyan ; Gao, Tianxiang ; Yanagimoto, Takashi ; Lu, Xia ; Luan, Sheng ; Kong, Jie ; Hu, Longyang ; Mao, Yong ; Zhong, Shengping ; Liu, Yan ; Zhao, Weihong ; Li, Caiyan ; Miao, Hui - \ 2017
Chinese Journal of Oceanology and Limnology 35 (2017)2. - ISSN 0254-4059 - p. 466 - 467.
Unfortunately for all articles of Vol. 35 No. 1 the future journal title “Journal of Oceanology and Limnology” was used instead of the current journal title “Chinese Journal of Oceanology and Limnology”. All articles in the issue are aff ected. Please make sure to cite the articles with the following Vol. and No. info: Chinese Journal of Oceanology and Limnology, Vol. 35 No. 1, [page range].
Mest verzilveren
Verdoes, Nico - \ 2016

Mest verzilveren
Boeren moeten verplicht worden om mestoverschotten naar centrales te brengen, vindt de
commissie-Nijpels. Het advies: haal er waardevolle stoffen uit en verkoop die op de wereldmarkt.
Mest als goudmijn, hoe realistisch is dat?

erwijl fosfaat wereldwijd schaarser wordt, komt Ne- derland er in om. Deze be- langrijke stof voor
de voed-
selproductie zit overvloedig in mest. Haal het er uit en verkoop het, zegt de commissie-Nijpels.
,,De gedachte erachter is uiterma- te boeiend’’, zegt ir. Nico Verdoes. De mestexpert van
Wageningen Unive- sity & Research trof in het rapport van Nijpels open deuren aan, maar ook twee
inspirerende uitgangspun- ten: ,,Grootschalige mestverwerking en een mestcertificeringssysteem.’’
,,De urgentie is er. Aanvankelijk leek er voor nog slechts 60 jaar fos- faat in de mijnen te
zitten. Dat zou betekenen dat er al snel geen leven op aarde meer mogelijk is. De jong- ste
schattingen gaan echter uit van 300 jaar. We hebben iets meer tijd.’’ Die is nodig ook. Want wat
Nijpels voor ogen heeft, zegt Verdoes, be- staat nog nergens.

Wat kan er al wel?
,,Er zijn tientallen mechanische mestscheiders. Die maken een dikke en een dunne fractie. De dikke
bevat vooral organische stof en fosfaat. Op dit moment exporteert Nederland veel dikke fractie. De
export van fos- faat is prima, maar eigenlijk hebben we de organische stof zelf nodig, want de
bodemvruchtbaarheid loopt hier terug. Dus wat nodig is, is een techniek om die twee te schei- den.
Kleinschalig zijn er proeven, maar het is lang niet uitontwikkeld.’’

Wat maakt fosfaat afscheiden zo lastig?
,,Fosfaat zit vast in fytinezuur. Dat zijn ringen met allemaal elementen erin, onder andere het
element fos- faat. Om die uit de celstructuur los te maken, heb je hele sterke zuren no- dig.
Nadeel is dat je dan de organi- sche stof beschadigt. Nog lastiger is het om fosfaat heel zuiver
uit de mest te halen. Het is vaak ‘bevuild’ met organische stof.’’

Andere opties?
,,Een andere methode is verbranden. Dat gebeurt in Moerdijk met jaar- lijks 400.000 ton
pluimveemest. De fosfaat die hier uit komt, is moeilijk oplosbaar. Het wordt toegepast in wegenbouw
en in bakstenen. Eigen- lijk is dat een verlies van fosfaat. Je brengt het niet in de landbouw-
kringloop. Het proces is ook duur, want de schadelijke stoffen die bij verbranden vrijkomen, worden
af- gevangen met dure apparatuur.’’

