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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    Nestelmogelijkheden voor solitaire bijen in bodems van bloemrijke bermen : Een vergelijkend onderzoek tussen ingezaaide en niet-ingezaaide bermen in de gemeente Sint Anthonis
    Sanders, Dianne ; Groot, Arjen de; Goedhart, Paul W. ; Dimmers, Wim J. ; Kats, Ruud van; Scheper, Jeroen A. ; Roessink, Ivo - \ 2020
    Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 3019) - 35
    Er zijn sterke aanwijzingen dat zowel de aantallen als de soortendiversiteit van bestuivers de laatste decennia sterk achteruit zijn gegaan. Een speerpunt van de Nationale Bijenstrategie is het verbeteren van het leefgebied van wilde bijen en andere bestuivers. De meeste initiatieven om leefgebied voor wilde bijen te creëren, richten zich op het aanleggen van een bloemrijke vegetatie. Belangrijk voor wilde bijen is echter dat naast voldoende voedsel ook voldoende geschikte nestlocaties aanwezig zijn. De bekende bijenhotels helpen daarbij, maar het overgrote deel van de Nederlandse wilde bijensoorten nestelt ondergronds. Nestgelegenheid voor deze bodemnestelende bijen kan o.a. worden gecreëerd door zogenaamde nestelhoopjes of nesteldijkjes vorm te geven, maar dergelijke maatregelen zijn lang niet overal mogelijk. Een voorbeeld zijn de wegbermen, waar relatief makkelijk meer bloemaanbod te genereren is, maar gezien de verkeersveiligheid minder ruimte is voor het creëren van kale bodem of taluds. Onduidelijk is in hoeverre bloemrijke grasstroken, zoals deze wegbermen, al functioneren als nestlocatie voor wilde bijen en hoe deze potentiële functie verder kan worden bevorderd. In het voorliggende onderzoek is die vraag nader onderzocht door gedurende twee jaren in wegbermen met en zonder ingezaaide bloemranden de aanwezigheid van bodemnestelende bijen te inventariseren.
    Nieuw monitoringsmeetnet kwelders Ameland-Oost : Jaarrapportage veldwerk 2019
    Puijenbroek, Marinka E.B. van; Sonneveld, Cor - \ 2020
    Den Helder : Wageningen Marine Research (Wageningen Marine Research rapport C022/20) - 26
    Dit rapport is een update van de vorige jaarrapportage (Duin et al. 2018), waaruit de meer algemene teksten deels zijn overgenomen. Op het Waddeneiland Ameland vindt sinds 1988 bodemdaling plaats als gevolg van gaswinning. Vanaf 1993 vindt er langlopende monitoring plaats naar de mogelijke effecten van de bodemdaling op Ameland-Oost. Een van de conclusies van de laatste integrale rapportage was dat de permanent kwadraten niet geheel representatief waren voor de hele kwelder, en daarom is er in 2019 een nieuw monitoringsplan opgesteld. Onderdeel zijn 80 permanente kwadraten (PQ’s) verspreidt over Neerlands Reid en de Hon waarin in 2019 de eerste vegetatieopnames zijn gemaakt en opslibbingsmetingen met de Sedimentatie-Erosiebalk uitgevoerd. Het ‘oude’ monitoringsnetwerk is voor de laatste keer volledig opgenomen in 2018, maar een aantal PQ’s zijn wel meegenomen in het nieuwe monitoringsnetwerk in 2019. Dit is het eerste jaar dat de nieuwe PQ’s gemeten zijn en opslibbingsresultaten kunnen pas berekend worden na de volgende meting in 2020. In de voorliggende rapportage wordt het nieuwe monitoringsplan geïntroduceerd. Daarnaast worden de laatste gegevens van de opslibbing van het ‘oude’ monitoringsnetwerk voor het jaar 2018 gepresenteerd en de opslibbingsresultaten van 2019 van de ‘oude’ PQ’s die in het nieuwe monitoringsnetwerk zijn opgenomen. Gebaseerd op de metingen uitgevoerd in 2019 van het oude en nieuwe meetnet kunnen we de volgende conclusies trekken: - De opslibbing in 2018 – 2019 was binnen de range van normale waarden voor een eilandkwelder en de sedimentatie volgde het normale patroon met de hoogste waarden aan de wadrand van de kwelder en op de oeverwallen. - In het nieuwe monitoringsnetwerk is op plekken waar regressie (22 PQ’s) heeft plaatsgevonden, vooral middenkwelder veranderd in lage kwelder (14 PQ’s). Er vond meer regressie van vegetatie plaats op het Neerlands Reid (18 PQ’s) dan op de Hon (4 PQ’s). - In kwelderdelen waar tussen 1993 en 2014 regressie van de vegetatie naar lage kwelder heeft plaatsgevonden is de bedekking van kale grond hoger dan in kwelderdelen waar lage kwelder al langer stabiel voorkomt. Een toename aan kale grond slibt minder snel op of erodeert en dat kan tot verdere regressie van de vegetatie leiden.
    Kolonisatie van Ecocorridor Zwaluwenberg door de kale bosmier
    M., Waanders ; Grift, E.A. van der - \ 2019
    Nature Today
    n 2015 is gestart met de monitoring van de verspreiding van bosmieren in ecocorridor Zwaluwenberg, een achthonderd meter lange ecologische verbindingszone ten zuiden van Hilversum. Het onderzoek richt zich op het gebruik van de verbindingszone door bosmieren. Uit monitoring tot 2018 blijkt dat na een snelle kolonisatie in 2014 en 2015 weinig tot geen verdere uitbreiding van het leefgebied binnen.
    Leeggevreten kale bomen langs de Ruurloseweg
    Vliet, Arnold van - \ 2019
    Wageningen UR helpt de Johan Cruijff Arena aan een mooie grasmat
    Struik, Paul - \ 2019

