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Unlabelled: The characteristics of tomato pericarp are closely associated with peelabililty, an important quality attribute of processing tomatoes. Different types of tissue exist in the pericarp of tomato. The outermost region of the pericarp, the red layer, is removed with the skin during peeling. This study investigated the morphological features and tissue properties of red layer and pericarp for 3 processing tomato cultivars using magnetic resonance imaging (MRI). The red layer can be visualized in MR images with T(2) weighting, indicating the red layer has different properties compared to the rest of the pericarp region. Tomatoes were imaged with a set of MRI sequences with signal intensity dependent on different water proton properties. Principal component analysis (PCA) of the statistical features revealed clustering of fruit by cultivar. The spatial distribution of cultivars in the PCA score plot followed their rank of peeling performance. MRI demonstrated potential as a nondestructive method to characterize tomato pericarp and evaluate the peelability of processing tomatoes., Practical Application: Peelability of tomatoes affects the quality of value-added whole peel and diced tomato products. The properties of the pericarp of tomato are directly related to the peelability of tomatoes. MRI provided a fast and nondestructive method to characterize the properties of tomato pericarp. The result of this work gives insight into the correlation between tomato pericarp characteristics and peelability., (© 2012 Institute of Food Technologists®)

Mixing is a unit operation that combines two or more components into a homogeneous mixture. This work involves mixing two viscous liquid streams using an in-line static mixer. The mixer is a split-and-recombine design that employs shear and extensional flow to increase the interfacial contact between the components. A prototype split-and-recombine (SAR) mixer was constructed by aligning a series of thin laser-cut Poly (methyl methacrylate) (PMMA) plates held in place in a PVC pipe. Mixing in this device is illustrated in the photograph in Fig. 1. Red dye was added to a portion of the test fluid and used as the minor component being mixed into the major (undyed) component. At the inlet of the mixer, the injected layer of tracer fluid is split into two layers as it flows through the mixing section. On each subsequent mixing section, the number of horizontal layers is duplicated. Ultimately, the single stream of dye is uniformly dispersed throughout the cross section of the device. Using a non-Newtonian test fluid of 0.2% Carbopol and a doped tracer fluid of similar composition, mixing in the unit is visualized using magnetic resonance imaging (MRI). MRI is a very powerful experimental probe of molecular chemical and physical environment as well as sample structure on the length scales from microns to centimeters. This sensitivity has resulted in broad application of these techniques to characterize physical, chemical and/or biological properties of materials ranging from humans to foods to porous media (1, 2). The equipment and conditions used here are suitable for imaging liquids containing substantial amounts of NMR mobile (1)H such as ordinary water and organic liquids including oils. Traditionally MRI has utilized super conducting magnets which are not suitable for industrial environments and not portable within a laboratory (Fig. 2). Recent advances in magnet technology have permitted the construction of large volume industrially compatible magnets suitable for imaging process flows. Here, MRI provides spatially resolved component concentrations at different axial locations during the mixing process. This work documents real-time mixing of highly viscous fluids via distributive mixing with an application to personal care products.

The main objective of this study was to compare the heating patterns of chicken fingers deep-fried conventionally and using a microwave. Two dimensional internal temperature maps of fried chicken fingers with rectangular geometry were measured post frying using magnetic resonance imaging (MRI). Frying was performed in a microwave oven at 365 W power level for 0.5 and 1.5 min after bringing the oil temperature to 180 +/- 1 degrees C. Samples were also fried in a conventional fryer at 180 degrees C for 2 and 5 min for comparison. Variations in internal temperature distribution increased proportionally to frying time in both microwave and conventional frying. Internal thermal equilibrium is reached in all samples after 13 min of holding time. Internal structural changes, void formation, were also visualized in the images. Void formation did not significantly impact cooling rates.

Magnetic resonance imaging (MRI) was used to monitor internal changes in harvested tomato (Solanum lycopersicum L. cv. Micro-Tom) fruit. Measurements of ethylene evolution, respiration, and ion leakage indicated that the fruit developed chilling injury (CI) after storage at 0. °C. Unlike these measurements, MRI provided spatially resolved data. The apparent diffusion coefficient (ADC), which is an indication of water mobility in tissues, was calculated from MRIs of the different parts of the fruit. Storage for 1 or 2 weeks at 0. °C caused no difference in the ADCs (D-values) in the pericarp, but it did lead to higher values in the inner tissues i.e., the columella and locular region compared to non-chilled fruit (P< 0.05). Changes in inner fruit D-values after 1 and 2 weeks of chilling at 0. °C were similar to changes in respiration, ethylene production and ion leakage which increased (P< 0.05) compared to the non-chilled controls. Most CI studies of tomato fruit used pericarp tissue. Our data indicate that columella tissue changes occur in response to chilling injury in tomato fruit and suggest that more caution is needed when interpreting data from experiments commonly used to study this phenomenon. © 2014 Elsevier B.V.

