Publications scientifiques

Publications scientifiques

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HAL : Dernières publications

  • [hal-04465924] Correlating structure and activity of pepsin enzyme in H2O and D2O for the study of gastric digestion

    D2O, an isotope of H2O, is commonly used as a solvent in neutron scattering; the large difference in scattering length density between H and D can provide better contrast between the sample and the solvent. However, this is of concern for studies using enzymes as the use of D2O can influence protein interactions (due to differences in hydrogen bonding) and is therefore expected to affect the function, activity and solubility of enzymes. Neutron-based in vitro digestion assays on proteins, including those found in food or as oral protein and peptide drugs, often involve different solvents or pH conditions where the activity of the digestive enzyme may not be optimal. Herein, we investigate the structure and activity of the main gastric protease, porcine pepsin, in both H2O and D2O at pH values in the range 1 – 8. We showed that the activity of pepsin was lower in D2O, although the relative change in activity with pH was similar for both solvents. We demonstrated using a combination of SAXS and CD that this relative change in activity was not related to any structural change within the protein but was, rather, linked to relative changes in solubility of the protein. (Meltem Bayrak) 21 Feb 2024
  • [hal-04509395] Revealing the dynamics and mechanisms of bacterial interactions in cheese production with metabolic modelling

    Cheese taste and flavour properties result from complex metabolic processes occurring in microbial communities. A deeper understanding of such mechanisms makes it possible to improve both industrial production processes and end-product quality through the design of microbial consortia. In this work, we caracterise the metabolism of a three-species community consisting of Lactococcus lactis, Lactobacillus plantarum and Propionibacterium freudenreichii during a seven-week cheese production process. Using genome-scale metabolic models and omics data integration, we modeled and calibrated individual dynamics using monoculture experiments, and coupled these models to capture the metabolism of the community. This model accurately predicts the dynamics of the community, enlightening the contribution of each microbial species to organoleptic compound production. Further metabolic exploration revealed additional possible interactions between the bacterial species. This work provides a methodological framework for the prediction of community-wide metabolism and highlights the added value of dynamic metabolic modeling for the comprehension of fermented food processes (Maxime Lecomte) 18 Mar 2024
  • [hal-04551059] Ferments, Ils vont révolutionner la nourriture du futur

    En consommation croissante, les produits fermentés constituent désormais une sérieuse solution de transition vers une alimentation moins carnée et moins sucrée. Un nouveau centre de recherche en région parisienne va explorer ce monde encore méconnu des bactéries, levures et champignons. (Romain Jeantet) 18 Apr 2024
  • [hal-04546199] The in vitro dynamic digestion : a suitable model to mimic the in vivo digestion of infant foods in terms of food deconstruction and protein hydrolysis

    Human infants are preferably fed human milk (HM), but a majority still receive infant formula (IF) as a HM substitute. Optimization of IF is still required to improve HM biomimetics, including digestion behavior biomimetics. While this can be studied in vivo, such experiments have to be reduced and appropriate in vitro models are needed. The present study aimed to compare food deconstruction and protein digestion of HM vs. IF using two infant digestion models, the mini-piglet and the in vitro dynamic gastrointestinal system (DIDGI®). Mini-piglets (Yucatan) were fed either a mature HM (n=9) or a standard IF (n=9) during 6 days. Piglet digesta were collected along the digestive tract 30 min after the last meal. The same foods were digested in triplicate using a term infant in vitro dynamic model with regular digesta sampling along time. Microstructure (confocal microscopy and laser diffraction) and protein digestion (SDS-PAGE, hydrolysis degree, peptidomics) were investigated in both digestion models. Data were statistically analyzed thanks to ANOVA and multidimensional analyses (hierarchical classification and multiple factor analyses). The microstructure of the digesta differed between HM and IF in a similar manner in vitro and in vivo along digestion. The meal dilution and emptying were similar between both digestion models, with a faster emptying for HM. Proteolysis, as investigated by SDS-PAGE, were similar between digestion models, with a lower hydrolysis level for HM caseins. Peptide mapping along the sequence of the major proteins was well correlated between models, particularly in the stomach and the proximal jejunum (r > 0.6). Similar result was found for bioactive peptide release. The ratio between bioaccessibility (in vitro) and bioavailability (in vivo) of amino acids was high (50-80%) at the cleavage sites of the pancreatic enzymes, more precisely for Arg, Tyr, Lys, Phe and Leu, but was much lower for the other amino acids (<30%). In overall, the in vitro dynamic gastrointestinal digestion model well predicted the in vivo digestion of HM and IF, particularly for protein hydrolysis, peptidomics and food deconstruction, while further improvement is needed to better correlate bioaccessibility and bioavailability. (Elise Charton) 15 Apr 2024
  • [hal-04547092] An original, remotely controlled set-up for studying in vitro digestion by MRI – application to bread

    Magnetic Resonance Imaging (MRI) has demonstrated its efficacy in characterizing food properties, offering great potential for quantitatively monitoring digestion. If MRI is a technique of choice for monitoring in vivo digestion, we believe in its great potential for in vitro exploration to provide insights into the composition and multi-scale structure of ingested foods; we are also expecting contributions to the in vivo approach, in terms of signal interpretation and proposals for innovative acquisition sequences. The objectives of this study were to develop a set-up compatible with a whole body MRI scanner to investigate oral-gastric-intestinal food digestion without human intervention in the MRI room, and to use this set-up to gain spatial insights via high-resolution MRI scans into the digestion mechanism of bread structure. The set-up comprises a compartment (referred to as 'cell') that can suit a wrist radiofrequency receive coil for MRI measurements and contain a ~ 1.5 cm wide food piece to be digested. Connected to the cell, another compartment, 'vessel’, is positioned outside the MRI room, linked through a circulating loop controlled by a peristaltic pump (flow rate: 8.4 mL/min). All the manipulations occurred in the vessel. Both the cell and vessel were equipped with water jackets to maintain temperature at 37 °C. The set-up underwent examination for temperature regulation and mixing, in particular for composition homogeneity between compartments. Subsequently, oral-gastric-intestinal digestion of a piece of bread crumb was conducted, with the bread installed in the cell. Manual control and sampling took place in the vessel, while MRI acquisitions, including Multi Spin-Echo and Ultra Short TE (UTE) sequences (for T2 mapping and morphology), were performed. Results demonstrated the set-up enabled the successful execution of digestion, with rapid mass transfer and mixing (complete renewal of the fluid in the cell in 4 min; pH and hydrolysed starch concentrations matching in the cell and vessel) and effective temperature regulation. MRI scans provided internal insights, quantitatively measuring bread piece erosion, pore changes, and local composition during digestion. The degradation level obtained from MRI aligned with the degree of digestion determined through analysis of peptides and hydrolysed starch in the digesta. The present study demonstrated the feasibility of monitoring real-time digestion in a set-up with two separate, potentially distant compartments, facilitated by the circulation of the digestion fluid, which ensures the continuous renewal of the fluid around the food cube. High-resolution MRI images acquired using this set-up offer spatial visualization of bread degradation. The developed setup holds promise for various applications on other foods, providing comprehensive insights into structure changes during digestion. (Ruoxuan Deng) 15 Apr 2024
  • [hal-04547163] A semi-dynamic gastric digestion protocol adapted to the population under proton pump inhibitors (PPI): Impact on the release of macro- and micro-nutrients of a mixed meal

    There are widespread concerns regarding gastric diseases and discomfort, such as heartburn and reflux. The common medicinal solution prescribed is the use of proton pump inhibitors (PPIs). PPIs function by blocking the gastric HK-ATPase, inhibiting gastric acid secretion and leading to a significantly higher pH in the stomach throughout digestion. However, the importance of a gastric acidic environment for food digestion, erosion, and enzyme activity cannot be overlooked, and the impact of PPIs on food digestion and nutrient release remains relatively unexplored. To address this knowledge gap, our study aims to propose an in vitro semi-dynamic digestion protocol under PPI mediation and investigate the effect of PPIs on the digestion of a mixed meal consisting of bread, cheese, and tomato. The PPI digestion protocol was developed based on the INFOGEST semi-dynamic digestion protocol and the reported influence of PPIs on the acidity and rate of gastric secretions in humans. Gastric fluid and rabbit gastric extract (RGE) were added continuously, and five gastric emptying steps were conducted. Consistently with the in vivo literature, a final targeted gastric pH of 4.2 could be obtained by reducing by half the concentration of gastric acid and its secretion rate compared to healthy conditions. The emptied digesta was analysed for the digestion of carbohydrates, proteins, lipids, and minerals using ion chromatography, OPA, thin-layer chromatography, and ICP, respectively. Results revealed that under PPI conditions, less arabinose, peptides, and minerals (Ca, Mg, P) were released during digestion, while other compounds showed similar patterns with the healthy condition. The observed effects on nutrient digestion are likely due to the higher gastric pH, resulting in less acidic erosion and modified enzymatic activities. These results are consistent with some of the well-known adverse effects of PPIs such as infections, hypomagnesemia, fractures, etc. In conclusion, this study presents a detailed semi-dynamic digestion protocol under PPI medication, shedding light on the effects of PPIs on macro- and micro-nutrients during gastric digestion. This protocol can serve as a valuable resource for researchers studying food digestion, contributing to a better understanding of the association between PPI intake and clinical side effects, ultimately promoting better health. (Ruoxuan Deng) 15 Apr 2024
  • [hal-04546844] Quantitative ultrasound to explore tactile perceptions of food elicited by tonguepalate friction: a biomimetic approach

    The tongue has a central role in the sensory experience of texture perception of food. Tongue mechanoreceptors have varied ranges of sensitivity, both in terms of amplitude and frequency of the mechanical stimuli to which they are exposed to. Understanding the behavior of these sensory receptors requires the development of innovative methods, with experimental approaches that integrate both the characteristics of the food and the complex properties of the tongue. In this work, a biomimetic device was composed with artificial tongues (polyvinyl alcohol cryogels) actuated by two translation stages to generate custom sequences of compressional and shearing motions against a rigid plate playing the role of the hard palate. The roughness of the tongues was designed to be reminiscent of the diversity of human tongue papillae height (20–140 µm). Newtonian aqueous solutions of glycerol (1–1400 mPa.s) were deposited on their surface and their frictional behavior was investigated during sequences of shearing motions against the palate. A multi-axes strain gauge sensor and a piezoelectric accelerometer were used to measure forces and vibrations between the tongue and the palate. In addition, non-destructive ultrasound (US) waves were propagated within the tongue with a pulse recurrence frequency of around 1 kHz, using a single-element sensor (5 MHz) positioned under the tongue. Signal processing methods were developed to characterize the evolution of the time of flight (ToF) of the echo corresponding to the reflections of US at tongue-palate interface. The low frequency component of ToF evolution (0–40Hz) was found to correlate both with the normal pressure exerted by the tongue on the palate, and with the thickness of the lubricating film at tongue-palate interface. At higher frequencies (>40 Hz), ToF fluctuations were correlated with vibrations induced by stick-slip phenomena between the tongue and palate, characteristic of the mixed lubrication regime. The study paves the way for the use of US methods (non-invasive and non-destructive) for the continuous monitoring of friction phenomena between the tongue and the palate. Implemented on such a biomimetic system, they make it possible to study the respective contributions of the properties of foods and of the physiological specificities of individuals on the biomechanical phenomena at the origin of texture perceptions. (Miodrag Glumac) 15 Apr 2024
  • [hal-04546162] Protein ingredient quality of infant formulas impacts gut physiology and microbiota in mini-piglets used as a human infant model

