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Ce numéro comprend les articles correspondant aux présentations du Colloque Casdar 2018; National audience; The « LACTAFF » program (2012-2015) aimed at improving the control of goat lactic farmhouse cheese ripening, a technology frequently used by farmers, by producing tools and references for producers and the technicians guiding them. Surveys conducted in 49 farms in the 6 main regions producing this kind of cheeses allowed to characterize the great diversity of cheeses, premises, equipment and practices, and to link cheese categories with practices, premises characteristics and air production conditions. In laboratory and experimental dairies, the key role of humidity was quantified during ripening and during drying, in which air speed is even more important. Atmospheric parameters effects on cheeses physicochemical composition and sensory characteristics were quantified for one type of cheeses. Specialist experience of cheese technology, premises design and climate control equipment and technician experience were capitalized at the same time. This project led to the writing of technical documents available online and a book about lactic farmhouse cheeses ripening.; Le programme LACTAFF (2012 – 2015) a eu pour objectif d’améliorer la maîtrise de l’affinage des fromages fermiers lactiques, technologie la plus couramment utilisée à la ferme, en fournissant des outils et des références aux producteurs et aux techniciens qui les accompagnent. Des enquêtes menées dans 49 fermes des 6 principales régions produisant ce type de fromage ont permis de caractériser la grande diversité des fromages fabriqués, des locaux, des équipements et des pratiques et d’établir des liens entre les grandes catégories de fromages et les pratiques, locaux et conditions d’ambiance. Par ailleurs, au laboratoire et en fromageries expérimentales, le rôle clé de l’hygrométrie a été quantifié en affinage, ainsi qu’au séchage où la vitesse d’air joue un rôle encore plus important. Les effets des paramètres d’ambiance sur la composition physico-chimique et les caractéristiques sensorielles des fromages ont été quantifiés pour un type de fromage donné.

Ce numéro comprend les articles correspondant aux présentations du Colloque Casdar 2018; National audience; The « LACTAFF » program (2012-2015) aimed at improving the control of goat lactic farmhouse cheese ripening, a technology frequently used by farmers, by producing tools and references for producers and the technicians guiding them. Surveys conducted in 49 farms in the 6 main regions producing this kind of cheeses allowed to characterize the great diversity of cheeses, premises, equipment and practices, and to link cheese categories with practices, premises characteristics and air production conditions. In laboratory and experimental dairies, the key role of humidity was quantified during ripening and during drying, in which air speed is even more important. Atmospheric parameters effects on cheeses physicochemical composition and sensory characteristics were quantified for one type of cheeses. Specialist experience of cheese technology, premises design and climate control equipment and technician experience were capitalized at the same time. This project led to the writing of technical documents available online and a book about lactic farmhouse cheeses ripening.; Le programme LACTAFF (2012 – 2015) a eu pour objectif d’améliorer la maîtrise de l’affinage des fromages fermiers lactiques, technologie la plus couramment utilisée à la ferme, en fournissant des outils et des références aux producteurs et aux techniciens qui les accompagnent. Des enquêtes menées dans 49 fermes des 6 principales régions produisant ce type de fromage ont permis de caractériser la grande diversité des fromages fabriqués, des locaux, des équipements et des pratiques et d’établir des liens entre les grandes catégories de fromages et les pratiques, locaux et conditions d’ambiance. Par ailleurs, au laboratoire et en fromageries expérimentales, le rôle clé de l’hygrométrie a été quantifié en affinage, ainsi qu’au séchage où la vitesse d’air joue un rôle encore plus important. Les effets des paramètres d’ambiance sur la composition physico-chimique et les caractéristiques sensorielles des fromages ont été quantifiés pour un type de fromage donné.

International audience; no abstract

Caractérisation des conduites d’affinage à la ferme et étude des liens avec les paramètres d’ambiance des locaux et la qualité des fromages. . Action 1 du projet "Qualité des fromagers fermiers lactiques: locaux et maîtrise de l'affinage (LACTAFF)" - Projet Casdar 1270

L'affinage des fromages fermiers lactiques

Effet des paramètres d'ambiance dans les locaux d'affinage sur la qualité des fromages en conditions expérimentales au laboratoire et en locaux pilotes