Mixing is a unit operation that combines two or more components into a homogeneous mixture. This work involves mixing two viscous liquid streams using an in-line static mixer. The mixer is a split-and-recombine design that employs shear and extensional flow to increase the interfacial contact between the components. A prototype split-and-recombine (SAR) mixer was constructed by aligning a series of thin laser-cut Poly (methyl methacrylate) (PMMA) plates held in place in a PVC pipe. Mixing in this device is illustrated in the photograph in Fig. 1. Red dye was added to a portion of the test fluid and used as the minor component being mixed into the major (undyed) component. At the inlet of the mixer, the injected layer of tracer fluid is split into two layers as it flows through the mixing section. On each subsequent mixing section, the number of horizontal layers is duplicated. Ultimately, the single stream of dye is uniformly dispersed throughout the cross section of the device. Using a non-Newtonian test fluid of 0.2% Carbopol and a doped tracer fluid of similar composition, mixing in the unit is visualized using magnetic resonance imaging (MRI). MRI is a very powerful experimental probe of molecular chemical and physical environment as well as sample structure on the length scales from microns to centimeters. This sensitivity has resulted in broad application of these techniques to characterize physical, chemical and/or biological properties of materials ranging from humans to foods to porous media (1, 2). The equipment and conditions used here are suitable for imaging liquids containing substantial amounts of NMR mobile (1)H such as ordinary water and organic liquids including oils. Traditionally MRI has utilized super conducting magnets which are not suitable for industrial environments and not portable within a laboratory (Fig. 2). Recent advances in magnet technology have permitted the construction of large volume industrially compatible magnets suitable for imaging process flows. Here, MRI provides spatially resolved component concentrations at different axial locations during the mixing process. This work documents real-time mixing of highly viscous fluids via distributive mixing with an application to personal care products.

This study was carried out to develop a prediction model for soluble solid content (SSC) of intact chestnut and to detect internal defects using nuclear magnetic resonance (NMR) relaxometry and magnetic resonance imaging (MRI). Inversion recovery and Carr–Purcell–Meiboom–Gill (CPMG) pulse sequences used to determine the longitudinal (T1) and transverse (T2) relaxation times, respectively. Partial least squares regression (PLSR) was adopted to predict SSCs of chestnuts with NMR data and histograms from MR images. The coefficient of determination (R2), root mean square error of prediction (RMSEP), ratio of prediction to deviation (RPD), and the ratio of error range (RER) of the optimized model to predict SSC were 0.77, 1.41 °Brix, 1.86, and 11.31 with a validation set. Furthermore, an image-processing algorithm has been developed to detect internal defects such as decay, mold, and cavity using MR images. The classification applied with the developed image processing algorithm was over 94% accurate to classify. Based on the results obtained, it was determined that the NMR signal could be applied for grading several levels by SSC, and MRI could be used to evaluate the internal qualities of chestnuts. [ABSTRACT FROM AUTHOR]

Featured Application: Magnetic resonance imaging technique can be applied to almost any agricultural produce, and food and dairy products to monitor internal physicochemical changes due to external impact, maturity stage, storage time, and condition, or other factors impacting quality. The maturity of tomato fruit is normally characterized by external color, and it is often difficult to know when fruit have achieved commercial maturity or become over-mature. The internal structure of tomato fruit changes during development and this study investigates the utility of nondestructive measurement of tomato fruit structure as a function of maturity using magnetic resonance imaging (MRI). The objective of this work is to use analysis of internal tomato fruit structural measurements to characterize maturity. Intact cherry tomato fruit were harvested at six different maturity stages. At each stage of maturity, the internal structure of the fruit was measured using a series of two-dimensional (2D) magnetic resonance (MR) images. Qualitative and quantitative image analyses were performed to correlate internal fruit structure with maturity. Internal structural changes observed in the pericarp region of the tomato fruit are highly correlated with fruit maturity. MR image information combined with classical analysis techniques provides a more complete understanding of structure and physicochemical changes in tomato fruit during maturation. This study demonstrates that MRI is a useful analytical tool to characterize internal changes in agricultural produce as the produce matures. This technique can be applied to almost any agricultural produce to monitor internal physical changes due to external impact, maturity stage, variation in climate, storage time, and condition, or other factors impacting quality. [ABSTRACT FROM AUTHOR]

The role of endocellulases and endoxylanase during liquefaction and saccharification of hydrothermally pretreated wheat straw was studied. The use of a flow-loop setup with in-line magnetic resonance imaging enabled frequent measurements of viscosity at 55°C during saccharification at 6% total solids content. Viscosity data were complemented with off-line measurements of fiber lengths and release of soluble sugars. A clear correlation between fiber attrition and a decrease in viscosity was found. Fiber lengths and viscosity dropped quickly within the first hour and then stagnated, while sugar yields increased substantially thereafter, illustrating that liquefaction and saccharification are separate mechanisms. Both endoglucanase and endoxylanase were shown to have a significant effect on viscosity during liquefaction while the addition of endoxylanase also increased sugar yield. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:923-931, 2014 [ABSTRACT FROM AUTHOR]