    STRDe grasmat van de Amsterdam Arena was jarenlang de risee van de Nederlandse voetbalwereld: losse plaggen, kale plekken, gladde grassprieten, er deugde niets van. Maar de laatste jaren is de kritiek verstomd. Mede dankzij de kennis van Wageningen UR?

    Visdieven in het IJsselmeergebied: broedplaatskeuze en broedsucces in een wetland met weinig dynamiek
    Winden, Jan van der; Dirksen, S. ; Doodeman, Debby ; Hogeweg, Niels ; Horssen, Peter van; Kelder, Leon ; Tulp, I.Y.M. ; Poot, Martin - \ 2019
    Limosa 92 (2019)2. - ISSN 0024-3620 - p. 49 - 64.
    Visdieven broeden op kale open pionierbiotopen in visrijke zoete en zoute wateren. De voormalige Zuiderzee bood een ideaal leefgebied voor deze
    vogelsoort dankzij de peilschommelingen, zoutinvloed en omvangrijke vispopulaties als voedselbron. Sinds de afsluiting van de Zuiderzee door de
    Afsluitdijk is een zoetwatersysteem ontstaan met weinig dynamiek en harde oevers. Het natuurbeleid in het IJsselmeer is mede gericht op behoud
    van soorten van dynamische biotopen. De vraag doet zich voor of het mogelijk is om Visdieven duurzaam een plek te geven in dit merengebied. Sinds 1990 is informatie over de ecologie van Visdieven verzameld die goed bruikbaar blijkt te zijn om het beschermingsbeleid van een wetland-systeem
    met een ingedamde dynamiek te evalueren.
    Automated assembly of species metabolomes through data submission into a public repository
    Salek, Reza ; Conesa, Pablo ; Cochrane, Keeva ; Haug, Kenneth ; Williams, M. ; Kale, Namrata ; Moreno, P. ; Jayaseelan, Kalai Vanii ; Macias, Jose Ramon ; Nainala, Venkata Chandrasekhar ; Hall, R.D. ; Reed, Laura ; Viant, Mark ; Donovan, C. ; Steinbeck, Christoph - \ 2017
    GigaScience 6 (2017)8. - ISSN 2047-217X - 4 p.
    Following similar global efforts to exchange genomic and other biomedical data, global databases in metabolomics have now been established. MetaboLights, the first general purpose, publically available, cross-species, cross-application database in metabolomics, has become the fastest growing data repository at the European Bioinformatics Institute in terms of data volume. Here we present the automated assembly of species metabolomes in MetaboLights, a crucial reference for chemical biology, which is growing through user submissions.
    Applying mealtime functionality to tailor protein-enriched meals to older consumer segments
    Uijl, Louise C. den; Jager, Gerry ; Zandstra, Elizabeth H. ; Graaf, Kees de; Kremer, Stefanie - \ 2017
    Food Quality and Preference 56 (2017)part A. - ISSN 0950-3293 - p. 28 - 37.
    Congruency - Mealtime functionality - Product tailoring - Protein-enriched meals - Satisfaction - Senior consumer clusters

