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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    Primary Food Processing : Cornerstone of plant-based food production and the bio-economy in Europe
    Logatcheva, K. ; Galen, M.A. van - \ 2015
    The Hague : LEI Wageningen UR (Report / LEI 2015-121) - 41
    primaire sector - agro-industriële ketens - landbouwindustrie - agro-industriële sector - voedselverwerking - industriële grondstoffen - biobased economy - primary sector - agro-industrial chains - agribusiness - agroindustrial sector - food processing - feedstocks - biobased economy
    This report describes the supply chains and special characteristics of plant-based primary food processors; producers of (wheat) flour, starches, vegetable oils and fats, sugar, and cocoa. The production value, direct employment in the industry, and indirect employment in farming were calculated. The significance of the plant-based primary food processing industry in terms of production value and share in the total food processing industry in the EU was estimated, and threats and opportunities were identified on the basis of desk research and interviews with PFP member organisations and companies.
    Maillard reaction products in pet foods
    Rooijen, C. van - \ 2015
    Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Guido Bosch; Peter Wierenga. - Wageningen : Wageningen University - ISBN 9789462575523 - 182
    gezelschapsdieren - huisdierenvoer - maillard-reactie - voedselverwerking - voedingswaarde - diergezondheid - lysine - stoom - omhullen - verteerbaarheid - voedselchemie - voedertechnologie - pets - pet foods - maillard reaction - food processing - nutritive value - animal health - lysine - steam - pelleting - digestibility - food chemistry - feed technology

    Pet dogs and cats around the world are commonly fed processed commercial foods throughout their lives. Often heat treatments are used during the processing of these foods to improve nutrient digestibility, shelf life, and food safety. Processing is known to induce the Maillard reaction, in which a reducing sugar binds to a free reactive amino group of an amino acid. In intact proteins, the ε-amino group of lysine is the most abundant free amino group. The reaction reduces the bioavailability of lysine and results in the formation of advanced Maillard reaction products. The aim of this thesis was to determine the occurrence and progression of the Maillard reaction during the manufacturing of pet foods, the subsequent impact on nutritive value of the food, and the bioavailability of Maillard reaction products in cats.

    In Chapter 2, the scientific literature was reviewed to investigate the current state of knowledge on the Maillard reaction and its potential effect on the nutritive value of pet foods and on pet health. Determination of the difference between total and reactive lysine by chemical methods provides an indication of the Maillard reaction in pet foods. Studies reported that the proportion of reactive lysine is on average 73% (range 39 – 100%) of total lysine, and that foods for growing dogs may be at risk of supplying less lysine than the animals require. The endogenous analogues of Maillard reaction products, advanced glycation end-products, have been associated with age-related diseases in humans, such as diabetes and impaired renal function. In dogs, data indicate higher advanced glycation end-product contents in plasma from dogs suffering from canine diabetes mellitus compared with healthy control animals. In addition, elevated levels of advanced glycation end-products in tissue proteins in dogs were observed for a number of diseases. To date it was unknown to what extent Maillard reaction products were present in pet foods, and whether dietary Maillard reaction products can be associated with the development of diseases such as diabetes and impaired renal function in pet animals. As the Maillard reaction is induced by processing, changing processing conditions should have an influence on the severity of the reaction. However, effects of processing conditions on the difference in total and reactive lysine contents in pet foods were inconsistent and did not always correspond to model systems. Processing temperature was reported to be the most important factor followed by moisture level. In addition, differences between total and reactive lysine were observed in several ingredients commonly used in pet foods. Reviewing the literature indicates that it is unknown to which extent the Maillard reaction occurs and whether Maillard reaction products are present in pet foods. There might be a risk for certain foods not meeting minimal lysine requirements. It is also unknown what the exact effect of processing on the Maillard reaction is in pet foods.

    The experiment described in Chapter 3 was designed to evaluate whether commercial pet foods meet minimal lysine requirements. Sixty-seven extruded, canned and pelleted commercially available dog and cat foods formulated for growth and maintenance were analysed using conventional amino acid analysis and O-methylisourea as reagent for reactive lysine. Sixty out of the 67 foods in this study, regardless of the type of processing technology used, contained a lower reactive lysine than total lysine content. On average, pelleted and extruded foods contain lower reactive to total lysine ratios compared to canned foods (0.85, 0.89, and 0.93, respectively). All cat foods and foods for adult dogs met minimal lysine requirements. However, eight dry foods for growing dogs contained reactive lysine contents between 96 and 138% of the minimal lysine requirement, indicating that reactive lysine has to be between 62 and 104% digestible to meet minimal requirement. Considering the variability in reactive lysine digestibility, these foods could be at risk of not meeting minimal lysine requirements for growing dogs.

    In Chapter 4, the foods from Chapter 3 were used to quantitate the Maillard reaction products fructoselysine (FL), carboxymethyllysine (CML), hydroxymethylfurfural (HMF), and the cross-linked amino acid lysinoalanine (LAL) using UPLC-MS. In all foods, Maillard reaction products and LAL were found but in highly variable amounts. Type of processing seems to be a key factor for the concentration of FL, CML and HMF, with on average higher amounts in canned foods than pelleted and extruded foods (on a dry matter basis). The contents of CML and HMF found in commercial pet foods are, on average, within the range reported in processed human food products. Average daily intake (mg/kg body weight0.75) of HMF was 122 times higher for dogs and 38 times higher for cats than the calculated average intake for adult humans. Average daily intake of CML was comparable to the intake of adult humans.

    As Chapters 3 and 4 indicated that pelleted foods contain more Maillard reaction products than extruded foods, despite the less severe production process, an experiment was designed to gain insight in the effect of steam pelleting on the Maillard reaction in a dog food (Chapter 5). The aim was to examine the effect of conditioning temperature (65 and 90°C) and die hole length (ø 5 × 45, 65, and 80 mm) during pelleting processing of a standard dry dog food on selected indicators of the Maillard reaction (total lysine, reactive lysine, FL, CML, HMF, LAL), browning development and CIE-Lab colour. Steam pelleting did not cause a significant loss of reactive lysine and change of absorbance values. This indicates that the effect of steam pelleting on the nutritive value of the foods is low. However, steam pelleting did increase the content of Maillard reaction products. The formation of the Maillard reaction products was associated with an increase in temperature and die hole length during the steam pelleting process. The unprocessed ingredient mix already contained a larger difference between reactive and total lysine, and contents of Maillard reaction products than was induced during steam pelleting. Therefore, the choice of the ingredients used in this study mainly determines reactive lysine content and Maillard reaction products in the pet food formulation.

