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International audience; In fresh vegetal materials, liquid is mostly located in cells. During processing, this liquid is distributed in the entire vegetal matrix volume including exctracellular volume. According to its location, it will be more or less available for physico-chemical mechanisms that takes place during processing of vegetal matrices. This availability greatly influences the quality of the final products. This work consisted in developing a method for determining the quantity of extracellular liquid in a cell-component food matrix. The method developed is spectrophotometric-based and consists in adding a known mass of polymer (poly(4-styrenesulfonate) sodium salt, PSS) to a rasped vegetal material and defining its concentration in the supernatant separated from the solid phase. The PSS molar mass prevents it from penetrating into plant cells. The PSS concentration measured makes it possible to calculate the extracellular liquid volume. The method validation and its application to rasped and processed (fermentation, pressing) cassava makes it possible to obtain results in agreement with those obtained with other methods.

Durum wheat gluten proteins are essential for pasta quality. Glutenin polymers undergo solubilization mechanisms during pasta processing. This study aims to investigate gluten proteins insolubilisation kinetics during a resting period applied to extruded. The goal is to investigate the contribution of time related recovery of large glutenin polymers and temperature related formation of glutenin cross-linked aggregates in the pasta quality. Extruded pasta were rested for 120 min at 20, 30 or 40 °C prior drying at high temperature (90 °C). Glutenins insolubilisation induced by resting and drying was assessed from the SE-HPLC elution profiles of the SDS-soluble proteins from fresh, rested and dried pasta. Final pasta were characterized for their organoleptic (color, surface roughness) and physical (diameter, cooking time, viscoelasticity index) properties, before and after cooking. Pasta quality is discussed in relation with the gluten network structure and the impact of resting time. Resting of freshly extruded pasta extrusion leads to spontaneous insolubilisations of glutenins by creation of weak interactions. High temperature drying induces a strong drop of solubility of all gluten protein fractions by creation of covalent bonds, impacting equally rested and not rested pasta. Dry and cooked pasta organoleptic and physical properties are not significantly impacted by a resting time.

International audience; Iron nanoparticles supported on montmorillonite (MMT-Fe) were synthesized via the reduction by sodium borohydride of iron salts dissolved in a suspension of MMT. The MMT-Fe black powder collected after the evaporation of the solvent was analysed by Transmission Electron Microscopy, which revealed the formation of aggregates of metallic nanoparticles with an average size of 57 ± 17 nm dispersed on the surface of MMT. According to the X-ray diffraction, no iron ions are intercalated in the interlayer spacing of MMT, and no other crystalline species are formed. 57Fe Mössbauer spectroscopy evidences the formation of mainly zero valent iron in the form of iron boride. The O2 absorption kinetic of the synthesized powders was found to follow a second-order law. The study of the O2 absorption properties of as-synthesized, dried and stored (40 days) powders shows reaction constant (k), coefficient of proportionality (n) and O2 absorption capacities of the same order of magnitude. The O2 absorption capacity of the as-synthesized, dried and stored powders were found equal to 0.20 ± 0.01, 0.14 ± 0.03 and 0.09 ± 0.00 g O2 per g of iron, respectively. The initial absorption rate was found within the range [0.5 - 1.5] % O2 min-1 g-1.

International audience; This work describes a process approach to study the oil leakage phenomenon in feeds for large Trout. Using a pilot vacuum coater, four experimental coating parameters were studied (stirring speed, pressure, filling rate, and time needed to restore atmospheric pressure) through an experimental design. The properties measured on the coated pellets were the oil leakage rate and three other important usage properties, i.e. durability, hardness, and floatability. The coating conditions had a significant influence on oil leakage rate, varying at 40 °C from 2.7 % to 1.2 % depending on the coating conditions used. Finally, the vacuum level was the most effective factor in reducing leakage. Indeed, a progressive reduction in oil leakage rate was observed as the pressure inside the coater was reduced during coating.

International audience; The substance isobutane is intended to be used as a foaming agent at max 4.5% to produce expanded polystyrene (EPS) to be used for packaging foods, such as fruits, vegetables, meat, fish and cheese, at room temperature or lower. Isobutane is approved in Europe as a food additive (E943b) to be used quantumsatis as a gas propellant only in vegetable oil pan spray (for professional use only) and water-based emulsion spray according to Regulation (EC) No1333/2008. The purity requirements for the use of isobutane as a food additive are described in Commission Regulation (EU) No231/2012. The substance is a gas at room temperature. It is a saturated hydrocarbon, obtained with a high level of purity, and is not expected to react under the processing conditions used to make foamed polystyrene materials and articles. Data on migration of isobutane from trays at 20 degrees C for 10days ranged from 0.2 to 0.4mg/kg food. Considering the intended applications, estimated exposure is extremely low based on migration data. In the absence of genotoxicity alerts and given the very low toxicity following repeated exposure with no observed adverse effect concentration (NOAEC) of several thousands of mg/m(3) by inhalation, it was considered that the use of isobutane as a foaming agent, at the expected exposure from food, does not raise a safety concern.

This scientific opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel) deals with the safety evaluation of the recycling process EstPak Plastik (EU register No RECYC150), which is based on the Starlinger Decon technology. The decontamination efficiency of the process was demonstrated by a challenge test. The input of this process is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post‐consumer PET containers, mainly bottles, containing no more than 5% of PET from non‐food consumer applications. In this technology, washed and dried PET flakes are preheated before being submitted to solid‐state polycondensation (SSP) in a continuous reactor (one single reactor or several reactors in parallel) at high temperature under vacuum and gas flow. Having examined the challenge test provided, the Panel concluded that the preheating (step 2) and the decontamination in the continuous SSP reactor (step 3) are the critical steps that determine the decontamination efficiency of the process. The operating parameters that control the performance of the process are well defined and are temperature, pressure, residence time and gas flow for steps 2 and 3. Under these conditions, it was demonstrated that the recycling process under evaluation, using the Starlinger Decon technology, is able to ensure that the level of migration of potential unknown contaminants into food is below a conservatively modelled migration of 0.1 μg/kg food. Therefore, the Panel concluded that the recycled PET obtained from this process intended to be used up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs for long‐term storage at room temperature, with or without hotfill, is not considered of safety concern. Trays made of this PET are not intended to be used, and should not be used, in microwave and conventional ovens.

International audience; Propionibacterium freudenreichii is a beneficial bacterium widely used in food as a probiotic and as a cheese-ripening starter. In these different applications, it is produced, dried, and stored before being used. Both freeze-drying and spray-drying were considered for this purpose. Freeze-drying is a discontinuous process that is energy-consuming but that allows high cell survival. Spray-drying is a continuous process that is more energy-efficient but that can lead to massive bacterial death related to heat, osmotic, and oxidative stresses. We have shown that P. freudenreichii cultivated in hyperconcentrated rich media can be spray-dried with limited bacterial death. However, the general stress tolerance conferred by this hyperosmotic constraint remained a black box. In this study, we modulated P. freudenreichii growth conditions and monitored both osmoprotectant accumulation and stress tolerance acquisition. Changing the ratio between the carbohydrates provided and non-protein nitrogen during growth under osmotic constraint modulated osmoprotectant accumulation. This, in turn, was correlated with P. freudenreichii tolerance towards different stresses, on the one hand, and towards freeze-drying and spray-drying, on the other. Surprisingly, trehalose accumulation correlated with spray-drying survival and glycine betaine accumulation with freeze-drying. This first report showing the ability to modulate the trehalose/GB ratio in osmoprotectants accumulated by a probiotic bacterium opens new perspectives for the optimization of probiotics production.