    The older adults group is highly heterogeneous, and its members do not always meet their recommended protein intake. We explored mealtime functionality as a basis for tailoring protein-enriched (PE) meal concepts to two senior consumer segments: 1) cosy socialisers, who eat mainly for cosiness and social interaction, and 2) physical nutritioners, who eat mainly for nutrients and physical needs. We hypothesised an increased ‘product–cluster fit’ when the functional meal associations are congruent to the clusters’ functional mealtime expectations. In a home-use test, participants (N = 91, mean age 68.1 (y) ± 5.3 (SD), 42 cosy socialisers) prepared and consumed three kale mash meal concepts once over three weeks: (1) a basic meal concept (without PE/tailoring), (2) a cosy meal concept (PE/tailored to mealtime expectations of cosy socialisers), and (3) a physical meal concept (PE/tailored to mealtime expectations of physical nutritioners). The participants reported their expectations and experiences with the recipes and dishes (e.g. expected liking; attractiveness recipe; actual liking; taste; smell; satisfaction). The results showed that the cosy meal concept was experienced as ‘traditional’ (p

    The kinetic of key phytochemical compounds of non-heading and heading leafy Brassica oleracea landraces as affected by traditional cooking methods
    Giambanelli, Elisa ; Verkerk, Ruud ; Antuono, L.F. D'; Oliviero, Teresa - \ 2016
    Journal of the Science of Food and Agriculture 96 (2016)14. - ISSN 0022-5142 - p. 4772 - 4784.
    Carotenoids - Cooking - Glucosinolates - Kale (Brassica oleracea ssp. acephala) - Retention - Total phenolic compounds

    BACKGROUND: Kales are often a key ingredient of traditional foods, containing high amounts of indolic glucosinolates (precursors of indole-3-carbinol and ascorbigen), carotenoids and phenolics. The present trend to associate traditional foods crops with health-promoting properties suggested to investigate the degradation kinetic of three Brassica oleracea landraces' phytochemicals subjected to boiling, steaming and stir-frying. RESULTS: Boiling led to substantial losses due to leaching. Glucosinolates followed a second-order degradation kinetic (20% of their initial values after 10min in Nero di Toscana). Phenolic content in leaves+cooking water remained unchanged, whereas their antioxidant capacity was reduced. Carotenoid content increased during the first minutes of boiling. Steaming showed the highest retention of phytochemicals, with often zero-order degradation kinetic, having however a strong effect on colour. Stir-frying produced high losses for all measured compounds; also, β-carotene reduced its content to 10-23% independently of variety. Conversion values for indole-derived compounds ranged from non-detectable to 23.5%. CONCLUSION: Variety strongly affected observed degradation rates because of a different glucosinolate composition and leaf structure. With this research, more information has been gained on the degradation kinetic of B. oleracea landraces' phytochemical compounds upon cooking, highlighting the possibility of improving bioactive component retention.