    Infant formulas (IFs), the only adequate substitute to human milk, are complex matrices that require numerous ingredients and processing steps. Previously, we showed that the quality of the dairy protein ingredients within IFs modulated protein microstructure and in vitro and in vivo digestive kinetics (protein digestion and amino acids plasma concentration). Therefore, the aim was to assess the consequences on gut maturation and microbiota, an important actor within the microbiota-gut-brain axis. Three isonitrogenous IFs were formulated with whey proteins from different origins (cheese whey: IF-A, vs. ideal whey: IFs-B/C) and casein with different organizations (micellar: IFs-A/B, vs. non-micellar: IF-C). Twenty-four Yucatan mini-piglets (2- to 21-day-old), used as an infant model, received one of the three IFs. Digestive contents, faeces, and tissues were analysed using metagenomic, histological, ex vivo permeability and gene expression approaches and a metabolomic analysis was done on serum. Univariate and multivariate statistical analyses were performed. Piglets fed with IF-C had a significantly higher colonic paracellular permeability than those fed with IF-A, which was also associated with a slight immune boost, potentially as the result of increased antigens passage through the gut barrier stimulating the mucosal immune system. Colonic transcellular amino acid transporters were less expressed in piglets fed with IF-C than with IF-A which could be the result of the increased paracellular permeability with IF-C, favouring paracellular transport. These results suggested a combined effect of whey origin and casein supramolecular organization on intestinal physiology in favour of IF-C, whose parameters were closer to those recently reported for human milk-fed piglets (Charton et al., 2022). Even though gut microbiota composition was moderately changed between diets, faecal short-chain fatty acid composition differed according to the whey protein origin, with higher butyrate concentration for ideal whey than for cheese whey. Differences in microbiota fermentative activity may result from differences in digestive kinetics previously observed in vitro between cheese whey-based IF (A) and ideal whey-based IFs (B and C), which could modulate the colonic substrate available for the microbiota. Serum metabolomic analysis showed that tryptophan metabolic pathway was different between IF-A-fed piglets and IF-C-fed piglets with higher serum concentrations of tryptophan, kynurenine and 3-indole acetic acid in IF-C-fed piglets than IF-A, IF-B being intermediate. Seric polyamines, bacterial metabolites from protein digestion, were also more concentrated in piglets fed with IF-C than IF-A. This study suggests that the use of ideal whey and the modulation of casein supramolecular organization are possible avenues to keep improving IFs towards more human milk biomimetics. (Lucile Chauvet) 15 Apr 2024
  • [hal-04546723] An INFOGEST international consensus static in vitro digestion model adapted to the general older adult population and its application to dairy products

    Understanding the mechanisms of food digestion is of paramount importance to determine the effect foods have on human health. Significant knowledge on the fate of food during digestion has been generated in healthy adults due to the development of physiologically-relevant in vitro digestion models. However, it appears that the performance of the oro-gastrointestinal tract is affected by ageing and that a model simulating the digestive conditions found in a younger adult (<65 y) is not relevant for an older adult (>65 y). The objectives of this work were: (1) to conduct an exhaustive literature search to find data on the physiological parameters of the older adult oro-gastrointestinal tract, (2) to define the parameters of an in vitro digestion model adapted to the older adult, (3) to apply it to the digestion of dairy products. International experts have discussed all the parameters during a dedicated workshop organized within the INFOGEST network. Data on food bolus properties collected in the older adult were gathered, including food particle size found in older adult boluses. In the stomach and small intestine, data suggest that significant physiological changes are observed between younger and older adults. In the latter, the rate of gastric emptying is slowed down, the pH of the stomach content is higher, the amount of secretions and thus the hydrolytic activities of gastric and intestinal digestive enzymes are reduced and the concentration of bile salts lower. The consensus in vitro digestion model of the older adult was applied to the digestion of 2 fermented dairy products formulated with a ratio of whey proteins to caseins of 80/20 and 20/80. Results showed that the digestion conditions used (young vs. older adult) influenced significantly the kinetics and extent of proteolysis in the gastric phase but not in the intestinal phase. (Didier Dupont) 15 Apr 2024
  • [hal-04546295] Characterization of the mucus lining a co-culture model of Caco-2/HT29-MTX cells

    The Caco-2 cell line is commonly used as a model to study various events occuring at the intestinal level such as the physiological impact of toxins or the absorption of nutriments. More recently, co-cultures integrating enterocyte-like and goblet cells types, namely Caco-2 and HT29-MTX cells, have been reported as promising models of a tunable1 and functional 2 epithelial barrier. One interest of including HT29-MTX cells is their ability to secrete mucins. It is therefore expected that the cell culture will be lined by a mucus layer, with functional consequences on absorption or bacterial adhesion for example. However, the spatial characteristics of this mucus layer (e.g. distribution or volume) is not fully described. The objective of this work was to visualize mucins in a co-culture of Caco-2/HT29-MTX cells, and to set up a method of mucus characterization based on image analysis. Caco-2 and HT29-MTX cells were routinely grown in DMEM medium supplemented with 10% fetal bovine serum and 1% penicillin/streptomycin. Cells were seeded at a density of 2.105 cells/cm2 on transwells in 24-well culture plates, at a ratio of 9:1 (Caco-2:HT29-MTX). Incubation was performed in a humidified atmosphere of 5% CO2 at 37 °C. On day 21, cultures were fixed with 4% PFA and double-stained for F-actin using phalloidin-rhodamine, and for sialic acid using WGA-Alexa488. This aimed at detecting the cytoskeleton (thereby enabling fine contouring of each cell) and mucins, respectively. Images were acquired on a Zeiss-LSM 880 confocal microscope. Two independent culture wells were observed. Five 3-D images (consisting of around 80 stacked images on average) were acquired per well, resulting in a dataset of 10 images. From a qualitative point of view, it was observed that cells at day 21 formed mostly a monolayer. Rather than being flat, cultures showed a clear topographic pattern, with domes that could reach 135 µm in height. Mucins were detected mainly on the apical side of the cells. Brightly-stained mucin clusters were visible in the extracellular apical space in close vicinity of some cells, most likely HT29-MTX cells. In addition, a more diffuse signal was also observed, sometimes lining large parts of the observation sites. This may correspond to secreted mucins spreading on top of the culture to form a typical intestinal mucus. With the objective of eventually study the impact of a treatment (e.g. digested food constituents) on this mucus structure, a method of image analysis was developed. Using the open-source software ilastik3, pixels were classified into three categories corresponding to bright staining mucin clusters, diffuse mucin staining and background. This analysis provides quantitative measurements on average mucin intensity and the volume proportion and average heights of mucin clusters. (Yann Le Gouar) 15 Apr 2024
  • [hal-04546794] In vivo study combining sensory analysis and ultrasound imaging to investigate food texture perceptions related to tongue biomechanics

    All along food oral processing, the tongue continuously evaluates the mechanical and structural properties of foods, all by guiding them towards the different organs involved in the formation of the bolus. The tongue thus steers the oral strategy, adapting to food type, individual preferences, and physiological constraints, playing an important role in sensory experience and swallowing safety. In the present study, sensory analysis was coupled with ultrasound (US) imaging to better understand the links between tongue motions and texture perceptions. Six commercially available semi-liquid foods (chocolate desserts) were selected for their diverse textures (including mousses, gels and creams). Sensory profile and temporal dominance of sensations were investigated with a trained panel of 16 volunteers. The mechanical interactions between food and an artificial tongue and palate were characterized on a biomimetic test bench embedding multi-axes force sensors, an accelerometer, and a linear US imaging probe. Feasibility US imaging measurements were performed on 10 volunteers, using a convex US probe positioned under the chin. Highly contrasting mechanical and sensory properties could be confirmed across the different food products. Image processing methods were developed on in vitro US imaging datasets to track the evolution of the dorsal surface of the artificial tongue (interface tracking algorithm) and characterize the deformation fields within the artificial tongue (particle image velocimetry). Tongue movement profiles were linked to food rigidity, while shear velocity fields in the bulk of the tongue correlated with friction and adhesion phenomena between the tongue and the palate. High inter-individual variability was reported in the morphology and contrast level of the US images from in vivo experiments. Even though the implementation of image analysis processing methods was challenging, the feasibility of tracking the dorsal surface of the tongue has been demonstrated. The type and number of tongue movements as well as the duration of the oral processing before food swallowing were characterized. The results underscore the potential of US imaging for monitoring and characterizing tongue biomechanics during oral processing, providing valuable insights into the diverse mechanical responses of different food products and their impact on sensory experiences. (Miodrag Glumac) 15 Apr 2024
  • [hal-04546756] In vitro digestion of protein-rich dairy products adapted to the specific needs of older adults

    Insufficient energy and protein intake can lead to a condition called sarcopenia, characterized by the loss of muscle mass, strength and function. To avoid this condition healthy older adults need to consume nutrient-dense foods and to increase the amount of high-quality proteins in their diet to promote muscle health. However, it is still unclear if changes in nutrients digestibility in old age may affect the anabolic effect of foods [1]. The objective of this study was to investigate in vitro the digestion of two high-protein dairy products similar to cream cheese (containing 24% w/w of proteins, and 20% w/w of lipids). Products were formulated with two different ratios of caseins to whey proteins: 80/20 (= WP20) similar to the ratio found in bovine milk, and 20/80 (WP80) in order to increase the leucine supply. The new static in vitro digestion model adapted to the general older adult population (≥65 y) proposed by INFOGEST [2] was implemented to investigate the digestion of these products, as well as the standard version of the protocol. Kinetics of proteolysis and lipolysis were compared between both models for each product, in the gastric and intestinal phase of digestion. Proteolysis was studied with the OPA method, SDS-PAGE, and amino acids were quantified by HPLC, while lipolysis was investigated through GC-MS, and the structure of the products in gastric conditions was observed by CLSM. In both products, the degree of protein hydrolysis (DHP) was significantly lower in older adults’ conditions than in young at the end of the gastric phase (-19% for WP20, and -44% for WP80), and at the end of the intestinal phase (-16% for WP20, and -20% for WP80). This is most probably due to the reduction in pepsin and pancreatin activities recommended in the older adult model compared to the standard protocol. The degree of lipid hydrolysis (DHL) was also significantly lower in older adults’ conditions than in young at the end of the digestion for WP20 (-30%), but interestingly it was not the case for WP80 (similar DHL were measured). Free fatty acids were also released faster from WP80 than from WP20 in both digestion conditions: after 5 min of intestinal digestion DHL was already ≈ 32% for WP80 against 14% for WP20. This was attributed to the different caseins/whey protein ratios in the products, leading to the formation of different gel structures that may in turn result in different patterns of deconstruction in the gastrointestinal tract. (Anaïs Lavoisier) 15 Apr 2024
  • [hal-04543878] Impact of the microstructure of two beef co-products on postprandial plasma amino acid kinetics