Enzymatic hydrolysis of cellulose for conversion to chemicals or fuels presents engineering challenges due to the large changes in suspension viscosity and yield stress that occur. A flow reactor with an in-line rheometer was used to investigate the role of changes in fiber structure on rheology. The evolution of the suspension yield stress was compared to amount of soluble sugars released and changes in fiber length and width. A model was constructed that links the yield stress, conversion, and fiber shape. These results provide insights into the relationship between fiber structure and transport properties during the early stages of hydrolysis of cellulosic biomass. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1582-1590, 2014 [ABSTRACT FROM AUTHOR]

Abstract: MRI and NMR relaxometry were used to monitor the water uptake at macroscopic and microscopic levels during cooking of navy beans. MRI images showed that water gradually penetrated into the center of the bean, and full hydration was achieved after 80 min. A biphasic model, which consists of an exponential phase and a linear phase, was applied to the water uptake data of the navy bean during cooking. The exponential stage finished after 80 min. The NMR relaxometry results indicated there are three water proton components in navy beans. The percentage of bound water decreased gradually as a function of cooking time. The population of the intracellular water reached its maximum at 80 min. A dramatic increase in the population of extracellular water was observed at 150 min. These results suggest that water was incorporated primarily with the intracellular content in navy beans during the initial exponential stage of water uptake. Further water uptake during the linear stage contributed to the increase in the water content in extracellular space. Optical microscopy of the navy bean provided more evidence for the changes in the water distribution at the microscopic level. [Copyright &y& Elsevier]

Abstract: In pomegranate, black heart disease develops inside the fruit without affecting the rind. Visual inspection is not effective for identification of black heart in pomegranate fruit because of the lack of external symptoms. It has been shown that the water proton T 2 relaxation time is sensitive to cell compartmentalization. Proton NMR relaxometry was used to investigate the water T 2 relaxation distribution in infected and healthy pomegranate arils, and to obtain information that indicates tissue damage. Multi-exponential inversion of the T 2 data of healthy arils gave three relaxation peaks, which correspond to different water compartments in tissue. In infected arils, the three relaxation components shifted to lower relaxation time and a new fast relaxation component appeared indicating there was water redistribution among cell compartments caused by the infection. The change in cell membrane integrity in arils was also investigated with the aid of paramagnetic ions. T 2-weighted fast spin echo images were acquired for healthy and pomegranates with black heart. Histogram features of images, including mean, median, mode, standard deviation, skewness, and kurtosis, were examined using partial least square discriminant analysis (PLS-DA). The PLS-DA model based on histogram features of MR image showed 92% accuracy in detecting the presence of black heart in pomegranate fruit. The significant change in T 2 relaxation distribution in arils after infection proved that T 2 relaxation time is a good indicator of black heart in pomegranate. The T 2 based MR imaging showed its potential as a nondestructive technique for black heart detection in pomegranate. [Copyright &y& Elsevier]

Abstract: Tomato maturity is one of the most important factors associated with the quality of processed tomato products. Magnetic resonance imaging (MRI) is capable of probing the local environment and density of water protons, and encoding the differences in water properties in the form of contrast in image signal intensity. This study investigated changes in tomatoes at different maturity using MRI and the potential for using MRI for tomato maturity classification. A set of 5 MR images was collected on processing tomatoes at various maturity stages. The 5 MRI sequences were selected so that information on water proton properties, including proton density, T 1, T 2, and diffusion rate, are encoded in the MR image signal intensity. A relative water diffusion rate map was also calculated. Changes in structural features and volume element (voxel) intensity in the images were observed as tomatoes develop from green to red stage. In image analysis, voxels in the region of interest (ROI) corresponding to the pericarp of the tomato were used to calculate statistical features of the voxel intensity for image characterization. Partial least square discriminant analysis (PLS-DA) was applied to a total of 48 image features calculated from 5 MR images of 144 processing tomatoes to predict the tomato maturity. The model with 4 latent variables captures 70% of the variation in tomato maturity. The classification accuracies of the PLS-DA model were around 90% for green, breaker-light red, and red maturity stages. The Variable Importance in Projection coefficient of the 48 image features in the model indicated that the diffusion weighted image and spin echo image with higher T 2 weighting were most important for tomato maturity classification. [Copyright &y& Elsevier]