National audience

Ce numéro d’Innovations Agronomiques rassemble les présentations du colloque « la biodiversité des ferments au service de l’innovation » qui s'est tenu à Paris le 25 juin 2015.; National audience; Packaging PDO cheeses is very specific. The gas and water vapor permeability characteristics of the packaging influence the composition of the microbial community and its metabolism as illustrated for two PDO cheeses. The Saint Nectaire portion packaging under film very few permeable to air and water vapor reduces the yeast levels and ripening bacteria, affects the appearance of the rind and impacts the profile of aromatic compounds. It is the same for Bleu d'Auvergne cheese stored in ripening cells with controlled content of O2 and CO2. An atmosphere with 2.5% oxygen and 10% CO2 would be the most suitable to get microbial (diversity of ripening bacteria) and aromatic profiles characteristics, similar to those of the whole cheeses. This methodology of characterization will orient the choice of packaging depending on their permeability.; Les fromages AOP sont des produits particuliers à emballer. Les caractéristiques de perméabilité aux gaz et à la vapeur d’eau des emballages influent sur la composition de la communauté microbienne et sur son métabolisme comme il est illustré pour deux fromages AOP. L’emballage de portion de Saint Nectaire sous film peu perméable à l’air et à la vapeur d’eau réduit les niveaux de levures et de bactéries d’affinage, altère l’aspect de la croute et modifie le profil aromatique. Il en est de même pour les fromages Bleu d’Auvergne conservés dans des cellules à teneurs contrôlées en O2 et CO2. Une atmosphère contenant 2,5% d’oxygène et 10% de C02 seraient la plus favorable pour obtenir des fromages ayant des caractéristiques microbiennes (diversité des bactéries d’affinage) et un profil de composés d’arôme proches de ceux conservés en pain entier. Cette méthodologie de caractérisation guidera le choix des emballages en fonction de leur perméabilité.

The best model for studying food digestion remains the Human himself. An alternative to in vivo assays is to use in vitro digestion system. The complexity is to perform a device able to mimic accurately the fate of the food occurring in the human digestive tract. The objective of this work was to develop a simple and rather cheap dynamic digestion system enabling the study of the disintegration occurring in the gastro-intestinal tract of neonate and to validate it towards in vivo data. Digestion of an infant formula was studied both in vitro and in vivo using the piglet model. The formula was adapted to the energy and protein requirements of piglets. Six piglets were slaughtered 30, 90 and 210 min after the meal intake. Effluents from the different compartments of the gut were collected at these 3 time points. In parallel, the same infant formula was digested using the in vitro dynamic digestion system. The device consists in two compartments i.e. stomach and small intestine, and is computer-controlled. Milk proteolysis was followed by SDS-PAGE and ELISA both in vivo and in vitro. The validation was assessed by comparing the kinetics of residual immunoreactivity of β-lactoglobulin and caseins. Results showed a good accordance between the 2 systems of digestion. A level of in vitro/in vivo correlation was established with a correlation coefficient of 0.987. Casein content decreased rapidly during the first 30 minutes of gastric digestion. In contrast, β-lactoglobulin remained much longer intact in the stomach (120 min after ingestion). Intestinal digestion resulted in rapid and drastic hydrolysis, no more intact proteins were detected. This validation on infant formula, using the piglet model, has confirmed that this in vitro dynamic digestion system is reliable.

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The best model for studying food digestion remains the Human himself. However, getting ethical agreement to perform such experiments on human is difficult. Developing in vitro digestion tools appears as a crucial step for monitoring the behaviour and the kinetics of hydrolysis of the food during the different phases of the digestion process. The objective of this work was to develop a simple and rather cheap dynamic digestion system enabling the study of the disintegration occurring in in the gastro-intestinal tract. The device consists in two compartments i.e. stomach and small intestine and is controlled by the STORM (STOmach Regulation and Monitoring) software. This digestion system simulates the GI physiological states as follows: i) flow of secretions and enzymes in physiological amounts (pepsin, lipase, bile, pancreatin), ii) appropriate pH (acidification curve in the stomach) and neutralization of the pH in the intestine, iii) mixing in each compartments, iv) physiological transit time for the gastric and intestinal step of digestion. The differents functions are monitored by the sofware and are saved all along the digestion process. Relevant physiological parameters are essential to simulate as close as possible the human GI tract. To achieve this aim, an exhaustive analysis of the data from the literature has been realized in order to adjust the parameters of the digestion model, and the key parameters such as gastric acidification curve, gastro-intestinal emptying rate and enzymes flow have been modelled as a function of the stage of life (infants vs adults). Validation of this model by a comparison of the kinetics of proteolysis of an infant formula observed either in an animal model (piglets) or in the in vitro model is currently under investigation. This model offers numerous advantages as compared to in vitro static models. Despite this, the model should be improved by (1) making the stirring conditions more physiologically relevant, (2) adding a dialysis membrane to mimic nutrients absorption in the intestinal compartment.