    Low Temperature Affects Stem Cell Maintenance in Brassica oleracea Seedlings
    Jonge, Jennifer de; Kodde, Jan ; Severing, Edouard I. ; Bonnema, Guusje ; Angenent, Gerco C. ; Immink, Richard G.H. ; Groot, Steven P.C. - \ 2016
    Frontiers in Plant Science 7 (2016). - ISSN 1664-462X
    Most of the above ground tissues in higher plants originate from stem cells located in the shoot apical meristem (SAM). Several plant species can suffer from spontaneous stem cell arrest resulting in lack of further shoot development. In Brassica oleracea this SAM arrest is known as blindness and occurs in an unpredictable manner leading to considerable economic losses for plant raisers and farmers. Detailed analyses of seedlings showed that stem cell arrest is triggered by low temperatures during germination. To induce this arrest reproducibly and to study the effect of the environment, an assay was developed. The role of genetic variation on the susceptibility to develop blind seedlings was analyzed by a quantitative genetic mapping approach, using seeds from a double haploid population from a cross between broccoli and Chinese kale, produced at three locations. The analysis revealed, besides an effect of the seed production location, a region on linkage group C3 associated with blindness sensitivity. A subsequent dynamic genome-wide transcriptome analysis resulted in the identification of around 3000 differentially expressed genes early after blindness induction. A large number of cell cycle genes were en masse induced early during the development of blindness, whereas shortly after, all were down-regulated. This miss-regulation of core cell cycle genes is accompanied with a strong reduction of cells reaching the DNA replication phase. From the differentially expressed genes, 90 were located in the QTL region C3. Among them are two genes belonging to the MINICHROMOSOMAL MAINTENANCE gene family, known to be involved in DNA replication, a RETINOBLASTOMA-RELATED gene, a key regulator for cell cycle initiation, and several MutS homologs genes, involved in DNA repair. These genes are potential candidates for being involved in the development of blindness in Brassica oleracea sensitive genotypes.
    OBO WP3a driftmetingen bloembollen; onderdeel C kale grond bespuitingen
    Zande, Jan van de - \ 2015
    Minder blad in winter bij veel meer groente- én sierteeltgewassen mogelijk : Leo Oprel pleit voor denken vanuit de winter
    Kromwijk, Arca ; Gelder, Arie de - \ 2015
    horticulture - greenhouse horticulture - vegetable growing - ornamental horticulture - tomatoes - anthurium - leaf area - biomass - greenhouse experiments - assimilation - winter - energy saving

    Onderzoek met een relatief ‘kale’ tomatenplant gaf vorige winter verrassende resultaten: iets meer productie, iets minder gasverbruik. Dit jaar is een nieuwe proef ingezet. Maar waarom zo’n systeem alleen toepassen bij tomaat? Leo Oprel (Kas als Energiebron) ziet nog veel meer mogelijkheden, ook bij siergewassen. Hij gaat in discussie met de onderzoekers Arca Kromwijk en Arie de Gelder.

