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Artificial boluses were prepared from sponge cake by grinding the food to a given particle size and hydrating with artificial saliva. The shear viscosity of the artificial food bolus was then measured by capillary rheometry, and its variations with shear rate were studied as a function of four main factors: bolus water content, particle size, temperature and saliva viscosity. The flow curves can be fitted according to the Herschel-Bulkley model, which allows for the derivation of two main properties: yield stress and consistency. Saliva plasticizing coefficients are defined by the variations of these properties as a function of the water content. Their value, close to 12, is in good agreement with values obtained for molten starch (10 < α < 20). Particle size has little influence, whereas the effect of temperature and saliva viscosity is not monotonous. They underline the complexity of the structure of the bolus and the interplay between the saliva, acting as a lubricant and a swelling agent. Finally, the extensional viscosity of the artificial bolus is also determined by capillary rheometry, and it is shown to be of importance when comparing the viscous properties of the artificial bolus with those of real ones from literature.

Pulses extruded foods can be envisaged asall solid foams with voids and walls, the latter being considered as a dense starch/protein composite. Pea flour (PF) and blends of pea starch and pea protein isolate (PPI) with different protein contents (0.5-88% dry basis) were extruded to obtain models of dense starch-protein composites. Their morphology was revealed by CLSM microscopy, and their mechanical properties were investigated using a three-point bending test complemented by Finite Element Method (FEM) modelling. Composite morphology revealed protein aggregates dispersed in the starch matrix. It was described by a starch-protein interface index I

In homogeneous solid-state reactions, the single-crystal nature of the starting material remains unchanged, and the system evolves seamlessly through a series of solid solutions of reactant and product. Among [2+2] photodimerizations of cinnamic acid derivatives in the solid state, those involving salts of the 4-aminocinnamic acid have been recognized to proceed homogeneously in a "single-crystal-to-single-crystal" fashion by X-ray diffraction techniques. Here the bromide salt of this compound class is taken as a model system in a Raman spectroscopy study at low wavelengths, to understand how such a mechanism defines the trend of the crystal lattice vibrations during the reaction. Vibrational mode calculations, based on dispersion corrected DFT simulations of the crystal lattices involved in the transformation, have assisted the interpretation of the experiments. Such an approach has allowed us to clarify the spectral signatures and to establish a correlation between the dynamics of the monomer and dimer systems in a process where chemical progress and crystal structural changes are demonstrated to occur simultaneously.

International audience; This study investigated the oral processing and bolus formation mechanisms of two soft cereal products fortified with pulse proteins, sponge-cake (FSC) and brioche (FB), in the elderly population, and their relationship with the perception of oral comfort. Twenty subjects aged 65 and over participated in the study. They were classified in two groups according to dental status (poor vs. satisfactory) and presented varying stimulated salivary flow rate (SSF). Bolus properties (hydration ratio, apparent viscosity and particle size) were characterized after three chewing stages. Results showed that subjects with a poor dental status (DS) had a longer chewing duration for FB, while individuals with a higher SSF had a shorter duration for FSC. Compared to FSC, more saliva was added to the FB boli, and the viscosity and particle size of FB bolus were also higher. Based on the bolus particle size evolution during chewing, FB was considered to be more difficult to fragment than FSC, this latter showing a dramatic particle size reduction from the beginning of chewing. From the viscosity data, a model was used to represent the variations of the bolus structure index during chewing and a coefficient of interaction of saliva with food was defined. For both products, the perception of comfort depended more on the DS than on SSF. Bolus apparent viscosity was related to the perception of oral comfort in FSC, while the chewing duration and the bolus particle size at the beginning of chewing contributed to explain oral comfort in FB. Finally, the comparison of these results with those obtained previoulsy with standard (i.e. non enriched) sponge cake and brioche suggested that the proposed protein fortification did not challenge the oral comfort perception by the elderly.

International audience; The properties of artificial food bolus are studied by dynamic oscillatory and capillary rheometry as functions of bolus water content (WC), in the usual range of saliva hydration, for four cereal products: sponge cake, extruded flat bread and their counterpart enriched in legume proteins. All boluses followed the same rheological behavior characterized by (1) solid -like in the linear viscoelastic domain and (2) Herschel-Bulkley model for large shear strain. Hence, four characteristic rheological properties are determined: modulus at viscoelastic plateau, characteristic stress at transition to flow, yield stress and consistency in the flow regime. The decrease of these properties with WC was fitted by an exponential decay function, from which was extracted a coefficient alpha (5 = alpha < 30), defined as a coefficient of interaction of the food with water. The values of alpha are of the same order of magnitude as the plasticization coefficient of starch by water. They were larger for the extruded pea based (EFP, alpha >= 15), and were lower for the sponge cake (SC, alpha < 15). The variations for the different rheological properties are discussed in terms of matter state, envisioning bolus as a suspension of soft swellable particles. The comparison of these values with those encountered for real boluses from similar foods suggests that these results contribute to define a coefficient of interaction of food with saliva.