    The increasing demand for proteins is driving the search for alternative food sources. From this point of view, the valorization of co-products, such as meat co-products that are little valorized in human nutrition, is a promising way, in line with the principle of the circular economy. The present study focused on two protein ingredients of bovine origin, co-products of the fat rendering process, Greasy Greaves Recovered Proteins (GGRP) and Water Recovered Proteins (WRP), previously shown to display valuable but different functional properties. The aim of the present study was to evaluate the nutritional quality of these proteins and the relationship between the structure of these two meals and the postprandial plasma amino acid (AA) kinetics. The structure adopted by these two meals during the gastric digestion was investigated using an in vitro semi-dynamic model (INFOGEST). Gastric digesta were collected at 0, 40, 80 and 120 min; their microstructure was analyzed by confocal microscopy, particle size distribution by laser diffraction, and their viscosity was measured by oscillation test. The nutritional quality and postprandial AA kinetics were determined in vivo on ten growing pigs, cannulated at the ileal level and catheterized in the jugular vein, and receiving over a 2.5-day period one of the two experimental meals according to a cross-over design. Ileal digesta and blood samples were collected during the 9 postprandial hours and AA contents were analyzed by ion-exchange chromatography. Data were statistically analyzed using linear models. WRP and GGRP presented a similar and moderate true ileal protein digestibility (81-84%, p>0.05), however due to their different amino acid profile, the DIAAS was much lower for WRP than GGRP with a value of 18 vs. 74% with Trp being the first limiting AA for both protein sources. The plasma AA concentration reached its maximal value between 3 h and 5 h postprandial for WRP and GGRP, thus qualifying both protein ingredients as slowly digested sources. GGRP tended to have a slower appearance rate of plasma AA. This could be explained by the higher viscosity of this meal (25 to 35 times higher) than that of WRP meal (p < 0.05). Nevertheless, the viscosity of both meals sharply decreased during digestion by an equivalent factor (around 34), from 1.3 to 0.04 Pa.s at 10 s-1 for WRP, and from 35 to 1 Pa.s for GGRP. In addition, the GGRP digesta contained a higher proportion of very large particles than the WRP ones. The higher viscosity and larger particle size for GGRP digesta than for WRP ones could explain the trend for the slower rates of digestion and absorption of GGRP. Overall, the GGRP bovine co-product appears as an interesting dietary protein source for human, while WRP presents mainly valuable functional properties but low nutritional ones. (Rozenn Le Foll) 12 Apr 2024
  • [hal-04546976] Determination of digestive enzymes activities in human duodenal fluids

    The improvement of in vitro digestion models is essential and depends, among others, on a better knowledge of the enzymatic activities in the digestive tract of humans. Within the framework of a collaboration between INFOGEST and UNGAP, a cost action on oral drug absorption, access to intestinal fluids was possible. Human intestinal fluids were collected under fasting and fed state conditions using a catheter placed in the duodenum. Intestinal fluids from 13 healthy adult volunteers were used for the determination of digestive enzyme activities. Intestinal fluids were collected kinetically over 110 min after ingestion of 240 ml of water (fasted) or 400 ml of Ensure Plus vanilla followed 20 min after by 240 mL of water (fed), leading to a total of 88 samples. Immediately after collection, intestinal fluids were mixed with glycerol (1:1) and inhibitors to protect digestive enzymes from enzymatic breakdown. Then, trypsin, chymotrypsin, and lipase activities were determined using the enzymatic assays protocols described in Brodkorb et al. (2019), except that the temperature for the trypsin assay was 37°C. The pH of each sample was also measured immediately after collection. Mean values of 64.9 ± 28.5, 24.2 ± 10.2 and 389 ± 253 Units /ml of duodenal content (fasted) and 62.8 ± 28.9, 22.9 ± 9.6 and 1071 ± 60.7 Units /ml of duodenal content (fed) were obtained for trypsin, chymotrypsin and lipase, respectively. Mean pH was 6.3 ± 1.3 and 6.1 ± 0.8 under fasted and fed state conditions, respectively. No effect of nutritional state (fasted vs fed) on the enzymatic nor on the pH was observed. Due to a high inter-individual variability between volunteers, no effect of the time of sampling was observed on the activity level of trypsin, chymotrypsin and lipase in the duodenum. Few data are currently available in the literature and this new set of data is of major importance. More in vivo data on enzymes activities in the upper part of the gastro-intestinal tract in different prandial states would be needed to help the scientific community improving in vitro digestion models. (Olivia Ménard) 15 Apr 2024
  • [hal-04546269] Age-optimized digestion of two high protein dairy products: Gastric in vitro semi-dynamic digestion model of adult vs older adults

    [...] (Shannon Gwala) 15 Apr 2024
  • [hal-04547062] Quantifying intestinal lipolysis with Magnetic Resonance Imaging: Proof of concept using fresh cream digested in vitro

    Understanding lipid digestion is crucial for health strategy development in managing energy intake and nutrient bioavailability. Lipolysis kinetics can be studied by assessing the chemical composition, which requires sample purification and lipid extraction. For online monitoring of lipolysis, non-invasive methods like MRI remain to be developed. A recent study suggested that the MRI water-fat separation method enables quantifying undigested lipids, but not lipolytic products (Musse et al., 2023). To find out the mechanism behind this and to assess the feasibility of monitoring lipolysis using this approach, the lipid quantification by MRI during in vitro intestinal digestion of a commercial fresh cream was supplemented by thin-layer chromatography (TLC) for quantifying lipolysis and Time Domain (TD)-NMR for characterization in details of transverse (T2) relaxation times. The TLC analysis showed that around 96% of the triacylglycerols (TAG) was hydrolysed into lipolytic products (including free fatty acids (FFA), diglycerides (DAG), and monoglycerides (MAG)) after the in vitro intestinal digestion. The MRI results demonstrated that the loss of lipid signal correlated with the degree of lipolysis of the samples. The TD-NMR results showed a remarkable difference in the T2 of undigested lipids (~120 ms; in this study, mostly TAG) and that of lipolytic products (~2 ms; FFA, DAG, and MAG). The very short T2 of lipolytic products is likely due to the semi-crystalline structures they formed with bile salts (micelles, vesicles, liposomes, etc.) and they were suspended in the aqueous phase. Notably, The MRI water-fat separation method is not able to capture the signal from such fast-relaxing protons (short T2), which explains why the signal of lipolysis products cannot be detect. Nonetheless, the MRI method proves effective in quantifying lipolysis by monitoring the decreasing amount of undigested lipids during in vitro digestion. Moreover, the MRI imaging parameters could even be optimized to acquire rapid mapping on lipolysis in 13 seconds (within a breath hold), opening up many opportunities for future in vivo applications. In conclusion, magnetic resonance techniques are potential methods for investigating digestion processes. MRI water-fat separation method can quantify the lipolysis of cream during in vitro digestion and may serve as a promising method in studying real-time lipolysis of other foods in the gastrointestinal digestive tract, both in vitro and in vivo. (Ruoxuan Deng) 15 Apr 2024
  • [hal-04548420] Encapsulating DHA oil promotes the digestion process in vitro and profoundly modifies the metabolism of DHA in vivo

    An oil consisting of triglycerides highly enriched in docosahexaenoic acid (DHA), a valuable omega 3 fatty acid, was encapsulated with whey proteins to form Pickering emulsions (1). The emulsion or crude DHA oil was then cooked in an omelette. In vitro digestion showed that the bioaccessibility of DHA was significantly improved by the encapsulation of DHA oil. As much DHA was released during digestion after one hour of lipase activity when the DHA oil was encapsulated, as after two hours of digestion when the DHA oil was not encapsulated (2). On the basis of this observation, omelettes containing encapsulated or non-encapsulated DHA oil were administered to young rats for 4 weeks to observe the metabolic effects. Firstly, the encapsulation of DHA oil tended to increase the bioavailability of DHA, although plasma levels were not significantly different with the encapsulation of DHA oil. It also modified feeding behaviour by stimulating rodent chow consumption. This effect promoted the animal’s growth. Secondly, administration of DHA oil significantly altered the profiles of oxygenated fatty acid derivatives, drastically reducing the overall levels of omega-6-derived oxylipins in the plasma and the heart, but not in the brain (3). This effect was greatly accentuated when the DHA oil was encapsulated. On the other hand, DHA-derived oxylipins were increased overall in the heart and brain, even more so when the DHA oil was encapsulated. Thirdly, administration of DHA oil also modified the profiles of endocannabinoid derivatives of fatty acids (4). Endocannabinoids and N-acylethanolamides were greatly reduced in plasma and brain, but without the impact of DHA encapsulation. The heart showed a different pattern, with an increase in DHEA from DHA, specifically when DHA oil was encapsulated. In conclusion, these results show that modifying the food structure allows a nutrient to be delivered differently, and thus to modify not only its digestion process but also its subsequent metabolism. They also highlight the fact that the impact of the food structure may not really influence the levels of the target nutrient in the body, but may completely affect its metabolism into lipid derivatives, which must be investigated and quantified. (Jun Wang) 16 Apr 2024
  • [hal-04546322] The fate of salivary proteins-apple polyphenols complexes during gastric digestion

