14 research outputs found
Multi-response Modelling of the Maillard reaction in a model cheese
International audienceProcessed cheese derives from a secondary milk processing step that involves mixing and heating dairy (cheese, butter and milk powders) and non-dairy products (emulsifiers). This processing yields a homogeneous product, usually spreadable, with a shelf-life often longer than 6 months. During cheese processing and storage, lipid oxidation, caramelization and Maillard reactions occur and produce odour-active compounds. In this study, a methodological approach was used in order to (i) identify odorants responsible for flavor attributes or compouds involved in the reaction chain, (ii) monitor the evolution of these markers during the heat treatment applied to the matrix, (iii) establish an observable reaction scheme and (iv) model and predict the evolution of these compounds during thermal operations. In this aim, a model cheese and a cooking cell were elaborated. Various couplings of gas chromatography with olfactometry were used to identify odorous compounds. Two-dimensional comprehensive chromatography allowed a semi-quantitation of trace and ultra-trace compounds, while precursors were quantitated by high performance liquid chromatography. An observable reaction scheme of the Maillard reaction was extracted from these data and makes the multi-response modeling step possible despite a partial quantitation of the volatile compounds. Finally, we obtained a formal model combining 19 components (including four odorants) connected by 14 stoechiometric balanced reactions. This model makes it possible to predict the evolution of these components depending on the initial content of lactose, galactose and according to the heat treatment applied to the cheese matrix. This work was carried out with the financial support of the ANR-Agence Nationale de la Recherche-The French National Research Agency under the Programme National de Recherche en Alimentation et nutrition humaine , project ANR-06-PNRA-023REACTIAL "Prediction and control of the appearance or disappearance of reactional markers during food process and conservation "
Multi-response Modelling of the Maillard reaction in a model cheese
International audienceProcessed cheese derives from a secondary milk processing step that involves mixing and heating dairy (cheese, butter and milk powders) and non-dairy products (emulsifiers). This processing yields a homogeneous product, usually spreadable, with a shelf-life often longer than 6 months. During cheese processing and storage, lipid oxidation, caramelization and Maillard reactions occur and produce odour-active compounds. In this study, a methodological approach was used in order to (i) identify odorants responsible for flavor attributes or compouds involved in the reaction chain, (ii) monitor the evolution of these markers during the heat treatment applied to the matrix, (iii) establish an observable reaction scheme and (iv) model and predict the evolution of these compounds during thermal operations. In this aim, a model cheese and a cooking cell were elaborated. Various couplings of gas chromatography with olfactometry were used to identify odorous compounds. Two-dimensional comprehensive chromatography allowed a semi-quantitation of trace and ultra-trace compounds, while precursors were quantitated by high performance liquid chromatography. An observable reaction scheme of the Maillard reaction was extracted from these data and makes the multi-response modeling step possible despite a partial quantitation of the volatile compounds. Finally, we obtained a formal model combining 19 components (including four odorants) connected by 14 stoechiometric balanced reactions. This model makes it possible to predict the evolution of these components depending on the initial content of lactose, galactose and according to the heat treatment applied to the cheese matrix. This work was carried out with the financial support of the ANR-Agence Nationale de la Recherche-The French National Research Agency under the Programme National de Recherche en Alimentation et nutrition humaine , project ANR-06-PNRA-023REACTIAL "Prediction and control of the appearance or disappearance of reactional markers during food process and conservation "
Heat-induced volatiles and odour-active compounds in a model cheese
International audienceThe aim of this work was to identify and characterize the volatile compounds formed during the cooking of a model cheese. Particular attention was paid to the generation of the odour-active volatile fraction, which can contribute to the sensory characteristics of cheeses. To this end we used various analytical methods including two-dimensional gas chromatography coupled with time-of-flight mass spectrometry and chromatographyâolfactometry. The changes observed in the volatile fraction enabled us to follow several markers of lipid oxidation, caramelization and Maillard reaction mechanisms during cooking. Maltol and furaneol, though present in only trace amounts, gave rise to "overcooked" odour defects in the cheese matrices
Retrospective multicentric study on Campylobacter spp. bacteremia in France: the Campylobacteremia study