International audience; This study investigated the mechanisms of fragmentation leading to bolus formation during chewing in the elderly population for two cereal foods of different compositions and cellular structure: sponge-cake (SC) and brioche (B). For both products, mechanical properties were characterized by uniaxial compression and 3D cellular structure was determined using x-ray micro-tomography. Stress-strain curves showed two distinct ductile-like behaviors: product B underwent plastic deformation, whereas product SC displayed a hyper-elastic behavior. Twenty subjects aged 65 years and over with two different oral health conditions (poor vs satisfactory dental status, variable stimulated salivary flow rate) were asked to consume both products. Bolus particle size was determined at three different chewing stages through image analysis, and the resulting particle size distribution (PSD) curves were fitted by Gompertz model. The model parameters were related to bolus particle heterogeneity and fragmentation, thanks to their correlations with median particle size diameter D-50 and interquartile ratio (D-75/D-25), directly extracted from PSD curves. The use of model parameters allowed discriminating between chewing sequences for both products and revealed different fragmentation patterns: while SC boli exhibited a continuous particle size reduction during chewing, B displayed a combination of fragmentation and agglomeration. In addition, results showed that subjects with a satisfactory dental status produced significantly more degraded boli than those with a poor dental status. These results highlight distinct fragmentation mechanisms for these two soft products that were interpreted in relation to their differences in composition, structure and mechanical behavior.

International audience; The structure of extruded pea flour can affect chewing performances. Our objective was to relate the bolus properties (fragmentation, moisture content and viscosity) of chewed extruded pea snacks to their structure. In order to have control over oral physiological parameters, we opted for an in vitro approach using a chewing simulator, the variables of which were the flow rate of artificial salivary fluid and chewing time. The structure of the extruded pea snacks was characterized by its density and protein solubility in dithioerythritol (DTE), which reflected the amount of protein aggregates cross-linked by disulphide bonds. The particle size distribution and median width (D-50) of the bolus fragments were determined by imaging technique. Bolus viscosity and saliva uptake (Delta WC) were respectively determined by capillary rheometry and gravimetric method. Extruded snacks were persistently reduced to small particles (similar to 2 mm) during chewing process following a unique curve of D-50 = f (chewing time) fitted by a power function. Delta WC evolution during chewing process was expressed as a function of the structure index, defined as the product of the snacks' relative density by protein solubility in DTE. The boluses' viscosity exhibited a shear thinning behaviour the consistency index of which was negatively correlated to the saliva uptake (Delta WC) through a plasticization coefficient (alpha). alpha values (< 2) were much smaller than those reported for cereal products (15-30) and depended on protein solubility in DTE.

International audience; This paper presents a digital learning tool, MESTRAL (“Modélisation Et Simulation des TRansformations ALimentaires”, “Modelling and Simulating Food Processing” in English), that can provide educators with a tool to teach food processing using simulators and a broad range of models derived from research in food science & engineering. It was built using electronic knowledge books (eK-book). The eK-book represents knowledge in the form of concept maps and knowledge sheets, connected via a network of hypertext links. MESTRAL encompasses 15 modules, that cover approximately 150 h of teaching and a broad range of real systems, from a single unit operation (e.g., frying a banana) to a logistic chain (e.g., ham cold chain). Each module conveys information on a food product or a food process, and includes a simulator based on a published scientific model. Altogether, the models address various scale of systems and are based on different theoretical frameworks. For each simulator, the model inputs and outputs are stored in a database. Outputs are visualized through abacuses, which can be used for virtual practice. MESTRAL modules also include training exercises and tests to help students to assess the knowledge they have acquired during consultation of the modules. Finally, MESTRAL has already been successfully tested by different audiences according to various learning forms.