    Despite recognized health benefits, some polyphenols referred to as tannins exhibit anti-nutritional properties. Binding of tannins by proteins prior to the stomach may therefore act as a protective mechanism against their deleterious effects on digestion1. Illustration is provided by the particular case of salivary proteins, especially Proline-Rich Proteins (PRPs) with high affinity for tannins. Polyphenols-salivary proteins complexes are formed in the oral cavity, but it is not entirely clear how they behave in the harsh digestive environment. The overall objective of this study was to describe the interactions between salivary proteins and apple polyphenols, and the impact of gastric digestion on such interactions. A polyphenol extract was obtained from Dous Moën cider apples and mixed with pooled human saliva to reach different ratios of polyphenols to saliva proteins. In parallel, saliva, polyphenols extract or mixtures were subjected to the gastric phase of the INFOGEST static in vitro digestion procedure. Samples were centrifuged at 10000 g, 4 °C for 10 minutes. Protein profiles in supernatants and pellets were analyzed by SDS-PAGE. Proteins contained in bands of interest were identified by nano-LC-ESI MS/MS after in-gel trypsinolysis, and by staining of PRP with Coomassie blue R-250. Native polyphenols were quantified in supernatants by UPLC-UV-MS. Before digestion, increasing the polyphenols load resulted in a rise of turbidity of the mixtures suggesting the formation of progressively larger aggregates. Supernatants showed a protein profile similar to that of saliva while four bands were enriched in pellets. These proteins, identified as carbonic anhydrase 6, PRP and S100-A8, formed insoluble complexes with apple polyphenols. At low polyphenols load, the interaction with saliva induced a significant (p<0.05) concentration decrease in the supernatants of procyanidin oligomers (dimers PA-B1, PA-B2, PA-B5, trimer PA-C1, tetramer DP4), catechins and hydroxycinnamic acids. At a higher polyphenol load, the only affected compound was DP4, indicating that when polyphenols are abundant, highly polymerized procyanidins are preferentially complexed with proteins. After digestion of saliva, samples containing the highest polyphenols load showed specificities, namely the persistance in pellets of two bands at 60 kDa (identified as α-amylase) and at 20kDa (containing PRP). In addition, digestion of low polyphenols-saliva mixtures resulted in a large decrease of procyanidins PA-B5, PA-C1 and DP4 from the soluble fractions of digests compared to digestion of polyphenols alone. This suggests that insoluble complexes between salivary proteins and those tannins are formed and remain stable during gastric digestion. This study supports that saliva modulates the nature and amount of polyphenols that reach the digestive tract in free or soluble form. (Müzeyyen Berkel Kasikci) 15 Apr 2024
  • [hal-04536979] Recombinant probiotic Lactococcus lactis delivering P62 mitigates moderate colitis in mice

    Introduction and objective: p62 is a human multifunctional adaptor protein involved in key cellular processes such as tissue homeostasis, inflammation, and cancer. It acts as a negative regulator of inflammasome complexes. It may thus be considered a good candidate for therapeutic use in inflammatory bowel diseases (IBD), such as colitis. Probiotics, including recombinant probiotic strains producing or delivering therapeutic biomolecules to the host mucosal surfaces, could help prevent and mitigate chronic intestinal inflammation. The objective of the present study was to combine the intrinsic immunomodulatory properties of the probiotic Lactococcus lactis NCDO2118 with its ability to deliver health-promoting molecules to enhance its protective and preventive effects in the context of ulcerative colitis (UC). Material and methods: This study was realized in vivo in which mice were supplemented with the recombinant strain. The intestinal barrier function was analyzed by monitoring permeability, secretory IgA total levels, mucin expression, and tight junction genes. Its integrity was evaluated by histological analyses. Regarding inflammation, colonic cytokine levels, myeloperoxidase (MPO), and expression of key genes were monitored. The intestinal microbiota composition was investigated using 16S rRNA Gene Sequencing. Results and discussion: No protective effect of L. lactis NCDO2118 pExu:p62 was observed regarding mice clinical parameters compared to the L. lactis NCDO2118 pExu: empty. However, the recombinant strain, expressing p62, increased the goblet cell counts, upregulated Muc2 gene expression in the colon, and downregulated pro-inflammatory cytokines Tnf and Ifng when compared to L. lactis NCDO2118 pExu: empty and inflamed groups. This recombinant strain also decreased colonic MPO activity. No difference in the intestinal microbiota was observed between all treatments. Altogether, our results show that recombinant L. lactis NCDO2118 delivering p62 protein protected the intestinal mucosa and mitigated inflammatory damages caused by dextran sodium sulfate (DSS). We thus suggest that p62 may constitute part of a therapeutic approach targeting inflammation. (Juliana Guimarães Laguna) 08 Apr 2024
  • [hal-04509491] Innovative beef protein co-products to substitute gelatine as gelling agents, and sodium caseinate as emulsifiers: Determination of optimal conditions using the response surface methodology (RSM)

    Meat co-products are a promising alternative for meeting the increasing demand for protein, especially for the formulation of meat products. The present study aims to determine the optimal conditions under which two innovative bovine co-products, resulting from the fat rendering process, can mimic the gelling and emulsifying properties of commercial gelatines and sodium caseinate (NaCas), respectively, using Response Surface Methodology (RSM). The desirability function was used to determine the values for protein concentration, pH and NaCl content that enable the two co-products to effectively mimic gelatine and NaCas. The co-product obtained from water recovered during the fat rendering process proved to be the most suitable to mimic commercial gelatines. Very high desirability scores were obtained with this ingredient on 4 criteria out of 7, and a high overall score as well, provided 90 g/L protein was used to mimic a 50 g/L gelatine 150 Bloom. Both co-products appeared as effective alternatives to NaCas as emulsifiers, especially regarding their capacity in stabilizing emulsions. The co-product made of greasy greaves can be even regarded as more effective than NaCas, as less proteins are needed to obtain the same performances (110 g/L vs 125 g/L, respectively). (Rozenn Le Foll) 18 Mar 2024
  • [hal-04504057] Granulation behaviour of high lactose dairy superconcentrates

    Granulation of whey permeate (WP) and demineralised whey (DW) superconcentrates was evaluated by addition of powder using a high-shear mixer during which consumption of electrical current was monitored. Granulation of DW required 50% more energy than that of WP and the resulting DW granules were larger (~2×) indicating greater resistance to fragmentation. Furthermore, addition of whey protein isolate (WPI) into the back-mix powder resulted in more efficient granulation (reduced energy, finer granules etc.) of superconcentrated WP. This was linked to the higher water-holding capacity of WPI and a simple model based on protein content was proposed to predict occurrence of granulation. This study sheds light on granulation behaviour under these conditions. Interestingly, while high cohesiveness of superconcentrates, which is related to protein content, has been previously shown to negatively impact granulation, increasing the protein content of the granulating powder was shown here to have positive effects, which offers great potential for design of formulated products. (Maheshchandra H Patil) 14 Mar 2024
  • [hal-04531737] Unlocking the Potential of Probiotics: A Comprehensive Review on Research, Production, and Regulation of Probiotics

    This review provides a comprehensive overview of the current state of probiotic research, covering a wide range of topics, including strain identification, functional characterization, preclinical and clinical evaluations, mechanisms of action, therapeutic applications, manufacturing considerations, and future directions. The screening process for potential probiotics involves phenotypic and genomic analysis to identify strains with health-promoting properties while excluding those with any factor that could be harmful to the host. In vitro assays for evaluating probiotic traits such as acid tolerance, bile metabolism, adhesion properties, and antimicrobial effects are described. The review highlights promising findings from in vivo studies on probiotic mitigation of inflammatory bowel diseases, chemotherapy-induced mucositis, dysbiosis, obesity, diabetes, and bone health, primarily through immunomodulation and modulation of the local microbiota in human and animal models. Clinical studies demonstrating beneficial modulation of metabolic diseases and human central nervous system function are also presented. Manufacturing processes significantly impact the growth, viability, and properties of probiotics, and the composition of the product matrix and supplementation with prebiotics or other strains can modify their effects. The lack of regulatory oversight raises concerns about the quality, safety, and labeling accuracy of commercial probiotics, particularly for vulnerable populations. Advancements in multi-omics approaches, especially probiogenomics, will provide a deeper understanding of the mechanisms behind probiotic functionality, allowing for personalized and targeted probiotic therapies. However, it is crucial to simultaneously focus on improving manufacturing practices, implementing quality control stand ards, and establishing regulatory oversight to ensure the safety and efficacy of probiotic products in the face of increasing therapeutic applications. (Tales Fernando da Silva) 04 Apr 2024
  • [hal-04514551] Intra- and interindividual variability in fasted gastric content volume

    Background: Gastric fluid plays a key role in food digestion and drug dissolution, therefore, the amount of gastric fluid present in a fasted state may influence subsequent digestion and drug delivery. We aimed to describe intra- and interindividual variation in fasted gastric content volume (FGCV) and to determine the association with age, sex, and body size characteristics. Methods: Data from 24 MRI studies measuring FGCV in healthy, mostly young individuals after an overnight fast were pooled. Analysis included 366 participants with a total of 870 measurements. Linear mixed model analysis was performed to calculate intra- and interindividual variability and to assess the effects of age, sex, weight, height, weight*height as a proxy for body size, and body mass index (BMI). Results: FGCV ranged from 0 to 156 mL, with a mean (± SD) value of 33 ± 25 mL. The overall coefficient of variation within the study population was 75.6%, interindividual SD was 15 mL, and the intraindividual SD was 19 mL. Age, weight, height, weight*height, and BMI had no effect on FGCV. Women had lower volumes compared to men (MD: -6 mL), when corrected for the aforementioned factors. Conclusion: FGCV is highly variable, with higher intraindividual compared to interindividual variability, indicating that FGCV is subject to day-to-day and within-day variation and is not a stable personal characteristic. This highlights the importance of considering FGCV when studying digestion and drug dissolution. Exact implications remain to be studied (Julia J M Roelofs) 21 Mar 2024
  • [hal-04531832] Exploring the contraction actuation of magnetically functionalized electrospun tubes

    Recently, magnetically functionalized polymer tubes (MFPTs) have been fabricated through a multistep electrospinning process. These innovative MFPTs can serve as ducts suitable for microfluidic components and biomedical devices. Considering these applications, it is crucial to investigate the effectiveness of inducing oscillating contractions at low frequencies. For this purpose, we designed an experimental setup to study the cross-sectional contraction of these smart tubes when subjected to a magnetic field produced by the oscillation of a small permanent magnet. A magnetoelastic wave resonator placed near the MFPT section detects the induced contraction, enabling the calculation of both its magnitude and response times. The results demonstrate that oscillating contractions, resulting in a maximum reduction of duct radius by approximately 43%, can be achieved with an oscillating magnetic induction field of amplitude around 10 mT, at a low frequency not exceeding 1/2 Hz. These findings highlight the potential of such innovative MFPTs, particularly in the fields of surgery and endoscopy. (Vincenzo Iannotti) 04 Apr 2024
  • [hal-04495275] Animal board invited review: Improving animal health and welfare in the transition of livestock farming systems: Towards social acceptability and sustainability