International audience; During filtration of skimmed milk, the casein micelles accumulate at the membrane surface and their presence has a crucial impact on the performances of the operation and on the products properties. Information is still scarce, especially at ‘low’ temperature (≈8-12°C), about how the casein micelles behave at the membrane surface and interact in such concentrated regimes. The aim of this work was to understand the structural organization and behavior of concentrated casein micelles accumulated at the membrane during crossflow filtration (concentration, sol-gel transition, cohesiveness and reversibility) with a focus on impact of temperature. The strategy consisted in combining in-situ measurements by Small-Angle X-Ray Scattering coupled to crossflow filtration, with ex-situ characterization of concentrated dispersions of casein micelles using osmotic stress technique and rheology. Swelling-re-dispersion experiments were carried out to characterize the cohesiveness of micelles concentrates. During in-situ filtration performed at constant pressure, increasing temperature (12, 25, 42°C) increased permeate flux (which was mainly attributed to the decrease of viscosity of permeate) and led to higher accumulation of casein micelles and a thicker deposit. The relaxation of pressure showed that casein micelles deposit was more cohesive at low temperature. With osmotic stress and rheology experiments, it was observed that compressibility (concentration reached at given osmotic pressure) and sol-gel transition concentration of casein micelles increased with the temperature increasing from 7 to 20°C. Moreover, swelling of casein micelles gels at 7°C resulted in lower redispersion rate as compared to the swelling at 20°C regardless of the gel formation temperature. It was also observed that casein micelles gels obtained at 7°C are more cohesive than those prepared at 20°C. This work shows that carrying out filtration at low temperature led to a lower accumulation of casein micelle (lower compressibility of casein micelles), but to a higher cohesiveness of the accumulated micelles (lower sol/gel transition and swelling properties). These results were attributed to physico-chemical modifications of casein micelles (voluminosity, hydration) under temperature changes.

The cleaning phase is seldom included in the eco-design of food processes, since few cleaning kinetics models exist. The goal of this study was to investigate benefits of including a cleaning kinetics model, which considers three major operating parameters of cleaning (concentration, temperature and flow rate), in the eco-design of a food process. To this end, we developed an eco-design approach for a dairy evaporator process that includes both production and cleaning phases. A cleaning kinetics model was selected to predict cleaning duration as a function of the operating parameters of cleaning. Cleaning duration also depends on the fouling surface density, which depends on the duration of the production phase. Fouling surface density was predicted using three hypothetical fouling kinetics laws. After optimization, environmental and economic improvements were observed in process performance. The evaporation process is optimized at a high cleaning temperature (95 °C), a flow-rate similar to that used during the production phase and a low caustic soda concentration (

This study aimed at investigating the chemical composition and microstructure of spray dried camel and cow milk powders' surfaces with two different milk-fat contents (1 and 20g 100 g−1). The SEM (Scanning Electron Microscopy) micrographs showed that spherical particles with a ‘brain’-type surface for both milk powders were produced. The surface roughness (Ra) of whole (WDMP) and skimmed (SDMP) camel milk powders (Ra = 7.6 ± 0.4 nm and 5.6 ± 0.7 nm, respectively) were significantly lower as compared with the partially skimmed (PSCMP) and skimmed (SCMP) cow milk powders. The XPS (X-ray Photoelectron Spectroscopy) analysis highlighted that the surface of skimmed camel milk powders contained twice the lactose amount (17.7 ± 0.8%) as compared to cow milk powders (8.7 ± 0.4%). Furthermore, both milk powders showed the overexposure of proteins and fats at their surfaces regardless of the fat content. The CLSM (Confocal Laser Scattering Microscopy) micrographs highlighted that most of the camel milk fat globules were encapsulated by the proteins near the powder surface. Camel milk fat behavior during particle formation was attributed to their lower size distribution and their higher crystallization temperature.

This study aimed to perform Temporal Dominance of Sensations by modality (M-TDS) combined with a multi-intake approach to investigate texture and flavor perception in semi-solid products. Trained panelists (n = 15) evaluated fat-free strawberry yogurts enriched with functional proteins involving texture modifications. As yogurt is a semi-solid product, its in-mouth residence time is short. A multi-intake approach was therefore expected to give more reliable information about the sensory properties perceived by panelists. The two modalities of texture and flavor were analyzed separately to characterize the effect of added proteins. Trials were made according to an experimental design with two factors (protein type and concentration) and three levels each. Different statistical treatments, taking or not the temporality of attributes into account, were performed on standardized and non-standardized data. The implementation of M-TDS was essential to highlight differences of flavor perception in addition to the more evident texture modifications. The study of sensory trajectories evidenced that texture modifications, induced by the use of different whey proteins, slightly modified the perception of flavor and sweetness. The global flavor perception of the samples varied with the number of spoons, which particularly impacted the taste attributes. This study highlighted the importance of using M-TDS when studying texture and flavor in semi-solid products, and the relevance of the multi-intake approach to characterize flavor perception. This methodology enabled panelists to evidence both marked texture differences and subtler flavor modifications, and these useful data were emphasized by combining different statistical treatments.

International audience; The conversion of poplar wood biomass to highly value-added chemicals and molecular building blocks was achieved by using the dispersed mixed oxide Zn3V2O8 (ZVO) in water under 100 kPa of 10% O-2/N-2 at 160, 180, and 200 degrees C for 4 h. This nanostructured mixed oxide was prepared via the precipitation process and then characterized by several techniques. The results showed that this mixed oxide has interesting catalytic properties and is a versatile catalyst for biomass delignification and lignin and hemicellulose depolymerization. ZVO exhibited high activity on poplar biomass delignification and fractionation (degree delignification > 97%) and lignin and holocellulose conversion with high yield into aromatic and furan compounds (80 mg/g initial wood at 200 degrees C), with high selectivities for 5-hydroxymethylfurfural (HMF) (25 mg/g of initial wood), vanillin, and syringaldehyde.

National audience; La naturalité des produits alimentaires représente une demande forte des consommateurs des pays développés. La naturalité s’entend comme une réduction de l’emploi des additifs pour la fabrication, le stockage, la distribution ou l’usage des produits alimentaires, mais aussi la préservation des propriétés organoleptique et santé des macro- et micronutriments constitutifs. Les protéines sont des constituants essentiels pour texturer des aliments. Il existe cependant 2 limites à l’utilisation des protéines pour leurs propriétés de texture : une trop faible concentration en protéines ne permet pas de texturer une matrice alimentaire de façon satisfaisante, tandis qu’une trop forte concentration en protéines thermo-sensibles, comme les protéines de lactosérum, conduit à une agrégation excessive ou une gélification pendant leur traitement thermique. Un recours à l’addition d’agents gélifiants ou stabilisants est donc nécessaire pour atteindre la texture souhaitée (solide, visqueuse, fluide). Dans le cadre d’un projet interrégional, Profil, nous avons étudié le rôle de différentes fractions protéiques du lait pour contrôler la texture des émulsions sur une large gamme de concentration en protéines de lactosérum et sans ajout d’additif en combinant les propriétés de stabilité thermique des assemblages de protéines de lactosérum et les propriétés interfaciales des caséines. A teneur faible en protéines, notamment en caséines, les assemblages de protéines de lactosérum s’adsorbent à l’interface et connectent les globules gras, ce qui permet de texturer l’émulsion. A plus forte concentration en caséines, celles-ci couvrent l’interface au détriment des assemblages de protéines de lactosérum qui restent dans la phase dispersée et les émulsions sont fluides et stables après traitement thermique, même à forte concentration en protéines. Ces travaux ouvrent une voie innovante pour la création de produits laitiers sans additif répondant à la demande de naturalité des consommateurs. La compréhension du rôle de l’interface eau/huile dans la texturation des émulsions et son ingénierie constituent des leviers pour mieux contrôler la texture de produits existants. Ils offrent également des pistes pour la création de nouveaux produits correspondant à de nouveaux usages et de nouvelles habitudes de consommation. Les assemblages protéiques façonnés par traitements thermomécaniques permettent d’obtenir des propriétés fonctionnelles adaptées à un usage culinaire cible. Or, ces traitements impactent la structure des protéines et partie de leurs propriétés santé. Pour pleinement répondre aux enjeux de naturalité des produits alimentaires, la préservation des propriétés santé des protéines constitue également un enjeu majeur de l’alimentation de demain. Des pistes sont actuellement à l’étude pour répondre à ce double enjeu de maitrise de la techno-fonctionnalité et de la préservation de la bio-fonctionnalités des protéines.