International audience; The effect of pea protein fortification on the rheological properties of sponge-cake batters and their continuous phases, as well as their relationship with the final product properties were studied. Foams made out of whole egg and sugar were prepared in a planetary mixer; wheat flour (WF) was added to form a typical sponge-cake batter. Pea protein isolates (PP) were added in substitution to WF to form five batters with various PP concentrations expressed as the percentage of WF substitution: 0, 10, 20, 30 and 40%. The batter air volume fraction decreased when increasing PP concentration, which led to an increase in the cake density and apparent Young modulus. All batters and their respective continuous liquid phases showed shear-thinning behavior, which was modeled by a power law. They showed a predominant elastic behavior at intermediate frequencies, and a cross-over point at high frequencies. All of the rheological properties increased by a factor of about 10 when the PP concentration increased from 0 to 40%. Free-drainage experiments showed that batter stability increased with increasing PP concentration. PP had larger particles than WF, and showed a higher water binding capacity than WF, but no significant difference in solubility. Observations of the batter and cake microstructure revealed PP formed a network of interconnected "bridged" particles in the continuous phase. These results suggest that PP first acted as fillers that swelled and connected to each other in the continuous phase, and were the main driver for the increase of rheological properties.

The structure of cereals and snack foods during processing is developed according to structural changes at various levels of matter organization. At macroscopic scale, two main consecutive mechanisms rule these changes: (1) the transition from a powder (the flour) to a viscoelastic liquid (the dough, the paste) and (2) the transition from a liquid to a solid, soft or rigid. At mesoscopic scale, these changes can be first captured through state diagrams that represent the material rheological properties as functions of the composition. These diagrams and functions can be enriched with the paths followed by the food product along processing. All together, these representations, called basic knowledge models, can provide scientists and engineers with a comprehensive basis to predict the development of structure and final properties of the food. In this chapter, we will strive to apply basic knowledge models for predicting texture properties to several types of airy cereal and snack foods (bread, biscuits, cakes, and extruded snacks taken as examples). A specific effort is devoted to build a generic approach of structure development that can be applied to the design of cereal foods with targeted sensory and nutritional properties.

International audience; Dehulled yellow pea flour (48.2% starch, 23.4% proteins, d.b.), was processed by a twin-screw extruder at various moisture contents MC (18-35% w.b.), product temperature T (115-165 degrees C), and specific mechanical energy SME (50-1200 kJ/kg). Structural changes of extruded pea flour were determined at different scales by measurements of density (expansion), crystallinity (X-ray diffraction), gelatinisation enthalpy (DSC), starch solubility in water and protein solubility in SDS and DTE (SE-HPLC). Foam density dropped from 820 to 85 kg/m3 with increase in SME and T (R-2 >= 0.78). DSC and XRD results showed that starch was amorphous whatever extrusion conditions. Its solubility in water augmented up to 50%. Increasing temperature from 115 to 165 degrees C decreased proteins soluble in SDS from 95 to 35% (R-2 = 0.83) of total proteins, whereas the proteins soluble in DTE increased from 5 to 45% (R-2 = 0.75) of total proteins. These trends could be described by sigmoid models, which allowed determining onset temperatures for changes of protein solubility in the interval [125, 146 degrees C], whatever moisture content. The SME impact on protein solubility followed similar trends. These results suggest the creation of protein network by S-S bonds, implicating larger SDS-insoluble protein aggregates, as a result of increasing T and SME, accompanied by creation of covalent bonds other than S-S ones. CSLM images suggested that extruded pea flour had a composite morphology that changed from dispersed small protein aggregates to a bi-continuous matrix of large protein aggregates and amorphous starch. This morphology would govern the expansion of pea flour by extrusion.

This work presents a Raman based approach for the rapid identification of the molecular conformation in a series of new 2,3-thienoimide capped quaterthiophenes, whose crystal structures were determined by synchrotron radiation X-ray powder diffraction. These systems display two conformational polymorphs, known as forms A and B, as a result of the anti–anti–anti and syn–anti–syn arrangements of the quaterthiophene cores. In a micro-Raman and computational study, the spectroscopic differences between the conformers were detected and proved to be suitable markers for polymorph identification. Thus, the synergic employment of diffraction and Raman spectroscopy techniques yields a full and reliable characterization of 2,3-thienoimide capped quaterthiophene compounds in their solid state.

The objective of this paper was to describe the clinical features, the management and the outcome of nine small breed dogs affected with lateral patella luxation referred during the period between January 2010 and December 2014. Patellar luxations were classified according to: breed, age, sex, weight, and grade of patellar luxation, as well as if unilateral or bilateral, and concurrent cranial cruciate ligament lesion. In affected dogs, surgical correction consisted in the combination of tibial tuberosity transposition and soft tissue procedure. Adjunctive condroplasty or trochleoplasty was performed as needing. The outcome was found positive after surgical management with low complication rate and complications have been easily managed with high success rate.Keywords: Dog, Lateral, Luxation, Patellar.