    As it is unknown to which extent extrusion processing influences the Maillard reaction in pet foods, the effect of extrusion processing on selected indicators of the Maillard reaction was determined (Chapter 6). The extrusion parameters temperature (140 and 165°C), moisture content (200 and 300 g/kg) and screw speed (100 and 200 rpm) were applied to two dry dog foods formulated using either intact or hydrolysed proteins. Extrusion processing in general results in a decrease in total and reactive lysine and an increase in FL, CML, HMF and LAL content. However, this effect appeared more pronounced in the diet containing hydrolysed protein. Decreasing temperature and moisture content led to higher total and reactive lysine contents, and less Maillard reaction products in the dog foods. Increasing screw speed had a positive influence on total and reactive lysine, but a negative influence on Maillard reaction products. As was found in Chapter 5, the unprocessed ingredient mixtures in this experiment contained already more Maillard reaction products than was induced during extrusion processing.

    Whether the Maillard reaction products reported in pet foods are physiologically relevant in pet animals depends on the bioavailability of these components. Therefore, urinary excretion was studied in adult cats fed commercial moist and dry foods containing varying amounts of FL, CML and the amino acid LAL (Chapter 7). A pilot study was first conducted to determine the adaptation time required for stable urinary excretion of the Maillard reaction products when changing diets with contrasting contents of Maillard reaction products. An adaptation time of 1 d was deemed sufficient in adult cats. The short adaptation time indicates an effective urinary excretion of Maillard reaction products. In the main study, six commercially processed dry and six moist diets were fed to 12 adult female cats in two parallel randomized, 36-day, balanced Latin square designs. Urine was collected quantitatively and FL, CML and LAL were analysed in foods and collected urine using HPLC-MS. Daily urinary excretion of FL and CML showed a positive relationship with daily intake in the dry and moist foods. For LAL, no significant relationship was observed. The observed increase in urinary excretion with increasing dietary intake indicates that dietary Maillard reaction products are absorbed from the gastro-intestinal tract of cats and excreted in the urine. Minimum apparent absorption based on urinary excretion (assuming 100% of the excreted component originates from the diet) of FL, CML and LAL was found to range between 8 to 23%, 25 to 73% and 6 to 19%, respectively. Urinary recovery (% ingested) showed a negative relationship with daily intake for FL, CML and LAL in the dry foods and for CML and LAL in the moist foods. The observed decrease in urinary recovery with increasing intake suggests a limiting factor in digestion, absorption, metabolism or urinary excretion.

    The studies reported in this thesis are one of the first to determine Maillard reaction products in pet foods and the bioavailability of FL, CML and LAL in cats. In addition, the results highlight the importance of reactive lysine measurement in foods for growing dogs used as weaning diets. Contribution of the absorption of dietary Maillard reaction products to the pathogenesis of various health conditions requires further study, as well as the potential role of restriction of dietary Maillard reaction products in prevention and treatment of long-term health implications. Extrusion and pelleting processing do increase the Maillard reaction, however, choice of ingredients appears to have a larger effect on the content of Maillard reaction products and can, therefore, be a useful strategy for pet food manufacturers that want to decrease the content of Maillard reaction products in their pet foods.

    LEI-BIA : Hoe worden champignons verwerkt? - Teun Koolen, champignonkwekerij en Alfons Beldman, LEI Wageningen UR
    Beldman, A.C.G. - \ 2014
    Wageningen : Wageningen UR
    eetbare paddestoelen - champignonbedrijven - agaricus - voedselverwerking - agrarische bedrijfsvoering - marketing van voedingsmiddelen - paddestoelen - innovaties - edible fungi - mushroom houses - agaricus - food processing - farm management - food marketing - mushrooms - innovations
    LEI-BIA staat voor LEI-Business Innovation Approach, een initiatief van LEI Wageningen UR. Het LEI is bij uitstek toegerust om ontwikkeltrajecten met ondernemers naar meer markt- en klantgerichtheid te begeleiden.
    Optimization-based decision support systems for planning problems in processing industries
    Claassen, G.D.H. - \ 2014
    Wageningen University. Promotor(en): Jack van der Vorst. - Wageningen : Wageningen University - ISBN 9789462572089 - 171
    operationeel onderzoek - logistiek - voedselverwerking - voedselindustrie - pulp- en papierwarenindustrie - beslissingsondersteunende systemen - optimalisatie - procesoptimalisatie - wiskundige modellen - operations research - logistics - food processing - food industry - pulp and paper industry - decision support systems - optimization - process optimization - mathematical models

    Summary

    Optimization-based decision support systems for planning problems in processing industries

    Nowadays, efficient planning of material flows within and between supply chains is of vital importance and has become one of the most challenging problems for decision support in practice. The tremendous progress in hard- and software of the past decades was an important gateway for developing computerized systems that are able to support decision making on different levels within enterprises. The history of such systems started in 1971 when the concept of Decision Support Systems (DSS) emerged. Over the years, the field of DSS has evolved into a broad variety of directions. The described research in this thesis limits to the category of model-driven or optimization-based DSS.

    Simultaneously with the emergence of DSS, software vendors recognized the high potentials of available data and developed Enterprise Systems to standardize planning problems. Meanwhile, information oriented systems like MRP and its successors are extended by the basic concepts of optimization based decision support. These systems are called Advanced Planning Systems (APS). The main focus of APS is to support decision making at different stages or phases in the material flow, i.e. from procurement, production, distribution to sales (horizontal-axis), on different hierarchical aggregation levels (vertical-axis) ranging from strategic (long-term) to operational (short- term) planning. This framework of building blocks decomposes planning tasks hierarchically into partial planning problems. This basic architecture of the planning processes in APS is known as the Supply Chain Planning Matrix (SCPM).

    Compared to, for instance, discrete parts manufacturing, planning tasks are much more complicated in processing industries due to a natural variation in the composition of raw materials, the impact of processing operations on properties of material flows, sequence dependent change-over times, the inevitable decline in quality of product flows and relatively low margins. These specific characteristics gave rise to focus on optimization-based decision support in the domain of processing industries. The problems to be addressed in this field call for (inter-related) decisions with respect to the required raw materials, the production quantities to be manufactured, the efficient use of available resources, and the times at which raw materials must be available.