    The farming systems of potential potato production areas of Chencha, southern Ethiopia
    Mazengia, W. ; Schulte, R.P.O. ; Tadese, Y. ; Griffin, D. ; Schulz, S. ; Struik, P.C. - \ 2015
    In: Potato and sweetpotato in Africa : / Low, J., Nyongesa, M., Quinn, S., Parker, M., Cambridge : CABI - ISBN 9781780644202 - p. 382 - 395.
    A survey was conducted in 2012 to assess the diversity of farming systems in the potential potato production areas of Chencha in southern Ethiopia. It was part a PhD research study on evaluation and optimization of sustainability of farming systems which is part of an initiative to make the area a potato centre of excellence. Household surveys (n=57) and farmers' group discussions were used to collect data from 21 villages. A mixed farming system was the prevailing system in the area where crops and livestock are simultaneously grown. The major crops grown in the area were potato, enset, wheat, barley and kale. Most crops were grown as food and cash crops. Barley and enset were mainly grown for household consumption. Farmers used improved varieties mainly for potato (73% of respondents) and wheat (77%). There were two cropping seasons per calendar year and crop rotation is common in the area. The dominant rotation system practised by 95% of the respondents was planting potato followed by wheat or barley. The common intercropping practices were mixed intercropping of barley with lentil and wheat with linseed. Based on local classification there were 12 soil types. The most common ones were Modo (dark loam), Gobo (red clay) and Kalta (brown clay). Fertilizers used were farmyard manure (97% of households), compost (40%), urea (78%) and diammonium phosphate (DAP) (81%). Farmers used low rates of inorganic fertilizers due to shortage of cash. Most of the households (55%) obtained a cash income from agricultural activities, mainly from crop production. The most important off-farm activity was weaving. Household food demands were met from own farm and external sources. Constraints of the farming system that need research and policy interventions include soil fertility depletion, low productive crop varieties, shortages of land, improved seed and cash.
    EKHC end line report - MFS II country evaluations, Civil Society component
    Klaver, D.C. ; Jacobs, J. ; Terefa, W. ; Getaw, H. ; Getu, D. - \ 2015
    Wageningen : Centre for Development Innovation, Wageningen UR (Report / Wageningen UR, Centre for Development Innovation CDI-15-033) - 78
    rural development - civil society - society - empowerment - development projects - ethiopia - east africa - africa - plattelandsontwikkeling - maatschappelijk middenveld - samenleving - empowerment - ontwikkelingsprojecten - ethiopië - oost-afrika - afrika
    This report describes the findings of the end line assessment of Ethiopian Kale Heywit Church (EKHC) in Ethiopia is a partner of Tear Fund Netherlands under the ICCO Alliance. It assesses EKHC’s efforts to strengthening Civil Society in Ethiopia based upon the CIVICUS analytical framework. It is a follow-up of a baseline study conducted in 2012. Key questions that are being answered comprise changes in the five CIVICUS dimensions to which EKHC contributed; the nature of its contribution; the relevance of the contribution made and an identification of factors that explain EKHC’s role in civil society strengthening. The evaluation was commissioned by NWO-WOTRO, the Netherlands Organisation for Scientific Research in the Netherlands and is part of the programmatic evaluation of the Co-Financing System - MFS II financed by the Dutch Government, whose overall aim is to strengthen civil society in the South as a building block for structural poverty reduction. Apart from assessing impact on MDGs, the evaluation also assesses the contribution of the Dutch Co-Funding Agencies to strengthen the capacities of their Southern Partners, as well as the contribution of these partners towards building a vibrant civil society arena.
    Sixty-five data sets of profit, labour input, fertilizer and pesticide use in seventeen vegetable crops of the Arusha region, Tanzania
    Everaarts, A.P. ; Putter, H. de - \ 2015
    Lelystad : PPO AGV (PPO/PRI report 652) - 77
    groenteteelt - rentabiliteit - input van landbouwbedrijf - kosten - arbeid (werk) - inkomen - tanzania - investering - penen - voederkool - koolsoorten - tomaten - aardappelen - bemesting - gewasbescherming - vegetable growing - profitability - farm inputs - costs - labour - income - tanzania - investment - carrots - kale - cabbages - tomatoes - potatoes - fertilizer application - plant protection
    This report contains the 65 individual crop data sets to the related report A.P. Everaarts, H. de Putter and A.P. Maerere, 2015. Profitability, labour input, fertilizer application and crop protection in vegetable production in the Arusha region, Tanzania.PPO Report 653.
    Profitability, labour input, fertilizer application and crop protection in vegetable production in the Arusha region, Tanzania
    Everaarts, A.P. ; Putter, H. de; Maerere, A.P. - \ 2015
