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MARCELLINUS BERNARDUS JOHANNES MEINDERS - One of the best experts on this subject based on the ideXlab platform.
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effect of morphology on water sorption in Cellular Solid foods part ii sorption in cereal crackers
Journal of Food Engineering, 2012Co-Authors: D C Esveld, M M Witek, Carel W. Windt, John P. M. Van Duynhoven, R G M Van Der Sman, MARCELLINUS BERNARDUS JOHANNES MEINDERSAbstract:Abstract Experimental dynamical moisture profiles of crackers with a fine and coarse morphology are successfully predicted using a pore scale network model. Experimental profiles are obtained using a single point imaging (SPI) NMR technique that enables 3D mapping of the moisture content of relatively immobile water at low water activity. The relative vapor conductivity trough the structure is 33% and 64% for the fine and coarse structured crackers, respectively. It can be argued that this is due to their difference in cell connectivity and not directly related to their difference in average cell diameter (0.33 and 0.75 mm, respectively). It was found that the retarded local sorption dynamics of the Solid matrix has a noticeable influence on the moisture profiles that arise in the first hours. This is crucial for the moisture sorption dynamics of sub centimeter size samples, for which there is a distinct non-equilibrium between the vapor and the sorbed water phase. The local sorption at low water activity is a factor 3 faster for the fine structure cracker compared to the coarse one. This is due to their differences in average lamellae thickness (54 and 93 μm, respectively). However, for the description of the overall moisture sorption dynamics of the few cm thick samples, on a time scale of days, it valid to assume local equilibrium and to use an effective diffusivity model. The relative vapor conductivity together with the porosity and the derivative of the sorption isotherm determines the effective moisture diffusivity for these open structures, which is a factor 3 lower for the fine structured cracker compared to the coarse one. The single sided moisture sorption in the 2.5 thick cracker samples is not even completed after 5 days, mainly because at higher water content (near 20%) there is very little gradient in relative humidity to drive the vapor transport. This is reflected in the predicted effective moisture diffusivities which for the coarse cracker decrease from 16 × 10 −9 m/s 2 (at 1% MC, 16% a w ) to 7.6 × 10 −10 m/s 2 (at 20% MC, 86% a w ).
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effect of morphology on water sorption in Cellular Solid foods part i pore scale network model
Journal of Food Engineering, 2012Co-Authors: D C Esveld, R G M Van Der Sman, G Van Dalen, J P M Van Duynhoven, MARCELLINUS BERNARDUS JOHANNES MEINDERSAbstract:A pore scale network model is developed to predict the dynamics of moisture diffusion into complex Cellular Solid foods like bread, crackers, and cereals. The morphological characteristics of the sample, including the characteristics of each Cellular void and the open pore connections between them are determined from X-ray micro-tomography (XRT) data by means of 3D image analysis techniques. The 3D network allows to simulate the water vapor transport between the air cells through the open pores and the local sorption kinetics in the lamellae that separate them. In this way realistic moisture ingress profiles can be simulated in complex morphologies without need of unknown effective parameters. It is shown that the fine structure related transport characteristics embedded in the cell discretized network can be volume averaged to obtain a steady state relative vapor conductivity and a quasi-steady-state sorption time constant. These essential morphology related parameters can be used for an equivalent continuous two-equation description for a homogeneous product.
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Predictive model to describe water migration in Cellular Solid foods during storage
Journal of the Science of Food and Agriculture, 2011Co-Authors: Juliën A Voogt, Anita Hirte, MARCELLINUS BERNARDUS JOHANNES MEINDERSAbstract:Background: Water migration in Cellular Solid foods during storage causes loss of crispness. To improve crispness retention, physical understanding of this process is needed. Mathematical models are suitable tools to gain this physical knowledge. Results: Water migration in Cellular Solid foods involves migration through both the air cells and the Solid matrix. For systems in which the water migration distance is large compared with the cell wall thickness of the Solid matrix, the overall water flux through the system is dominated by the flux through the air. For these systems, water migration can be approximated well by a Fickian diffusion model. The effective diffusion coefficient can be expressed in terms of the material properties of the Solid matrix (i.e. the density, sorption isotherm and diffusion coefficient of water in the Solid matrix) and the morphological properties of the Cellular structure (i.e. water vapour permeability and volume fraction of the Solid matrix). The water vapour permeability is estimated from finite element method modelling using a simplified model for the Cellular structure. Conclusion: It is shown that experimentally observed dynamical water profiles of bread rolls that differ in crust permeability are predicted well by the Fickian diffusion model. © 2011 Society of Chemical Industry.