    Although different APS modules can interact directly, coordination and integration is often restricted to the exchange of data flows between different modules. Given the need for specific integrated decision support, the research presented in this thesis focusses particularly on medium to short term decision support at production stage in processing industry, including the vertical and horizontal integration and coordination with adjacent building blocks in the SCPM.

    Extensive reviews from literature show that the gap between research and practice of DSS is widening. As the field of DSS was initiated as an application oriented discipline, the strategy of what is referred to as “application-driven theory” was taken as the preferred approach for this thesis. “Application-driven” refers to a bottom-up approach which means that the relevance of the research should both be initiated and obtained from practice. The intended successful use of the proposed approaches should, where possible, be represented by tests of adequacy. Simultaneously, the contribution to “theory” aims to be a recognizable part of the research effort, i.e.

    obtained understanding and insights from problems in practice should provide the basis for new approaches. Based on the preceding considerations we defined the following general research objective:

    General research objective

    To support medium- to short term planning problems by optimization-based models and solution techniques such that:

    i) The applicability and added value of (prototype) systems is recognized and carried by decision makers in practice

    ii) The proposed approaches contribute to knowledge, understanding and insights from a model building and solving point of view.

    In order to link the general objective with the different studies in the thesis, we defined five, recurring research premises, i.e. Professional relevance and applicability (P1), Aggregation (P2), Decomposition and reformulation (P3), Vertical integration at production level (P4), and Horizontal coordination and integration (P5).

    The overarching premise P1 refers to the first part of the research objective. All other premises refer to the second part of the research objective, i.e. model building and/or – solving. Several planning issues are studied to give substance to the research objective and each study is connected to at least two research premises.

    Study 1: Planning and scheduling in food processing industry

    The main question in Chapter 2 was:” How to apply aggregation, decomposition and reformulation in model-based DSS at planning and scheduling level such that the aspect of decision support is recognized and appreciated by decision makers in practice, and which level of aggregation is needed to integrate production planning (i.e. lot-sizing) and scheduling problems in a single model?

    The study consists of two parts. The first part of the study refers to a case study for the bottleneck packaging facilities of a large dairy company. The goal was to develop, implement and test a pilot DSS which was able to deliver solutions recognized and carried by decision makers at lower decision levels. The latter aim implied that a straight-forward aggregation on time, product type, resources or product stage, was not preferred. The key to develop an approach for regular use was to identify and take advantage of specific problem characteristics. Clustering of numerous jobs, while retaining information at order level, could be exploited in a reformulation approach. The inclusion of (combined) generalized- and variable upper bound constraints gave very tight lower bounds and sparse search trees.

    An extensive test phase in daily practice showed that the main benefit of the DSS was the initial quality of the generated plans including the time needed to generate these schedules. Hence, decision makers could i) postpone their planning tasks, ii) conveniently cope with rush orders or planned maintenance and iii) easily generate

    alternatives or revised plans when unforeseen disturbances occur. Moreover, the graphical presentation and overview of the (future) working schedule enabled order acceptance to make use of remaining capacity.

    The study also showed that planning problems in practice cannot be captured exhaustively by a (simplified) model. Decision makers need the opportunity to modify automatically generated plans manually and use human judgement and experience such that the solution is tuned to the actual situation. Hence, the DSS should not be considered as an optimizer but rather as a tool for generating high quality plans to be used for further analysis. Within this context the various options of a user-friendly, graphical, and fully interactive user interface, were of major importance.

    Although the case study clearly demonstrates the validity of earlier case based DSS research for current days APS, the proposed approach is hardly a generic solution for a complete vertical integration between lot-sizing and scheduling. If lot-size decisions are strongly affected by the sequence of jobs, production planning and scheduling should be performed simultaneously.

    As the described case refers to an earlier study and today’s APS do not provide modules for integrated lot-sizing and scheduling, the second part of the study gives an overview of developments in literature regarding lot-sizing and scheduling models and assess their suitability for addressing sequence-dependent setups, non-triangular setups and product decay. The review shows a tendency in which so-called Big Bucket (BB) models are currently proposed for short term time horizons too. However, we argue that segmentation of the planning horizon is a key issue for simultaneous lot-sizing and scheduling. The advantage of BB models may become a major obstacle for i) the effectiveness of simultaneous lot-sizing and scheduling, and ii) addressing specific characteristics in food processing industry.

    Study 2: Vertical integration of lot-sizing and scheduling in food processing industry

    Chapter 3 focused on a complete integration of lot-sizing and scheduling decisions in a single model. The main question was:” How to integrate production planning (i.e. lot- sizing) and scheduling problems in a single model, such that common assumptions regarding the triangular setup conditions are relaxed and issues of product decay and limited shelf lives are taken into account?”

    The literature research in Chapter 2 revealed that the computational advantage of time oriented aggregation in BB models may become a major obstacle in addressing the identified characteristics in FPI. In addition, product decay is primarily associated with the “age” of products and consequently relates to the segmentation of the time- horizon. Therefore, two SB models are developed to demonstrate the impact of non- triangular setups and product decay on the generated solutions. Small scale examples were used to demonstrate how a small change in the balance between inventory - and

    changeover costs may generate significantly different solutions, especially when the triangular setup conditions do not hold.

    The developed models are potentially very large formulations and, as expected, hard to solve. Exploratory research was conducted with a Relax-and-Fix (R&F) heuristic. The heuristic is based on a decomposition of the time horizon. Numerical results of small to medium sized problem instances are promising. However, solving real-size problem instances is not possible yet.

    Study 3: Integrated planning between procurement and production

    The case study in Chapter 4 focussed on the need for horizontal coordination and integration between the phases procurement and production, which is of particular importance in inter-organizational supply chains. The main question was:” How to model and solve an integrated planning problem between procurement and production, both on a mid-term and short-term planning level, in an inter-organizational supply chain? The research question was projected on an illustrative milk collection problem in practice.

    The aim was to develop a pilot DSS that lifted decision support for a “weaker” partner in a food supply chain to a higher level, and to illustrate the importance of horizontal integration between the phases procurement and production in an APS framework.

    Problem analysis revealed that the problem can be classified as an extension of the Periodic Vehicle Routing Problem (PVRP). The problem was decomposed into more tractable sub problems on different hierarchical levels, i.e. the daily (vehicle) routing problem was separated from a medium-term planning problem. On the higher planning level, numerous suppliers were aggregated such that total supply within a cluster met (multiple) vehicle loading capacities. The continuous supply of relatively small amounts from many suppliers had to be balanced with strict delivery conditions at processing level. A model was developed to assign a single (stable) collection rhythm to each cluster such that the total, weighted deviation of desired processing levels on various days in the planning horizon was minimized.