    Highlights: • Improving jointly health and welfare of farm animals raises new research questions. • An integrated measure of animal health through their lifespan has to be developed. • Synergies and tensions between health, welfare and production need to be investigated. • Improving animal health and welfare challenges in industrial and territorial dimensions. • Livestock farmer and citizen expectations towards animal condition need consideration. Abstract: The need to integrate more clearly societal expectations on livestock farming has led the authors of this article to consider that livestock farming systems must be redesigned to position health and welfare at the heart of their objectives. This article proposes a vision of the advances in knowledge required at different scales to contribute to this transformation. After defining health and welfare of animals, the article emphasises the need to consider health in a broader perspective, to deepen the question of positive emotional experiences regarding welfare, and raises the question of how to assess these two elements on farms. The positive interactions between health and welfare are presented. Some possible tensions between them are also discussed, in particular when improving welfare by providing a more stimulating and richer environment such as access to outdoor increases the risk of infectious diseases. Jointly improving health and welfare of animals poses a number of questions at various scales, from the animal level to the production chain. At the animal level, the authors highlight the need to explore: the long-term links between better welfare and physiological balance, the role of microbiota, the psycho-neuro-endocrine mechanisms linking positive mental state and health, and the trade-off between the physiological functions of production, reproduction and immunity. At the farm level, in addition to studying the relationships at the group level between welfare, health and production, the paper supports the idea of co-constructing innovative systems with livestock farmers, as well as analysing the cost, acceptability and impact of improved systems on their working conditions and well-being. At the production chain or territory levels, various questions are raised. These include studying the best strategies to improve animal health and welfare while preserving economic viability, the labelling of products and the consumers’ willingness to pay, the consequences of heterogeneity in animal traits on the processing of animal products, and the spatial distribution of livestock farming and the organisation of the production and value chain. At the level of the citizen and consumer, one of the challenges is to better inter-relate sanitary and health perspectives on the one hand, and welfare concerns on the other hand. There is also a need to improve citizens’ knowledge on livestock farming, and to develop more intense and constructive exchanges between livestock farmers, the livestock industry and citizens. These difficult issues plead for interdisciplinary and transdisciplinary research involving various scientific disciplines and the different stakeholders, including public policy makers through participatory research. (Christian Ducrot) 08 Mar 2024
  • [hal-04470095] Deciphering the metabolism of <i>Lactobacillus delbrueckii</i> subsp. <i>delbrueckii</i> during soy juice fermentation using phenotypic and transcriptional analysis

    In the context of sustainable diet, the development of soy-based yogurt fermented with lactic acid bacteria is an attractive alternative to dairy yogurts. To decipher the metabolism of Lactobacillus delbrueckii subsp. delbrueckii during soy juice (SJ) fermentation, the whole genome of the strain CIRM-BIA865 (Ld865) was sequenced and annotated. Then Ld865 was used to ferment SJ. Samples were analyzed through out fermentation for their cell number, carbohydrate, organic acid, free amino acid, and volatile compound contents. Despite acidification, the number of Ld865 cells did not rise, and microscopic observations revealed the elongation of cells from 3.6 µm (inoculation) to 36.9 µm (end of fermentation). This elongation was observed in SJ but not in laboratory-rich medium MRS. Using transcriptomic analysis, we showed that the biosynthesis genes of peptidoglycan and membrane lipids were stably expressed, in line with the cell elongation observed, whereas no genes implicated in cell division were upregulated. Among the main sugars available in SJ (sucrose, raffinose, and stachyose), Ld865 only used sucrose. The transcriptomic analysis showed that Ld865 implemented the two transport systems that it contains to import sucrose: a PTS system and an ABC transporter. To fulfill its nitrogen needs, Ld865 probably first consumed the free amino acids of the SJ and then implemented different oligopeptide transporters and proteolytic/peptidase enzymes. In conclusion, this study showed that Ld865 enables fast acidification of SJ, despite the absence of cell division, leads to a product rich in free amino acids, and also leads to the production of aromatic compounds of interest. IMPORTANCE To reduce the environmental and health concerns related to food, an alternative diet is recommended, containing 50% of plant-based proteins. Soy juice, which is protein rich, is a relevant alternative to animal milk, for the production of yogurt-like products. However, soy &quot;beany&quot; and &quot;green&quot; off-flavors limit the consumption of such products. The lactic acid bacteria (LAB) used for fermentation can help to improve the organoleptic properties of soy products. But metabolic data concerning LAB adapted to soy juice are lacking. The aim of this study was, thus, to decipher the metabolism of Lactobacillus delbrueckii subsp. delbrueckii during fermentation of a soy juice, based on a multidisciplinary approach. This result will contribute to give tracks for a relevant selection of starter. Indeed, the improvement of the organoleptic properties of these types of products could help to promote plant-based proteins in our diet. (Olivier Harlé) 21 Feb 2024
  • [hal-04465062] The structure of the food matrix at different length scales drives the mechanism of digestion and the nutrient bioaccessibility and bioavailability

    The food matrix structure is one of the key drivers to control the fate of food in the digestive tract and, consequently, the kinetics of nutrient release. Using in vitro and in vivo digestion models (pigs), we have demonstrated that, at identical composition, differences in dairy product macrostructure (liquid vs gel vs solid) lead to differences in gastric emptying, protein hydrolysis in the gut and amino acid bioavailability. When macrostructures are identical, differences at the microscopic scale can also have a strong impact on food digestion. For instance, egg white gels made by heat treatment at different pHs and ionic strengths exhibit differences in digestion kinetics depending on the ability of pepsin to diffuse into the egg white gel structure. Several examples of food matrix effect on the bioaccessibility/bioavailability of other nutrients (DHA, vitamins, minerals…) will be given. Correlation between bioaccessibility and bioavailability will be presented for different nutrients. The structure of food at different length scales can therefore be considered as a lever to control the kinetics of nutrients release during digestion and fulfil the nutritional needs of specific populations (elderly, obese, athletes) . (Didier Dupont) 19 Feb 2024
  • [hal-04464979] Monitoring the effect of consumption temperature of full-fat milk on in vitro gastric digestion using Magnetic Resonance Imaging

    This study employed Magnetic Resonance Imaging (MRI) to assess the impact of the consumption temperature of full-fat milk (4 • C, 37 • C, and 60 • C) on its behaviour during in vitro gastric digestion. Using the INFOGEST semidynamic protocol, and replicating human gastric temperature profiles for cold, warm and hot beverages, it was observed that consuming milk at 4 • C delayed protein coagulation compared to 37 • C and 60 • C by more than 5 min. 3D-MRI lipid quantitative analyses showed that fat-rich particles tended to float to the top of the digesta in a process similar to creaming with the 4 • C and 37 • C milks, a phenomenon that was not observed with the 60 • C milk. The quantities of released proteins and free primary amines in the digesta supernatant, indicative of pepsin activity, showed no significant variation with milk temperature. These findings highlight the influence of consumption temperature on the structural reorganization of whole milk during gastric digestion and prompts further inquiry into the potential implications of milk temperature on nutrient delivery into the small intestine. (Conor J Fitzpatrick) 19 Feb 2024
  • [hal-04443133] Model of steady-state cross flow filtration of colloidal suspensions with formation of non-Newtonian concentration polarization layer and compressible deposit layer

    [...] (Hossein Gholamian) 07 Feb 2024
  • [hal-04440517] Les fermentations : des savoir-faire traditionnels et empiriques aux procédés maitrisés, porteurs d'innovations.

    Nourrir 10 milliards de personnes en diminuant l’impact écologique de l’alimentation est un enjeu planétaire majeur pour les 30 prochaines années. Alors que la fermentation est utilisée depuis des millénaires, pourquoi est-elle aujourd’hui perçue comme une puissante source d’innovations alimentaires capable de répondre aux futurs besoins alimentaires ? T (Yves Le Loir) 06 Feb 2024
  • [hal-04399583] Fava bean (Vicia faba L.) protein concentrate added to beef burgers improves the bioaccessibility of some free essential amino acids after in vitro oral and gastrointestinal digestion

    The influence of partial replacement of animal protein by plant-based ingredients on the protein digestibility of beef burgers was investigated. Beef burgers were supplemented with fava bean protein concentrate (FB) or a mixture of FB and flaxseed flour (FBFS), both processed by extrusion, at different levels: 0 (control), 10, 15, and 20 % (w/w). A pilot sensory analysis was conducted to select the percentage of flour inclusion for further assays: control, 10 % FB, and 10 % FBFS. Protein digestibility, amino acid profile, and protein secondary structure of these burgers after in vitro oral and gastrointestinal digestion were studied. In vitro boluses were prepared with the AM2 masticator, simulating normal mastication, and static in vitro digestion of boluses was performed according to the INFOGEST method. Inclusion of 10 % FB in beef burgers did not alter their flavour or tenderness compared to the control, whereas tenderness and juiciness scored slightly higher for the 10 % FBFS burgers compared to 15 % and 20 % FBFS ones. Poor lipid oxidative stability during storage was observed with 10 % FBFS burgers. Total protein content was significantly higher (p &lt; 0.05) in 10 % FB burgers than in control burgers after in vitro oral digestion. Additionally, 10 % FB burgers presented higher amounts of free essential amino acids like isoleucine, leucine, phenylalanine, and valine at the end of digestion, as well as methionine, tyrosine, and histidine. Partial substitution of meat protein by 10 % FB improves the nutritional profile of beef burgers, without altering their sensory qualities. (Susana Ribes) 17 Jan 2024
  • [hal-04322697] Propionibacterium freudenreichii CIRM-BIA 129 mitigates colitis through S layer protein B-dependent epithelial strengthening. P. freudenreichii inhibits inflammation-induced epithelial break-down