Thioindigo (2-(3-Oxo-1-benzothiophen-2(3H)-ylidene)-1-benzothiophen-3(2H)-one) is a synthetic dye related to the natural compound Indigo. Notwithstanding the interest aroused recently by its employment as a functional material in a number of applications, a satisfactory characterization of its solid state is still missing. In this work, we study the occurrence of the two thioindigo α and β polymorphs under various growth conditions, and find that their structural similarity implies they often coexist. However, whereas polymorph β is certainly predominant in the bulk phase, polymorph α grows preferentially on substrates, turning out to be the surface stabilized phase in highly homogeneous and ordered films obtained by the bar‐assisted meniscus shearing method (BAMS). DFT calculations support the experimental findings, aiding in the polymorph spectroscopic identification and to the interpretation of the order in the films of polymorph α., We thank CINECA Supercomputing Center for providing computer time through the ISCRA scheme (project C – HP10CA2TWT). The authors thank the Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), the DGI (Spain) project, FANCY CTQ2016-80030-R, the Generalitat de Catalunya (2017-SGR-918) and the Spanish Ministry of Economy and Competitiveness, through the ‘Severo Ochoa‘ Programme for Centres of Excellence in R&D (SEV- 2015–0496). We acknowledge the Elettra Synchrotron Trieste for beamtime allocation and thank Luisa Barba for assistance in using beamline XRD1. T.S. acknowledges the H2020-MSCA-COFUND-2014 Programme (P-SPHERE, Grant agreement 665919).

International audience; Starch-legume protein composites were obtained by extrusion of pea flour and pea starch-protein blend at various specific mechanical energies (100-2000 kJ/kg) and a temperature low enough to avoid expansion. The morphology of these composites displayed protein aggregates dispersed in a starch matrix, revealed by microscopy. Image analysis was used to determine the median width of protein aggregates (D-50), their total perimeter and surface, from which a protein/starch interface index (I-i) was derived. The mechanical properties of composites were determined by a three-point bending test. The pea flour composites had a higher interface index I-i (1.8-3.1) with lower median particle width D-50 (8-18 mu m) and a more brittle behaviour than the blend composites that had a lower I-i (1-1.1) and higher D-50 (22-31 mu m). For both materials, rupture stress and strain were negatively correlated with I-i. This result suggested that there was a poor interfacial adhesion between the pea starch and proteins.

International audience; A phenomenological model is proposed for calculating the volumetric (VEI) and radial (SET) expansion indices, and the anisotropy factor of extruded starch from the melt shear viscosity (eta). The model parameters depend on the moisture content (MC), the specific mechanical energy (SME), the melt temperature (T) and the melt storage modulus (E'). The latter represents the contribution of the elongational viscosity. The model is developed using a large data-set covering a wide range of thermomechanical conditions and Theological properties. The cellular structure is also predicted by linking the anisotropy factor to the cellular fineness (F). The model is validated using both a specific validation data-set and data taken from the literature. The simulation results show that eta, MC and T influence negatively VEI and positively F, while E" positively affects both properties. These trends make it possible to adjust the structure of the extruded starches by selecting appropriate processing conditions. Finally, an optimization method based on overlaid contour plots is applied to determine the range of input variables leading to a targeted cellular structure.

International audience; The aim of this study was to investigate food oral processing and bolus formation in the elderly population, and their relationship with the perception of oral comfort, for two soft cereal products of different composition: sponge-cake and brioche. Twenty subjects aged 65 and over participated in the study. They were classified in two groups according to dental status (poor vs. satisfactory) and presented various stimulated salivary flow rate (SSF) in each group. Food bolus properties (hydration ratio and apparent viscosity) were characterized after three chewing stages for both groups. Results showed that chewing duration did not depend on food product but rather on physiology: subjects with a poor dental status had a shorter chewing duration. For each chewing stage, sponge-cake boli showed a higher hydration ratio than brioche boli, which showed higher apparent viscosity. For sponge-cake, perception of oral comfort was primarily driven by SSF rate, irrespective of the dental status. In the case of brioche, oral comfort was also partially explained by SSF in the case of subjects with poor dental status. This result suggests that perception of oral comfort in brioche could be driven by product related attributes rather than oral health. For both foods, a phenomenological model of bolus viscosity as a function of stimulated salivary flow and chewing duration was proposed.

International audience; The mechanical properties of sponge cake (SC) and brioche (B), and their pulse protein fortified version (F SC and FB) have been characterized under compression (>90% in height reduction); during recording the evolution of their cellular structure was recorded using high resolution X-ray tomography. Due to protein reinforcement, FB had smaller gas cells and slightly larger cell walls than B, whereas FSC had only smaller cells than SC. The four products displayed non-linear mechanical behavior, with plastic deformation in the case of brioches. Results showed that sponge cakes, having thinner cell walls, exhibited premature fracture, while brioches, characterized by thicker cell walls, buckled, making the food sample more difficult to form fragments. Three dimensional Finite Element models were implemented based on the X-Ray micro-tomography 3D images. Results have shown that brioches, and particularly FB, displayed less efficient stress transfer, and thus were less prone to fragmentation. By comparison with results previously obtained on real food boluses, these results allowed understanding the mechanisms that govern food fragmentation during chewing and underlined the importance of the cellular structure of these cereal foods.