The work includes development of a multiphase porous media model and magnetic resonance imaging (MRI) experiments to study microwave combination heating. Combination of electromagnetic, convective and radiant heating was considered. The material being heated was modeled as a hygroscopic porous medium with different phases: solid matrix, water and gas, and included pressure driven flow, binary diffusion and phase change. The three-dimensional transport model was fully coupled with electromagnetics to include the effect of variable properties. MRI was used to obtain spatial temperature and moisture distributions to validate the model. The model demonstrated that high and low moisture materials behave differently under different combinations of heating and general guidelines for combining heating modes were obtained. Low moisture materials can be heated effectively using higher microwave power which is not possible in high moisture material. Cycling of microwave was found to be useful in distribution of excessive volumetric heat generated by microwaves. © 2011 American Institute of Chemical Engineers AIChE J, 2012 [ABSTRACT FROM AUTHOR]

Oil migration from a high oil content filling into adjacent chocolate causes changes in product quality. The objective of this study was to quantify the oil migration from a cream filling system into cocoa butter, which provided a model for the behavior of chocolate-enrobed confectionery products with a soft, creamy center. Magnetic resonance imaging (MRI) was used to monitor spatial and temporal changes of liquid lipid content. A multislice spin echo pulse sequence was used to acquire images with a 7.8 ms echo time and a 200 ms repetition time using a 1.03 T Aspect Imaging MRI spectrometer. Samples were prepared as a 2-layer model system of cocoa butter and model cream filling. Three methods were used to prepare the cocoa butter: static, seeded, and sheared. Samples were stored at 25 °C for a time frame of 56 d. The rate of oil migration was quantified by a kinetic expression based on the linear dependence of oil uptake by cocoa butter and the square root of the time. Samples showed distinctly different rates of oil migration, as evidenced by quantitative differences in the kinetic rate constant. Practical Application: This work will be helpful to elucidate the influence of crystallization process and structural properties such as crystal nanostructure and crystal habit on the migration of oil through a crystalline fat matrix. [ABSTRACT FROM AUTHOR]

Divalent salts are used commonly for gelation of polymer molecules. Calcium, Ca+2, is one of the most common divalent ions that is used in whey protein gels. Manganese, Mn+2, is also divalent, but paramagnetic, enhancing relaxation decay rates in magnetic resonance imaging (MRI) and can be used as a probe to understand the behavior of Ca+2 in whey protein gels. The objective of this study was to investigate the diffusion of Ca+2 and Mn+2 ions in heat-set whey protein gels by using MRI and nuclear magnetic resonance (NMR) relaxometry. Whey protein gels were immersed in solutions containing MnCl2 and CaCl2 at neutral pH. Images obtained with gels immersed in MnCl2 solution revealed a relaxation sink region in the gel's surface and the thickness of the region increased with time. These 'no signal' regions in the MR images were attributed to uptake of Mn+2 by the gel. Results obtained with CaCl2 solution indicated that since Ca+2 did not have the paramagnetic effect, the regions where Ca+2 diffused into the gel exhibited a slight decrease in signal intensity. The relaxation spectrums exhibited 3 populations of protons, for gels immersed in MnCl2 solution, and 2 populations for gels in CaCl2 solution. No significant change in T2 distributions was observed for the gels immersed in CaCl2 solution. The results demonstrated that MRI and NMR relaxometry can be used to understand the diffusion of ions into the whey protein gel, which is useful for designing gels of different physical properties for controlled release applications. Practical Application: Design of food systems for delivery of bioactive compounds requires knowledge of diffusion rates and structure. Utilizing magnetic resonance imaging the diffusion rates of ions can be measured. Relaxation spectra could yield information concerning molecular interactions. [ABSTRACT FROM AUTHOR]

ABSTRACT Peeling outcomes of processing tomatoes were predicted using multivariate analysis of magnetic resonance (MR) images. Tomatoes were obtained from a whole-peel production line. Each fruit was imaged using a 7-tesla MR system, and a multivariate data set was created from 28 different images. After imaging, the fruits were individually tagged and processed in a pilot peeling system. An expert grader then assessed the peeling outcome for each fruit; outcomes included 'whole peel,''some skin attached' and seven others. The multivariate analysis techniques of partial least squares-discriminant analysis (PLS-DA) and soft independent modeling of class analogy (SIMCA) were used to predict peeling outcome from the 28 MR images. The PLS-DA model for the 'whole peel' (best) outcome correctly classified 81% of the fruit that were in this category. The SIMCA model performed well for rejecting non-'whole peel' fruit but did not perform as well for identification of 'whole peel' fruit. PRACTICAL APPLICATIONS Fruit processors seek methods for predicting the quality of their finished products from measurements of their raw materials (individual fruit). Such predictions will ensure optimal allocation and processing of each fruit, which will result in raw material cost savings, improved product quality, wastewater reduction and energy efficiency. In the case of processing tomatoes, peeling outcome is the metric of interest. This study demonstrates the feasibility of predicting final product quality using MR imaging of raw food materials. [ABSTRACT FROM AUTHOR]