    The growing incidence of human diseases involving inflammation and increased gut permeability makes the quest for protective functional foods more crucial than ever. Propionibacterium freudenreichii (P. freudenreichii) is a beneficial bacterium used in the dairy and probiotic industries. Selected strains exert anti-inflammatory effects, and the present work addresses whether the P. freudenreichii CIRM-BIA129, consumed daily in a preventive way, could protect mice from acute colitis induced by dextran sodium sulfate (DSS), and more precisely whether it could protect from intestinal epithelial breakdown induced by inflammation. P. freudenreichii CIRM-BIA129 mitigated colitis severity and inhibited DSS-induced permeability. It limited crypt length reduction and promoted the expression of Zonula Occludens-1 (ZO-1), without reducing interleukin-1beta mRNA (il-1ß) expression. In vitro, P. freudenreichii CIRM-BIA129 prevented the disruption of a Caco-2 monolayer induced by pro-inflammatory cytokines. It increased transepithelial electrical resistance (TEER) and inhibited permeability induced by inflammation, along with an increased ZO-1 expression. Extracellular vesicles (EVs) from P. freudenreichii CIRM-BIA129, carrying the surface layer protein (SlpB), reproduced the protective effect of P. freudenreichii CIRM-BIA129. A mutant strain deleted for slpB (ΔslpB), or EVs from this mutant strain, had lost their protective effects, and worsened both DSS-induced colitis and inflammation in vivo. These results shown that P. freudenreichii CIRM-BIA129 daily consumption has the potential to greatly alleviate colitis symptomss and, particularly, to counter intestinal epithelial permeability induced by inflammation by restoring ZO-1 expression through mechanisms involving S-layer protein B. They open new avenues for the use of probiotic dairy propionibacteria and/or postbiotic fractions thereof, in the context of gut permeability. NEW : 1. P.freudenreichii reduces DSS-induced intestinal permeability in vivo 2. P.freudenreichii does not inhibit inflammation but damages linked to inflammation 3. P.freudenreichii inhibits intestinal epithelial breakdown through S-layer protein B NOTEWORTHY : 1. The protective effects of P.freudenreichii depends on S-layer protein B 2. Extracellular vesicles from P. freudenreichii CB 129 mimic the protective effect of the probiotic ownloaded from at INRAE Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement ( on (Marine Mantel) 05 Dec 2023
  • [hal-04465859] Evaluation environnementale par Analyse de Cycle de Vie d’un nouveau procédé de fabrication de formules infantiles

    [...] (Juliane Floury) 19 Feb 2024
  • [hal-04483180] Two human milk–like synthetic bacterial communities displayed contrasted impacts on barrier and immune responses in an intestinal quadricellular model

    The human milk (HM) microbiota, a highly diverse microbial ecosystem, is thought to contribute to the health benefits associated with breast-feeding, notably through its impact on infant gut microbiota. Our objective was to further explore the role of HM bacteria on gut homeostasis through a &quot;disassembly/reassembly&quot; strategy. HM strains covering the diversity of HM cultivable microbiota were first characterized individually and then assembled in synthetic bacterial communities (SynComs) using two human cellular models, peripheral blood mononuclear cells and a quadricellular model mimicking intestinal epithelium. Selected HM bacteria displayed a large range of immunomodulatory properties and had variable effects on epithelial barrier, allowing their classification in functional groups. This multispecies characterization of HM bacteria showed no clear association between taxonomy and HM bacteria impacts on epithelial immune and barrier functions, revealing the entirety and complexity of HM bacteria potential. More importantly, the assembly of HM strains into two SynComs of similar taxonomic composition but with strains exhibiting distinct individual properties, resulted in contrasting impacts on the epithelium. These impacts of SynComs partially diverged from the predicted ones based on individual bacteria. Overall, our results indicate that the functional properties of the HM bacterial community rather than the taxonomic composition itself could play a crucial role in intestinal homeostasis of infants. (Charles Le Bras) 29 Feb 2024
  • [hal-04213765] Beef protein ingredients from fat rendering process are promising functional ingredients

    The valorization of co-products may be a promising way to meet the dual challenge of increasing global food resources and sustainability of food systems. In particular, meat co-products may be nutritionally interesting protein resources, if they offer functional properties in accordance with food applications. In that aim, two bovine co-products, resulting from the fat rendering process, have been characterized, regarding the protein solubility, gelling, and emulsifying properties. The effect of protein concentration, pH variation and NaCl addition on these properties was tested. Despite an effect of the ionic strength on the protein solubility of the two ingredients, a little or no significant impact was observed on the functionalities. Similarly, the functional properties were scarcely affected by pH. In the end, the protein concentration has proven to be the only important parameter, which points to an easy utilization of these ingredients in many food conditions. (Rozenn Le Foll) 21 Sep 2023
  • [anses-04453336] Avis de l'Anses relatif à un document d’appui aux lignes directrices de l’arrêté du 7 mars 2011 relatives à l’évaluation de l'efficacité antimicrobienne des auxiliaires technologiques utilisés comme agents de décontamination des denrées d’origine végétale

    Un auxiliaire technologique est défini par le règlement (CE) n° 1333/2008 comme « toute substance : 1) non consommée comme ingrédient alimentaire en soi ; 2) volontairement utilisée dans la transformation de matières premières, de denrées alimentaires ou de leurs ingrédients pour répondre à un certain objectif technologique pendant le traitement ou la transformation ; et 3) pouvant avoir pour résultat la présence non intentionnelle mais techniquement inévitable de résidus de cette substance ou de ses dérivés dans le produit fini, à condition que ces résidus ne présentent pas de risque sanitaire et n’aient pas d’effets technologiques sur le produit fini ». Le décret n° 2011-509 du 10 mai 2011 fixe les conditions d’autorisation et d’utilisation des auxiliaires technologiques pouvant être employés dans la fabrication des denrées destinées à l'alimentation humaine. L’arrêté du 7 mars 2011 définit les prescriptions relatives à la constitution d’un dossier de demande d’autorisation d’emploi des auxiliaires technologiques dans une annexe intitulée « LIGNES DIRECTRICES POUR LA CONSTITUTION DES DOSSIERS […] ». La note d’appui scientifique et technique de l’Anses du 5 octobre 2018 (Anses 2018c) est également un document de référence et d’appui pour la constitution de ces dossiers. Elle apporte des précisions sur les données à fournir pour les aspects relatifs à l’innocuité et à la sécurité d’emploi, au regard des prescriptions susmentionnées. L’annexe de l’arrêté du 7 mars 2011 précise également qu’ « une justification de l'usage, de l'intérêt et de l'efficacité de la substance ou du mélange de substances, ainsi que l'explication du mode d'action et du rôle technologique dans le procédé de transformation, devraient être fournies, mentionnant les actions technologiques principales recherchées et secondaires éventuelles, si connues ». A cet égard, l’Afssa (Agence française de sécurité sanitaire des aliments) avait formulé en 2005 des « recommandations pour la présentation des données permettant d’évaluer l’efficacité des antimicrobiens appliqués sur, ou incorporés dans, les aliments » (Afssa 2005). L’expérience montre que les dossiers contiennent souvent des informations parcellaires et insuffisantes pour que l'Agence puisse évaluer l'efficacité antimicrobienne revendiquée par le pétitionnaire. Dans ce contexte, l’Anses a été saisie pour expliciter, par un document scientifique et technique, les termes des lignes directrices de l’arrêté relatives à l'efficacité antimicrobienne des auxiliaires technologiques. Ce document a vocation à se substituer aux recommandations publiées par l’Afssa en 2005. Cette expertise ne concerne que la catégorie d’auxiliaires technologiques « agents de décontamination des produits végétaux » mentionnée dans l’annexe 1 du décret n° 2011-509, c’est-à-dire les « substances utilisées pour réduire ou maîtriser la contamination des denrées alimentaires d’origine végétale inhérente à leur provenance. Leur utilisation ne doit en aucune manière se substituer aux bonnes pratiques d’hygiène et leur utilisation doit être suivie d’une élimination par rinçage » [Saisine liée n° 2003-SA-0363] (Régine Talon) 13 Feb 2024
  • [hal-04317337] Human milk bacteria individually or as a synthetic community exhibited contrasted immunomodulatory profiles and impact on the gut epithelial barrier

    Breastfeeding is recommended for the first 6 months of life. Many bioactive compounds of the human milk (HM) support the development of the intestinal immune system and barrier functions in infants. Our hypothesis was that HM microbiota contributes to these health benefits. Our objective was to characterise in vitro the role of HM bacteria, either individually or combined in synthetic communities (SynCom), on gut homeostasis. A collection of bacterial isolates, reflecting HM microbiota composition, was made from 28 healthy mothers exclusively breastfeeding. Firstly, the immunomodulatory profile of 84 HM bacterial isolates belonging to 38 species was characterized using blood mononuclear cells (PBMC). Secondly, the impact of a subset of 29 strains was deeply investigated on epithelial immune and barrier functions using a quadricellular (Caco2, HT29-MTX-E12, M cell, THP1 cells) model of the intestinal epithelium. Strains were characterized for their ability to modulate cellular IL-10 and TNF-α production and the expression of genes related to the barrier, immune and apoptosis/proliferation functions. Based on these results, 2 SynComs were designed and characterized on the quadricellular model. HM bacteria displayed a large range of immunomodulatory properties. Using MultiDimensionate Scaling (MDS) on IL-10 and TNF-α production by PBMC, isolates were classified into 5 groups with specific signatures, highlighting the anti- and/or pro-inflammatory profiles of HM bacteria. Further, the MDS analysis of cytokine production and gene expressions of the quadricellular model stimulated by each of the 29 bacteria, classified strains into 3 groups named Quadri1, 2 and 3, according to their immunomodulatory activity and their impact on the epithelial barrier function. The composition of each group did not reveal major taxonomic biases between the 3 groups, but a diversity of the HM bacteria impact on gut epithelium within each genus or species. Quadri3 and, to a lesser extent, Quadri1 strains stimulated the immune function whereas Quadri2 hardly affected it. Besides, Quadri1 and 3 strains reinforced the epithelial barrier whereas an opposite effect was observed with Quadri2 strains. Finally, strains belonging to prevalent HM genera and with contrasted immunomodulatory profiles were assembled in two HM-like SynCom of 11 strains. The 2 Syncoms displayed different immunomodulatory properties, yet less contrasted than individual strains, whereas they both exhibited beneficial impact on barrier function. This study showed the great diversity of immunomodulatory potential and impact on the barrier function of HM bacteria, individually or assembled in SynCom, highlighting the potential of the HM microbiota to modulate the intestinal development. (Charles Le Bras) 01 Dec 2023
  • [hal-04350660] Microbial communities of a variety of 75 homemade fermented vegetables