    The applied aggregation on the higher planning level turned out to be very beneficial for the required disaggregation at the lower planning level. Once supplier farms were geographically grouped into clusters and the aggregated supply within a cluster was assigned to a single collection rhythm with fixed collection days, the (initial) daily routing problem was considerably easier to solve for vehicle schedulers.

    The computational complexity of the problem was reduced by exploiting application-based properties algorithmically in a specific branch-and-bound scheme, i.e. a customized approach of Special Ordered Sets type 1 (SOS1) This approach made it possible to solve the generated problems exactly for real-size problem instances.

    The various facilities of a user-friendly and interactive man-machine interface (i.e. an input, planning, simulation and analysing module) turned out to be essential. Decision makers could easily change the data, and the generated plans, in a separate simulation module. However, the impact of any modification was immediately visualised by several (conflicting) indicators in the output screens, both on supply and demand level.

    Study 4: Mixed Integer (0-1) Fractional Programming in Paper Production Industry

    The study in Chapter 5 focussed on the impact of technical settings of production units on material flows. The main question was:” How to support decision-makers in practice if crucial properties of end products simultaneously depend on (endogenous) types of raw materials with different chemical or physical properties and (endogenous) technical settings of processing units?

    The goal of the study was to revise and upgrade an existing, locally used DSS, to a tailored and flexible tool for decision support within the enterprise. The study revealed that the aimed extension towards multi-objective decision support, together with new physical insight for calculating properties of end products due to process operations, had a substantial impact on the optimization module.

    The proposed solution procedure takes advantage of the problem characteristics and gives rise i) to apply and extend a classical reformulation approach for continuous linear fractional programming (FP) problems to a more general class of mixed integer (binary) FP problems and ii) to exploit the special structure between the original non- linear mixed integer model and the continuous, linear reformulation by applying the concept of Special Ordered Sets type 1 (SOS1).

    Although Chapter 5 focusses in particular on the reformulation and solution approach, the DSS consists of four main building blocks, i.e. the user interface, a scenario manager, a simulation- and optimization routine. The optimization module provides a powerful tool to find feasible solutions and the best (unexpected) recipes for any available set of raw materials. Moreover, it provides an innovative way of decision support for purchasing (new) pulps on the market, for assigning available pulps to different paper grades, and for attuning available stock levels of raw materials to (changing) production targets for different paper grades. The results of the optimization routine are mainly used to obtain alternative recipes for different paper grades. Usually, these recipes are stored as base scenarios and adapted to daily practice in the simulation module.

    Main conclusions and future research

    Based on the studies in the Chapters 2 and 3 we conclude that no generically applicable models and/or solution approaches exist for simultaneous planning and scheduling in processing industries. More industry-specific solutions are needed incorporating specificities of different production environments into those models. The key to develop solvable approaches for contemporary practice may be i) to use knowledge and experience from practice and take advantage of specific characteristics in different problem domains during model construction, and/or ii) to identify and exploit special problem structures for solving the related models.

    We conclude that surprisingly little research has been devoted to issues of coordination and integration between “procurement” and “production”. The studies in the chapters 4 and 5 confirm that sourcing of (raw) materials flows needs more attention in processing industries, particularly in push-oriented, inter-organizational networks. The valorisation of raw materials can be improved even more if the composition of raw materials is considered too in future planning problems at production level.

    In the second part of this thesis we focused on extensions for the applicability of Special Ordered Sets type 1 (SOS1), both from an algorithmic (Chapter 4) and modelling (Chapter 5) point of view. We conclude that the concept of SOS1 can extend a classical reformulation approach for continuous fractional programming (FP) problems, to a specific class of mixed integer (0-1) FP problems. Moreover, we conclude that a natural ordering of the variables within the sets is not necessary to make their use worthwhile. A separate (user defined) reference row or weights associated to the variables in the sets might be omitted for an efficient use of SOS1 in commercially available mathematical programming packages. However, this requires further research and extensive computational tests.

    Sustainable production of food
    Padt, A. van der - \ 2014
    Wageningen : Wageningen University, Wageningen UR - ISBN 9789461739698 - 20
    voedselproductie - voedselverwerking - levensmiddelenproceskunde - duurzaamheid (sustainability) - food production - food processing - food process engineering - sustainability
    Valorisatie van Pompoen reststromen : inventarisatie en aanbevelingen voor de keten
    Wijk, C.A.P. van - \ 2014
    Lelystad : PPO AGV (PPO pub. 590) - 28
    pompoenen - vollegrondsgroenten - reststromen - voedselverwerking - rassenproeven - biologische landbouw - biobased economy - pumpkins - field vegetables - residual streams - food processing - variety trials - organic farming - biobased economy
    Een groot deel van de biologische pompoen wordt op enkele plaatsen in Nederland centraal bewaard en gedurende de winter afgezet. Hierbij wordt, (naast rot product) ook bruikbaar product uitgesorteerd omdat deze bijvoorbeeld buiten de gewenste sortering valt, misvormd is, dan wel beperkt aangetast is. Deze reststroom kan wellicht nog verwerkt worden tot sap, soep, babyvoeding of decoratief product. Bij verwerking komen ook zaden vrij, die wellicht tot waarde gemaakt kunnen worden in baksels, brood en notenmengsels of geperst kunnen worden voor de olie. Wat de mogelijkheden van valorisatie van de pompoen reststroom in Nederland is, is onvoldoende bekend. In 2012 en 2013 is daarom een ketenproject uitgevoerd met als doel: Inventarisatie van de valorisatie mogelijkheden van de pompoen reststromen in Nederland.
    Solid state fermentation for foods and beverages
    Chen, J. ; Zhu, Y. ; Nout, M.J.R. ; Sarkar, P.K. - \ 2013
    Boca Raton, FL : CRC (Fermented foods and beverages series ) - ISBN 9781439844960 - 408
    voedingsmiddelen - dranken - fermentatie - vast-substraatfermentatie - voedselverwerking - gefermenteerde voedingsmiddelen - fermentatieproducten - foods - beverages - fermentation - solid-state fermentation - food processing - fermented foods - fermentation products
    The book systematically describes the production of solid-state fermented food and beverage in terms of the history and development of SSF technology and SSF foods, bio-reactor design, fermentation process, various substrate origins and sustainable development. It emphasizes Oriental traditional foods produced by SSF such as sufu, vinegar, soy sauce, Chinese distilled spirit, and rice wine. The author address such engineering issues as mass and heat transfer and energy equation calculation of solid-state fermentation, dynamic modeling of solid-state fermentation, and process control of solid-state fermentation. The book provides a detailed introduction to various solid-state fermented foods and beverages, including product category, characteristics, functionalities, safety issues, and consumer perception. It explores real advantages of SSF processes and how their application at real scale for high-quality production that is more efficient and less costly.
    Food processing and health: a case on the glucosinolate - myrosinase system in dried broccoli
    Oliviero, T. - \ 2013
    Wageningen University. Promotor(en): Tiny van Boekel; Matthijs Dekker; Ruud Verkerk. - Wageningen : Wageningen University - ISBN 9789461738004 - 161
    broccoli - glucosinolaten - gedroogde voedingsmiddelen - voedselverwerking - gezondheid - broccoli - glucosinolates - dried foods - food processing - health
    Processing of marula (Sclerocarya birrea subsp. Caffra) fruits : a case study on health-promoting compounds in marula pulp
    Hiwilepo-van Hal, P. - \ 2013
    Wageningen University. Promotor(en): Tiny van Boekel, co-promotor(en): Matthijs Dekker; Ruud Verkerk; P.G. Bille. - S.l. : s.n. - ISBN 9789461737427 - 177
    sclerocarya birrea - voedselverwerking - voedingswaarde - sclerocarya birrea - food processing - nutritive value

