Evi Bongaers - Academia.edu (original) (raw)

Papers by Evi Bongaers

European Journal of Pharmaceutics and Biopharmaceutics, 2015

In this study calendering is used as a downstream technique to shape monolithic co-extruded fixed... more In this study calendering is used as a downstream technique to shape monolithic co-extruded fixed-dose combination products in a continuous way. Co-extrudates with a metoprolol tartrateloaded sustained-release core and a hydrochlorothiazide-loaded immediate-release coat were produced and immediately shaped into a monolithic drug delivery system via calendering, using chilled rolls with tablet-shaped cavities. In vitro metoprolol tartrate release from the ethylcellulose core of the calendered tablets was prolonged in comparison to the sustained release of a multiparticulate dosage form, prepared manually by cutting co-extrudates into mini-matrices. Analysis of the dosage forms using X-ray micro-computed tomography only detected small differences between the pore structure of the core of the calendered tablet and the mini-matrices. Diffusion path length was shown to be the main mechanism behind the release kinetics. Terahertz pulsed imaging visualized that adhesion between the core and coat of the calendered tablet was not complete and a gradient in coat thickness (varying from 200 to 600 µm) was observed. Modulated differential scanning calorimetry and X-ray diffraction indicated that the solid state properties of both drugs were not affected by the calendering procedure.

De Graef/1 st International, 2013

Micro-Computed Tomography (microCT) is a powerful technique to visualize the microstructure of va... more Micro-Computed Tomography (microCT) is a powerful technique to visualize the microstructure of various materials, both biological as non-biological, in a non-destructive way. By means of x-rays the internal structure is revealed on a micro- or nanometer scale. As an example this paper will focus in the study of pores and pore networks in rocks for oil exploration. The resulting dataset of a micro-CT scan is a set of thin, virtual slices through the object. 3d analysis software can extract unique numerical characteristics, such as internal porosity, size distribution for pores or grains, etc. Visualisation software shows a realistic 3D object on the screen, Micro-CT has an added value and can provide new information in 3D, leading to new insights in materials and processes.

Postharvest Biology and Technology, 2014

El artículo seleccionado no se encuentra disponible por ahora a texto completo por no haber sido ... more El artículo seleccionado no se encuentra disponible por ahora a texto completo por no haber sido facilitado todavía por el investigador a cargo del archivo del mismo.

Postharvest Biology and Technology, 2013

ABSTRACT Unfavourable gas conditions during controlled atmosphere storage may cause browning symp... more ABSTRACT Unfavourable gas conditions during controlled atmosphere storage may cause browning symptoms in ‘Braeburn’ apple fruit (‘Braeburn’ browning disorder or BBD). These symptoms are likely to reflect massive changes in the microstructure of the fruit tissue. In this study, individual cells, the internal air network and the 3-D distribution of pores inside ‘Braeburn’ apple tissue were examined using high resolution X-ray micro computed tomography. Different stages of BBD could be clearly resolved on the virtual cross-sections, granting a unique 3-D insight in tissue flooding and formation of cavities in ‘Braeburn’ tissue during the development of the disorder. Image analysis methods were applied to extract morphometric parameters such as porosity, anisotropy and connectivity to characterise microstructure. The discriminative power of these descriptors was proven by their ability to classify fruit tissue as healthy and disordered with a success rate of 97%. The observed distinct radial patterns of porosity, anisotropy and connectivity may help in explaining why ‘Braeburn’ is susceptible to BBD.

Student theses are made available in the TU/e repository upon obtaining the required degree. The ... more Student theses are made available in the TU/e repository upon obtaining the required degree. The grade received is not published on the document as presented in the repository. The required complexity or quality of research of student theses may vary by program, and the required minimum study period may vary in duration. General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain TU/e technische universiteit eind hoven

Most fruit tissues are microstructured. The structural arrangements of cells and intercellular sp... more Most fruit tissues are microstructured. The structural arrangements of cells and intercellular spaces create specific pathways for transport of gaseous chemical compounds, indispensible for maintaining fundamental metabolic equilibria in the tissue. By determining important traits such as fruit size and texture, microstructure also influences consumer appreciation and marketability. Until recently, the measurement of cell size distribution was essentially based on light or electron microscopy. These methods often require invasive sample preparation and are restricted to 2D imaging of a limited number of cross-sections. We used high-resolution 3D X-ray micro-CT images of apple (‘Jonagold’, ‘Braeburn’, ‘Kanzi’) and pear (‘Conference’) tissue to develop a rapid and minimally invasive method for characterising 3D fruit microstructure at the level of single cells and pores, and determine size and shape distributions.