    Fermentation is an ancient practice of food preservation. Fermented vegetables are popular in Eastern European and Asian countries. They have received a growing interest in Western countries, where they are mainly manufactured at domestic and artisanal scales and poorly characterized. Our aim was to investigate the microbial communities and the safety of French homemade fermented vegetables, in the frame of a citizen science project. Fermented vegetables and the data associated with their manufacture were collected from citizens and characterized for pH, NaCl concentration, and microbiology by culturomics and 16S DNA metabarcoding analysis. Lactic acid bacteria (LAB) and yeast isolates were identified by 16S rRNA gene sequencing and D1/D2 domains of the large subunit of the rRNA gene, respectively. The 75 collected samples contained 23 types of vegetables, mainly cabbage, followed by carrots and beets, and many mixtures of vegetables. They were 2 weeks to 4 years old, and their median pH was 3.56, except for two samples with a pH over 4.5. LAB represented the dominant viable bacteria. LAB concentrations ranged from non-detectable values to 8.7 log colony-forming units (CFU)/g and only depended on the age of the samples, with the highest most frequently observed in the youngest samples (&lt;100 days). The 93 LAB isolates identified belonged to 23 species, the two mains being Lactiplantibacillus pentosus/plantarum and Levilactobacillus brevis. The other microbial groups enumerated (total aerobic bacteria, halotolerant bacteria, Gram-negative bacteria, and acetic acid bacteria) generally showed lower concentrations compared to LAB concentrations. No pathogenic bacteria were detected. Viable yeasts were observed in nearly half the samples, at concentrations reaching up to 8.0 log CFU/g. The 33 yeast clones identified belonged to 16 species. Bacterial metabarcoding showed two main orders, namely, Lactobacillales (i.e., LAB, 79% of abundance, 177 of the 398 total ASVs) and Enterobacterales (19% of abundance, 191 ASVs). Fifteen LAB genera were identified, with Lactiplantibacillus and Levilactobacillus as the most abundant, with 41 and 12% of total reads, respectively. Enterobacterales members were mainly represented by Enterobacteriaceae and Yersiniaceae. This study is the first wide description of the microbiota of a large variety of homemade fermented vegetables and documents their safety. (Anne Thierry) 18 Dec 2023
  • [hal-04341836] Poligny. Une boisson faite à partir du petit lait : des chercheurs y pensent

    Le projet européen FAIRCHAIN coordonné par INRAE (Institut National de Recherche pour L'Agriculture, L'Alimentation et L'Environnement) se terminera fin 2024 et porte, entre autre, sur les résultats de la valorisation du lactosérum (petit lait) et sa distribution qui ont été présentés et discutés à Poligny, dans les bâtiments de l'Enilbio (Isabelle Grandvaux) 13 Dec 2023
  • [hal-04341776] Ces chercheurs de l’Enilbio qui testent de nouveaux débouchés pour le petit-lait: Deux produits retenus sur les neuf élaborés

    L’Inrae de Rennes travaille sur un programme européen dénommé Fairchain. Ce projet, développé dans huit pays, a pour objectif de proposer des solutions technologiques, organisationnelles et sociales, innovantes, dans les secteurs des produits laitiers et des fruits et légumes. C’est ainsi que l’Inrae de Rennes a sollicité l’Eniblio dans la recherche et le développement. Le projet dure quatre ans. « Il a pour objectif d’aider les petites et moyennes entreprises à devenir plus compétentes », affirme Geneviève Gésan-Guiziou. Y sont inscrites les notions de partage de valeur, reconnaissance et traçabilité du produit dans une filière courte. C’est bien le cas en Franche-Comté avec le petit-lait récupéré à Vevy, travaillé avec des jus de fruits de Sellières. Le projet intègre une dimension de réutilisation du verre. Les jus sont conservés dans les bouteilles issues de la filière J’aime mes bouteilles, dont les consignes se font principalement dans les Biocoop. (Maryline Chalon) 13 Dec 2023
  • [hal-04344691] La qualité des ingrédients protéiques laitiers impacte la physiologie intestinale et le microbiote d’un modèle animal du nourrisson

    Les préparations pour nourrissons (PPNs), seul substitut adéquat du lait humain, sont des matrices complexes qui nécessitent de nombreux ingrédients et étapes de transformation. Précédemment, nous avons montré que la qualité des ingrédients protéiques laitiers des PPNs modulaient leur microstructure, leurs cinétiques digestives in vitro et in vivo. L'objectif était donc d’évaluer l'impact de la qualité des protéines laitières sur la physiologie intestinale et le microbiote. Trois PPNs contenant des protéines du lactosérum avec différents niveaux de dénaturation (PPNs-A/-B) ou des caséines d’organisation différentes (PPNs-B/-C) ont été fabriquées. Vingt-quatre mini-porcelets Yucatan, ont reçu l'une des trois PPNs entre 2 et 21 jours d’âge. Les contenus et tissus digestifs ont été analysés via des approches métagénomique, histologique, de perméabilité ex vivo et d’expression génique. Des analyses statistiques univariée et multivariée ont été réalisées. La perméabilité paracellulaire colique était augmentée et un léger boost immunitaire était observé pour les porcelets nourris avec la PPN-C par rapport à la PPN-A, en faveur de la PPN-C, comparativement aux données d’une étude récente sur le lait humain chez le porcelet (Charton et al., 2022). L’expression colique de certains transporteurs d'acides aminés était diminuée chez les porcelets nourris avec la PPN-C par rapport à la PPN-A. La composition du microbiote était similaire selon les régimes et seule la composition fécale en acides gras libres différait selon l’origine du lactosérum dans les PPNs. L’utilisation de lactosérum idéal et la modulation de l’organisation des caséines semblent se présenter comme des pistes d’améliorations pour les PPNs. (Lucile Chauvet) 14 Dec 2023
  • [hal-04342627] Développement et digestion in vitro de produits laitiers adaptés aux besoins nutritionnels spécifiques des personnes âgées

    Il est généralement admis que le vieillissement entraine des modifications de la fonctionnalité du système digestif qui se traduisent par une diminution de la digestibilité des aliments, ce qui pourrait notamment affecter l’effet anabolisant d’aliments riches en protéines, mais les études portant sur ce sujet sont rares. L’objectif principal de cette étude était donc d’améliorer notre connaissance de la digestion de produits laitiers riches en protéines dans le tractus gastrointestinal vieillissant afin de mieux cibler les besoins spécifiques des personnes âgées (&gt;65ans) lors de la formulation de nouveaux aliments cherchant à promouvoir la santé musculaire Matériel et méthodes Pour cela, nous avons développé deux fromages à tartiner contenant 20% de lipides et 24% de protéines, avec un ratio caséines/protéines sériques soit de 80/20 (observé typiquement dans le lait de vache), soit de 20/80, par opposition et avec l’intention d’améliorer et de prolonger la libération postprandiale d’acides aminés essentiels (en particulier la leucine) pour stimuler la synthèse des protéines musculaires. Ces deux produits ont ensuite été digérés in vitro en utilisant le modèle de digestion statique INFOGEST adulte classique [1], ainsi que la nouvelle version de ce modèle, publiée récemment et adaptée pour représenter au mieux la digestion des personnes âgées [2]. Cela nous permet tout d’abord d'étudier in vitro l'influence de l'âge sur la lipolyse et la protéolyse de ces deux produits, mais également d'évaluer l'impact de la composition protéique des produits sur leur digestion in vitro. Résultats et analyses statistiques L'hydrolyse des protéines par la pepsine est plus lente dans les conditions de digestion correspondant aux personnes âgées et, par conséquent, malgré une durée de phase gastrique plus longue, le degré de protéolyse atteint à la fin de la phase gastrique est plus faible avec le modèle personne âgée qu'avec le modèle adulte classique. De plus, deux scénarios différents sont observés selon le ratio caséines/protéines sériques étudié : la protéolyse est plus lente en phase gastrique pour le ratio 80/20 que pour le 20/80. En fin de phase intestinale, le degré de protéolyse reste significativement plus faible avec le modèle personne âgée qu'avec le modèle adulte. Cependant, contrairement à ce qui était attendu, des concentrations plus faibles en leucine libre semblent être observées dans les digestats à la fin de la phase intestinale lorsque le fromage contient une majorité de protéines sériques. Conclusion Les conditions de digestion utilisées influencent de manière significative la cinétique et l'étendue de la protéolyse en phase gastrique et intestinale in vitro. L’analyse des résultats concernant la lipolyse est en cours (GC-FID), ainsi qu’une étude clinique comparant l'effet de ces deux produits sur la synthèse musculaire postprandiale d’un groupe de personnes âgées, ce qui devrait nous permettre de déterminer si nos résultats sont pertinents physiologiquement. (Anaïs Lavoisier) 13 Dec 2023
  • [hal-04342725] Qualité nutritionnelle des protéines de deux coproduits bovins déterminée chez le porc en croissance

    Introduction et but de l’étude : La demande croissante en protéines conduit à la recherche de sources alternatives. La valorisation de coproduits, comme les coproduits carnés peu valorisés dans l’alimentation humaine, est une voie prometteuse pour relever ce défi, qui s’inscrit par ailleurs dans le principe d’économie circulaire. La présente étude visait à évaluer la qualité nutritionnelle de deux ingrédients protéiques d’origine bovine (Greasy Greaves Recovered Proteins-GGRP et Water Recovered Proteins-WRP), tous deux coproduits du processus de fonte des graisses. Matériel et méthodes : La digestibilité iléale vraie (TID), le score d'acides aminés indispensables digestibles (DIAAS) et la cinétique de libération des acides aminés plasmatiques (AA) ont été mesurés sur ces deux ingrédients protéiques chez dix porcs en croissance selon un plan expérimental en cross- over. Chaque ingrédient protéique était inclus dans un régime expérimental en tant que seule source de protéines brutes (CP) et d'AAs, de sorte que les régimes étaient iso-azotés. Le dioxyde de titane (3 g/kg) a été utilisé comme marqueur non digestible. Un régime sans protéine, administré à la fin de la période expérimentale, a permis d’évaluer les pertes endogènes en N et AA. Des échantillons de digesta et de sang ont été prélevés tout au long des 9 heures suivant l'ingestion d'un repas et les teneurs en azote (N) et AAs ont été analysées respectivement par la méthode Dumas et par chromatographie par échange d'ions. Les données ont été analysées statistiquement à l'aide de modèles linéaires. Résultats et analyse statistique : La TID du N total n'était pas différente (p &gt; 0,05) entre WRP et GGRP (84,2 ± 3,2 et 81,2 ± 2,3 %, respectivement ; moyenne ± écart-type). Le principal AA limitant était le tryptophane pour les deux ingrédients protéiques, avec un DIAAS beaucoup plus élevé pour le GGRP (74 %) que pour le WRP (18 %) pour les enfants âgés, adolescents et adultes. La cinétique de libération des AAs différait selon les protéines, la concentration plasmatique postprandiale d'AA atteignant sa valeur maximale plus tôt pour le WRP (3 h) que pour le GGRP (5 h). La concentration plasmatique des AA totaux et essentiels était plus élevée (p &lt; 0,001) avec le repas GGRP qu'avec le repas WRP ; l'inverse était vrai pour l'urée (p &lt; 0,001). La différence de concentration plasmatique en urée suppose un catabolisme hépatique des AA et un déficit en AA essentiel plus important pour le WRP par rapport au GGRP. A l’inverse une meilleure utilisation des AA pour la synthèse protéique est envisagée pour le GGRP. Conclusion : Le GGRP a une qualité nutritionnelle adaptée pour répondre aux besoins des enfants âgés, adolescents et adultes, tandis que le WRP doit être complété par d'autres sources de protéines riches en AA essentiels pour répondre aux besoins nutritionnels. (Rozenn Le Foll) 13 Dec 2023
  • [hal-04353506] La qualité des ingrédients protéiques laitiers impacte la physiologie intestinale et le microbiote d’un modèle animal du nourrisson