Kunnen bacteriën iets betekenen?
,,Jawel. Nadeel is dat biologische sys- temen moeilijker te sturen zijn, en je kunt nooit alle
fosfaten winnen.’’
Fosfaat laten neerslaan, zoals bij waterzuiveringen gebeurt?
,,Dan maak je er korreltjes van, zoals struviet. In de waterzuivering is struviet zuiverder te
isoleren dan bij de mestverwerking. Het kost dan ook veel geld om het los te maken. ’’

Dit klinkt in de verse verste niet naar een oplossing.
,,We hebben nog een lange weg te gaan. Er is veel fundamenteel onder- zoek nodig voordat we zuiver
calci- umfosfaat of zuivere struviet uit mest kunnen winnen. Wil je er iets mee doen in een
mineralenkring- loop, dus terug in de landbouw, dan moet je voldoen aan eisen van de
kunstmestfabrikant, zoals een be- paalde zuiverheid, grote hoeveelhe- den en een goede prijs.
Voorlopig kunnen we het goedkoper uit een fosfaatmijn halen.’’

Nijpels noemt de voedselindustrie al als gedroomde afnemer.
,,Jaha. Voedseladditieven…dat is nog weer een paar stapjes verder. Je kunt bijvoorbeeld fosforzuur
maken uit fosfaat, en dat kun je toepassen in cola. Ik heb ooit aan iets dergelijks meegewerkt, het
ging toen om een middel voor varkensvoer. Een ont- zettend tijdrovend traject met labo-
ratoriumstudies, pilots, allerlei cer- tificeringssystemen. Je moet een enorm dossier overleggen.
Je bent zo tien jaar verder.’’

Hoe realistisch is het plan-Nijpels?
,,Het is een oplossing voor de lange termijn, niet voor de korte. Het for- muleert een
onderzoeksopdracht en zet sporen uit.‘’

Wanneer is er op zijn vroegst een profijtelijke oplossing?
,,Dat duurt zeker meer dan tien jaar. Het is ook afhankelijk van de fosfaat- prijzen. Een paar jaar
terug gingen de fosfaatprijzen ineens enorm om- hoog na alarmerende signalen over uitgeputte
mijnen. Later werden die afgezwakt en daalden de prijzen. Zo- dra fosfaat heel erg duur wordt, heb
je snel interessante business.’’
Nijpels ziet ook kansen voor stik- stof, kalium en zink.
,,Stikstof winnen gebeurt al. Dat is simpel, maar het brengtniet veel op. Kali is een vrij klein
element dat overal doorheen fietst, je kunt het niet scheiden. Wel zijn er dure me- thoden om
kalizouten te maken. Daarmee hebben we geëxperimen- teerd op de Dairy Campus. Er zijn ook
experimenten met de produc- tie van stikstofkaliconcentraat uit mest. Als je daar de stikstof
uithaalt, hou je ook kali over. Dat gebeurt nu op ongeveer acht plekken, vooral op loonbedrijven
met varkens- mest.’’

Nijpels pleit voor centrale verwer- king. Is decentraal niet handiger? Het scheelt transportkosten.
,,Ik zie niet snel gebeuren dat vee- houders zelf een installatie neerzet- ten waarin ze kalizout
maken of zuiver fosfaat winnen. Veehouders zijn geen procestechnologen. We hebben dat gezien bij de
co-vergis- tingsinstallaties op bedrijfsniveau. Die zijn bijna allemaal ter ziele. Boe- ren hebben
geen tijd voor inkoop van grondstoffen of temperaturen monitoren. Wil je ingewikkelde producten
maken, dan heb je tech- nologische hoogstandjes nodig. Die zijn voorbehouden aan centrale fa-
brieken. Daar zitten de experts, de operators en de storingsdiensten. Uiteindelijk zal een
installatie van
100.000 kuub goedkoper zijn dan tien installaties van 10.000 kuub.’’

Waar moeten die centrales staan?
,,Dat wordt een probleem. Het Zui- den lijkt logisch, te midden van de varkensboeren. Die hebben
geen ei- gen grond. Maar in het Zuiden is veel weerstand van de bevolking. Sinds de uitbraak van
Q-koorts, die niets met varkens had te maken, is er grote angst voor enge ziektekie- men. Alle
bouwplannen van mest- verwerkingbedrijven worden er momenteel tegengehouden. In melkveegebieden
zijn ze minder lo- gisch. Melkveehouders hebben een mestoverschot van gemiddeld on-
geveer 20 procent. Zij kunnen hun
mest goeddeels kwijt op het eigen bedrijf. En in het Noorden ook mak- kelijk op akkerbouwgrond in
de buurt. Momenteel zie je dat varkens- mest op de binnenlandse markt wordt verdrongen door mest
van melkveehouderijbedrijven. Die kun- nen meer betalen en hun transport- kosten zijn lager door de
nabijheid van akkerbouwgebieden.’’