    Lelystad : PPO AGV (PPO/PRI report 653) - 37
    groenteteelt - rentabiliteit - input van landbouwbedrijf - kosten - arbeid (werk) - inkomen - tanzania - investering - penen - voederkool - koolsoorten - tomaten - aardappelen - bemesting - gewasbescherming - vegetable growing - profitability - farm inputs - costs - labour - income - tanzania - investment - carrots - kale - cabbages - tomatoes - potatoes - fertilizer application - plant protection
    An analysis was made of the inputs, costs and profit of vegetable production in three areas in the Arusha region of Tanzania. The major aim of the study was to establish whether vegetable producers would have the means to invest in modern production methods, such as hybrid seeds and drip irrigation, to improve and intensify their production.
    Host plant resistance towards the cabbage whitefly in Brassica oleracea and its wild relatives
    Pelgrom, K.T.B. ; Broekgaarden, C. ; Voorrips, R.E. ; Bas, N. ; Visser, R.G.F. ; Vosman, B.J. - \ 2015
    Euphytica 202 (2015)2. - ISSN 0014-2336 - p. 297 - 306.
    aleyrodes-proletella homoptera - glucosinolate polymorphism - insect-resistance - cultivars - populations - fruticulosa - tomato - tabaci
    The cabbage whitefly (Aleyrodes proletella) is a phloem-feeding insect that is a serious problem in Brassica oleracea crops like Brussels sprouts, kale and savoy cabbage. In order to develop whitefly-resistant varieties it is essential to identify effective sources of resistance. In this study, we screened a large collection of 432 accessions, including wild material and landraces of Brassica oleracea as well as crop wild relatives, to determine whitefly performance in a no-choice field experiment. Putatively resistant accessions were further tested under greenhouse conditions. Resistant accessions were identified among B. oleracea var. capitata (cabbage) landraces and in the species B. villosa, B. incana and B. montana. Whereas resistance in cabbage is only expressed in plants of at least 12 weeks old, some wild relatives were already starting to express resistance at 6 weeks. This could open up possibilities for breeding cabbages that are resistant at a young(er) plant age. Our research also shows again the importance of crop wild relatives for finding pest resistances.
    Drift van 95% driftreducerende spuitdoppen opveldspuit en bijbehorende teeltvrije zone
    Zande, J.C. van de - \ 2014
    Plant Research International, Business Unit Agrosysteemkunde (Rapport / Plant Research International 596) - 16
    verstuiven (insectenbestrijding) - spuitapparatuur - spuitstukken - emissiereductie - emissie - oppervlaktewater - chemische bestrijding - pesticiden - plantenkwekerijen - boomkwekerijen - drift spraying - spraying equipment - nozzles - emission reduction - emission - surface water - chemical control - pesticides - nurseries - forest nurseries
    In bepaalde Waterschappen is het eerder gehanteerde vergunningenstelsel over gegaan op de naleving volgens het Activiteitenbesluit. Hierdoor zijn in de vergunningen vermelde combinaties van driftreducerende spuittechnieken en de gebruikte spuitvrije zones veranderd in teeltvrije zones. Dit geeft verlies aan teeltoppervlak in gebieden met intensieve teelt grenzend aan oppervlaktewater (zoals de boomkwekerij sector in de regio Boskoop). Hierdoor verslechtert het rendement op de bedrijven door een minder goede ruimtebenutting. Voor veel gemechaniseerde spuittechnieken geldt voor intensief gespoten gewassen volgens het Activiteitenbesluit een teeltvrije zone van minimaal 1,0 m. Vanuit eerder uitgevoerd onderzoek en berekeningen is bekend dat er door op veldspuiten 95% driftreducerende spuitdoppen te gebruiken een versmalling van de teeltvrije zone tot 0,5 m mogelijk is. In deze rapportage is door middel van berekening aan eerder uitgevoerde metingen deze uitspraak onderbouwd. Uit de berekeningen blijkt dat bij bespuitingen van een kale grond of een gewas met een veldspuit uitgerust met 95% driftreducerende spuitdoppen en een kantdop in combinatie met een teeltvrije zone van 0,50 m de driftdepositie op wateroppervlak en op oppervlaktewater (insteek-insteek) vergelijkbaar of lager is dan door een bespuiting van een gewas met een DRT90 techniek en een 1,50 m teeltvrije zone en een DRT95 techniek met een 0,50 m teeltvrije zone. Dit biedt de mogelijkheid voor bespuitingen met een veldspuit uitgerust met 95% driftreducerende spuitdoppen en kantdoppen een smallere teeltvrije zone te definiëren van 0,50 m in plaats van de nu gebruikte 1,00 m bij DRT90 spuittechnieken
    Plant science meets food science: genetic effects of glucosinolate degradation during food processing in Brassica
    Hennig, K. - \ 2013
    Wageningen University. Promotor(en): Tiny van Boekel, co-promotor(en): Guusje Bonnema; Matthijs Dekker; Ruud Verkerk. - S.l. : s.n. - ISBN 9789461736345 - 167
    glucosinolaten - brassica - voedselverwerking - thermische afbraak - genetische effecten - glucosinolates - brassica - food processing - thermal degradation - genetic effects
    Background