Xanthan-curdlan hydrogel complex (XCHC) has been shown capable of retaining moisture up to 5 freeze-thaw cycles (FTCs); however, moisture distribution in the complex in relation to the hydrogel composition and structure remains uncharacterized. In the present study, magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR) relaxometry, rheology, and scanning electron microscopy (SEM) were used to examine the effect of water distribution and interaction with 2.0% aqueous solutions of xanthan, curdlan, and XCHC consisting of equal amounts of both polysaccharides. A gel structure with an indication of syneresis was clearly seen in the MR image of curdlan alone, whereas the distribution of protons throughout xanthan and XCHC samples remained homogeneous and showed no detectable syneresis. The three-dimensional network, indicated by frequency sweeps, of curdlan was responsible for curdlan's gel structure. The frequency sweep and slope of the storage modulus (G′) of XCHC was significantly closer to curdlan with higher elasticity and less dependency upon angular frequency than xanthan alone. The reduction in XCHC dynamic moduli (G′ and G″) compared to curdlan could be attributed to the formation of wavy layers instead of a fully cured three-dimensional structure. Addition of xanthan to curdlan restricted XCHC spin-spin relaxation time ( T2) to intermediate and slower exchange regimes, namely approximately 110 and 342 ms, respectively, promoting the polymer's interaction with water while inhibiting interpolymer interactions found in curdlan. A 3rd proton pool with the slowest T2 seen in curdlan was not found in XCHC, correlating to the absence of syneresis. Practical Application: The combination of texture measurements and discrete noninvasive techniques was found capable of providing insightful understanding of water distribution in a gel system. These techniques may be applied to other hydrogel complexes. The XCHC system investigated has the potential to enhance freeze-thaw stability in frozen food products by minimizing syneresis due to undesirable temperature fluctuations during distribution and consumer application. [ABSTRACT FROM AUTHOR]

Oil migration from high oil content almond confections into adjacent chocolate causes changes in product quality. The objective of this study was to quantify the oil migration from almond products to dark chocolate. Magnetic resonance imaging (MRI) was used to monitor spatial and temporal changes of liquid lipid content. A multislice spin echo pulse (MSSE) sequence was used to acquire images with a 7.8-ms echo time and a 1000-ms repetition time using a 1.03T Aspect AI MRI spectrometer. Samples were prepared as a 2-layer model system of chocolate and almond confection. Six different almond products and 1 type of dark chocolate were used. Samples were stored at 20, 25, and 30°C for a time frame of several months. Rate and extent of migration were quantified by a kinetic expression based on the linear dependence of oil uptake by chocolate and the square root of the time. Samples showed distinctly different rate and extent of oil migration, as evidenced by quantitative differences in the kinetic rate constants and equilibrium uptake for the different sample types. This work will be helpful to design formulations for almond and almond-based products in confections. Practical Application: This work will be helpful to design formulations for almond use in confections. [ABSTRACT FROM AUTHOR]

Effective means for controlled delivery of nutrients and nutraceuticals are needed. Whey protein-based gels, as a model system and as a potential delivery system, exhibit pH-dependent swelling when placed in aqueous solutions. Understanding the physics that govern gel swelling is thus important when designing gel-based delivery platforms. The extent of swelling over time was monitored gravimetrically. In addition to gravimetric measurements, magnetic resonance imaging (MRI) a real-time noninvasive imaging technique that quantified changes in geometry and water content of these gels was utilized. Heat-set whey protein gels were prepared at pH 7 and swelling was monitored in aqueous solutions with pH values of 2.5, 7, and 10. Changes in dimension over time, as characterized by the number of voxels in an image, were correlated to gravimetric measurements. Excellent correlations between mass uptake and volume change ( R2= 0.99) were obtained for the gels in aqueous solutions at pH 7 and 10, but not for gels in the aqueous solution at pH 2.5. To provide insight into the mechanisms for water uptake, nuclear magnetic resonance (NMR) relaxation times were measured in independent experiments. The relaxation spectrum for the spin-spin relaxation time ( T2) showed the presence of 3 proton pools for pH 7 and 10 trials and 4 proton pools for pH 2.5 trials. Results demonstrate that MRI and NMR relaxation measurements provided information about swelling in whey protein gels that can constitute a new means for investigating and developing effective delivery systems for foods. [ABSTRACT FROM AUTHOR]

The article presents the physics-based computational modeling and magnetic resonance imaging (MRI) that are used to study heat transfer during microwave combination heating. The factors that affect the effectiveness of combination heating as a food preparation method are considered, including the type of heating modes, the placement of sample and microwave cycling. MRI was used to identify the three-dimensional (3D) spatial and temporal variation in temperatures during the combination heating process.