    Marula is a multipurpose tree from Southern Africa, used by local people for its fruit, and cosmetic oil from the seed and for medicinal products from the bark and leaves. Fruits are eaten raw, or used to prepare juices, jams, conserves, dry fruit rolls, or fermented to make alcoholic beverages like beer, wine and Amarula. The fruit is a vital source of vitamin C for rural people most of whom cannot afford other more expensive sources of vitamin C. The specific processing methods and conditions of making marula juice vary among different regions. This thesis investigated the fate of antioxidants, i.e. vitamin C, and their activities due to heat processing and fermentation of the marula pulps and its juices.

    The results showed that marula fruit pulp has a vitamin C content higher than that of most fruits, ranging from 62 mg/100 g fresh weight– to over 400 mg/100 g. Juice production was optimized by an experimental design combined with response surface modelling: adding pectinase (in the range of 0.1 to 0.14%) increased the yield of marula juice by 23%. The optimal extraction temperature for the content of vitamin C and polyphenols as well as for the antioxidant activity ranged between 40 and 60°C. At heating temperatures below 125ºC, ascorbic acid in marula pulp was about 15-fold more stable than in mango and guava pulp. The results further revealed that marula peel contained more volatile compounds (75) including all the identified volatiles (41) of the flesh.

    Marula fruit is a rich source of vitamin C and other antioxidants. The use of unfermented juice should be encouraged since it can contribute to the energy intake of the marula juice drinkers. Marula juice is a rich source of natural antioxidants. In addition, marula processors are advised to incorporate (part of) the skin in products such as juices, jams, jellies and alcoholic beverages during processing to enhance the unique characteristic marula flavor in the products which are currently claimed not to have a strong marula like flavour.

    Managing technological aspects of Lupinus mutabilis from a food sovereignty perspective in Ecuador
    Carvajal Larenas, F.E. - \ 2013
    Wageningen University. Promotor(en): Tiny van Boekel, co-promotor(en): Anita Linnemann; Rob Nout. - S.l. : s.n. - ISBN 9789461736789 - 222
    lupinus mutabilis - bitterheid - voedselverwerking - voedselgewassen - ecuador - toxiciteit - voedselsoevereiniteit - lupinus mutabilis - bitterness - food processing - food crops - ecuador - toxicity - food sovereignty

    The present thesis deals with the technological aspects of the debittering process of lupin in a food sovereignty framework. Of all investigated lupin species,Lupinus mutabilishas the best nutritional composition, which is similar to that of soya bean (Glycine max). Lupins can be used to fortify the protein content of many products. In addition, specific lupin protein concentrates or isolates display functional properties of industrial interest (as emulsifier, gelling and foaming agent). On the other hand, lupins contain bitter alkaloids that have to be removed prior consumption because are toxic (the fatal acute dose of lupin alkaloids was reported as 10 mg kg-1 body weight (bw) for infants and children, and 25 mg kg-1 bw for adults). However, alkaloids also have medical uses for their hypocholesterolemic, anti-arrhythmic and immunosuppressive activity. Bitter lupins have been detoxified by biological, chemical or aqueous processes. However, our research concentrated on the aqueousprocessing because this is the only way to produce debittered lupin for human consumption in an environment-friendly manner.The process investigated involved soaking, cooking, and washing of the raw seeds. This process showed to be inefficient because it took 5.7 ±1.0 days, used water at almost 62 times the weight of the raw dry and bitter lupine, and caused a 22% loss of total solids, principally fat, minerals, and carbohydrates. In addition, the microbiological quality deteriorated during this debittering process. Mathematical modeling based on Fickian diffusion suggested that the diffusion coefficient of alkaloids would be expected to vary between 10-10 and 10-11 m2s-1 because the process is carried out in unsteady conditions. In this scenario, it was clear that a new technology for debittering lupins is needed. For this purpose ahydro-agitator was designed, built and used to test the effect of different washing conditions on alkaloids content, solids in the product, final weight, processing time and water and energy consumption. Results were modeled and optimal processing conditions were inferred from a technological point of view; the optimum solution comprised 18h of soaking, 1h cooking, 3 changes of water/day and 22h of agitation/day. For estimating the washing time a mathematic function was inferred (∂c / ∂t = kc;k= -0.188- 4.973-3*Agitation – 0.0043 * Changes - 1.681-3 Agitation*Changes). Then, the products obtained from different processing conditions were evaluated by consumers on the basis of their willingness to pay in relation to their appreciation scores and product price. Results were modeled. Treatments with more processing increased the product price and diminished liking level. However, the willingness to pay is the combined effect of both variables. For example, people would accept an increase in price of 0.3$/kg if the liking level increases from “like slightly” to “like moderately”. The new developed technology could be used to optimize processes such as hydration and/or removal of undesired materials of legumes and other seeds. The approach used in this study also seems suitable to estimate relationships between processing conditions, liking, price and willingness to pay in other products. The generated information can be helpful in decision making, such as selection of consumers´ preferred process and liking in relation to pricing.

    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.