Wave-packet scattering from a stationary potential is significantly modified when the wave-packet is subject to an external time-dependent force during the interaction. In the semiclassical limit, wave--packet motion is simply described by Newtonian equations and the external force can, for example, cancel the potential force making a potential barrier transparent. Here we consider wave-packet scattering from reflectionless potentials, where in general the potential becomes reflective when probed by an accelerated wave-packet. In the particular case of the recently-introduced class of complex Kramers-Kronig potentials we show that a broad class of time dependent forces can be applied without inducing any scattering, while there is a breakdown of the reflectionless property when there is a broadband distribution of initial particle momentum, involving both positive and negative components., 13 pages, 4 figures, to appear in Phys. Rev. A

Indigo [2,2′-bis(2,3-dihydro-3-oxoindolyliden)], a commonly used natural dye, has been shown to exhibit a highly promising semiconducting behavior, allowing for the realization of ambipolar devices. Nevertheless, up to date, it is still unclear which crystal structure is present in the thin films, a piece of information relevant for device applications. In this work, we address this issue by an in-depth characterization of the polymorphs of Indigo in the bulk and in drop-cast films. To do this, X-ray diffraction (XRD) and micro-Raman spectroscopy have been employed jointly, with the support of state-of-the-art density functional theory calculations in the solid state. Structural and spectroscopic characterizations have established that the two known A and B polymorphs grow as concomitant in the bulk under most of the experimental conditions adopted in this work. In the drop-cast films, XRD cannot unambiguously identify the structure, but Raman spectroscopy is effective in establishing that only the B form is present. The calculations augment the experiments, providing valuable insights into the relative thermodynamic stability of the two forms as a function of temperature. They also allow for a more comprehensive characterization of the Raman modes.

We perform ultrafast pump-probe spectroscopy of plasmonic structures beyond the perturbative excitation regime. As a prototypical system we choose gold nanorods dispersed in water, which display both longitudinal and transverse plasmon resonances. A broadband investigation reveals a complex scenario for the saturation of the transient optical response as a function of the pump fluence, with strong dependence on the probe wavelength. In particular, we observed stronger saturation effects for the high energy transverse plasmonic resonance as compared to the low energy longitudinal one. This behavior is well captured by a three-temperature model and is understood in terms of the nonlinearity of the Fermi-smearing mechanism, presiding over the optical nonlinearity of noble metal nanomaterials. Our results highlight a universal saturation dynamics in the transient optical response of plasmon-enhanced photonic structures excited by intense light beams, with potential impact on many applications, from the all-optical modulation of light to photovoltaics and photocatalysis.

This study addresses the effect of Fucus vesiculosus seaweed powder addition up to 8% (flour basis, f.b.) on wheat flour dough and bread properties. Rheological properties and proofing behaviour of dough and density, colour, and crumb texture of bread were determined. Compared to a typical wheat bread formulation, the addition of Fucus vesiculosus seaweed powder raised elongational dough viscosity, which was responsible for a lower porosity of dough at the end of proofing. The wheat dough consistency index (power law) increased from 6.6-22.1 10(-3) Pa s(n) with FV addition and the flow index values were low (0.24-0.29) showing a strong shear-thinning behaviour. Fucus vesiculosus seaweed powder addition significantly increased density from 0.23 g/cm(3) (≤ 2% f.b.) up to 0.40 g/cm(3) (8% f.b.), crumb firmness from ≈18 kPa (≤4% f.b.) up to 45 kPa (8% f.b.), and green colour of bread crust. The results showed that a maximum of (4% f.b.) Fucus vesiculosus seaweed powder could be added, without impairing the density and crumb texture of enriched breads.

Wheat flour doughs were processed with soluble dietary fibres (DF) added up to 40% (w/w flour). DF were made of a ternary mixture of maltodextrins (MT, 3/5), pectins (PE, 1/5) and inulin (IN, 1/5). The addition of DF decreased the specific mechanical energy developed by the mixer, mainly because of water addition. It increased the ratio of storage moduli and the elongational viscosity of the dough, but decreased the strain hardening index. Energy input and rheological changes at mixing largely explained the decreases of porosity characteristic time and stability time during fermentation. It was possible to add up to 30% DF with a moderate increase of bread density, and 20%, with little change of crumb cellular structure. Hence, the changes of bread crumb texture were not mainly due to bread density, but rather likely to the changes of properties of the intrinsic material. Results obtained by addition of single fibre source, especially inulin, deviated from the main trends observed for texture and rheological properties. These results provide a good basis to design breads with increased dietary fibre content.