Mathematical models, combined with experimental evaluation, provide an approach to understand, design, and optimize food process operations. Magnetic resonance imaging (MRI), as an experimental technique, is used extensively in both medical and engineering applications to measure and quantify transport processes. Magnetic resonance (MR) was used in this study to assess a mathematical model based on Fourier's second law. The objective was to compare analytical solutions for the prediction of internal temperature distributions in foods during oven-based convective heating to experimental temperature measurements and determine at what point during the heating process a coupled heat and mass transport process should be considered. Cylindrical samples of a model food gel, Russet potato and rehydrated mashed potato were heated in a convection oven for specified times. Experimentally measured internal temperatures were compared to the internal temperatures predicted by the analytical model. Temperatures distributions in the axial direction compared favorably for the gel and acceptably for the Russet and mashed potato samples. The MR-acquired temperatures in the radial direction for the gel resulted in a shallower gradient than predicted but followed the expected trend. For the potato samples, the MR-acquired temperatures in the radial direction were not qualitatively similar to the analytical predictions due to moisture loss during heating. If temperature resolution is required in the radial direction, moisture losses merit the use of transport models that couple heat and mass transfer. [ABSTRACT FROM AUTHOR]

Fast detection of seeds and freeze damage in mandarine citrus fruit was performed using magnetic resonance imaging. A 1 T industrial grade permanent magnet was used to acquire the image data. The spatial resolution of the image was 550 μm. A fast spin echo pulse sequence was used to detect freeze damage and seeds. The signal intensity of seeds and freeze damaged regions was weaker than normal tissue. Threshold based image analysis has proven successful in detecting seeds and quantifying freeze damage. [ABSTRACT FROM AUTHOR]

The effects of periodic velocity fluctuations on magnetic resonance flow images are investigated experimentally and theoretically. In the experiments, laminar pipe flow of water was examined. The flow was driven by a constant pressure head with a superimposed sinusoidal component with the frequency ωz varied from 0 to 1 Hz, whereas in the simulations ωz was between 0 to 65 Hz. The velocity profiles obtained from the experimental results compare well with the theoretical calculations. Both theory and experiment show that flow fluctuations produce artifacts in the form of "ghosts" of the primary image, which are spaced at equal intervals in the phase encoding (flow) direction. The distance between ghosts depends on the fluctuation frequency and on the experimentally specified parameters (phase encoding gradient step, repetition time, phase encoding duration, and time difference between phase encoding gradient lobes). The amplitudes of the ghosts depend on amplitude of the flow fluctuation and diminish at frequencies higher than 30 Hz. [ABSTRACT FROM AUTHOR]

Reports on findings of batch sedimentation experiments conducted with suspensions of noncolloidal spherical particles using the nuclear magnetic resonance imaging. Measurement of the time evolution of the volume fraction versus height profile for initial suspension volume fractions; Hindered settling function; Measured values of the self-induced hydrodynamic diffusivity.

Inline mixing is an important unit operation in industrial processes. SMX mixers, which split, rotate and recombine flow, are considered the best static mixer for laminar mixing for a wide range of fluid viscosities. The objective of this work was to characterize mixing within a 9-element SMX mixer for miscible liquids using magnetic resonance imaging (MRI). Both Newtonian and non-Newtonian fluids were evaluated through the acquisition of consecutive MR images that provided spatially localised data of the mixing of 2 equal volume fluids. These images were viewed qualitatively and quantitatively. Mixing indices as a function of axial positions indicated that mixing is more rapid for Newtonian fluids than the non-Newtonian fluid for 50–50 by volume mixing. Characterisation of mixing behaviour within the SMX mixer allows improved prediction of performance based on fluid properties, flow ratio and injection location. [ABSTRACT FROM AUTHOR]

Static mixers are implemented across many industries and are used for mixing, heating and reacting processes. This paper reports the combined use of positron emission particle tracking (PEPT) and magnetic resonance imaging (MRI) to assess mixing in the industrially important SMX static mixer geometry. The focus of this study was distributive mixing for a Newtonian fluid, glycerol, flowing in the laminar regime in the standard SMX static mixer. By implementing PEPT and MRI techniques, the work elucidated mixing indices that incorporate both local velocities and concentration fields within the structure of the mixer element at 0.5 mm intervals over a length of nine 1.0 L / D SMX elements. The experimental results are placed in context with previously published computational studies for this geometry. [ABSTRACT FROM AUTHOR]

Reports on clinical findings which suggest that the brain may be able to reorganize its neural networks to compensate for damage caused by multiple sclerosis. Details of a study done at the University College in London, England; Use of functional magnetic resonance imaging (fMRI); How the optic nerves in several people with multiple sclerosis appeared to be repaired neurologically following optic neuritis.

Reports on the advent of magnetic response (MR) neurography. Use of MR technology to see nerves; The previous difficulty of seeing nerves; Hyperintensitivity; Prediction that MR neurograms will become standard practice in peripheral neurosurgery.