    Magnetic Resonance in Food Science - Food for Thought
    Duynhoven, J.P.M. van; Belton, P.S. ; Webb, G.A. ; As, H. van - \ 2013
    London : RSC Books - ISBN 9781849736343 - 235
    voedselwetenschappen - voedingsmiddelen - kernspintomografie - diagnostische technieken - voedselverwerking - spectroscopie - afbeelden - voedselkwaliteit - voedselveiligheid - food sciences - foods - magnetic resonance imaging - diagnostic techniques - food processing - spectroscopy - imagery - food quality - food safety
    There are many challenges and problems in food science and magnetic resonance methods may be used to provide answers and deepen both fundamental and practical knowledge. This book presents innovations in magnetic resonance and in particular applications to understanding the functionality of foods, their processing and stability and their impact on health, perception and behaviour. Coverage includes structure and function, emphasizing respectively applications of spectroscopy/relaxometry and imaging/diffusometry; high resolution NMR spectroscopy as applied to quality and safety and foodomics; and dedicated information on perception and behaviour demonstrating the progress that has been made in applications of fMRI in this field.
    Meer flexibiliteit in verpakkingen
    Pekkeriet, E.J. - \ 2013
    Kennis Online 10 (2013)jan/febr. - p. 9 - 9.
    kasgewassen - voedselverwerking - verpakkingen - verpakkingsmaterialen - innovaties - flexibele verpakking - kwaliteitszorg - greenhouse crops - food processing - wrappings - packaging materials - innovations - flexible packaging - quality management
    Telers en verpakkers kunnen binnen een paar jaar veel flexibeler vers en bewerkt voedsel automatisch verpakken, met een nog beter gegarandeerde kwaliteit.
    Rapid prediction of pork quality : correlation of fresh meat measurements to pork water holding capacity and its technological quality
    Kapper, C. - \ 2012
    Wageningen University. Promotor(en): Bert Urlings, co-promotor(en): R.E. Klont; J.M.A.J. Verdonk. - S.l. : s.n. - ISBN 9789461734280 - 135
    varkensvlees - vleeskwaliteit - waterbergend vermogen - voedselverwerking - kwaliteit voor voedselverwerking - pigmeat - meat quality - water holding capacity - food processing - food processing quality

    Water holding capacity (WHC) of pork defines the sensory appreciation and processing yields of meat. Pork varies in WHC and is mainly generated by differences in post mortem muscle metabolism of carcasses. Nowadays, the pork processing industry performs sorting of carcasses and primal cuts on the basis of weight and lean characteristics. Additional sorting by WHC can further optimize processing yields of pork products. The aim of this thesis was to validate rapid prediction of pork WHC. The first objective of this thesis was to investigate the possibilities of a rapid prediction of pork WHC by measuring parameters such as pH, colour L*, drip loss%, water absorption, and by NIRS at laboratory scale and at pig processing plant scale. Results revealed that NIRS prediction equations could be developed to predict drip loss% and colour L* of pork samples. Equations for colour a*, b*, and pHu were not applicable for prediction of WHC. The positive results of NIRS to predict WHC and colour L* at laboratory scale led to further research to study NIRS prediction of pork quality (pH, colour L*, and WHC) under pig processing plant conditions. It was concluded that NIRS prediction equations can be used for screening WHC at pig processing plants. Also, characterization of moisture loss from muscle early post mortem and whether these losses are useful in predicting WHC of fresh pork was investigated. Results revealed moisture losses from muscle tissue early post mortem which suggested that select time periods correspond to culmination of biochemical and physical events facilitating moisture release, which can be used for early drip prediction. Results suggested an approach for capturing moisture release early post mortem which may be used to predict WHC in pork. The second objective was to investigate if predictions of pork WHC could be used to optimize processing of pork. Technological yields could not be predicted (R2< 0.21 and RPD < 1.1) by NIRS. Pre-selection of back bacons by NIRS predicted WHC values, did result in significant different average pHu and colour L* between both groups. It was concluded that NIRS can be used to predict rapid fresh ham quality for sorting and optimization of the cooked ham process. The overall conclusion of this thesis is that NIRS prediction equations for WHC can be developed for pork loin samples measured at pig processing plants and that these prediction equations can be used to optimize processing of pork.

    Keeping local foods on the menu: a study on the small-scale processing of cowpea
    Madodé, Y.E.E. - \ 2012
    Wageningen University. Promotor(en): Tiny van Boekel; D.J. Hounhouigan, co-promotor(en): Anita Linnemann; Rob Nout. - S.l. : s.n. - ISBN 9789461734358 - 176
    vignabonen - voedselverwerking - landrassen - antinutritionele factoren - verteerbaarheid - west-afrika - benin - cowpeas - food processing - landraces - antinutritional factors - digestibility - west africa - benin

    Agriculture plays a significant role in the economy of most African countries. Yet malnutrition and micronutrient deficiencies occur regularly. Concomitantly, many carbohydrate rich staple foods and meat products are dumped on the African market and compet strongly with local products. The present thesis studied the potential of indigenous resources and locally developed practices to supply culturally acceptable and nutritious foods to African resource-poor people, using cowpea as model crop. This research is implemented using an interdisciplinary approach, which comprised plant breeding, food science and technology, human nutrition and social sciences. This thesis reports the findings of the research on food science and technology.

    This study aimed to (i) characterise cowpea landraces in use in Benin with regard to nutritional, anti-nutritional and functional properties; (ii) determine present cowpea processing methods and eating habits with special reference to the content of cowpea dishes in available iron, zinc and calcium; (iii) assess the effect of the use of alkaline cooking aids on amino acids of cooked cowpea, and (iv) assess the impact of processing techniques on the flatulence generated by the intake of cowpea foods.

    The genetic, nutritional and technological characterisation of cowpea landraces in use in Benin showed that a high level of similarity among unpigmented landraces as opposed to pigmented landraces. The cluster of unpigmented landraces significantely differed from the pigmented landraces for their fibre (24 vs. 56 g/kg, d.w.) and phenolics (3 vs. 8 g/kg, d.w.) contents as well as their seed size (200 vs. 139 g/1000 seeds, d.w.) and water absorption capacity (1049 vs. 1184 g/kg, d.w.).