Le besoin de développer la nano-instrumentation intégrée de détection, à bas coût à haute sensibilité sur des principes de résonances est un défi majeur et crucial pour les domaines industriels de la cosmétique, de l’agroalimentaire, de la pharmacologie galénique, de la biologie, et du biomédical ; la nécessité étant d’assurer les diagnostiques à réaliser en termes d’analyses, de contrôle qualité et de sécurité des substances, des aliments, des médicaments en solutions, des lotions actives, des crèmes, des mousses... L’ensemble de ces états de la matière en chimie et physique se nomme la matière molle et ses changements les transitions d’états, de phases ou de consistances… A titre d’exemple non exhaustif dans le domaine de la pharmacologie galénique, certaines solutions fluides avec principes actifs incorporés en suspension seront actives tant que les éléments ne sédimentent pas ; caractéristique qui induirait une qualité moindre de la solution médicamenteuse ou bien une forme de péremption. Sur ce principe d’interaction matière-lumière résonante sur puce intégrée, des mesures fines sur la nouvelle plateforme et le suivi dynamique des dits produits et substances ont permis de détecter des transitions de phases (gel/fluide/mixe émulsion/poudre solide), de mesurer des vitesses de sédimentation et même des phénomènes et mécanismes comme le séchage, la floculation, les effets Marangoni, ou encore les effets spontanées d’émulsion encore incompris [1-3]…

Microfiltration, MF is largely used in dairy industry to separate casein micelles from whey proteins. The weak performances of polymeric membranes compared to ceramic membranes are a restriction for their implementation in industry. Adding a diafiltration step is promising to improve polymeric MF performances, however most of the works have focused on the hydraulic performances and few have investigated the repercussion of diafiltration on protein separation. This work aims at investigating the impact of both the nature of solvent and the diavolume ratio on the MF efficiency. Pilot-scale MF using polymeric membrane (Synder, 800 kDa) was carried out on thermized skimmed milk at 12 °C with a volume reduction ratio, VRR from 2.5 to 3.2 and a transmembrane pressure of 0.7 bar. Continuous diafiltration was performed using reverse osmosis water (ROW) or milk ultrafiltrate (PUF). Permeation flux and β-lactoglobulin transmission were evaluated. During PUF-diafiltration of VRR-2.8-retentate, permeation flux is stable and β- lactoglobulin transmission declines by 26 % after 4.8 diavolumes. During ROW-diafiltration, permeation flux increases linearly until 2.9 diavolumes, then reaching an upper value. Simultaneously β-lactoglobulin transmission follows a parabolic curve with a maximum increase of 68 % for VRR-3.2-retentate and 10 % for VRR-2.5-retentate. According to Darcy’s law, the reduction of permeate viscosity during ROW-diafiltration leads to the improvement of permeation flux. This behavor is accentuated by the fouling layer relaxation consequent to the diminution of the ionic strength. In case of high repulsive forces in the concentration layer (low ionic strength), the transmission of negatively charged whey proteins is however restricted. The decrease of protein concentration during diafiltration may also limit whey protein transmission for high diavolume ratios. Diafiltration using ROW is recommended to increase transmission of whey proteins. However, volume of solvent has to be adapted to the VRR reached prior diafiltration to enable an optimum transmission

International audience; Food packaging plays a crucial part in the post-harvest environmental impact of fresh foods. Packaging is usually wrongly considered as additional economical and environmental costs. However, by minimizing food waste and losses, it could significantly contribute to decrease the overall environmental impact of the food itself. A good balance between environmental burden (resource consumption and additional waste management issues) and real benefit in usage condition (reduction of food losses) should be thus defined when dimensioning a packaging for a given application. Beyond food waste and environmental impact reduction, various kinds of considerations about packaging, sometimes conflicting, are generally expressed by the stakeholders (food and packaging industries, health authorities, consumers, waste management authority, etc.) related to safety, practicality, perceptions of the packaging material, etc. Therefore, to help the parties deciphering all these arguments, we designed an argumentation-based tool to take into account the conflicting preferences expressed. The requirements concerning packagings are modeled by several arguments provided by the stakeholders expressing their viewpoints and expertise. Based on a new attack relation, the argumentation tool computes sets of compatible arguments which are used to rank alternative packagings under debate. In this paper, we present a complete workflow implemented as a software prototype starting by defining a structured representation of experts arguments and poll results, and ending by a ranking of packaging solutions. We show and discuss the results obtained by the software on a use case study (fresh strawberries) to determine the justifiable choices between several packaging materials based on stakeholders' arguments.

Introduction et but de l’étude: La pepsine, sécrétée dans l’estomac, est la première protéase rencontrée par les protéines alimentaires au cours de la digestion. L’estomac acidifie lentement les bols alimentaires et il a été montré que le pH gastrique a un impact majeur sur les cinétiques de protéolyse 1.En effet, il est généralement admis que la pepsine n’est active qu’à pH acide, pour pH ≤ 5, avec un maximum d’activité autour de pH 2 pour beaucoup de substrats 2.Elle est également représentée comme un diacide 3, ce qui semble vrai lorsqu’elle agit sur l’hémoglobine, substrat de référence pour mesurer son activité. Ce comportement en fonction du pH n’a pas été validé sur des mélanges de protéines alimentaires telles que les caséines, principales protéines du lait, ou les protéines du blanc d’œuf. L’objectif principal de cette étude est de comparer les profils d’activité de la pepsine en fonction du pH sur les caséines du lait de vache (CA) et les protéines du blanc d’œuf (BO).Matériel et méthodes: Les cinétiques d’hydrolyse de protéines de BO entier et de micelles de CA par la pepsine, à différents pH compris entre 1 et 8, ont été suivies au pH-stat pendant 2h, avec quantification du degré d’hydrolyse final (DH) par la méthode OPA. Les vitesses initiales ont été calculées à partir de ces cinétiques entre 0 et 5 minutes. Les concentrations en substrat et en pepsine étaient les mêmes pour chaque expérience, et l’environnement salin était celui du protocole INFOGEST 4. Les CA se présentent en structures supramoléculaires, les micelles, qui précipitent à pH acide. Une étape d’acidification à pH 4 des CA a permis d’étudier des suspensions d’agrégats tous formés dans les mêmes conditions. L’aspect et la taille de ces agrégats ont été observés par microscopie confocale et par morpho-granulométrie.Résultats et Analyse statistique: Les cinétiques d’hydrolyse obtenues suivent, dans leur majorité, des profils de type loi de puissance en fonction du temps. Pour les protéines de BO, le DH final est maximal à pH1 (14,4%) et diminue de manière linéaire en fonction du pH,jusqu’à atteindre des valeurs négligeables pour les pH ≥6. A l’inverse, les valeurs de DH finaux sur les CA ne sont pas significativement différentes sur la gamme de pH 1 à 5 (7,5 ± 1,4 %) puis diminuent à partir de pH 6 et atteignent des valeurs négligeables à pH 8.Le rapport entre la vitesse d’hydrolyse initiale et le DH final des CA est supérieur à celui des protéines du BO quel que soit le pH, suggérant une cinétique d’hydrolyse plus rapide pour les CA.Ces résultats montrent que les caséines du lait,dont le pH se situe un peu au-dessus de 6, n’ont pas besoin d’être longuement acidifiées pour que l’hydrolyse par la pepsine puisse commencer dans l’estomac, atteignant une activité quasi optimale de la pepsine dès pH 5.Conclusion: Les cinétiques d’hydrolyse par la pepsine en fonction du pH diffèrent donc entre un substrat de type protéines globulaires comme l’œuf, et les caséines du lait. Le profil d’activité de la pepsine en fonction du pH est également différent de celui du standard hémoglobine. En outre, contrairement à ce qui est généralement admis, la pepsine peut hydrolyser certains substrats à des pH plus hauts que pH 5.