Magnetic resonance imaging (MRI) was used to monitor internal changes in harvested tomato (Solanum lycopersicum L. cv. Micro-Tom) fruit. Measurements of ethylene evolution, respiration, and ion leakage indicated that the fruit developed chilling injury (CI) after storage at 0 °C. Unlike these measurements, MRI provided spatially resolved data. The apparent diffusion coefficient (ADC), which is an indication of water mobility in tissues, was calculated from MRIs of the different parts of the fruit. Storage for 1 or 2 weeks at 0 °C caused no difference in the ADCs (D-values) in the pericarp, but it did lead to higher values in the inner tissues i.e., the columella and locular region compared to non-chilled fruit (P < 0.05). Changes in inner fruit D-values after 1 and 2 weeks of chilling at 0 °C were similar to changes in respiration, ethylene production and ion leakage which increased (P < 0.05) compared to the non-chilled controls. Most CI studies of tomato fruit used pericarp tissue. Our data indicate that columella tissue changes occur in response to chilling injury in tomato fruit and suggest that more caution is needed when interpreting data from experiments commonly used to study this phenomenon. [ABSTRACT FROM AUTHOR]

Abstract: Exploring the effects of cations in whey protein-based gels (WPG) is of importance when these gels are used for controlled release applications in food systems. The objective of this study was to evaluate both water uptake and cation release from heat-set WPGs. Magnetic Resonance Imaging and NMR relaxometry were employed to study the uptake and release. A non-paramagnetic (Ca+2) and a paramagnetic cation (Mn+2) were incorporated into the WPG as model divalent cations. Cylindrical pieces of WPGs with manganese were immersed in water (pH 2.40, 7.00, 10.40) or in EDTA solution whereas WPGs with calcium were immersed in water at pH 2.40. Water uptake by the gels was influenced by both ionic environment and pH. The release of Mn+2 from WPG was enhanced by the presence of EDTA. Relaxation spectra of Mn+2-loaded gels were significantly influenced by pH of the suspending fluid and by the presence of EDTA. Results of relaxometry experiments, obtained with Ca+2-loaded gels immersed in water at pH 2.40, indicated a strong correlation (R 2 > 0.99) between relative areas of the proton pools and the amount of calcium released to the medium. Results support the use of MRI and NMR to monitor cation release and water uptake in WPG, non-destructively. [Copyright &y& Elsevier]

Sanitation is a critical step to reduce microbial load in many process industries. To assess and monitor the efficacy of sanitation processes, there is a need to rapidly measure microbial resistance to sanitizers and determine the critical concentration of sanitizers above which significant reduction in microbial load can be achieved in a complex environment. In this study, a rapid and label-free magnetic resonance (MR) imaging and relaxometry method was developed to measure resistance of Escherichia coli and Listeria monocytogenes to hydrogen peroxide based on the activity of intracellular catalase enzymes. Intracellular catalase activity is a measure of resistance of bacteria to hydrogen peroxide as these enzymes can degrade hydrogen peroxide to oxygen and water. Using sub-lethal and lethal concentration of hydrogen peroxide, the resistance of both the exponential and stationary growth phase E. coli suspended in PBS and in high organic content solution was characterized. The results show that in stationary growth phase E. coli , molecular oxygen, generated by the interaction of endogenous catalases with 1% H 2 O 2, results in an 8 fold increase in MR imaging signal intensity and a 22 fold decrease in spin-lattice relaxation time (T 1 ) compared to the controls. Furthermore, the resistance of E. coli and L. monocytogenes to H 2 O 2 , measured using the MR method, was correlated with the bacterial reduction, quantified with traditional plate counting method. The comparison between the two methods shows the MR method developed in this study can determine the critical concentration of H 2 O 2 above which a significant reduction in bacterial culturability (at least 4 logs) was achieved. Overall, this study demonstrates the potential of MR imaging and relaxometry method to predict the efficacy of H 2 O 2 in high organic load environment. [ABSTRACT FROM AUTHOR]

Abstract: Characterizing water and fat distributions in fried foods is of major importance in terms of taste and nutrition. The objective of this study was to introduce a new technique to quantify water and fat distributions of chicken nuggets coated with methylcellulose (MC) through the use of magnetic resonance imaging (MRI) and NMR relaxometry. Multi-slice-multi-echo (MSME-Spin Echo based) images were performed on a 1.03 T spectrometer for the whole chicken nuggets to obtain relaxation time distribution of different regions (core and crust) of the nugget. MSME images provided the relaxation spectra of the core and crust separately and showed that relaxation times and relative areas of the proton pools in crust and core regions are correlated (mostly, R 2 > 0.85) with moisture and fat content. Results demonstrated that MSME images in combination with T 2 relaxometry are appropriate tools to quantify spatial water and fat distribution in various food products. [Copyright &y& Elsevier]