1 BIOSYST-MeBioS, K.U.Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium, 2 VCBT, Flanders Centr... more 1 BIOSYST-MeBioS, K.U.Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium, 2 VCBT, Flanders Centre of Postharvest Technology, Willem de Croylaan 42, 3001 Leuven, Belgium 3 SkyScan, Kartuizersweg 3B, 2550 Kontich, Belgium 4 SGGW, Warsaw University of Life Sciences, Dep. Food Eng. & Process Management, 02776 Warsaw, Poland 5 VSG, Visualization Sciences Group SAS, Avenue Kennedy 87 BP 50227, Merignac Cedex 33708, France

Additive manufacturing is revolutionizing processin g in many applications including 3D food prin... more Additive manufacturing is revolutionizing processin g in many applications including 3D food printing. A Fused Deposition Modelling printing method was developed to produce cookies. In order to design food of particular text ure, a fine element model was established to predict the mechanical propertie s of structured products. Cookie structures were en gin ered to achieve desirable texture properties in silico and dedicate d print files were created for 3D printing. In orde to validate the model, the properties of the printed cookies were measured and analysed. Compression tests were performed to dete rmin Young’s modulus. X-ray micro-CT imaging was applied to characterize th 3D microstructure of the printed cookies sample s. Micro-CT imaging provided a better understanding about the effects o f the 3D printing process on cookie structure. Fina lly, a better fit of the prediction model was obtained by adjusting the mode l geometry to the scanned printed structure, which indicates th...

Many foods contain structural features (such as air spaces, cells, inclusions) that are manifeste... more Many foods contain structural features (such as air spaces, cells, inclusions) that are manifested over a large range of dimensions, including the nanometer range. To make significant advances in delivering foods with excellent quality, the role of microstructure, and its interactions with composition and external conditions must be understood and controlled. This can only be achieved by first developing accurate techniques that detect changes in the internal structure of foods. X-ray CT is a powerful tool for obtaining highly detailed 3D information on internal food structures. Moreover, because of the penetrating capabilities of X-rays, samples can be investigated in a non-destructive manner, thus not majorly altering internal structures by invasive sample preparation. Another advantage of this technology is that it can be used in a range of relevant resolutions to obtain images in the range of millimeter to micron (X-ray micro-CT) and even nanometer (Xray nano-CT) pixel resolutio...

Foods

Additive manufacturing or 3D printing can be applied in the food sector to create food products w... more Additive manufacturing or 3D printing can be applied in the food sector to create food products with personalized properties such as shape, texture, and composition. In this article, we introduce a computer aided engineering (CAE) methodology to design 3D printed food products with tunable mechanical properties. The focus was on the Young modulus as a proxy of texture. Finite element modelling was used to establish the relationship between the Young modulus of 3D printed cookies with a honeycomb structure and their structure parameters. Wall thickness, cell size, and overall porosity were found to influence the Young modulus of the cookies and were, therefore, identified as tunable design parameters. Next, in experimental tests, it was observed that geometry deformations arose during and after 3D printing, affecting cookie structure and texture. The 3D printed cookie porosity was found to be lower than the designed one, strongly influencing the Young modulus. After identifying the c...

Acta Horticulturae, 2015

ABSTRACT

Sensors and Actuators B: Chemical, 2010

The need for more advanced, accurate and lower cost sensor platforms is constantly growing. Howev... more The need for more advanced, accurate and lower cost sensor platforms is constantly growing. However, for certain applications the already existing sensing systems based on biological recognition elements have sometimes restrictions, which limit their use. As a result, sensors with synthetic recognition elements, such as molecular imprinted polymers (MIPs), can be interesting alternatives. Molecular imprinting leads to the formation of inert polymer particles with nanocavities, which can exhibit similar selectivity and specificity to target molecules as antibodies or enzymes. It is demonstrated that MIPs can be readily incorporated into two different sensor platforms for the detection of histamine in aqueous media. The first platform is based on electrochemical impedance spectroscopy and allows for the accurate detection of histamine in the nanomolar range. The second sensing technique is based on microgravimetry and allows for the detection of histamine in the micromolar range. Using the analogous molecule histidine, it is demonstrated that both sensor platforms are specific for the detection of histamine.