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Modeling water sorption dynamics of Cellular Solid food systems using free volume theory
Food Hydrocolloids, 2009Co-Authors: MARCELLINUS BERNARDUS JOHANNES MEINDERS, Ton Van VlietAbstract:Water sorption and dynamical properties of bread crust were studied using gravimetric sorption experiments. Water uptake and loss were measured while relative humidity (RH) was step-wise in- or decreased. Experimental results were compared with Fickian diffusion models and empirical models like the exponential and power-law model. From comparison of experimental sorption curves and the power-law model for short times it followed for all bread crust that the diffusional coefficient n is close to one. It turned out that this is not due to so-called case II diffusion and water transport that is limited by relaxation of the Solid material but due to the fact that RH did not instantaneously but gradually increased to the set value. Sorption curves of isotherm experiments could be best described by the Fickian diffusion model for low RH and by the exponential model for large RH. Transport rates depend on moisture content and show a maximum around RH = 0.7, corresponding to a water mass fraction ω1 = 0.12. Diffusion rates could be well described by free volume theory up to the maximum, but this theory could not explain the strong decrease at higher ω1. Indications for a local glass-rubber transition at room temperature were found near a water mass fraction ω1 ≈ 0.09. This corresponds very well to the start of the crisp–non-crisp transition as measured by a sensory panel, but not to the glass-rubber transition at ω1 ≈ 0.12 as measured by other techniques like Differential Scanning Calorimetry. So it seems that more than one glass-rubber like transitions may be important to describe the properties of heterogeneous Cellular food systems.
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Scaling of sound emission energy and fracture behavior of Cellular Solid foods
Physical Review E, 2008Co-Authors: MARCELLINUS BERNARDUS JOHANNES MEINDERS, Ton Van VlietAbstract:A detailed study was performed of the fracture behavior of toasted rusk rolls, a Cellular Solid food, at different water activities and morphologies. We find that the energies of the emitted sound pulses follow Gutenberg-Richter power laws with characteristic exponents b~1.5. The scaling exponents varied only within a range of 0.2 when the method of fracture, humidity, or morphology was changed. However, differences in b were observed, indicating nonuniversal behavior, that seems to be related to morphology and water activity. Also, power law scaling behavior was observed for the waiting time distributions with an exponent a~1.9.
Marc Baldus - One of the best experts on this subject based on the ideXlab platform.
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studying assembly of the bam complex in native membranes by Cellular Solid state nmr spectroscopy
Journal of Structural Biology, 2017Co-Authors: Cecilia De Agrela Pinto, Deni Mance, Manon Julien, Mark Daniels, Markus Weingarth, Marc BaldusAbstract:Significant progress has been made in obtaining structural insight into the assembly of the β-barrel assembly machinery complex (BAM). These crystallography and electron microscopy studies used detergent as a membrane mimetic and revealed structural variations in the central domain, BamA, as well as in the lipoprotein BamC. We have used Cellular Solid-state NMR spectroscopy to examine the entire BamABCDE complex in native outer membranes and obtained data on the BamCDE subcomplex in outer membranes, in addition to synthetic bilayers. To reduce spectral crowding, we utilized proton-detected experiments and employed amino-acid specific isotope-labelling in (13C, 13C) correlation experiments. Taken together, the results provide insight into the overall fold and assembly of the BAM complex in native membranes, in particular regarding the structural flexibility of BamC in the absence of the core unit BamA.