A specific equipment, made of an assembly of 10-20 vertical metal pins, has been implemented to assess the crusty texture of French breads by a so called multi-indentation test. It was connected to a force sensor set on a material testing machine in the range [0; 100 N]. The height of each pin was adjustable to the irregular surface of the crust of the tested specimen. Breads with varying texture were prepared under various dough mixing conditions and formats, different baking times (8, 11, 15 and 17 min), and with various contents of bioprocessed fibres. They were crushed, by the multi-indenter at a constant rate (50 mm/min), followed by a relaxation step while maintaining stable the final strain at 2/3rd of the initial sample height. Main variables measured from the resulting texture profile were related to crust stiffness and crumb firmness. The relevant bread format, accurate baking time and fibres content could be selected in function of given crust properties. Overall, the multi-indentation test proved a useful procedure to contribute to the design of breads with target texture. (C) 2013 Elsevier Ltd. All rights reserved.

We show that invisible localized defects, i.e. defects that can not be detected by an outside observer, can be realized in a crystal with an engineered imaginary potential at the defect site. The invisible defects are synthesized by means of supersymmetric (Darboux) transformations of an ordinary crystal using band-edge wave functions to construct the superpotential. The complex crystal has an entire real-valued energy spectrum and Bragg scattering is not influenced by the defects. An example of complex crystal synthesis is presented for the Mathieu potential.

International audience; In this paper, a reduced order mechanistic model is proposed for the evolution of temperature and humidity during French bread baking. The model parameters are identified using experimental data. The resulting model is then used to estimate the potential energy saving that can be obtained using jet impingement technology when used to increase the heat transfer efficiency. Results show up to 16% potential energy saving under certain assumptions. (C) 2013 Elsevier Ltd. All rights reserved.

We present a rationalization of the solid state behaviour of 1,1,4,4-tetraphenyl-1,3-butadiene (TPB), a well-known blue luminescent molecule, which retains its emissive properties in the solid state. The crystal structures of four polymorphs and one solvate form are discussed and their relative thermal stability is assessed. The experimental occurrence of the four polymorphs is rationalized on the basis of thermodynamic and kinetic considerations.

International audience; During extrusion of starchy products, the molten material is forced through a die so that the sudden abrupt pressure drop causes part of the water to vaporize giving an expanded, cellular structure. The objective of this work was to elaborate a phenomenological model of expansion and couple it with Ludovic® mechanistic model of twin screw extrusion process. From experimental results that cover a wide range of thermomechanical conditions, a concept map of influence relationships between input and output variables was built. It took into account the phenomena of bubbles nucleation, growth, coalescence, shrinkage and setting, in a viscoelastic medium. The input variables were the moisture content MC , melt temperature T, specific mechanical energy SME , shear viscosity η at the die exit, computed by Ludovic®, and the melt storage moduli E’(at T > T g ). The outputs of the model were the macrostructure (volumetric expansion index VEI, anisotropy) and cellular structure (fineness F) of solid foams. Then a general model was established: VEI = α (η/η 0) n in which α and n depend on T, MC , SME and E’ and the link between anisotropy and fineness was established.

International audience; Background: Expansion phenomenon is a key-point of the development of extruded starchy foods. Despite the huge number of studies, the complexity of the phenomenon still challenges its modeling. Current available models based on continuum mechanics are still too complex to be coupled with any 1D extrusion model available, in order to predict the density and the cellular structure of the starchy foams.Scope and approach: In this paper, the different modeling approaches for vapor expansion are reviewed. Then, a survey of the different mechanisms (bubbles nucleation, growth, coalescence, shrinkage and setting), using qualitative knowledge representation and reasoning, allows to improve the understanding of the effect of extrusion variables (temperature, moisture content, die geometry ...) and material rheological properties on the expansion phenomenon. Based on experimental results reported in the literature, a phenomenological model of expansion can then be suggested.Key findings and conclusions: The knowledge representation and reasoning leads to a concept map of the causal influences between input, physical mechanisms and output variables. The phenomenological model would allow to predict output variables characterizing foam macrostructure (bulk expansion indices and anisotropy factor) and cellular fineness based on X-ray tomography measurements. A scale down from macrostructure to cellular structure could be achieved by establishing a link between anisotropy factor and cellular fineness. Once validated, this model could be coupled with any 1D extrusion model in order to build a global model for the design of cereal-based extruded foods. (C) 2015 Elsevier Ltd. All rights reserved.