Wat is het verhaal achter de kwali- teitsborging die Nijpels voorstelt?
,,Alle verwerkende of producerende sectoren werken met een kwaliteits- systeem. Melk voldoet aan
eisen, kunstmest ook, anders mag het de markt niet op. Mest voldoet nog ner- gens aan. Als je van
mest een waar- devol product wilt maken, terwijl het nu als afval wordt beschouwd, heb je
kwaliteitseisen nodig. Zo’n systeem kan je alleen opzetten bij grootschalige verwerking,’’

Welke factoren kunnen het succes van centrale scheidingsfabrieken ondermijnen?
,,Allerlei bedrijven bezien hun afval in nieuw licht en kijken wat er te up- cyclen valt. Als je
uit een ander afval- product veel goedkoper fosfaat kunt winnen, krijgt de mestsector het erg

Is het slim om in te zetten op hoog- waardige toepassingen?
,,Je kunt mikken op producten met een lage toegevoegde waarde, dan heb je op korte termijn een
oplos- sing. Maar vanuit de circulaire ge- dachte is het logisch te streven naar een zo hoog
mogelijk toegevoegde waarde. Om daar te komen, is veel tijd en geld nodig.’’
,,Een van mijn collega’s is in de top van de waardepiramide bezig. Hij zoekt naar een antibioticum
in mest, naar hormonen, naar vezels en eiwitten. Stel dat hij er in slaagt eiwit te isoleren dat
helpt bij de be- strijding van kanker, dan is hij spek- koper. Dan is mest van onschatbare waarde.
Om daar te komen, is een moeizame weg van tientallen ja- ren.’’

Is mest het bruine goud?
,,Haha. Men wordt al wat wijzer. Oud-minister Gerda Verburg van Landbouw gebruikte die term. Nij-
pels is gematigder. Hij spreekt van ‘waarde verzilveren’.’’
‘We hebben nog een lange weg ‘te gaan’’
‘Stel dat je een
kankermedicijn uit mest kunt halen’
Brussel eist dat Nederland zijn mest- probleem snel oplost. Hoe nu verder? De Leeuwarder Courant
wijdt de komende weken een verhalenserie aan mest in al zijn facetten. Vandaag aflevering 3: Hoe
brengen we mest op
nieuwe manieren tot waarde?

A systematic assessment of quality assurance-based food safety management system of Chinese edible oil manufacturer in view of context characteristics
Ren, Yingxue ; He, Zhen ; Luning, Pieternel A. - \ 2016
Total Quality Management & Business Excellence (2016). - ISSN 1478-3363 - 15 p.
diagnostic instrument - edible oil - food safety - food safety management system - quality management

This study uses a framework of a food safety management system-diagnostic instrument (FSMS-DI), for the assessment of the context of a Chinese edible oil manufacture through the view of a case study, and an evaluation of the performance of the FSMS of a Chinese edible oil company. The study includes a structured interview with the quality assurance manager. FSMS-DI is used to diagnose the core control and assurance activities, as well as the riskiness of context factors and output of the system. A factory tour is done to verify the information collected during the interview. The company is operating in a low to moderate risk context. The control activities are overall operating at an advanced level, while the assurance activities are at an average level. Although the food safety output of the FSMS is good, improvements are advised on the assurance activities to develop towards a more robust FSMS. This study gives an insight into the current situation of implemented FSMS in view of the context riskiness of the food business. Quantitative studies and further exploration of typical Chinese context characteristics may help food safety authorities, supporting (branch of industry) organisations, and food companies to advance towards a more effective food safety control in the food sector.

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