Postharvest Biology and Technology, 2014

Watercore is an internal disorder that appears as water-soaked, glassy regions near the core in a... more Watercore is an internal disorder that appears as water-soaked, glassy regions near the core in apples. Fast and non-destructive solutions for sensing watercore would be readily accepted in the postharvest industry. X-ray CT and MRI were compared as potential imaging technologies for detecting this particular disorder. After matching the 3D datasets of X-ray CT and MRI, the images that were obtained on identical fruit were compared quantitatively. Both MRI and CT were able to detect watercore, however the contrast in MRI images was superior. High-resolution micro-CT images showed the microstructural changes in watercore fruit: the intercellular spaces of the affected apple tissue are filled with water. This explained the higher density that is detected here by the X-rays and the higher water content in the MRI. Mean and variance of the frequency distribution of MRI and X-ray CT intensity appeared to be a parameter that allows the identification of healthy apples from affected fruit. Automatic image processing based on thresholding the images resulted in comparable watercore classification accuracy of up to 89% for X-ray CT and 79% for MRI data, despite the better contrast in the MRI images.

Postharvest Biology and Technology, 2013

ABSTRACT Optical coherence tomography (OCT) has emerged recently as a non-destructive technique t... more ABSTRACT Optical coherence tomography (OCT) has emerged recently as a non-destructive technique to visualize subsurface structures of materials. The objective of this work was to investigate whether OCT is an appropriate method to non-destructively assess the peel structural properties of apple fruit and to compare OCT to confocal microscopy and micro-CT. Peel structural properties of apples from different cultivars (‘Braeburn’, ‘Arlet’, ‘Royal Gala’ and ‘Ida Red’) were measured. The effects of preharvest fertilization treatments and storage duration on calculated structural properties of apple peel from OCT images were investigated. It was found that OCT is a fast, high resolution and high field of view technique that renders 2D and 3D images of apple peel. En-face OCT allows the visualization of the surface topology including cracks in the wax, surface roughness and lenticels. Depth scans with OCT reveal the cellular structure down to a few hundreds of micrometre into the fruit, superior to confocal imaging. Spectral-domain OCT resulted in higher quality images than time-domain OCT. Cuticle, epidermis and hypodermis cells can be resolved in a superior way compared to micro-CT. It was concluded that OCT can be used to visualize peel structural differences between apples, as well as to measure structural changes that occur during storage. OCT is a fast method and allows for combining a high depth resolution with a wide lateral image size.

European Journal of Pharmaceutics and Biopharmaceutics, 2015

In this study calendering is used as a downstream technique to shape monolithic co-extruded fixed... more In this study calendering is used as a downstream technique to shape monolithic co-extruded fixed-dose combination products in a continuous way. Co-extrudates with a metoprolol tartrateloaded sustained-release core and a hydrochlorothiazide-loaded immediate-release coat were produced and immediately shaped into a monolithic drug delivery system via calendering, using chilled rolls with tablet-shaped cavities. In vitro metoprolol tartrate release from the ethylcellulose core of the calendered tablets was prolonged in comparison to the sustained release of a multiparticulate dosage form, prepared manually by cutting co-extrudates into mini-matrices. Analysis of the dosage forms using X-ray micro-computed tomography only detected small differences between the pore structure of the core of the calendered tablet and the mini-matrices. Diffusion path length was shown to be the main mechanism behind the release kinetics. Terahertz pulsed imaging visualized that adhesion between the core and coat of the calendered tablet was not complete and a gradient in coat thickness (varying from 200 to 600 µm) was observed. Modulated differential scanning calorimetry and X-ray diffraction indicated that the solid state properties of both drugs were not affected by the calendering procedure.

De Graef/1 st International, 2013

Micro-Computed Tomography (microCT) is a powerful technique to visualize the microstructure of va... more Micro-Computed Tomography (microCT) is a powerful technique to visualize the microstructure of various materials, both biological as non-biological, in a non-destructive way. By means of x-rays the internal structure is revealed on a micro- or nanometer scale. As an example this paper will focus in the study of pores and pore networks in rocks for oil exploration. The resulting dataset of a micro-CT scan is a set of thin, virtual slices through the object. 3d analysis software can extract unique numerical characteristics, such as internal porosity, size distribution for pores or grains, etc. Visualisation software shows a realistic 3D object on the screen, Micro-CT has an added value and can provide new information in 3D, leading to new insights in materials and processes.

Postharvest Biology and Technology, 2014

El artículo seleccionado no se encuentra disponible por ahora a texto completo por no haber sido ... more El artículo seleccionado no se encuentra disponible por ahora a texto completo por no haber sido facilitado todavía por el investigador a cargo del archivo del mismo.