International audienceAbstract Background Campylobacter spp. bacteremia is a severe infection. A nationwide 5-year retrospective study was conducted to characterize its clinical features and prognostic factors. Methods Patients diagnosed with Campylobacter spp. bacteremia in 37 French hospitals participating in the surveillance network of the National Reference Center for Campylobacter and Helicobacter were included from January 1, 2015, to December 31, 2019. The goal was to analyze the effects of a delay of appropriate antibiotic therapy and other risk factors on 30-day mortality, antibiotic resistance, patient characteristics and prognosis according to the Campylobacter species. Findings Among the 592 patients, Campylobacter jejuni and Campylobacter fetus were the most commonly identified species (42.9 and 42.6%, respectively). The patients were elderly (median age 68 years), and most had underlying conditions, mainly immunodepression (43.4%), hematologic malignancies (25.9%), solid neoplasms (23%) and diabetes (22.3%). C. jejuni and Campylobacter coli were associated with gastrointestinal signs, and C. fetus was associated with secondary localizations. Among the 80 patients (13.5%) with secondary localizations, 12 had endocarditis, 38 vascular, 24 osteo-articular and 9 ascitic fluid infections. The thirty-day mortality rate was 11.7%, and an appropriate antibiotic treatment was independently associated with 30-day survival (odds ratio [OR]=0.47, 95% CI [0.24â0.93], p=0.03). The median efficient therapy initiation delay was quite short (2 days, IQR [0â4]) but it had no significant impact on 30-day mortality (p=0.78). Interpretation Campylobacter spp. bacteremia mainly occurred in elderly immunocompromised individuals with variable clinical presentations according to the species involved. Appropriate antimicrobial therapy was associated with improved 30-day survival
Le chant, acteur de l'histoire
Le projet de cet ouvrage part d'un constat : les historiens se sont peu attachĂ©s Ă l'Ă©tude des textes appuyĂ©s sur un support musical et ils les ont trop souvent traitĂ©s comme des Ă©crits ordinaires. La raretĂ© des travaux dans ces domaines rĂ©sulte pour une large part du statut mixte d'un genre inadaptĂ© aux procĂ©dures de l'analyse et du commentaire du texte. Ă la diffĂ©rence des « catĂ©chismes » et manuels de tout genre dont on retient les formules apprises par cĆur, du discours politique ou du sermon dont on retient plus l'esprit que les formules, l'assimilation du texte chantĂ© se fait Ă la fois par un air et par des paroles. Qu'il s'agisse de la chanson politique ou du chant religieux, c'est la musique qui guide les paroles, qui aide Ă les mĂ©moriser et contribue Ă maintenir une atmosphĂšre, des sentiments, des convictions que l'air simplement fredonnĂ© suffit Ă faire revivre. On pressent donc facilement que l'impact du chant ne rĂ©sulte pas seulement d'une opĂ©ration intellectuelle, mais qu'il dĂ©pend des formes de sociabilitĂ© et qu'il structure des reprĂ©sentations et concerne au premier chef l'Ă©ducation des sens, de l'Ă©motion et du goĂ»t. Tous les mouvements idĂ©ologiques ou religieux ont utilisĂ© le support musical pour convaincre, pour rallier, pour souder foules, militants ou croyants. L'essai d'une Ă©tude simultanĂ©e de l'organisation formelle des textes et des structures musicales fonde l'originalitĂ© mĂȘme de cet ouvrage qui supposait l'intervention conjointe d'historiens, de musicologues et d'ethnomusicologues. Du Moyen Ăge Ă Yves Montand, de la Bretagne ancienne Ă celle du xxe siĂšcle, ces textes illustrent, dans leur nĂ©cessaire diversitĂ©, les aspects d'une problĂ©matique riche de promesses
: Rapport d'Ă©tape 2015
Ce rapport reprend les principaux objectifs du projet d'étude de la recolonisation de la Sélune et de ses affluents. Ces rappels sont suivis d'une synthÚse des résultats obtenus en 2015, année qui a été écourtée du fait de la signature tardive de la convention de recherche entre l'INRA et l'AESN : il s'agit de ce fait d'un rapport d'étape sur les actions prévues pour 2015, et non d'un rapport final
: Rapport d'Ă©tape 2015
Ce rapport reprend les principaux objectifs du projet d'étude de la recolonisation de la Sélune et de ses affluents. Ces rappels sont suivis d'une synthÚse des résultats obtenus en 2015, année qui a été écourtée du fait de la signature tardive de la convention de recherche entre l'INRA et l'AESN : il s'agit de ce fait d'un rapport d'étape sur les actions prévues pour 2015, et non d'un rapport final
: Rapport d'Ă©tape 2015
Ce rapport reprend les principaux objectifs du projet d'étude de la recolonisation de la Sélune et de ses affluents. Ces rappels sont suivis d'une synthÚse des résultats obtenus en 2015, année qui a été écourtée du fait de la signature tardive de la convention de recherche entre l'INRA et l'AESN : il s'agit de ce fait d'un rapport d'étape sur les actions prévues pour 2015, et non d'un rapport final
: Rapport d'Ă©tape 2015
Ce rapport reprend les principaux objectifs du projet d'étude de la recolonisation de la Sélune et de ses affluents. Ces rappels sont suivis d'une synthÚse des résultats obtenus en 2015, année qui a été écourtée du fait de la signature tardive de la convention de recherche entre l'INRA et l'AESN : il s'agit de ce fait d'un rapport d'étape sur les actions prévues pour 2015, et non d'un rapport final
: Rapport final des travaux liés à la convention annuelle 1054505-1
Ce rapport porte sur un état des lieux démographique, génétique et phénotypique de taxons susceptibles de subir de fortes modifications de leur distribution spatiale et de leurs interactions intra-et inter-spécifiques suite à l'arasement prévu de deux barrages hydro-électriques sur le fleuve Sélune. Il contient les éléments déjà transmis dans le rapport d'étape établi fin 2015 auxquels ont été ajoutés les données et analyses obtenues lors de la fin de l'exercice sur lequel portaient ces travaux : le présent rapport ne complÚte pas mais remplace le rapport d'étape, ce qui permet une présentation complÚte et cohérente de l'ensemble des travaux réalisés, sans obligation pour le lecteur de naviguer entre deux rapports