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Efficient Cellular Solid-state NMR of membrane proteins by targeted protein labeling
Journal of Biomolecular NMR, 2015Co-Authors: Lindsay A. Baker, Mark Daniels, Elwin A. W. Cruijsen, Gert E. Folkers, Marc BaldusAbstract:Solid-state NMR spectroscopy (ssNMR) has made significant progress towards the study of membrane proteins in their native Cellular membranes. However, reduced spectroscopic sensitivity and high background signal levels can complicate these experiments. Here, we describe a method for ssNMR to specifically label a single protein by repressing endogenous protein expression with rifampicin. Our results demonstrate that treatment of E. coli with rifampicin during induction of recombinant membrane protein expression reduces background signals for different expression levels and improves sensitivity in Cellular membrane samples. Further, the method reduces the amount of time and resources needed to produce membrane protein samples, enabling new strategies for studying challenging membrane proteins by ssNMR.
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Cellular Solid-state nuclear magnetic resonance spectroscopy
Proceedings of the National Academy of Sciences, 2012Co-Authors: M. P. Bos, R. Tommassen-van Boxtel, J A Post, Jan Tommassen, Marc Baldus, M RenaultAbstract:Decrypting the structure, function, and molecular interactions of complex molecular machines in their Cellular context and at atomic resolution is of prime importance for understanding fundamental physiological processes. Nuclear magnetic resonance is a well-established imaging method that can visualize Cellular entities at the micrometer scale and can be used to obtain 3D atomic structures under in vitro conditions. Here, we introduce a Solid-state NMR approach that provides atomic level insights into cell-associated molecular components. By combining dedicated protein production and labeling schemes with tailored Solid-state NMR pulse methods, we obtained structural information of a recombinant integral membrane protein and the major endogenous molecular components in a bacterial environment. Our approach permits studying entire Cellular compartments as well as cell-associated proteins at the same time and at atomic resolution.
Ton Van Vliet - One of the best experts on this subject based on the ideXlab platform.
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Modeling water sorption dynamics of Cellular Solid food systems using free volume theory
Food Hydrocolloids, 2009Co-Authors: MARCELLINUS BERNARDUS JOHANNES MEINDERS, Ton Van VlietAbstract:Water sorption and dynamical properties of bread crust were studied using gravimetric sorption experiments. Water uptake and loss were measured while relative humidity (RH) was step-wise in- or decreased. Experimental results were compared with Fickian diffusion models and empirical models like the exponential and power-law model. From comparison of experimental sorption curves and the power-law model for short times it followed for all bread crust that the diffusional coefficient n is close to one. It turned out that this is not due to so-called case II diffusion and water transport that is limited by relaxation of the Solid material but due to the fact that RH did not instantaneously but gradually increased to the set value. Sorption curves of isotherm experiments could be best described by the Fickian diffusion model for low RH and by the exponential model for large RH. Transport rates depend on moisture content and show a maximum around RH = 0.7, corresponding to a water mass fraction ω1 = 0.12. Diffusion rates could be well described by free volume theory up to the maximum, but this theory could not explain the strong decrease at higher ω1. Indications for a local glass-rubber transition at room temperature were found near a water mass fraction ω1 ≈ 0.09. This corresponds very well to the start of the crisp–non-crisp transition as measured by a sensory panel, but not to the glass-rubber transition at ω1 ≈ 0.12 as measured by other techniques like Differential Scanning Calorimetry. So it seems that more than one glass-rubber like transitions may be important to describe the properties of heterogeneous Cellular food systems.
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Scaling of sound emission energy and fracture behavior of Cellular Solid foods
Physical Review E, 2008Co-Authors: MARCELLINUS BERNARDUS JOHANNES MEINDERS, Ton Van VlietAbstract:A detailed study was performed of the fracture behavior of toasted rusk rolls, a Cellular Solid food, at different water activities and morphologies. We find that the energies of the emitted sound pulses follow Gutenberg-Richter power laws with characteristic exponents b~1.5. The scaling exponents varied only within a range of 0.2 when the method of fracture, humidity, or morphology was changed. However, differences in b were observed, indicating nonuniversal behavior, that seems to be related to morphology and water activity. Also, power law scaling behavior was observed for the waiting time distributions with an exponent a~1.9.