Postharvest Biology and Technology, 2013

ABSTRACT Unfavourable gas conditions during controlled atmosphere storage may cause browning symp... more ABSTRACT Unfavourable gas conditions during controlled atmosphere storage may cause browning symptoms in ‘Braeburn’ apple fruit (‘Braeburn’ browning disorder or BBD). These symptoms are likely to reflect massive changes in the microstructure of the fruit tissue. In this study, individual cells, the internal air network and the 3-D distribution of pores inside ‘Braeburn’ apple tissue were examined using high resolution X-ray micro computed tomography. Different stages of BBD could be clearly resolved on the virtual cross-sections, granting a unique 3-D insight in tissue flooding and formation of cavities in ‘Braeburn’ tissue during the development of the disorder. Image analysis methods were applied to extract morphometric parameters such as porosity, anisotropy and connectivity to characterise microstructure. The discriminative power of these descriptors was proven by their ability to classify fruit tissue as healthy and disordered with a success rate of 97%. The observed distinct radial patterns of porosity, anisotropy and connectivity may help in explaining why ‘Braeburn’ is susceptible to BBD.

Student theses are made available in the TU/e repository upon obtaining the required degree. The ... more Student theses are made available in the TU/e repository upon obtaining the required degree. The grade received is not published on the document as presented in the repository. The required complexity or quality of research of student theses may vary by program, and the required minimum study period may vary in duration. General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain TU/e technische universiteit eind hoven

Most fruit tissues are microstructured. The structural arrangements of cells and intercellular sp... more Most fruit tissues are microstructured. The structural arrangements of cells and intercellular spaces create specific pathways for transport of gaseous chemical compounds, indispensible for maintaining fundamental metabolic equilibria in the tissue. By determining important traits such as fruit size and texture, microstructure also influences consumer appreciation and marketability. Until recently, the measurement of cell size distribution was essentially based on light or electron microscopy. These methods often require invasive sample preparation and are restricted to 2D imaging of a limited number of cross-sections. We used high-resolution 3D X-ray micro-CT images of apple (‘Jonagold’, ‘Braeburn’, ‘Kanzi’) and pear (‘Conference’) tissue to develop a rapid and minimally invasive method for characterising 3D fruit microstructure at the level of single cells and pores, and determine size and shape distributions.

1 BIOSYST-MeBioS, K.U.Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium, 2 VCBT, Flanders Centr... more 1 BIOSYST-MeBioS, K.U.Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium, 2 VCBT, Flanders Centre of Postharvest Technology, Willem de Croylaan 42, 3001 Leuven, Belgium 3 SkyScan, Kartuizersweg 3B, 2550 Kontich, Belgium 4 SGGW, Warsaw University of Life Sciences, Dep. Food Eng. & Process Management, 02776 Warsaw, Poland 5 VSG, Visualization Sciences Group SAS, Avenue Kennedy 87 BP 50227, Merignac Cedex 33708, France

Additive manufacturing is revolutionizing processin g in many applications including 3D food prin... more Additive manufacturing is revolutionizing processin g in many applications including 3D food printing. A Fused Deposition Modelling printing method was developed to produce cookies. In order to design food of particular text ure, a fine element model was established to predict the mechanical propertie s of structured products. Cookie structures were en gin ered to achieve desirable texture properties in silico and dedicate d print files were created for 3D printing. In orde to validate the model, the properties of the printed cookies were measured and analysed. Compression tests were performed to dete rmin Young’s modulus. X-ray micro-CT imaging was applied to characterize th 3D microstructure of the printed cookies sample s. Micro-CT imaging provided a better understanding about the effects o f the 3D printing process on cookie structure. Fina lly, a better fit of the prediction model was obtained by adjusting the mode l geometry to the scanned printed structure, which indicates th...

Many foods contain structural features (such as air spaces, cells, inclusions) that are manifeste... more Many foods contain structural features (such as air spaces, cells, inclusions) that are manifested over a large range of dimensions, including the nanometer range. To make significant advances in delivering foods with excellent quality, the role of microstructure, and its interactions with composition and external conditions must be understood and controlled. This can only be achieved by first developing accurate techniques that detect changes in the internal structure of foods. X-ray CT is a powerful tool for obtaining highly detailed 3D information on internal food structures. Moreover, because of the penetrating capabilities of X-rays, samples can be investigated in a non-destructive manner, thus not majorly altering internal structures by invasive sample preparation. Another advantage of this technology is that it can be used in a range of relevant resolutions to obtain images in the range of millimeter to micron (X-ray micro-CT) and even nanometer (Xray nano-CT) pixel resolutio...