International audience; Le lait maternel est la référence en nutrition néonatale, en particulier pour les prématurés. Il pourrait réduire le risque de complications liées à la prématurité et serait bénéfique au neurodéveloppement de l’enfant. Le lait maternel de don, pasteurisé pour prévenir la transmission des pathogènes, est le premier choix pour nourrir les prématurés lorsque le lait de la mère n'est pas disponible. Cependant, la pasteurisation altère la qualité du lait en dénaturant certains composants biologiques. Le but de cette étude est d’évaluer in vitro l’impact de la pasteurisation du lait maternel sur la digestion gastro-intestinale chez l’enfant prématuré et sur l’absorption intestinale des lipides. Matériel et méthodes: Les cinétiques de digestion de lait maternel pasteurisé à 62,5°C pendant 30 min (LP) ou cru (LC) ont été réalisées dans un modèle de digestion in vitro statique que nous avons adapté pour simuler la capacité de digestion des prématurés. La protéolyse a été déterminée par électrophorèse en gel de polyacrylamide et la lipolyse par chromatographie sur couche mince. Puis, des cellules Caco-2/TC7, modèle d’absorption intestinale, ont été incubées avec le LP et le LC préalablement digérés. L’absorption lipidique a été quantifiée par analyse d’image numérique des gouttelettes lipidiques après coloration à l’Oil Red O dans les cellules et par mesure de la sécrétion de triglycérides dans le milieu extracellulaire. L’expression de certains gènes impliqués dans l’absorption intestinale des lipides a aussi été analysée. Résultats et Analyse statistique : A la fin de la phase intestinale de digestion in vitro du LP et du LC, la protéolyse de la lactoferrine, de la β-caséine et de l’α-lactalbumine comme la lipolyse n’étaient pas significativement différentes. Le nombre de pixels dans les gouttelettes lipidiques des cellules Caco-2/TC7 était diminué après 16h d’incubation avec le LP digéré par rapport à LC digéré (p=0,04). Le nombre de gouttelettes lipidiques par image était identique pour les 2 laits (p=0,26) mais l’aire moyenne des gouttelettes était plus petite dans les cellules Caco-2/TC7 incubées avec le LP digéré (p=0.01). La sécrétion des triglycérides dans le milieu baso-latéral après 16h d’incubation des cellules avec le LP ou le LC digérés n’était pas différente (36.1 vs 42.9 µmol/L respectivement, p=0.26). De plus, aucune différence dans l’expression de certains gènes impliqués dans le métabolisme des lipides n’a été mise en évidence. Conclusion: La pasteurisation du lait maternel n’entraine pas de modification importante de la protéolyse ni de la lipolyse en fin de digestion gastro-intestinale par rapport au lait cru. Dans les cellules Caco-2/TC7, les gouttelettes lipidiques étaient plus petites après incubation avec LP digéré qu'avec LC digéré mais la quantité de triglycérides sécrétés était similaire avec les 2 laits, suggérant que la pasteurisation n’a pas d’impact majeur sur l’absorption intestinale des lipides dans ces modèles in vitro. L’utilisation de lait maternel pasteurisé semble une bonne alternative par rapport au lait maternel cru d’un point de vue nutritionnel.

National audience; Introduction et but de l’étude Le processus de fabrication des préparations pour nourrissons (PPNs) implique des traitements thermiques, modifiant les propriétés physico-chimiques des protéines et éventuellement leur cinétique de protéolyse. L'objectif de l'étude consiste en l’analyse des effets de la composition et des structures protéiques thermo-induites des PPNs sur la cinétique de protéolyse. Matériel et méthodes Deux PPNs modèles ont été formulées à 1,3% de protéines. Elles se distinguent par la qualité des protéines du lactosérum (α-lactalbumine, β-lactoglobuline et lactoferrine) : la PPN « standard » mime la composition protéique de la majorité des PPNs 1er âge commercialisées et la PPN « LF+ ALA+ » celle du lait maternel. Les PPNs ont été traitées thermiquement à 67,5°C ou 80°C avec un taux de dénaturation des protéines du lactosérum identique de 65%. Les PPNs sans traitement thermique ont servies de référence. Les structures protéiques thermo-induites ont été caractérisées par électrophorèse, fractionnement d’écoulement de champ couplé à la diffusion de lumière multi-angle et microscopie électronique. D’autre part, les PPNs ont été soumises à la digestion gastro-intestinale en condition statique in vitro au stade nouveau-né à terme (n = 3). Le degré d’hydrolyse a été mesuré par dosage des amines primaires, la cinétique de protéolyse suivie par électrophorèse et l’évolution de la structure au cours de la digestion par granulométrie à diffraction laser. Résultats et analyse statistique A taux de dénaturation protéique équivalent, les caractéristiques morphologiques des structures protéiques thermo-induites diffèrent selon la composition protéique des PPNs et la température de traitement thermique. La formation d’agrégats solubles a été observée uniquement pour la PPN « standard », tandis que la fixation de protéines dénaturées sur les micelles de caséines a été constatée pour les deux PPNs. Les agrégats formés à 67,5°C ont une plus petite masse pour la PPN « standard » et un plus petit diamètre pour la PPN « LF+ ALA+ » que ceux formés à 80°C. Au cours de la phase gastrique, le traitement thermique accélère la cinétique de protéolyse des caséines de la PPN « standard » contrairement à la PPN « LF+ ALA+ ». La cinétique de protéolyse de l’α-lactalbumine dépend de la composition protéique des PPNs et de la température de chauffage de la PPN « LF+ ALA+ ». La protéolyse de la lactoferrine est fortement affectée par le traitement thermique. Les entités protéiques formées par agrégation en fin de phase gastrique sont affectées par la composition protéique des PPNs et le traitement thermique. Conclusion Notre étude a permis de mettre en évidence les effets de la composition protéique des PPNs et des structures protéiques thermo-induites sur les cinétiques de protéolyse. Ces deux paramètres sont donc à prendre en compte pour l’optimisation des PPNs en termes de stratégie nutritionnelle.

National audience; La fortification du lait de femme (LF) est une pratique courante dans l’alimentation des prématurés, pour les aider à rattraper leur retard de croissance. Les fortifiants, généralement à base de protéines de lait de vache hydrolysées (FV), peuvent poser des problèmes d’intolérances alimentaires de par l’immaturité du système digestif du prématuré. Un nouveau fortifiant à base de protéines entières de lait d'ânesse (FA) a été mis au point et testé lors d’un essai clinique randomisé chez les prématurés. Il a été démontré que la fortification de LF par FA réduisait l'intolérance alimentaire, les résidus gastriques bilieux et les épisodes de vomissements par rapport à FV, contenant des protéines hydrolysées. Le but de ce travail était d’évaluer comment ces différents fortifiants (FA, FV) affectaient la digestion des macronutriments (protéines et lipides) du LF. Matériel et méthodes: Du LF d’enfant prématuré, enrichi avec FA ou FV en conditions isoprotéique et isocalorique, a été digéré à l’aide d’un modèle de digestion in vitro dynamique adapté aux conditions digestives du nouveau-né prématuré. Les échantillons ont été prélevés à différents temps de digestion gastro-intestinale et ont été caractérisés en termes de protéolyse par suivi en électrophorèse et par mesure du degré d’hydrolyse (technique OPA) et de lipolyse par chromatographie en couche mince. La microstructure a été suivi au cours de la digestion par granulométrie à diffraction laser (distribution de taille de particules) et microscopie confocale. Résultats et Analyse statistique : Les cinétiques d’hydrolyse des protéines majoritaires de LF ne différaient pas entre les laits au cours de la digestion. Concernant le degré d’hydrolyse global, il était plus élevé avant digestion pour LF+FV que pour LF+FA de par la présence de protéines hydrolysées dans FV. Cette différence était maintenue entre les deux laits au cours de la digestion, mais l’écart était réduit en fin de phase intestinale. Le degré de lipolyse augmentait de la même manière pour les deux types de fortifications au cours de la digestion. De gros agrégats étaient présent dans LF+FA avant et pendant la digestion gastrique. La taille de ces particules était réduite après 60 min de digestion gastrique. Dans la phase intestinale, l'évolution de la taille des particules était similaire entre LF+FA et LF+FV. Conclusion: La libération des peptides et acides aminés est ralentie pour le lait de femme fortifié avec les protéines entières de lait d’ânesse par rapport à celui fortifié aux protéines hydrolysées de lait bovin. Ceci sera compléter par le dosage des peptides et acides aminés libérés au cours de la digestion. Apporter des protéines entières au nouveau-né avec le FA pourrait d’apporter au prématuré les acides aminés de manière plus progressive, et pourrait ainsi avoir un intérêt physiologique bénéfique pour la maturation du système digestif et immunitaire