SummaryCase description: A three-year-old cat was referred to the Veterinary Teaching Hospital, University of Naples, Italy. The cat had severe pelvic limb deformity, and abnormal development of all four paws.Clinical findings: Radiographs revealed bilateral tibial agenesis, syndactyly, and digital hypoplasia.Treatment and outcome: No treatment was instituted because of the severity of the injury, the adaptation of the cat to the abnormal condition, and the owner's refusal to permit any treatment.Clinical relevance: Congenital limb deformities are rarely reported in the cat and tibial agenesis is considered a very rare disease. This congenital anomaly is well documented and classified in man, and it has been associated with other abnormalities in more complex syndromes. This paper reports clinical and radiographic findings in a cat affected by bilateral complete tibial agenesis associated with other congenital anomalies.

Two series of dough pieces were prepared: (a) at constant composition and different mixing conditions, and (b) by modifying only composition. For both, elongational properties were measured by lubricated squeezing flow (LSF) and proofing kinetics determined by 2D imaging. Elongational viscosity followed a power law in the strain interval [0.1, 1.25] and varied from 140 to 1400 kPa s, for Hencky strain and strain rate values of 1 and 10 −3 s −1 , respectively. Strain hardening index varied little, in the interval [1.2, 2]. Positive correlation between consistency K and flow index n (series a) suggested that mixing conditions modify gluten network crosslinking, whereas negative correlation between K and n (series b) showed that liquid fraction plasticized the network. Porosity kinetics were found to be mainly governed by gas production factors, rather than dough rheology. Finally, elongational viscosity contributed to limit stability loss during fermentation, which could be attributed to the resistance it imparted to bubbles coalescence.

Three breads of different densities and salt contents were chewed by 16 healthy subjects, with controlled physiological characteristics, for three different stages of mastication until swallowing. The distribution of chewed bread particle size was determined by imaging of the boluses at each stage, for the 3 breads and all subjects. Bread piece was reduced into an increasing number of small particles with a median size, function of mastication time, taking an average value of 1.9 mm at swallowing. Bolus moisture content could be predicted from theoretical salivary flow and particle median size. Bolus consistency was derived from the apparent viscosity measured by capillary rheometry. It decreased with chewing time, and this decrease was linked to bolus moisture by a plasticization coefficient, which varied with the individual (12 < alpha < 30). A basic model involving hydration and fragmentation could be suggested to predict bread destructuration, defined by the ratio of consistency of the bolus on that of initial bread.

International audience; 64 breads were baked in a deck oven under conventional French baking conditions. Their hearth and surface temperatures were measured at various baking times using thermocouples and Infra-red thermometer; their moisture content was determined after sampling of the external layer, termed the "crust", and by weighing breads. In addition, an image analysis method, based on saturation and colors, allowed determination of a mask of crust and the kinetics of its mean thickness. Associated with hydrothermal kinetics, it showed that the development of crust was achieved at a final local temperature of 160 degrees C and moisture of 5% for an average final thickness of 1.7 mm. DSC analysis of crust samples also underlined the significance of non gelatinized starch in the crust. This result was interpreted by representing the hydrothermal history of crust in a starch melting diagram. (c) 2012 Elsevier Ltd. All rights reserved.

Here we show an innovative, simple and reliable method to fabricate micro-lasers by self-assembly of rod-shaped nanocrystals. We use dot/rod core/shell CdSe/CdS nanorods to form optical micro-resonators by exploiting their self-organization into well-defined coffee stain rings. The fabrication process merely consists of capillary jet deposition of a nanorod solution onto a glass substrate, and is scalable, economic, and highly reproducible. Upon optical pumping of the micro-resonators we obtain laser emission in the red or in the blue-green spectral region, demonstrating lasing both from core and shell transitions, with low pumping thresholds. Modeling by full-wave numerical simulations according to generalized (i. e. scattering) formulation of laser theory demonstrates lasing from complex modes of the self-assembled cavity.