Foods

Additive manufacturing or 3D printing can be applied in the food sector to create food products w... more Additive manufacturing or 3D printing can be applied in the food sector to create food products with personalized properties such as shape, texture, and composition. In this article, we introduce a computer aided engineering (CAE) methodology to design 3D printed food products with tunable mechanical properties. The focus was on the Young modulus as a proxy of texture. Finite element modelling was used to establish the relationship between the Young modulus of 3D printed cookies with a honeycomb structure and their structure parameters. Wall thickness, cell size, and overall porosity were found to influence the Young modulus of the cookies and were, therefore, identified as tunable design parameters. Next, in experimental tests, it was observed that geometry deformations arose during and after 3D printing, affecting cookie structure and texture. The 3D printed cookie porosity was found to be lower than the designed one, strongly influencing the Young modulus. After identifying the c...

Acta Horticulturae, 2015

ABSTRACT

Sensors and Actuators B: Chemical, 2010

The need for more advanced, accurate and lower cost sensor platforms is constantly growing. Howev... more The need for more advanced, accurate and lower cost sensor platforms is constantly growing. However, for certain applications the already existing sensing systems based on biological recognition elements have sometimes restrictions, which limit their use. As a result, sensors with synthetic recognition elements, such as molecular imprinted polymers (MIPs), can be interesting alternatives. Molecular imprinting leads to the formation of inert polymer particles with nanocavities, which can exhibit similar selectivity and specificity to target molecules as antibodies or enzymes. It is demonstrated that MIPs can be readily incorporated into two different sensor platforms for the detection of histamine in aqueous media. The first platform is based on electrochemical impedance spectroscopy and allows for the accurate detection of histamine in the nanomolar range. The second sensing technique is based on microgravimetry and allows for the detection of histamine in the micromolar range. Using the analogous molecule histidine, it is demonstrated that both sensor platforms are specific for the detection of histamine.

Postharvest Biology and Technology, 2014

Watercore is an internal disorder that appears as water-soaked, glassy regions near the core in a... more Watercore is an internal disorder that appears as water-soaked, glassy regions near the core in apples. Fast and non-destructive solutions for sensing watercore would be readily accepted in the postharvest industry. X-ray CT and MRI were compared as potential imaging technologies for detecting this particular disorder. After matching the 3D datasets of X-ray CT and MRI, the images that were obtained on identical fruit were compared quantitatively. Both MRI and CT were able to detect watercore, however the contrast in MRI images was superior. High-resolution micro-CT images showed the microstructural changes in watercore fruit: the intercellular spaces of the affected apple tissue are filled with water. This explained the higher density that is detected here by the X-rays and the higher water content in the MRI. Mean and variance of the frequency distribution of MRI and X-ray CT intensity appeared to be a parameter that allows the identification of healthy apples from affected fruit. Automatic image processing based on thresholding the images resulted in comparable watercore classification accuracy of up to 89% for X-ray CT and 79% for MRI data, despite the better contrast in the MRI images.

Postharvest Biology and Technology, 2013

ABSTRACT Optical coherence tomography (OCT) has emerged recently as a non-destructive technique t... more ABSTRACT Optical coherence tomography (OCT) has emerged recently as a non-destructive technique to visualize subsurface structures of materials. The objective of this work was to investigate whether OCT is an appropriate method to non-destructively assess the peel structural properties of apple fruit and to compare OCT to confocal microscopy and micro-CT. Peel structural properties of apples from different cultivars (‘Braeburn’, ‘Arlet’, ‘Royal Gala’ and ‘Ida Red’) were measured. The effects of preharvest fertilization treatments and storage duration on calculated structural properties of apple peel from OCT images were investigated. It was found that OCT is a fast, high resolution and high field of view technique that renders 2D and 3D images of apple peel. En-face OCT allows the visualization of the surface topology including cracks in the wax, surface roughness and lenticels. Depth scans with OCT reveal the cellular structure down to a few hundreds of micrometre into the fruit, superior to confocal imaging. Spectral-domain OCT resulted in higher quality images than time-domain OCT. Cuticle, epidermis and hypodermis cells can be resolved in a superior way compared to micro-CT. It was concluded that OCT can be used to visualize peel structural differences between apples, as well as to measure structural changes that occur during storage. OCT is a fast method and allows for combining a high depth resolution with a wide lateral image size.