    An inventory of 18 cowpea dishes was obtained, which are produced by the combination of the following main unit operations: cooking, dehulling, deep-fat frying, steaming, roasting and soaking. Fermentation and germination are unusual technological practices in West-Africa. Consumers mainly consume Ata, Atassi and Abobo. These dishes contain little available iron because their [phytate] : [iron] molar ratio is above the required thresholds for a good iron uptake by the human body. The incorporation of cowpea leaves in certain dishes resulted in appropriate available iron and calcium potentials.

    The constraints to cowpea processing were identified as: their long cooking time, the tediousness of the dehulling process and the perishability of beans and dishes. The local answer to the long cooking time is the use of alkaline cooking aids. These alkaline salts and the applied cooking conditions did not induce any significant change in the amino acid composition of pigmented landraces. Moreover, the toxicity potentially associated with this practice was not confirmed as no lysinoalanine could be quantified while using up to 0.5 % (w/v) of alkaline cooking aids.

    Flatulence was indicated as the main constraint to cowpea consumption. Cowpea hulls are usually pointed as the main responsible for flatulence. In this research, galactose-oligosaccharides that are indigestible for humans and cause flatulence formation were not found in cowpea hulls. Fermentation wih Rhizopus or Bacillus bacteria reduced significantly the fermentability of cowpea in vitro and in vivo as compared with traditional processes.

    The present study demonstrates the opportunities to improve the quality of cowpea dishes by the incorporation of the leaves and the possibilities to sustain the consumption of cowpea by focusing on soaking and/or fermentation processes.

    Risk assessment approaches to setting thermal processes in food manufacture
    Bean, D. ; Bourdichon, F. ; Bresnahan, D. ; Davies, A. ; Geeraerd, A. ; Jackson, T. ; Membré, J.M. ; Pourkomailian, B. ; Richardson, P. ; Stringer, M. ; Uyttendaele, M. ; Zwietering, M.H. - \ 2012
    Belgium : ILSI (ILSI Europe Report Series ) - 40
    voedselverwerking - fabricage - risicoschatting - warmtebehandeling - food processing - manufacture - risk assessment - heat treatment
    NovelQ: Novel processing methods for the production and distribution of high-quality and safe foods
    Vries, H.S.M. de; Matser, A.M. - \ 2011
    Wageningen : Wageningen UR - Food & Biobased Research
    voedselverwerking - voedselverpakking - innovaties - plantaardige producten - food processing - food packaging - innovations - plant products
    The EU-funded Integrated Project “NovelQ” was designed to stimulate innovations in novel food processing and packaging. In this project, integrated strategic solutions for technical and basic research hurdles have been formulated for complex, real food products rather than food constituents. Enhancements to the state-of-the-art in novel processes focused on high pressure processing (HPP) for preservation of food, quantitative studies on the effect of pulsed electrical fields (PEF) on food pathogens and cold plasma as a surface disinfecting method. Other innovative topics included coupling of new packaging concepts to novel processing and solving R&D hurdles in implementation of advanced heating technologies. Key scientific emphasis has been placed on plant-based products, both solid and liquids, including carrot, tomato, strawberry, apple and broccoli. These commodities were selected because they integrate (i) food structure issues, (ii) colour and flavour-related aspects, (iii) health-related components, including allergens, and (iv) food safety issues. However, the results have broad applicability to other type of products, to the level of whole meals – including regional recipes that are typical of the rich and diverse European cuisine. To most effectively address these opportunities, further knowledge on consumer perception is crucial and therefore studied in NovelQ.
    Allergenicity in food allergy : influence of food processing and immunomodulation by lactic acid bacteria
    Vissers, Y.M. - \ 2011
    Wageningen University. Promotor(en): Harry Wichers; Huub Savelkoul, co-promotor(en): E.N.C. Mills. - [S.l.] : S.n. - ISBN 9789085859161 - 226
    voedselallergieën - voedselverwerking - immunotherapie - aardnoten - melkzuurbacteriën - food allergies - food processing - immunotherapy - groundnuts - lactic acid bacteria


    Allergic diseases such as allergic rhinitis, allergic asthma, atopic eczema and food allergy have become an increasing health problem world-wide, affecting between 20-30% of the total population. Peanut allergy (prevalence ~1%) is a common and persistent food allergy accounting for severe allergic reactions. Peanuts are often consumed after thermal processing (e.g. boiling, roasting) which can alter the protein structure and change its immunoreactivity and allergenicity. In vitro diagnostic testing, however, is generally performed using the native, unprocessed protein and more knowledge on the effect of processing on allergens is necessary to improve these diagnostic procedures. In addition, rationally designed processing could also lead to reduction of the allergen content in certain products and therefore be an effective food technological approach in allergy management. Another approach in allergy management is the use of immunomodulating foods, such as probiotics. There are indications that probiotics, e.g. specific lactic acid bacteria, could be beneficial for many conditions, including different clinical expressions of allergy.
    Chapter 1 gives an overview of several aspects of allergy with a focus on food allergy. Firstly the basic mechanism and the involved immune cells are discussed, after which the prevalence of food allergy in the context of the EuroPrevall project is described. Different food allergens are discussed with an emphasis on the allergens from peanut and different methods are described to assess the potential allergenicity of proteins under widely used processing conditions, including heating and the Maillard reaction. Lastly, different methods to prevent or treat allergies are discussed with a special emphasis on immunomodulation by lactic acid bacteria. This introduction chapter is concluded with the research aim and thesis outline.