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an improved instrumental characterization of mechanical and acoustic properties of crispy Cellular Solid food
Journal of Texture Studies, 2007Co-Authors: Ton Van Vliet, H. Luyten, Eva M Castroprada, Wim Lichtendonk, Rob J HamerAbstract:A detailed study was performed to simultaneously measure the mechanical and acoustic properties of crispy Cellular Solid foods. Different critical aspects are discussed in order to assess optimal test conditions. These are primarily data sampling rate, microphone positioning, frequency spectrum of interest, sound/noise ratio and selection of measuring probe. A data sampling rate of more than 50 kHz was shown to be sufficient to register fracture event and acoustic event, and the frequencies audible by human ear (at least 40 kHz needed). The optimum positioning of the microphone with respect to the test piece should be a compromise between a distance that the microphone registers a good sound over the whole human audible frequency spectrum and a good sound/noise ratio. It is shown that test method selection has to depend on whether the goal is determining material fracture behavior or correlation of data to consumer perception. The best method from a fracture mechanics point of view does not have to be the best choice for a combined fracture and acoustic measurement. © 2007. Blackwell Publishing.
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CRISPY/CRUNCHY CRUSTS OF Cellular Solid FOODS: A LITERATURE REVIEW WITH DISCUSSION
Journal of Texture Studies, 2005Co-Authors: H. Luyten, J.j. Plijter, Ton Van VlietAbstract:Literature on the crispy/crunchy behavior of Cellular Solid foods with a crust is discussed. The emphasis is on products with a dry crispy or crunchy crust as bread and various snacks and especially on mesoscopic and macroscopic aspects. Successively, the sensory sensations involved, the mechanical and fracture behavior of crispy/crunchy products, morphological aspects, and the relation between crispy and crunchy behavior and mobility of the macro-molecules and plasticizer (primarily water) involved, are discussed. Finally, some ideas for an integrated approach of crispy/crunchy behavior of Cellular Solid foods with a dry crust will be discussed.
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crispy crunchy crusts of Cellular Solid foods a literature review with discussion
Journal of Texture Studies, 2005Co-Authors: H. Luyten, Ton Van Vliet, J.j. PlijterAbstract:Literature on the crispy/crunchy behavior of Cellular Solid foods with a crust is discussed. The emphasis is on products with a dry crispy or crunchy crust as bread and various snacks and especially on mesoscopic and macroscopic aspects. Successively, the sensory sensations involved, the mechanical and fracture behavior of crispy/crunchy products, morphological aspects, and the relation between crispy and crunchy behavior and mobility of the macro-molecules and plasticizer (primarily water) involved, are discussed. Finally, some ideas for an integrated approach of crispy/crunchy behavior of Cellular Solid foods with a dry crust will be discussed.
Amos Nussinovitch - One of the best experts on this subject based on the ideXlab platform.
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Dry Bead Formation, Structure, Properties, and Applications
Polymer Macro- and Micro-Gel Beads: Fundamentals and Applications, 2010Co-Authors: Amos NussinovitchAbstract:The drying of hydrocolloid beads results in Cellular moieties, and this chapter therefore deals with Cellular Solids. A few manufacturing methods for hydrocolloid Cellular Solids are described. They include, but are not limited to, drying bicarbonate-containing gels after acid diffusion, and Cellular Solids produced by fermentation and enzymatically. A special section deals with the inclusion of oils in gels and their influence on the properties of the resultant dried Cellular Solid. Several methods, e.g., compression studies, are described for evaluating the mechanical properties of the dried beads. The chapter also details the models used for describing these beads’ stress–strain behavior. The structure and acoustic properties of such Cellular Solids as a result of production method are also addressed. The applications of dried beads have never been thoroughly reviewed. This chapter attempts to redress this by describing their use as carriers for vitamins, as study models, and for separation, and includes special dry beads for water treatment and matrices entrapping hydrocolloid Cellular beads. Hydrocolloid Cellular carriers for agricultural uses are also presented, e.g., the preservation of biocontrol agents in a viable form by dry Cellular bead carriers, and the carriers’ capacity to protect these agents against UV radiation. The chapter ends with a discussion on the textural features of dried hydrocolloid beads.