About one third of the world's population suffers from micronutrient deficiencies with short and long-term consequences on individual life.Food fortification is one of the solutions for nutritional optimization to overcome these deficiencies, but the conditions for its maximum effectiveness remain to be defined regarding the actual bioavailability of these micronutrients.The impact of food structure on the kinetics of macronutrient digestion has been widely documented. However, with regard to micronutrients, studies do not always distinguish the matrix structure effect from the composition effect on their bioavailability. The main objective of this thesis is to evaluate the impact of food structure only on the digestion process and on the bioavailability of micronutrients, using real complex foods.Four foods with identical composition but different structures and textures have been designed, and enriched with icronutrients (lutein and vitamins D, B9 and B12). The structure of the food matrix had actually an impact on the bioavailability of lutein, and vitamins D and B9 in adult healthy men, in both quantitative and kinetics terms, thus providing proof of concept. The in vitro studies confirmed the food structure effect observed in vivo and allowed to study in depth the degradation of the food matrix, the release of micronutrients from the matrix, and thus their bioaccessibility.This work highlights the importance of the matrix effect for food digestion. It also suggests that a deep understanding of the digestion mechanisms could enable, in the future, the control over the digestion process with a targeted food design.; Un tiers de la population mondiale souffrirait d’une carence en micronutriments entraînant des conséquences à court et long terme sur la vie des individus. L’enrichissement des aliments est une des pistes de l’optimisation nutritionnelle visant à lutter contre ces carences, mais les conditions de son efficacité maximale restent à définir au regard de la biodisponibilitéréelle de ces micronutriments. L’impact de la structure des aliments sur la cinétique de digestion des macronutriments a été largement démontré. En revanche, en ce qui concerne les micronutriments, les études ne permettent pas toujours de distinguer les effets composition et structure de la matrice sur leur biodisponibilité. L’objectif principal de cette thèse est d’évaluer l’impact de la seule structure d’aliments réels sur le processus de digestion et la biodisponibilité des micronutriments.Quatre aliments de même composition mais de structures et textures variables ont été conçus et enrichis en micronutriments (lutéine et vitamines D, B9 et B12). La structure de la matrice alimentaire a effectivement influencé la biodisponibilité de la lutéine et des vitamines D et B9 chez l’Homme, et ce de manière quantitative et cinétique, apportant ainsi une preuve de concept. Les études in vitro ont permis de confirmer l’effet structure observé in vivo et d’étudier en détail la dégradation de la matrice alimentaire, la libération des micronutriments et donc leur bioaccessibilité.Ce travail souligne l’importance de l’effet matrice dans la digestion des aliments. Il suggère aussi que la compréhension fine des mécanismes de digestion pourrait permettre, à terme, la maîtrise du déroulement de la digestion par un design ciblédes aliments.

The objective of this work is to bring new information about the influence of temperatures (7 &deg, C and 20 &deg, C) on the equation of state and sol&ndash, gel transition behavior of casein micelle dispersions. Casein micelle dispersions have been concentrated and equilibrated at different osmotic pressures using equilibrium dialysis at 7 &deg, C. The osmotic stress technique measured the osmotic pressures of the dispersions over a wide range of concentrations. Rheological properties of concentrated dispersions were then characterized, respectively at 7 &deg, C and at 20 &deg, C. The essential result is that casein micelle dispersions are less compressible at 7 &deg, C than at 20 &deg, C and that concentration of sol&ndash, gel transition is lower at 7 &deg, C, with compressibility defined as the inverse to the resistance to the compression, and that is proportional to the cost to remove water from structure. From our interpretations, these two features were fully consistent with a release of soluble &beta, casein and nanoclusters CaP and an increased casein micelle hydration and apparent voluminosity at 7 &deg, C as compared with 20 &deg, C.

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.

Non-aqueous Taylor dispersion analysis (TDA) was used for the size-characterization of natural and synthetic polyisoprenes (4 × 103–2 × 106 g/mol molar mass). Not only the weight-average hydrodynamic radius (Rh), but also the probability distribution of the hydrodynamic radius, were both derived from the Taylorgrams by a simple integration of the elution profile and by a more sophisticated constrained regularized linear inversion of the Taylorgram, respectively. Results in terms of size characterization (hydrodynamic radii between 2 and 100 nm) were compared to size exclusion chromatography coupled to a refractive index-based mass detector. Multimodal size distributions were resolved by TDA for industrial and natural polyisoprenes, with the advantage over the chromatographic technique that, in TDA, there is no abnormal elution of microaggregates (hydrodynamic radii ∼ 40–50 nm). Considering the importance and the difficulty of characterizing polyisoprene microaggregates, TDA appears as a promising and simple technique for the characterization of synthetic and natural rubber. (Resume d'auteur)

International audience; Agricultural waste is a huge pool of untapped biomass resources that may even represent economic and environmental burdens. They can be converted into bioenergy and bio-based products by cascading conversion processes, within circular economy, and should be considered residual resources. Major challenges are discussed from a transdisciplinary perspective, focused on Europe situation. Environmental and economic consequences of agricultural residue management chains are difficult to assess due to their complexity, seasonality and regionality. Designing multi-criteria decision support tools, applicable at an early-stage of research, is discussed. Improvement of Anaerobic Digestion (AD), one of the most mature conversion technologies, is discussed from a technological point of view and waste feedstock geographical and seasonal variations. Using agricultural residual resources for producing high-value chemicals is a considerable challenge analysed here, taking into account innovative eco-efficient and cost-effective cascading conversion processes (bio-refinery concept). Moreover, the promotion of agricultural residues-based business is discussed through industrial ecology, to promote synergy, on a local basis, between different agricultural and industrial value chains. Finally, to facilitate a holistic approach and optimise materials and knowledge flows management, the connection of stakeholders is discussed to promote cross-sectorial collaboration and resource exchange at appropriate geographic scales.

The granulation step determines the production yield and the final characteristics of the agglomerated couscous grains of durum wheat. The objective of the present work was to explore the capability of the fluidised bed technology to produce agglomerates of durum wheat semolina. The impacts of different processing conditions have been investigated on the structure and functional properties of the agglomerates. The size, shape, water content, compactness, and mechanical strength of the granules were measured. The fluidized bed agglomeration process has been found to produce agglomerates of durum wheat with different attributes compared to those produced by granulation using the low shear mixers. The results were discussed in regard to the hydro-textural approach, in order to get a better understanding of the mechanisms and relationships between process, structure, and properties. Two major agglomeration mechanisms contribute to the growth of the wet agglomerates: a fractal-structuring process followed by a phenomenon of densification. By studying the evolution of the compactness, diameter and water content, it was demonstrated that inter granular arrangements led to an expansion followed by a densification of the wet agglomerates. A relationship was proposed to describe the growth using a fluidized bed of the wet agglomerates of durum wheat semolina.

Graphical abstract, Evaluating the quality changes of packed strawberries during storage requires multiple, time consuming and costly measurements such as sensorial, chemical and decay identification. In order to efficiently assess the quality of strawberries in Modified Atmosphere Packaging (MAP) while reducing the number of analysis done, we propose to gather the main visual quality changes under one unique, overall measurement. For this end, a protocol associated to a deterioration grid was built to evaluate surface deterioration as a function of time considering color change, texture softening and microorganism development. The developed method has permitted to build the deterioration kinetic of strawberries packed in different conditions (MAP or no MAP). It allows to mimic the quality analysis made by the consumer, at a glance, during purchase. To the best of our knowledge, the presented method is a breakthrough unlike most common usual methods mainly relying on the number of spoiled strawberries. • Global measurement of the deterioration encompassing microorganism development, color change and texture softening. • An annotation grid built to be used as reference for the attribution of the percentage of strawberries’ deterioration. • Measurements of a percentage of surface deterioration was found more accurate than counting the number of rotten strawberries.

International audience; In this study, wheat in pasta was partially or completely replaced by faba to increase its protein quantity and improve its quality. Increasing the ratio of faba:wheat protein from 0:100 to 100:0 (gig) in pasta enlarged its protein network at the microscopic scale and linearly diluted the covalently linked gluten network of wheat pasta by weakly linked proteins. A concomitant linear increase in the cooking loss (up to 2.6 fold), a decrease in resilience (up to 1.4 fold) and an increase of the in-vitro protein digestion (up to 25%) were observed in pasta. The increase in drying temperature (90 degrees C vs. 55 degrees C) promoted the covalent aggregation of proteins in all pasta, but was more efficient in legume pasta, enhancing their resilience and reducing their cooking loss, without altering the degree of protein hydrolysis. This was partly explained by the reduction in trypsin inhibitory activity in all legume pasta dried at 90 degrees C. Interestingly, scores for sensory attributes such as liking attributed to pasta containing 80% faba-protein were close to scores given to a commercial whole wheat pasta. Pasta made exclusively from faba dried at 55 degrees C or 90 degrees C tended to be liked more than their commercial gluten-free counterparts.

