Portail HAL ONIRIS VetAgroBio Nantes
Not a member yet
11563 research outputs found
Sort by
Développement d’un traitement de chauffage par micro-ondes comme substitut au procédé classique de stérilisation en autoclave
No full textThis research investigates the development of a microwave-based heat treatment process as a sustainable alternative to conventional sterilization, focusing on the thermo mechanical behavior of food packaging during high-temperature processing of a model food product (mashed potato). Conventional sterilization studies on rigid metal containers combined experiments and numerical modelling using COMSOL Multiphysics® to analyze temperatures within the food product and pressure evolution within the head space, showing that dry air contributes to total internal pressure mainly during the early heating stage, while vapour pressure becomes dominant during the rest of the process. Flexible polypropylene (PP) trays (empty and filled with mashed potato) were then examined under different mechanical constraints to evaluate their structural response under air injection, convective heating treatment, and microwave heating. Although the application of mechanical constraints increased internal pressure tolerance of the packaging, rupture consistently occurred at the heat-seal interface. The final study was conducted with a rigid Polyether ether ketone (PEEK) container designed to withstand internal pressure during microwave heating, achieving internal temperatures above 118 °C. Overall, this work lays the groundwork for understanding the thermo–mechanical dynamics of food packaging during heat treatment, providing a foundation for designing safer and more energy-efficient food processing systems.Cette recherche porte sur le développement d’un procédé de traitement thermique par micro-ondes comme alternative durable à la stérilisation conventionnelle, en mettant l’accent sur le comportement thermo mécanique des emballages alimentaires soumis à des températures élevées. Les études de stérilisation conventionnelle réalisées sur des récipients métalliques rigides ont combiné des expériences et des modélisations numériques sous COMSOL Multiphysics® afin d’analyser l’évolution de la température et de la pression. Les résultats ont montré que l’air sec contribue principalement à la pression interne totale au début du chauffage, tandis que la pression de vapeur devient dominante pendant le reste du processus. Des barquettes flexibles en polypropylène (PP) ont ensuite été étudiées sous différentes contraintes mécaniques afin d’évaluer leur réponse structurelle lors d’injections d’air, de traitements thermiques et de chauffages par micro-ondes. Bien que l’application de contraintes ait augmenté la tolérance à la pression interne, la rupture s’est produite de manière récurrente au niveau de la zone de scellage. L’étude finale a été réalisée avec un récipient rigide en polyétheréthercétone (PEEK) conçu pour résister à la pression interne lors du chauffage par micro ondes, atteignant des températures supérieures à 118 °C. Dans l’ensemble, ce travail pose les bases du développement des procédés de stérilisation par micro-ondes en établissant, dans un premier temps, une compréhension scientifique des dynamiques thermo-mécaniques des emballages alimentaires lors du traitement thermique, ouvrant la voie à la conception de systèmes de transformation des aliments plus sûrs et plus économes en énergie. mécaniquement confinés constituent une voie prometteuse vers un traitement thermique sûr, sans eau et économe en énergie
Coupled CFD-Structural Mechanics Simulation Of Deformation In Non-Rigid Polypropylene Food Packaging
No full textInternational audienc
Impact of breeding methods on microbiota composition, Campylobacter contamination, and its dynamics on broiler carcasses during refrigerated storage
No full textInternational audienc
RBA4SDS – Risk–benefit assessment for sustainable dietary shifts
No full textInternational audienceDiets are evolving to cope with the ecological transition and reduce the environmental impact of agri‐food systems. The alternatives currently available will influence the nutritional content of diets and will also change consumers' exposure to microbiological and chemical hazards. Health impacts need to be considered to suggest safe, nutritious and sustainable alternatives. Quantifying this overall health impact is now possible using methods of food risk–benefit assessment (RBA), a recognised and well‐established approach that integrates scientific knowledge on nutrition, toxicology, microbiology and human epidemiology. The Risk–Benefit Assessment for Sustainable Dietary Shift (RBA4SDS) project aimed to train a fellow to analyse the overall health impacts of dietary transitions towards more climate‐friendly diets. This included performing RBA and applying the necessary quantitative tools to evaluate nutritional, microbiological and toxicological risks and benefits. The present project focused on a practical case considering the substitution of meat by insects and plant‐based alternatives including lentil and red kidney bean for Croatia, France and Greece. As part of the programme, the