International audience; The main objective of the present work was to assess the effects of sequential air ventilation on: (i) the working conditions of an industrial large-scale ripening room used for PDO Saint-Nectaire cheese ripening, (ii) the reduction of electrical energy consumption, (iii) the evolution of cheese ripening dynamics and final quality. Six ripening trials were performed: 2 with continuous ventilation (reference conditions), 2 with time-based sequential ventilation, and 2 with temperature-based sequential ventilation. The main findings are as follows: Cheese ripening caused substantial respiratory activity. This activity was not significantly affected by either continuous or sequential room ventilation procedure. Air renewal and door opening were identified as the two major factors acting on the amount of CO2 and O2 measured in the room. In the conditions of this study, mean economy on electrical energy consumption when adopting temperature-based sequential ventilation with a temperature variation range close to 0.7°C reached 125 kWh per day and corresponded to a 0.42% increase in ripening room productivity. Finally, sequential ventilation had no significant effect on ultimate cheese quality: focusing on ripening microbial flora, the main biological characteristics of the cheese, and sensory descriptors, there was little evolution versus ripening time compared to continuous ventilation.

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International audience; The influence of the temperature at the rennet addition (31.2, 32.0 and 32.8 °C) and of the starter type on the soft cheese drainage process was studied. Off-line measurements of pH, calcium and phosphorous concentrations, as well as dry matter of the curd were performed in parallel with on-line measurements of the weight and pH of the whey. Only the starter type was found to have a significant influence on the curd and whey pH, on the calcium concentration in the curd and on the calcium/dry matter ratio. Correlations were established between weight of the whey and dry matter of the curd, as well as between pH of the whey and physico-chemical measurements in the curd. Linear regressions gave satisfactory results only when performed separately for each type of starter. Artificial neural networks allowed the building of common models for both starters and predicting curd pH, calcium concentration and the calcium/dry matter ratio using the pH of the whey at one hour after moulding.; Au cours de l'égouttage en moule de fromages à pâte molle, des mesures de pH, de concentrations en calcium et phosphore ainsi que de l'extrait sec du caillé ont été effectuées parallèlement aux mesures en ligne de la masse et du pH du sérum. Les effets de la température d'emprésurage (31,2 ; 32,0 et 32,8 °C) et de la nature des levains ont été évalués sur l'évolution de ces grandeurs. Seule la nature des levains présente un effet significatif sur les évolutions du pH du caillé et du sérum, sur la concentration en calcium du caillé et sur le rapport Ca ++ /extrait sec. Des corrélations sont établies entre la masse de sérum égoutté et l'extrait sec du caillé ainsi qu'entre le pH du sérum et les grandeurs physico-chimiques mesurées dans le caillé. Dans ces relations, les régressions linéaires multiples n'apportent des résultats corrects que lorsqu'elles sont établies séparément, en fonction du levain utilisé. La mise en oeuvre de réseaux de neurones artificiels permet d'établir un modèle unique pour l'ensemble des variables recherchées.

276 vins de même cépage, le Gamay, ont été collectés durant 3 années (1998, 1999, 2000) et analysés par spectroscopie moyen infrarouge à transmission afin d'authentifier les régions d'origine, Gaillac, Beaujolais ou Touraine. Les analyses spectroscopiques en transmission sont réalisées sur des membranes en polyéthylène sur lesquelles 75 μL de vin mélangés avec le même volume d'acétone sont déposés et séchés sous vide au dessiccateur. Les données spectrales, comprises entre 800 cm-1 et 1800 cm-1, sont traitées par trois méthodes de classification: a) classement par la méthode du plus proche voisin (PPV); b) sélection pas à pas des nombres d'onde les plus significatifs associée à une analyse factorielle discriminante avec validation croisée (AFD); c) régression par les moindres carrés partiels (PLS). La première méthode (PPV) donne des résultats peu satisfaisants; 65% seulement des échantillons de validation sont correctement classés dans leur groupe d'origine. Par AFD et par PLS, les taux d'échantillon bien classés sont de 90% et de 85% respectivement.

This study evaluated the ability of dairy matrices, different in composition (with and without fat) and structure (liquid and gel), to enhance microorganisms survival through digestion. The viability of three dairy microorganisms Streptococcus thermophilus, Brevibacterium aurantiacum and Hafnia alvei was measured during in vitro and in vivo digestion. S. thermophilus was highly sensitive to gastric stress, and was not found in the duodenal compartment. B. auranticum was moderately sensitive to gastric stress but resistant to duodenal stress. H. alvei was highly resistant to both stresses. LIVE/DEAD confocal microscopy's images, probed the effect of low pH on microorganisms survival. However, in vivo analyses (16S rRNA gene metabarcoding) failed to confirm in vitro observations since tested microorganisms were not detected. Despite of the different evolutions during digestion on buffer capacity, lipolysis, and rheological characteristics, we did not observe any protective effect of the dairy matrices on microorganisms survival.