International audience; The antioxidant properties of trans-aconitic acid (TAA) alone or in the presence of usual antioxidants were assessed by DPPH assay. The IC 50 value equal to 70 mM was very high compared to usual antioxidants (vitamin C and trolox). A joint experimental/theoretical study suggested that hydrogen atom abstraction in TAA by DPPH. was located on –CH 2– methylene bridge because the corresponding radical was more stabilized than COO. and C=C. radicals. In combination with antioxidants (vitamin C, gallic acid, caffeic acid, trolox), synergy or additivity effects were noticed. The magnitude of the synergistic effect varied between 1.06 and 1.24 depending on the type and concentration of antioxidant for a concentration of TAA equal to 22.3 mM. Especially, the addition of TAA at a concentration below 32 mM to a solution containing 20 lM of vitamin C had a synergy effect. Beyond this concentration, TAA showed an additive effect.

Avant tout usage de la matière végétale, celle-ci est en règle générale broyée dans un objectif de densification, voir fractionnée pour obtenir des particules aux fonctions/propriétés ciblées. Le fractionnement de matières lignocellulosiques telles que les pailles de maïs, tiges de miscanthus, produit des particules de morphologie très poly disperse. La distribution des paramètres morphologiques est un critère important, soit pour la compréhension et le pilotage des procédés de fractionnement, soit pour l’utilisation de ces particules, par exemple dans la production de matériaux. Il est donc important d’avoir accès aux caractéristiques morphologiques des particules telles que leur taille et leur allongement. Nous nous sommes intéressés à deux systèmes de caractérisation utilisant des techniques d’acquisitions d’images optiques, mais dont la présentation de l’échantillon est différente : le système Qicpic (Sympatech) qui acquière avec une caméra rapide les images des particules qui sont dans un flux continu et le système MorphoG4 (Malvern) qui fait une acquisition d’image par transmission après dispersion sur une plaque en verre avec une faible pression. Pour les deux systèmes, l’analyse d’image se fait en système « boîte noire », mais nous avons ensuite accès à l’image de chaque particule identifiée et à des représentations de la dispersion des particules en fonction des diverses caractéristiques morphologiques. Notre démarche est de comparer les deux équipements à l’aide de deux poudres assez grossières (longueur des particules pouvant être supérieure au mm). Compte tenu de la taille et de la forme allongée de ces particules les techniques de granulométrie laser ne sont pas les mieux adaptées. Ces deux fractions contrastées sont issues du broyage de tiges de miscanthus via deux procédés de broyage différents et leur taille de particules est dans une gamme équivalente (200μm –800μm, obtenue par tamisage). Nous utilisons les équipements dans les conditions préconisées par les fournisseurs et avec un maximum d’étapes automatisées, qui seront idéalement utilisées pour la caractérisation des fractions futures. Les distributions volumique (ou en nombre) des paramètres morphologiques ont ainsi été comparée afin d’évaluer l’influence du mode de présentation sur les résultats obtenus.

L’imagerie multispectrale en autofluorescence consiste à mesurer les intensités de fluorescence émises à différentes longueurs d’ondes sous une ou plusieurs conditions d’excitation. Elle peut être réalisée à partir de microscopes d’épifluorescence à filtres et consiste alors à imager la même scène sous différents filtres (et donc différentes conditions d’excitation/émission de lumière). L’intensité de fluorescence émise est quantifiée et les signaux obtenus peuvent être assimilés à des pseudo-spectres de fluorescence qui peuvent être par la suite traités selon des approches chimiométriques. Ainsi des modèles de prédiction ou de classification peuvent être construits à partir d’une base de données de calibration issue d’images multispectrales, puis sont ensuite appliqués à d’autres jeux de données images. Si une standardisation de la préparation des échantillons et des conditions d’acquisition est recherchée, une variabilité peut exister, qu’elle soit anticipée ou pas. Ainsi la recherche d’échantillons de référence peut exiger la réalisation d’image de calibration sur des coupes d’échantillon alors que la prédiction se fera sur des échantillons pulvérulents. Par ailleurs les capacités d’acquisition rendant possible l’observation de grandes bases d’échantillons (ex images mosaïques en grand champs, sur de nombreux échantillon et sur plusieurs années) une augmentation de la variabilité entre des séries de jeux de données peut être suspectée. Connaître l’influence des modes de préparation sur le signal obtenu est primordial pour savoir si ils peuvent affecter ou non la robustesse des modèles et pour définir les stratégies à appliquer pour s’en affranchir (ex via l’acquisition des images ou le traitement des données). A travers des exemples liés à l’observation de structures végétales (grains, tiges de céréales), l’influence de certains modes de préparation (tel que l’épaisseur d’une coupe, le montage dans l’eau ou dans l’air, la nature de l’échantillon (coupe/poudre), ou le mode d’acquisition de l’image qui peut induire une multi-illumination de l’échantillon) sera évaluée sur les données spectrales d’autofluorescence. Leur conséquence sur les résultats finaux et les moyens de les prendre en compte via la chaîne globale d’analyse seront discutés

National audience

International audience; The production of milk powders is a strategic sector of the dairy industry. Due to its complex macromolecular composition, shedding light on the mechanisms governing milk drying constitutes a main industrial concern and a scientific challenge at the same time. In this study, we used the single droplet[1] and the directional drying[2] approaches to investigate the evaporation of colloidal mixes of the two major milk proteins (whey protein isolates and native phosphocaseinates). Notably, we observed the crack development in the samples to evaluate the competitive impact of the physico-chemical properties of whey proteins (rigid globular shape) and casein micelles (deformable sponge-like structure) on the drying process. Our outcomes are potentially useful to better control the functional properties of milk powders. Furthermore, they contribute to improve the understanding of the drying mechanisms in binary colloidal systems, which are still far from being fully elucidated.

International audience; Spray drying is a well-established process, but the phenomena ruling droplet-to-particle transition remain black box, resulting in variable powder properties and drying performances. Therefore, understanding precisely how the particle is formed and how to control its properties remain a major challenge. This work aims to breakdown the complexity of the drying phenomena using an exploratory multi-scale approach. Particle formation of different milk proteins (whey proteins and casein micelles) was investigated using different experimental systems (single pendant droplet, mono-dispersed droplets and spraying cone droplets) in controlled drying environments. The results showed that the drying of a single protein droplet included three distinct stages highlighting the occurrence of specific morphological events (constant rate shrinkage, buckling instability, vacuole nucleation). According to the type of proteins, these stages differed in drying kinetics and droplet dynamics, leading to characteristic and reproducible particle shapes irrespective of the droplet configuration and the drying conditions. These different drying behaviors were related to specific skin formation mechanisms at droplet air-liquid interface and consequent responses of the protein material to internal stresses. In this work, we aimed at understanding how the different physico-chemical properties of whey proteins (rigid globular shape) and casein micelles (deformable sponge-like structure) affect the mechanisms of formation of such a skin, and from this the particle final shape. However, the full understanding of the drying process of biocolloids is far to be achieved and, notably, the impact of solute properties on the morphological characteristics of the evaporating droplets, such as colloid segregation, skin formation and crack pattern development is not elucidated yet. To this aim, the use of model colloidal solutions, whose rheological behavior is more easily deducible, could represent a significant boost. Consequently, we compared the drying of droplets of whey proteins and casein micelles to that of dispersions of silica particles and polymer-coated silica particles, respectively. The mechanical behavior of such biological colloids and model silica dispersions was investigated through the analysis of crack formation, and the measurements of their mechanical properties using indentation testing. The study reveals numerous analogies between dairy and corresponding model systems, thus confirming these latter as powerful tools to highlight the signature of the matter on the drying process and at the molecular scale. The outcomes presented in this work represent a first step to shed light on the physics of drying dairy droplets; they open the road to further investigation about mixes of milk proteins. Moreover, the observation of mixtures of dairy colloids would contribute to improve the knowledge about the evaporation of colloidal polydisperse systems, which represents a current scientific challenge.

