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International audience; no abstract

Agri-food is one of the most important sectors of the industry and a major contributor to the global warming potential in Europe. Sustainability issues pose a huge challenge for this sector. In this context, a big issue is to be able to predict the multiscale dynamics of those systems using computing science. A robust predictive mathematical tool is implemented for this sector and applied to the wine industry being easily able to be generalized to other applications. Grape berry maturation relies on complex and coupled physicochemical and biochemical reactions which are climate dependent. Moreover one experiment represents one year and the climate variability could not be covered exclusively by the experiments. Consequently, harvest mostly relies on expert predictions. A big challenge for the wine industry is nevertheless to be able to anticipate the reactions for sustainability purposes. We propose to implement a decision support system so called FGRAPEDBN able to (1) capitalize the heterogeneous fragmented knowledge available including data and expertise and (2) predict the sugar (resp. the acidity) concentrations with a relevant RMSE of 7 g/l (resp. 0.44 g/l and 0.11 g/kg). FGRAPEDBN is based on a coupling between a probabilistic graphical approach and a fuzzy expert system

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.

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.

International audience

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.

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.