    Section 1: Influence of processing on allergenicity of proteins
    In our first study, described in Chapter 2, Ara h 2/6 was purified from raw peanut and heated in solution (boiling) in the presence or absence of glucose. Ara h 2 and 6 were also purified from roasted peanuts for comparison. Structural changes, the capacity to induce cell proliferation and cytokine production, and IgE-binding and IgE cross-linking capacity were evaluated. Although no effect of processing on T-cell reactivity was observed, heat-induced denaturation reduced the IgE-binding and cross-linking capacity. Interestingly, the soluble fraction of the Ara h 2/6 isolated from roasted peanuts retained the conformation and allergenic activity of the native protein.
    In Chapter 3 similar methods were used to assess the effect of heating and glycation on Ara h 1. Heating in solution, irrespective of their level of glycation, resulted in formation of aggregates having reduced IgE-binding and cross-linking capacity, while T-cell reactivity was retained. The soluble fraction of Ara h 1 isolated from roasted peanuts appeared to be highly denatured, formed more globular and smaller aggregates, and showed no evidence of glycation. However, these smaller aggregates retained IgE-binding capacity, unlike the aggregates formed after heating and glycating purified Ara h 1. These results could account for observed differences between boiled and roasted peanuts and suggest that other modifications than the Maillard reaction affect the allergenicity of Ara h 1.
    As peanuts are often consumed after roasting, the wet-thermal processing procedures, employed in the two previous described studies, were related to the effect of thermal treatment and Maillard reaction under low moisture conditions, which is described in Chapter 4. The extensive heating at low moisture resulted in hydrolysis of both Ara h 1 and Ara h 2/6. However, in contrast to Ara h 2/6, soluble Ara h 1 formed large aggregates. Thermally treated Ara h 2/6 had both a lower IgE-binding and degranulation capacity compared to the native form, and the presence of glucose during heating partly counteracted both the decrease in IgE-binding and degranulation capacity. The IgE-binding capacity of Ara h 1 was also decreased; however, the basophil degranulation capacity increased significantly. This demonstrates the importance of including degranulation assays in addition to IgE-binding assays, when assessing allergenic potency of allergens. In addition, we here propose a role for large aggregates in the increased IgE-cross-linking capacity of individual allergens.
    Chapter 5 describes the effect of glycation on the immunoreactivity and basophil degranulation capacity of Cor a 11, the 7S globulin from hazelnut (and thus a homologue of Ara h 1). Three processing methods (heating at low moisture content at 37, 60 and 145°C) resulted in proteins with increasing degrees of glycation. Glycation at 37°C did not influence the specific IgG or IgE binding, while both were decreased after heating at 60°C and 145°C. However, heating at 145°C in the absence or presence of glucose resulting in the formation of aggregated structures, increased the basophil degranulation capacity of Cor a 11 using sera high in Cor a 11 specific IgE, but not when using sera from peanut allergic patients low in Cor a 11 specific IgE. Therefore, this study besides showing the importance of the use of a combination of tests also indicated the importance of using well-characterized sera as a source of IgE.
    In Chapter 6 we focused on the clinical features of all our clinically well-defined peanut allergic patients of which immune cells and sera were used for the previously described studies. In addition, soy allergic patients were included and an extensive IgE profile was determined for all patients. Gly m 4 (Bet v 1 homologue from soy) sensitization was suggested to be an important indicator of severe soy allergy in the soy allergic patients, while in peanut allergic patients sensitization to allergens from soy and pea extract nor Gly m 5 and 6 was found to have a good diagnostic specificity. This is likely due to the presence of clinically non-relevant cross-reactivity between peanut-specific IgE and homologues soy and pea components.

    Section 2: Immunomodulation by Lactobacillus strains
    In the first in vitro study, described in Chapter 7, initially 51 Lactobacillus strains were screened of which 8 were selected and tested for their immunomodulating effects on peripheral blood mononuclear cells (PBMC) of healthy donors. All tested Lactobacillus strains were capable of inducing the production of IL-1β, IL-10, IFN-γ and TNF-α. Clear strain-specific effects were observed with L. plantarum strains showing significantly higher induction capacity of IFN-γ, IL-12 and TNF-α compared with L. acidophilus strains. We therefore concluded that especially L. plantarum strains are promising candidates in IgE-mediated allergy by their stimulation potential of the T-cell response toward a putative Th1 response.
    As healthy subjects, in contrast to allergic individuals, are assumed to finely regulate the Th1/Th2 balance by inducing sufficient Treg cell activity, immunomodulatory effects of six selected Lactobacillus strains were investigated on PBMC of pollen-allergic patients in Chapter 8. All strains could modulate PBMC to induce innate cytokine production and in addition, all strains had the ability to repress IL-13 production. Again a differential effect on IFN-γ and IL-12 induction was observed. In addition, one strain could extensively suppress proliferation induced by anti-CD3/anti-CD28 stimulation. Specific strains that were able to suppress the Th2 cytokine induction and induce Th1 cytokines might be beneficial for allergic patients.
    Effects found in vitro cannot directly be extrapolated to in vivo and therefore, in Chapter 9, we performed an in vivo screening including five Lactobacillus strains. Blood samples were collected before and after a 4-week intervention with probiotics from all 62 birch-pollen-allergic patients included. Four strains caused a decrease in birch-pollen-specific IgE and for one specific strain this coincided with significant decreases in IL-5 and IL-13 and an increase in IL-10 production by anti-CD3/anti-CD28 stimulated PBMC cultures and might therefore have the potential to alleviate seasonal allergy symptoms.
    The last chapter, Chapter 10, gives an overview of the most important results of this thesis and discusses the research limitations and future research perspectives. We hypothesize the role of protein aggregation in allergenicity and we elaborate on the importance of a proper stepwise approach to realize selection of a proper lactic acid strain for in vivo human testing.
    In conclusion, this thesis showed that processing effects can have profound and specific effects on the structure and the allergenicity of relevant allergens. However, to test putative effects on allergenicity, IgE-binding tests only are not sufficient and mediator release assays are important to include, particularly when testing aggregated proteins. These results might have consequences for the proper diagnosis of food allergy in daily practice. Finally, as effects of lactic acid bacteria are strain specific, a proper pre-selection of candidate strains is important to choose the most promising strains for clinical testing. In our in vivo screening, one strain, L. plantarum CBS125632, was found to be promising because of its desired immunomodulatory activity to test in a follow-up trial to reduce symptoms of birch-pollen allergy.

    Mitigating water pollution in Vietnamese aquaculture production and processing industry : the case of pangasius and shrimp
    Pham Thi Ahn, - \ 2010
    Wageningen University. Promotor(en): Arthur Mol; Carolien Kroeze, co-promotor(en): Simon Bush. - [S.l. : S.n. - ISBN 9789085857723 - 193
    garnalenteelt - visteelt - aquacultuur - waterverontreiniging - voedselverwerking - voedselindustrie - vietnam - aquacultuur en milieu - shrimp culture - fish culture - aquaculture - water pollution - food processing - food industry - vietnam - aquaculture and environment
    Baobab (Adansonia digitata L.) foods from Benin: composition, processing and quality
    Chadare, F.J. - \ 2010
    Wageningen University. Promotor(en): Tiny van Boekel; J.D. Hounhouigan, co-promotor(en): Anita Linnemann; Rob Nout. - [S.l. : S.n. - ISBN 9789085857051 - 182
    adansonia digitata - etnisch voedsel - voedingswaarde - etnografie - voedselverwerking - fermentatie - gefermenteerde voedingsmiddelen - benin - adansonia digitata - ethnic foods - nutritive value - ethnography - food processing - fermentation - fermented foods - benin
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