fellow was involved in the following activities: (i) understanding key steps of food health RBA, with a focus on nutrition, microbiology and toxicology; (ii) defining and characterising various sustainable diet alternatives, including meat, insect‐based and plant‐based options; (iii) identifying available and missing data inputs needed for RBA of selected alternative scenarios; (iv) applying RBA methods to assess a chosen alternative scenarios; (v) identifying strategies for further development of RBA methodologies. Within the research group, multi‐criteria decision analysis (MCDA) tool was used to rank sustainable options for alternative scenarios. The project enabled the fellow to define different sustainable food alternatives and to identify both available and missing inputs required to perform RBA and to suggest strategies to develop further RBA methodology
Investigation of the Hydrodynamic Structure of a Detached Two-Phase Bubble Flow and the Heat Exchange in a Rectangular Channel with an Obstacle
No full textInternational audienceAn experimental investigation of the hydrodynamic structure of a detached two-phase bubble flow and the heat exchange in a channel with an obstacle in the form of a rectangle, an isosceles trapezoid, or a rectangular trapezoid has been performed. The experiments were carried out for the flow of a liquid and with a gas content β = 0–5% at Reynolds numbers falling within the range 5000–12,500. The total hydrodynamic characteristics of this flow were measured by the PIV/PLIF method. It is shown that the introduction of bubbles into a liquid flow in the indicated channel shifts the points of its reattachment upstream, as compared to that of the one-phase flow, which is due to the increase in the velocity gradient of the two-phase liquid flow in the near-wall region of the channel. For estimating the heat exchange in the channel, the temperature of the outer wall of a heated stainless-steel plate mounted flush with the channel wall, was measured with the use of an infrared imager. It was established that the combined effect of the introduction of an obstacle into the channel and of bubbles into the liquid flowing in it makes it possible to intensify the heat exchange in the channel by 60%
Managing urban wastewater for potential reuse: coupling techniques for the elimination of emerging contaminants - Focus on adsorption of carbamazepine and sulfamethoxazole on activated carbon
No full textInternational audienc
Contribution of an epidemiological and population dynamics model in understanding the persistence of influenza a viruses in three pig farms in France
No full textInternational audienc
Intracellular Membrane Repair Dysregulation and Accumulation of Mature Myostatin Protein are Novel Markers of Muscle Pathophysiology in Pompe Disease
No full textInternational audiencePompe disease is a rare autosomal recessive metabolic disorder resulting from acid alpha-glucosidase deficiency. Clinically, it is defined by progressive skeletal muscle weakness and respiratory failure. In skeletal and cardiac muscles, it is characterized by an aberrant glycogen accumulation within lysosomes, which is associated with autophagic build-up, mitochondrial alterations, and myofibrillar disorganization. Despite increasing tissue damage, satellite cells (SCs), which are the main actor responsible for muscle repair processes, surprisingly fail to activate. This study aimed to investigate the phenotypic features of affected muscle, with particular focus on membrane repair, since membrane disruption is a central trigger for SC activation. A longitudinal transcriptomic analysis in a Pompe disease mouse model, supplemented by immunohistochemical and biochemical approaches, revealed early and persistent overexpression of key membrane repair proteins: dysferlin, annexin A2 and AHNAK2. Strikingly, these proteins displayed abnormal subcellular distribution with accumulation of dysferlin, annexin A2 and AHNAK2 at lysosomes, autophagosomes and T-tubules, respectively. Such mislocalization suggests a compensatory response aimed at maintaining intracellular structural integrity rather than canonical sarcolemmal repair. Analysis of muscle biopsies from late-onset Pompe disease patients confirmed these findings, showing sarcoplasmic accumulation of these proteins, which correlated with the severity of histopathological lesions. Furthermore, a persistent post-transcriptional accumulation of mature myostatin, a key negative regulator of muscle growth, was detected in the mouse model. This deregulation may contributes to defective SC activation and explains the absence of regenerative responses despite pronounced muscle injury.Overall, we found that Pompe disease muscle displays altered expression and subcellular distribution of membrane repair proteins, combined with deregulated myostatin signaling. These events emerge as critical factors in disease progression, accounting for defective regenerative capacity. These insights highlight novel therapeutic avenues, including enhancement of membrane repair mechanisms and modulation of myostatin pathway, to mitigate muscle damage and improve clinical outcomes in Pompe disease