Abstract: Mixing at low Reynolds numbers can be achieved by stretching and folding motions in static mixers. Simple shear flow can achieve a stretching motion that grows approximately linearly with time. Extensional flows, in contrast, are potentially more effective due to exponential stretching of fluid elements in time. The split and recombine (SAR) static mixer employs primarily extensional flow through expansions and contractions that results in the number of lamination layers duplicating through each mixing unit. A SAR mixer was constructed by aligning a series of thin plates to achieve six mixing sections. Shear thinning carbopol solutions, one with and one without a paramagnetic tracer, were pumped through the mixer. Using a magnetic resonance imaging technique, the mixing of the minor component in the major component was evaluated qualitatively and quantitatively. The multi-lamination pattern was established; molecular diffusion of the paramagnetic tracer was observed and compared with an analytical model. [Copyright &y& Elsevier]

Abstract: The objective of this study was to investigate the influence of boiling, roasting and frying on the digestion of peanuts in simulated gastric environment. Raw and processed peanuts were tested for disintegration in a model stomach system. The differences in disintegration rate were explained with respect to the changes in moisture absorption and texture. The absorption of moisture and the swelling of peanuts during gastric digestion were studied using Magnetic Resonance Imaging (MRI). The results show that processing improved the gastric disintegration of peanuts, and the disintegration rate was in an order of fried > roasted > boiled > raw peanuts. The changes in total weight, moisture and the dry solid loss in the samples were described by Linear–exponential equation, Peleg''s equation and the Weibull equation, respectively. Absorption of gastric juice played a critical role in softening the texture contributing to the breakdown of peanuts. Static soaking test indicated that the disintegration rate, as indicated by half time, has a good exponential relationship with the textural parameters of soaked samples. MRI shows potential as being used to analyze the mass transfer phenomenon in solid foods under digestion. [Copyright &y& Elsevier]

Abstract: The enzymatic hydrolysis of cellulosic material is a key step in the biochemical routes for production of renewable fuels and chemicals. This must be performed at high solids to be economically viable. High solids operations creates numerous processing challenges, most importantly the limitations due to mass transfer and poor mixing of enzymes in the cellulose suspensions. We use magnetic resonance imaging (MRI), a cylindrical penetrometer, and HPLC to demonstrate the importance of spatial homogeneity in the distribution of enzyme on the rates of liquefaction of the substrate and in the suspension mechanical strength. Our results show that the largest mechanical strength changes occur in a narrow interval of time during the initial stages of conversion. Differences in enzyme concentration distribution occurring at the centimeter-scale produced order of magnitude differences in liquefaction and saccharification rates, supporting the hypothesis that mixing quality has a major influence in both liquefaction and saccharification rates. [Copyright &y& Elsevier]

Abstract: Magnetic resonance imaging (MRI) and NMR relaxometry were used to monitor changes in feta cheese during 169h of brining at 4.8%, 13.0% and 23.0% salt solutions. Image and relaxation data were acquired to study salt uptake and water loss due to dehydration of cheese during brining. Saturation recovery and Carr–Purcell–Meiboom–Gill (CPMG) sequences were used to determine the longitudinal relaxation (T 1) and the transverse relaxation (T 2) times, respectively. Signal intensities of T 2 weighted images decreased during 169h of brining. An excellent linear correlation between the average signal intensity and the water content was obtained (R 2 =0.984). The T 1 values of cheese brined at 4.8% were almost constant but T 1 values decreased for both 13.0% and 23.0% salt brined cheeses. Analysis of the CPMG decays gave relaxation spectra containing two components which decreased during brining. The short component T 2a was highly correlated with salt content (R 2 =0.974). Results showed that NMR and MRI can be used to follow salt uptake and changes in water content in cheese during brining. [Copyright &y& Elsevier]

Guillain-Barré syndrome diagnosis is based on clinical presentation and supportive diagnostic testing. In its early stage, no single, reliable diagnostic test is available. However, a finding of nerve root enhancement on spinal magnetic resonance imaging may be useful. We evaluated the frequency of nerve root enhancement on spinal magnetic resonance imaging in children with Guillain-Barré syndrome. At a single tertiary pediatric center, we conducted a retrospective chart review of children with Guillain-Barré syndrome who had complete spinal or lumbosacral spinal magnetic resonance imaging with gadolinium administration from January 2002-January 2009. Twenty-four consecutive patients were identified. Spinal nerve root enhancement with gadolinium was present in 92% (22/24) of children with Guillain-Barré syndrome on initial spinal magnetic resonance imaging (95% confidence interval, 0.745-0.978). This finding increased to 100% of patients, after two patients underwent repeat spinal magnetic resonance imaging that did reveal nerve root enhancement. Patterns of enhancement were variable, but involved the thoracolumbar nerve roots in all patients. Enhancement of nerve roots with gadolinium on initial spinal magnetic resonance imaging was frequently present in these children with Guillain-Barré syndrome. Spinal magnetic resonance imaging is a sensitive diagnostic test and should be considered an additional diagnostic tool in select cases. [Copyright &y& Elsevier]