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Production, properties, and applications of hydrocolloid Cellular Solids
Molecular Nutrition and Food Research, 2005Co-Authors: Amos NussinovitchAbstract:Many common synthetic and edible materials are, in fact, Cellular Solids. When classifying the structure of Cellular Solids, a few variables, such as open vs. closed cells, flexible vs. brittle cell walls, cell-size distribution, cell-wall thickness, cell shape, the uniformity of the structure of the Cellular Solid and the different scales of length are taken into account. Compressive stress-strain relationships of most Cellular Solids can be easily identified according to their characteristic sigmoid shape, reflecting three deformation mechanisms: (i) elastic distortion under small strains, (ii) collapse and/or fracture of the cell walls, and (iii) densification. Various techniques are used to produce hydrocolloid (gum) Cellular Solids. The products of these include (i) sponges, obtained when the drying gel contains the occasionally produced gas bubbles; (ii) sponges produced by the immobilization of microorganisms; (iii) Solid foams produced by drying foamed solutions or gels containing oils, and (iv) hydrocolloid sponges produced by enzymatic reactions. The porosity of the manufactured Cellular Solid is subject to change and depends on its composition and the processing technique. The porosity is controlled by a range of methods and the resulting surface structures can be investigated by microscopy and analyzed using fractal methods. Models used to describe stress-strain behaviors of hydrocolloid Cellular Solids as well as multilayered products and composites are discussed in detail in this manuscript. Hydrocolloid Cellular Solids have numerous purposes, simple and complex, ranging from dried texturized fruits to carriers of vitamins and other essential micronutrients. They can also be used to control the acoustic response of specific dry food products, and have a great potential for future use in countless different fields, from novel foods and packaging to medicine and medical care, daily commodities, farming and agriculture, and the environmental, chemical, and even electronic industries.
P Fito - One of the best experts on this subject based on the ideXlab platform.
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advanced food process engineering to model real foods and processes the safes methodology
Journal of Food Engineering, 2007Co-Authors: N Betoret, M Lemaguer, P FitoAbstract:Food quality and safety are the main concerns of consumers and the principal target of the food industry processes. The concept of "food process engineering for product quality" has been arising in the last years with the aim of designing and controlling processes to produce food products with very specific properties of quality and safety, previously defined on the basis of market opportunities analysis. The final properties of food products are the result of the changes in raw material as a consequence of process conditions. In the case of colloidal or Cellular foods, these changes may be observed as differences in quality factors as food composition, nutritional facts, taste and flavour, aspect, shape and size, colour, texture, etc. These changes in food properties may be explained because physical and chemical phenomena produced in line with the process progression, as structure deformations, chemical or enzymatic reactions, phase transitions, etc. The models currently used in food process engineering simplify too much both the food system description and the mechanisms and rate equations of changes. The food system is supposed to be homogeneous and continuous. In this way, thermodynamic and kinetic equations deduced for ideal gas or liquids, in conditions close to equilibrium are applied to Cellular Solid foods, in conditions far away from the equilibrium. It is necessary to develop advanced concepts and methodologies in food process engineering. The new models for food and processes development must incorporate information about all these aspects (thermodynamic, structural, chemist and biochemist, and even mechanics). Only in this way they would be able to calculate and predict the real changes in the whole quality of food product in line with the process progression. The SAFES methodology (systematic approach to food engineering systems) recognizes the complexity of food system and allows coordinating the information about food structure, composition, quality, thermodynamic, etc. in adequate tools to develop real food and processes models. "In a complete theory there is an element corresponding to each element of reality" [Einstein, A., Podolsky, B., & Rosen, N., (1935). Can quantum-mechanical description of physical reality be considered complete? Physical Review, 47, pp. 777-780].