Wheat flour dough was mixed in a spiral mixer for different operating conditions, at a speed ranging from 80 to 320 rpm, for a period of 7-15 min. The specific mechanical energy E, delivered and the dough temperature T-d were continuously recorded and varied from 7 to 82 kJ/kg and T-d of 13.5 to 36 degrees C, respectively. E-s and T-d were strongly correlated because of viscous dissipation but variations of ingredients initial temperature allowed to uncouple them. The energy balance during mixing process was set through a simple model assuming constant heat transfer (h = 75 W/(m(2) degrees C)) which took into account thermal losses. Shear viscosity curves of the dough were determined by correlating volumic power to angular speed; by comparison to typical dough shear flow curve, a constant characteristic of the mixer geometry (K-s = 1.55) was determined like for models of mixer power consumption. The impact of mixing on small deformation rheological properties was assessed by DMA and the variations of the ratio, of maximum (75 degrees C) to minimum (50 degrees C) elastic modulus, was interpreted in relation with gluten network development. (C) 2011 Elsevier Ltd. All rights reserved.

Introduction et but de l’etude Alors que l’obesite peut s’expliquer par une surnutrition et l’ingestion de regimes riches en graisses et sucres, l’ingestion de fibres alimentaires est connue pour favoriser la perte de poids [1] . Notre etude vise a determiner si, en situation d’apport alimentaire superieur aux besoins (alimentation de type occidentale generant de l’obesite), les fibres alimentaires peuvent limiter l’apparition des deregulations metaboliques via notamment une reorganisation de l’utilisation des nutriments dans l’aire splanchnique (ASP : foie + tube digestif [TD]). Materiel et methodes Quatorze Miniporcs sont multicatheterises en artere, veine porte et veine sus-hepatique pour mesurer les flux nets de nutriments au travers de l’ASP. Les animaux ont ete nourris 60 jours avec un regime en surnutrition (14 911 kJ/j EM) supplemente en pain enrichi (F) (+ 2291 kj/j EM) ou non (T) (+ 2438 kj/j EM) en fibres (inuline, pectine, amidon resistant). Des prelevements sanguins ont ete realises a jeun apres 1, 14 et 60 jours de regime T ou F, ainsi que des prelevements tissulaires a l’euthanasie. Des analyses plasmatiques (AGCC, glucose, lactate, acides amines) et hepatiques (histologie : red oil) ont ete effectuees. Les flux nets des nutriments par l’ASP ont ete calcules par difference arterioveineuse. Les effets regimes/cinetiques ont ete evaluees par ANOVA a mesures repetees, signification p Resultats et analyse statistique A j60, le contenu lipidique dans le foie est inferieur chez F vs T (−33,6 % ; p Parmi les facteurs pouvant expliquer les changements dans l’utilisation des nutriments energetiques entre T et F, on constate une emission des AGCC par le TD superieure chez F vs T uniquement a j14, liee a la degradation des fibres solubles dans le colon. Or, les AGCC sont connus pour reguler les voies du metabolisme energetique via une action sur GPR41-43 [2] . Neanmoins, l’effet des fibres perdurant a j60, des mediateurs relais ou des regulations a long terme doivent s’etre mis en place. Conclusion La supplementation en fibres alimentaires limite le stockage des lipides dans le foie en situation de surnutrition. Cet effet pourrait etre medie dans les phases precoces du developpement des deregulations metaboliques par les AGCC via une alteration de la repartition des nutriments energetiques entre le foie et les tissus peripheriques. Pour analyser cette hypothese, des expressions de genes, des analyses de proteomique et des activites enzymatiques du metabolisme energetico-azote (foie, muscle, tissu adipeux) sont en cours.

This work investigates the mastication of two samples of typical cereal food products previously characterised by different sensory, textural and mechanical properties, by two complementary approaches. Electromyographic records and image analysis of chewed food particles first confirm the importance of the brittle behaviour of the products on human mastication. For both products, the fragmentation is followed by a significant agglomeration after less than 10 chewing cycles, both phenomena being correlated to the force magnitude and its evolution. Then, artificial mastication is undertaken to shed more light on the capability of the chewing simulator to discriminate both products under dry mastication conditions. The results depict a qualitative agreement with human mastication and texture properties.

International audience; Several fractions of wheat fibres were isolated from starchy endosperm, aleurone layer and bran, and characterized for their hydration properties and arabinoxylans (AX) content. The influence of their addition, up to 10%, to standard flour was studied through mixing tests, and rheological tests at small and large deformations. The effect of insoluble AX on dough development was accounted for by their capacity to retain water, whatever their origin and percentage of addition. The addition of insoluble AX increased the viscoelastic plateau modulus. The addition of soluble and insoluble AX to the dough did not modify the overall dough flow behaviour in shear, characterized by a Newtonian plateau at low shear rates followed by shear-thinning behaviour at larger shear rates. This behaviour could be fitted by the Cross model. The addition of water soluble AX modified the Newtonian viscosity value. Conversely, the addition of insoluble ones increased dough consistency, probably through a filler-like effect in the dough matrix.