International audience; Introduction: Donor human milk (DHM) represents the best alternative when mother’s own milk is not available, a common occurrence in Neonatal Intensive Care Units. Heat treatment of DHM is mandatory for safety reasons. Holder pasteurization (HoP, 62.5°C-30’) is recommended by all human milk bank guidelines. Recent studies have demonstrated that HoP affects the digestion profile and behavior of several human milk components. High Temperature-Short Time pasteurization (HTST, 71°C-15’’) is currently under evaluation as a promising alternative technology to limit the denaturation of some biological compounds of raw human milk. The aim of the present work was to assess whether the different types of pasteurization (HoP, HTST) impacted the digestive kinetics of human milk during in vitro dynamic digestion. Materials and Methods: pooled raw HM (RHM) was collected and processed by using the two pasteurization techniques. The pasteurized samples and RHM were digested in vitro using preterm gastrointestinal conditions. Samples were collected at different digestion times. Undigested and digested milks samples were characterized for their particle size distribution (PSD), triglyceride content, protein and amino acid (AA) profiles. Results: during gastric digestion, both pasteurization methods modified PSD, as compared to RHM. Caseins were rapidly hydrolyzed in the gastric phase unlike that for the whey proteins. Lactoferrin was hydrolyzed faster in the pasteurized samples in comparison to RHM, in which lactoferrin was resistant to gastro-intestinal digestion. Heat-treatments, consequently, affected the intestinal release of some AA, and a higher bioaccessibility of AA was found for HTST, as compared to HoP. Concerning lipolysis, at any time of the intestinal digestion phase, the lipolysis of HoP samples was significantly lower (p < 0.05) than in both RHM and HTST samples. Conclusions: this work provides the first important evidences on the differential impact of HoP and HTST pasteurization techniques on bioaccessibility of DHM nutrients and biological compounds, for preterm newborns.

International audience; Oil bodies (OB) are the natural form of storage of triglycerides (TG) in seeds. OB consists in a TG core stabilized by a phospholipid and proteins (oleosins) monolayer membrane. Some oleoproteaginous seeds, such as walnut, contain high levels of polyunsaturated fatty acids (PUFA) and yet remain quite stable to oxidation over storage and present nutritional interest. Moreover, the trend towards vegetalbased food products has renewed the interest for preserving and understanding the functionalities of OB. In this context, the objective of our study was to elucidate walnut OB’s oxidative behavior and its interfacial reactivity. Walnut OB were characterized either included in a complex matrix (i.e. under the form of walnuts “milk”) or isolated (i.e. under the form of aqueous dispersion). The walnut OB oxidation was investigated by setting up accelerated storage tests (PV, TBARS). Biophysical tools (tensiometry, ellipsometry, atomic force microscopy…) were used to characterize the interfacial behavior of native dispersed OB in comparison with oxidized OB. It was established that walnuts OB were stable to oxidation on the short term (few days). This phenomenon is related to the “assembly effect” of OB and to their unsaponifiable content. The stability of lipid dispersion was higher under “milk” form due to a complex “matrix effect”. Interfacial adsorption of objects was marked by OB unfolding and protein-TG domains formation. Oxidation phenomenon modified the physical integrity of the objects, which resulted in a different interfacial organization. Altogether, this study unveiled the interesting stability of OB and their specific interfacial reactivity opening the way to interesting food applications of these natural lipoproteic assemblies.

Current Status and Future Prospects of Biocatalysis in Deep Eutectic Solvents. 17. Euro Fed Lipid Congress

International audience

L’élimination du dépôt de filtration par rinçage et nettoyage des membranes est une essentielle pour assurer l’efficacité de la filtration efficace. Pourtant, on trouve que la discussion actuelle des différents mécanismes, qui conduisent à l’élimination du dépôt après la filtration (gonflement, érosion, détachement, …), est loin d’être exhaustive. Pour cette raison nous avons consacré ce travail à la modélisation du comportement du dépôt de filtration réversible pendant la relaxation de la pression après filtration sur membrane. L’objectif de ce travail est de décrire la cinétique du gonflement d’un dépôt de particules colloidales en prenant en compte la résistance hydraulique de la membrane de filtration, et d’étudier l’influence du gonflement de ce dépôt sur son élimination de la surface de la membrane. La théorie de filtration-consolidation a été adaptée pour la description du gonflement. Les valeurs des caractéristiques du dépôt (compressibilité, filtrabilité (résistance spécifique) et épaisseur du dépôt), ainsi que les paramètres opératoires (résistance hydraulique de la membrane, pression transmembranaire appliquée) utilisées pour la modélisation étaient choisies pour être représentatives de l’ultrafiltration d’une suspension colloïdale avec une forte compressibilité réversible de dépôt. Il a été démontré que le gonflement d’un dépôt réversiblement compressible peut être assisté par l’absorption du filtrat à travers la membrane (Fig. 1). Cet effet est expliqué par la relaxation de la pression de solide après la réduction de la pression transmembranaire appliquée. Plus la résistance hydraulique de la membrane est faible (forte perméabilité de la membrane), plus l’absorption du filtrat et la vitesse de gonflement du dépôt augmentent. Lorsque la résistance hydraulique de la membrane est faible et la résistance hydraulique du dépôt est forte, l’absorption du filtrat au travers la membrane peut conduire à une distribution non-uniforme de la concentration du solide dans le dépôt gonflé : le modèle prédit une distribution en forme de cloche (Fig. 2a). A la membrane, l’adhésion du dépôt diminue avec la diminution de la concentration locale, et la faible concentration en solide dans le dépôt (distribution en forme de « cloche ») peut faciliter son élimination de la surface de la membrane. Donc, un dépôt dont les propriétés de compressibilité sont réversibles peut être facilement éliminé de la surface d’une membrane ayant une faible résistance hydraulique, avant la fin du gonflement. En revanche, le gonflement du même dépôt à la surface d’une membrane peu perméable (résistance hydraulique élevée) est plus lent, et conduit à une distribution monotone de la concentration du solide (la concentration est la plus élevée à l’interface dépôt-membrane, Fig. 2b). Dans ce cas le dépôt s’élimine de la membrane après la fin du gonflement. Ces phénomènes doivent être pris en compte dans la planification des expérimentations et les analyses des résultats de filtration qui s’intéressent à l’étude de la force d’adhésion du dépôt à la membrane.

International audience; Phytoprostanes (PhytoPs) and phytofurans (PhytoFs) are isoprostanoids that result from the peroxidation of α-linolenic acid and are biomarkers of oxidative stress in plants and humans. These compounds exhibit several interesting biological activities (e.g. neuroprotection and anti-inflammatory activities). The aim of this research was to add value to coffee pulp (CP), cocoa husk (CH) and cocoa pod husk (CPH) by identifying and quantifying PhytoPs and PhytoFs by liquid chromatography–tandem mass spectrometry. The contents of PhytoPs and PhytoFs in CP, CH, and CPH were, respectively, 654.6, 474.3 and 179.9, and 543.2, 278.0 and 393.8 ng per g dry weight (dw). The main PhytoP found in CP (171.37 ng per g dw) and CPH (37.12 ng per g dw) was 9-epi-9-F1t-PhytoP, while ent-9-L1t-PhytoP was the most abundant in CH (109.78 ng per g dw). The main PhytoF found in all sources was ent-16(RS)-13-epi-ST-Δ14-9-PhytoF, at 196.56, 126.22, and 207.57 ng per g dw in CP, CH, and CPH, respectively. We provide the first complete profile of PhytoPs and PhytoFs for these agro-residues, which could be used in the functional food industry for enriching food or as nutritional supplements.