    Phytochemicals in plant-based foods have been linked to a reduced incidence and progression of diseases. Glucosinolates (GLs) are phytochemicals that are typical for Brassicaand other Cruciferousplants, such as cabbage, broccoli, Brussels sprouts, Chinese cabbage, mustard and horseradish. The intake of GLs has been associated with lowered risks of several types of cancer and other diseases. To reach a high level of GLs in the vegetables at the stage of consumption, research along the food chain aims to increase the concentrations of certain GLs and to lower the losses during food processing; however, effects of the different steps in the food chain are mostly investigated separately. In this thesis an interdisciplinary approach, combining food science and plant science, was applied to explore the possibilities to retain GLs throughout the food chain. The objective of this thesis was to investigate genetic effects related to GL degradation during food processing in order to test if food processing parameters can be used as phenotypic traits and breed for vegetables with improved GL retention.

    Methods

    One challenge of integrating plant science and food science is the high number of samples to be analysed to apply quantitative genetics to food technological traits. The analysis of GLs, as desulpho-GLs, was optimized to reach accurate results using a high throughput method. Kinetic modelling was applied to describe GL thermal degradation in a quantitative way, therefore an appropriate model was identified. Furthermore, genetic and environmental effects of GL thermal degradation were investigated in a broccoli and a Chinese kale genotype in two seasons. GL thermal degradation was determined in a segregating population, developed by crossing the broccoli and Chinese kale genotype investigated in the previous study. Thermal degradation rate constants were combined with molecular marker information to identify genetic regions associated with GL thermal degradation (quantitative trait loci). Moreover, a subset of the segregating population was tested for environmental variation. An untargeted metabolomics approach was applied to test if metabolites are associated with the thermal degradation rate constants and hence influence thermal degradation.

    Results

    The desulphation procedure applied to determine GLs as desulpho-GLs is crucial for the analytical result. For the first time an inverse effect of the sulphatase concentration on the peak area of a GL, glucotropaeolin, which is often used as internal standard, was shown, leading to a substantial overestimation of GL concentrations. We recommend the application of a purified sulphatase preparation to obtain accurate results for a broad range of samples.
    A first order kinetic model was identified to be appropriate to describe GL thermal degradation in two seasons. The resulting degradation rate constants (kdvalues) of chemically identical GLs did not differ between the broccoli and the Chinese kale genotype when grown in the same season, but were strongly affected by the season (20% to 80% difference). Despite the degradation rate constants of chemical identical GLs did not differ in the parental genotypes of the segregating population, rate constants varied 3-fold throughout the population for most GLs. Quantitative trait loci (QTL) were identified for the degradation of two different GLs (25% and 12% explained variation). A co-localization of the QTL and correlations between the rate constants of different GLs indicate that similar factors in the plant matrix influence GL degradation. In addition to the genotypic effects, the growing year influences GL degradation as well. An untargeted metabolomics approach revealed that 23 out of 413 detected metabolites were associated with GL thermal degradation rate constants. Three of them could be identified asflavonols and two as glucosinolates. QTL for two flavonols co-localize with the QTL for GLs degradation.

    Conclusions

    The research conducted in this thesis demonstrates that GL thermal degradation is partly genetically regulated. Furthermore, environmental factors, such as season and growing year, influence GL thermal degradation. The findings provide the methodology to breed for vegetables with increased GL retention during food processing. More studies are required to test the stability of the identified QTL in different environments and growing years to apply GL retention as breeding trait. Furthermore, one method was shown towards the identification of metabolic factors causing the variation of GL thermal degradation in different vegetables, which also requires future research to confirm these findings. In order to improve specific quality attributes of plant-based foods, breeding for quantitative food processing traits is a promising and challenging approach. It has potential to improve the nutritional quality of food products by combining the disciplines food and plant science to select and breed for varieties with not only higher initial amounts of phytochemicals but also with a high retention during processing.

    Sensorgestuurde onkruidbestrijding op sportvelden
    Evert, F.K. van; Molenaar, H. ; Duym, A. ; Schabbink, E. ; Kempenaar, C. - \ 2012
    Wageningen : S.n. - 15
    sportterreinen - herbiciden - onkruidbestrijding - monitoring - sensors - veldproeven - sports grounds - herbicides - weed control - monitoring - sensors - field tests
    In dit project wordt de techniek voor herkenning van breedbladig onkruid in grasland in biologisch beheerd grasland toegepast op sportvelden. Uit de metingen kwam naar voren dat met de IR camera goed onderscheid gemaakt worden tussen groen materiaal enerzijds en verharding of kale bodem anderzijds.Verder bleek dat met de IR camera de textuur-verschillen tussen gras en onkruid goed te zien zijn, maar dat de resolutie van de gebruikte opstelling onvoldoende was.
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