National audience; The Toulouse FFF Center (TFFFC) project aim is the development of a shared research platform for characterization of complex samples using Field-Flow Fractionation technologies. The project is built around collaborative projects with partners from various fields of activities such as agrifood, polymer chemistry, renewable carbon valorization and analytical equipment. The financial support of the Region Occitanie, European funds and industrial partners make possible the creation of an analytical platform dedicated to FFF technologies unique in Europe and to develop innovative approaches and tools allowing the characterization of complex samples by these Field-Flow Fractionation technologies. The performance of these techniques will be evaluated for the characterization various nano and micro-structures like proteins. We will also develop analytical methodologies using different FFF techniques to better characterize complex milk protein samples used as agro-food texturing agents and lignocellulosic materials, a product of interest in renewable carbon chemistry. These projects will be carried out in collaboration with industrial partners.

Additive manufacturing or 3D printing has the potential to displace some of the current manufacturing techniques and is particularly attractive if local renewable waste resources can be used. In this study, rice husk, and wood powders were compounded in polylactic acid (PLA) by twin screw extrusion to produce filaments for fused-deposition modeling 3D printing. The biomasses were characterized in terms of physical features (e.g., particle size, density) and chemical compositions (e.g., solid state nuclear magnetic resonance, ash content). The two biomasses were found to have a different impact on the rheological behavior of the compounds and the extrusion process overall stability. When comparing the complex viscosity of neat PLA to the biomass/PLA compounds, the integration of wood powder increased the complex viscosity of the compound, whereas the integration of rice husk powder decreased it. This significant difference in rheological behavior was attributed to the higher specific surface area (and chemical reactivity) of the rice husk particles and the presence of silica in rice husks compared to the wood powder. Color variations were also observed. Despite the biomass filler and rheological behavior differences, the mechanical properties of the 3D printed samples were similar and predominantly affected by the printing direction.

International audience; The objectives of the study were to: 1 Determine whether gastric emptying of an isoproteic solution of CM and CS are different or not (exp. 1) 2 Characterize the structure of the resulting chyme and determine if CM and CS are differently metabolized (exp. 2)

Shockwave processing and sous vide cooking improve sensorial and nutritional qualities of beef. Food Structure Digestion and Health congres

Milk microbiota: physiological and health implication.. Meeting du LIA Bact-Inflam

Inflammation, DNA damage and Staphylococcus aureus infection. Meeting du LIA Bact-Inflam

Modelling and optimizing food processes is a complicated task due to the high complexity of the food product itself, the lack of knowledge concerning mechanisms limiting process performances [1], and to the heterogeneity of the involved variables (ordinal, cardinal, discrete or continuous variables). This is the case for skim milk crossflow microfiltration with 0.1 μm pore size (MF 0.1 μm). This operation is commonly used in dairy industry to separate proteins: native casein micelles (retentate) are used in cheese making while serum proteins (permeate) are mainly used in food formulations for specific populations (elderly people, infants, etc). Despite the high interest in MF in the dairy sector, this process is not optimized by considering the different conflicting objectives of the industry such as maximizing protein recovery in the permeate fraction while minimizing economic costs. The choices of membrane configurations, processing designs and operating conditions are based on the know-how of operators and the available expert knowledge. This knowledge is partial and does not take into account links between the process operating variables, product state variables and optimization objectives. When the optimization of MF 0.1 μm is performed, it is often described as mono-objective and empirical problem [2] or as study cases showing the influence of one variable on a group of chosen variables [3]. This article presents a methodology for collecting, collating and representing expert knowledge necessary to the design of food processing multi-objective optimization problems focusing on skim milk MF.2. MethodsThe proposed methodology has four steps: formulation of the multi-objective optimization problem, modelling optimization objectives as functions, optimization of objective functions and choice of a solution to implement [4]. In this work, the focus is on the problem formulation. TheMF 0.1 μm optimization problem is multidisciplinary and the knowledges necessary to formulate and solve the problem are shared between several experts. By dividing the problem domain into domains of knowledge, the identification of experts and the knowledge collection are easier [5]. The semi-structured interview was used to elicit know-how and knowledge from experts. The influence relations between variables and objectives were collected from the interviews and represented as causal maps. Graphical representation allows expert to exchange easily about influence relations. After validations, maps of the same knowledge domain were merged, discussed and validated by the group of the domain experts. Maps represent the knowledge models to use for formulating the optimization objectives as functions from the literature or experimental data.3. Results and discussionIn this work, the operational objective is to be able to compare optimized microfiltration systems within a global process that can accept different membranes, processing designs and operating conditions. Optimization objectives were defined with the stakeholders: ten experts and decision makers. First, ten objectives were defined and reduced to six regarding industrial issues (maximization of the retentate composition, permeate composition, permeate protein recovery and stability of the permeation flux and minimization of the investment cost and operating cost). The MF 0.1 μm optimization problem domain was divided into nine knowledge domains: membrane properties, performance of the filtration, operating variables, permeate fraction, retentate fraction, process design, costs and environmental impacts. Each knowledge domain benefited from two to seven experts. Knowledge was collected during 36 interviews representing 14h30 of audio recording. For each knowledge domain, a causal map by expert was established and the whole merged as the causal map of the domain. After validations, each domain causal maps were discussed and validated by the different domain experts (industrialists, scientists, equipment manufacturers). One very important point of this step was to define a shared glossary and a generic process scheme representative of all the specific schemes. By the end, the extracted causal relations between variables were represented in 9 maps using approximately 250 variables.4. ConclusionsThe optimization problem studied is complex with conflicting objectives and heterogeneous variables. The integration of expert knowledge allows the identification of relevant objectives regarding to industrial issues. The MF process is considered from conception to performances with the identification of lack of knowledge in order to plan new experiments. Causal maps allow an easy to understand representation of the influences between the variables and make it possible to establish which variables influence which objectives. Based on these maps, the objective functions will be formalized allowing to perform the optimization.

Iron particles of sizes between 6 and 20 nm forming aggregates of 57 &plusmn, 17 nm were synthesized by chemical reduction of iron precursors on the surface of montmorillonite (MMT). This active MMT-Fe powder was then uniformly distributed in a linear low-density polyethylene (LLDPE) matrix by extrusion at atmospheric conditions, as confirmed by wide-angle X-ray scattering (WAXS), which also detected a partial exfoliation of the nanoclays. Thermogravimetric analysis (TGA) did not detect any significant modification of the degradation temperature between nanocomposites and active nanocomposites. 57Fe M&ouml, ssbauer spectroscopy evidenced the formation of a majority of iron boride in MMT-Fe as well as in the active film containing it. The LLDPE.Fu15.MMT-Fe3.75 and LLDPE.Fu15.MMT-Fe6.25 films had oxygen-scavenging capacities of 0.031 &plusmn, 0.002 and 0.055 &plusmn, 0.009 g(O2)/g(Fe), respectively, while the neat powder had an adsorption capacity of 0.122 g(O2)/g(Fe). This result confirms that the fresh film samples were partially oxidized shortly after thermomechanical processing (60% of oxidized species according to M&ouml, ssbauer spectroscopy). No significant difference in oxygen permeability was observed when MMT-Fe was added. This was related to the relatively small film surface used for measuring the permeability. The reaction&ndash, diffusion model proposed here was able to reproduce the observed data of O2 adsorption in an active nanocomposite, which validated the O2 adsorption model previously developed for dried MMT-Fe powder.

This data article contains annotation data characterizing Multi Criteria Assessment (MCA) Methods proposed in the agri-food sector by researchers from INRA, Europe's largest agricultural research institute (INRA, http://institut.inra.fr/en). MCA can be used to assess and compare agricultural and food systems, and support multi-actor decision making and design of innovative systems for crop production, animal production and processing of agricultural products. These data are stored in a public repository managed by INRA (https://data.inra.fr/; https://doi.org/10.15454/WB51LL). Keywords: Literature search query, INRA divisions, Trade-offs, Multicriteria decision, Multicriteria assessment

Fouling of heat exchangers is a major problem in the dairy industry. Deposits indeed produce a thermally insulating layer over the surface of the heat exchanger that decreases the heat transfer toward fluids and increases the pressure drop. Additionally , fouling can seriously affect the quality of food product s by favoring the development of harmful bacteria, and thus increase the costs and environmental impacts because thorough cleaning procedures have to be used. In this context, fouling control solut ions are thus required. The present work thus aimed at testin g graphite -based materials to heat exchangers for the dairy ind ustry. The fouling behavior was analyzed for four commercial graphite plates, submitted to pasteurization conditions in a pilot pasteurizer.