    Les préparations pour nourrissons (PPNs), seul substitut adéquat du lait humain, sont des matrices complexes qui nécessitent de nombreux ingrédients et étapes de transformation. Dans des études précédentes, nous avons montré que la qualité des ingrédients protéiques laitiers des PPNs modulaient leur structure, leurs cinétiques de digestion in vitro et les concentrations plasmatiques in vivo en acides aminés chez un modèle du nourrisson. L'objectif de cette étude était donc d’évaluer l'impact de la structure et de la qualité des lait humaindes PPNs sur la physiologie intestinale et le microbiote. Trois PPNs iso-azotées ont été formulées conformément à la réglementation européenne en vigueur, en utilisant des protéines de lactosérum (PS) de différentes origines (lactosérum de fromagerie : PPN-A, vs. lactosérum idéal : PPNs-B/-C) et de différents niveaux de dénaturation (élevé : PPN-A, vs. faible : PPNs-B/-C), et des caséines dont l’organisation supramoléculaire était différente (micellaire : PPNs-A/-B, vs. non-micellaire : PPN-C), avec un ratio PS/caséine de 60/40. Vingt-quatre mini-porcelets Yucatan, utilisés comme modèle du nourrisson, ont reçu l'une des trois PPNs entre 2 et 21 jours d’âge. La composition et l'activité du microbiote intestinal, la perméabilité en chambres d’Ussing et l'expression intestinale des gènes codant des protéines impliquées dans les fonctions barrière, immunitaire, entéroendocrine et de transport des nutriments ont été analysées. Des analyses statistiques univariée et multivariée ont été réalisées. La perméabilité paracellulaire colique ex vivo était plus élevée chez les porcelets nourris avec la PPN-C que chez les porcelets nourris avec les PPNs-A/-B, et plusieurs gènes codant pour des protéines des jonctions serrées (occludine et claudines-3 et -4) étaient également moins exprimées chez les porcelets nourris avec la PPN-C. La combinaison de la modulation de l'origine du lactosérum et de l'organisation des caséines a induit une légère augmentation de la réponse immunitaire colique (SOCS3, PIGR et TNFα) chez les porcelets nourris avec la PPN-C par rapport à ceux nourris avec la PPN-A. L'analyse multidimensionnelle a montré que l'expression de certains transporteurs d'acides aminés (SLC15A1, SLC7A7, SLC6A19, SLC7A9) contribuait à discriminer les porcelets nourris avec la PPN-C des porcelets nourris avec la PPN-A au travers d’une diminution de l’expression colique de ces transporteurs chez les porcelets nourris avec la PPN-C. Les indices de diversités α- et β du microbiote dans l'iléon, le côlon et les fèces n'étaient pas différents entre les PPNs et seules quelques modifications de la composition ont été observées au niveau des genres dans le côlon. La composition en acides gras libres différait entre les PPNs avec un taux d'acétate moins faible et un taux de butyrate plus élevé dans les fèces des porcelets nourris avec les PPNs-B/-C par rapport aux porcelets nourris avec la PPN-A. Bien qu'aucune corrélation significative entre le microbiote (composition et activité) et les fonctions physiologiques modulées (barrière, immunité et transporteurs d'acides aminés) n'ait été mise en évidence, l'hypothèse serait que les différences de cinétique digestive précédemment démontrées entre les PPNs modifieraient le substrat colique disponible pour l'activité fermentaire du microbiote, modulant à son tour les métabolites bactériens interagissant avec l'épithélium et par conséquent, influençant la maturation de ce dernier. Comparativement, les modifications de la perméabilité de la barrière épithéliale intestinale et de la réponse immunitaire des porcelets nourris avec la PPN-C que nous avons mesurées, étaient plus proches de celles observées dans une autre étude (Charton et al. 2022) chez des porcelets nourris avec du lait humain qu’avec une PPN, suggérant que la qualité des ingrédients sériques laitiers et l’organisation des caséines peuvent participer aux propriétés physiologiques des PPNs. (Lucile Chauvet) 19 Dec 2023
  • [anses-04350896] Avis de l'Anses relatif à la présence de parasites Toxocara spp. dans les viandes de sanglier sauvage

    Des analyses sur les carcasses de sangliers sauvages inspectées dans les établissements français de traitement de gibiers sauvages ont révélé depuis deux ans la présence régulière de larves de Toxocara spp. Ce constat a conduit les services vétérinaires d'inspection à saisir ces carcasses, conformément à l'article 45 du règlement d'exécution (UE) n°2019/627 de la Commission du 15 mars 2019 qui prévoit que les viandes présentant une infestation parasitaire sont déclarées impropres à la consommation humaine. La problématique pour le gestionnaire est double. Le premier enjeu est lié au risque de toxocarose pour les consommateurs de viandes de sanglier et des recommandations relatives à la conservation et la cuisson des viandes à adresser aux chasseurs. Le second enjeu est relatif à la gestion des lots de sangliers détectés positifs. Les demandes instruites dans le cadre de cette expertise sont les suivantes : Demande 1 : Établir un profil de risque pour Toxocara spp. dans les viandes de sanglier sauvage. Demande 2 : Évaluer l’efficacité de traitements assainissants de la carcasse sur la viabilité du parasite Toxocara spp., plus particulièrement la congélation et la cuisson, dans le cas où ces traitements sont réalisés, soit par les établissements du secteur alimentaire, soit directement par les consommateurs. (Philippe Fravalo) 12 Mar 2024
  • [hal-04321019] A Shared Perspective on in Vitro and in Vivo in Models to Assay Intestinal Transepithelial Transport of Food Compounds

    Assessing nutrient bioavailability is complex, as the process involves multiple digestion steps, several cellular environments, and regulatory-metabolic mechanisms. Several in vitro models of different physiological relevance are used to study nutrient absorption, providing significant challenges in data evaluation. However, such in vitro models are needed for mechanistic studies as well as to screen for biological functionality of the food structures designed. This collaborative work aims to put into perspective the wide-range of models to assay the permeability of food compounds considering the particular nature of the different molecules, and, where possible, in vivo data are provided for comparison. (Arancha Hevia) 04 Dec 2023
  • [hal-04317931] Human milk metabolites are bioactive and can modulate gut physiology : in vitro study in a pluricellular model of intestinal epithelium

    Human milk (HM) is associated with major short- and long-term health benefits for infants. However, infant formulas (IF), substitutes for HM, are widely used for infant nutrition. Although these IFs meet the nutritional needs of newborns, they are devoid of many bioactive compounds present in HM, such as immunoglobulins, hormones and a multitude of metabolites. HM metabolites include short chain fatty acids (SCFAs) (butyric acid, acetic acid, propionic acid), polyamines (putrescine, spermine, spermidine), tryptophan derivatives (indole, indole-lactic acid, kynurenine) as well as GABA and lactate. These metabolites are known to be produced within the gastrointestinal tract by the intestinal microbiota and to have effects on the host physiology but their relevance in HM has not been studied so far. The objective of our study was therefore to decipher the effects of HM metabolites on intestinal physiology using an in vitro pluricellular and polarized model of intestinal epithelium, including Caco-2 (as enterocytes), HT-29 MTX (as goblet cells), NCI-H716 (as enteroendocrine cells) and M cells. HM metabolites were studied at concentrations close to those found in HM, that is quite low. Their effects on trans-epithelial electric resistance (TEER) and on the expression of genes involved in the intestinal barrier, immune, antioxidant, endocrine and digestive functions were analyzed. SCFAs strongly modulated different intestinal functions, particularly the immune one with a significant downregulation of genes coding for IL-8, MyD88 and TFF3. They also modulated genes encoding tight junctions, as did GABA and polyamines, upregulating CLDN3, TJP1 and CLDN4 respectively and downregulating CLDN1 for SCFA and polyamines and CLDN7 for GABA. In parallel SCFAs significantly increased TEER, highlighting a potential reinforcing effect on the epithelial barrier while polyamines and GABA had no effect on TEER. Finally, SCFAs, GABA and lactic acid modulated the expression of some transporters involved in nutrition such as MCT1, GLUT1 and SGLT1 respectively. HM metabolites, despite their low concentration, are able to impact the intestinal barrier physiology, inviting us to consider their implementation in IF for a better mimicry of HM health benefits. (Sarah Blanchet) 01 Dec 2023
  • [hal-04302538] Fermented dairy and legume-based food products: from smart design of lactic acid bacteria to innovative products

    For reasons linked to lifestyle, health, nutrition and sustainability, our diets are tending to change, in particular by rebalancing animal and plant sources in Western diet. This leads to the development of new food products, particularly fermented ones. Actually, fermentation can confer hedonic, hygienic and probiotic properties to fermented products. Fermented dairy products are well known, while legume-based fermented dairy analogues are less familiar. The development of legume-based fermented products requires a combination of knowledge of the raw material and of bacterial potential, in order to select bacterial strains with appropriate functions. In our study, new fermented products were developed based on milk, on plant-based analogues, and on the mixes thereof, fermented by lactic acid bacteria and/or propionic acid bacteria, selected on their capability to hydrolyze carbohydrates, proteins and on their immunomodulatory properties. By taking advantage of the functional complementarity between strains, we designed bacterial consortia capable of transforming different raw materials into functional fermented food products, with improved technofunctional and health properties. The development of such fermented products also raises the question of how positive interactions between bacteria can be promoted in order to improve the final qualities of these products. (Valérie Gagnaire) 23 Nov 2023
  • [hal-04302599] Extracellular Vesicles and Surface Layer Proteins as the post-biotic active ingredient of the probiotic bacterium Propionibacterium freudenreichii against colitis and mucositis

    Gut inflammation constitutes a growing health concern in developed countries. It coincides with dysbiosis, including a lack of anti-inflammatory bacteria. As an example, propionibacteria are lacking in the microbiota of newborns which develop necrotizing enterocolitis. We investigated immunomodulatory properties of Propionibacterium freudenreichii. A screening led to the selection of P. freudenreichii CIRM-BIA129, a strain inducing high levels of regulatory IL-10 in human PBMCs. Consumption of this strain protected mice from colitis induced either by TNBS or by DSS. It alleviated severity of symptoms, modulated local and systemic inflammation, as well as colonic oxidative stress and epithelial cell damages. It further mitigated severity of mucositis induced by 5-fluorouracyl, preventing weight loss, reducing inflammation and mucosal damages. Mutation of the slpB gene, encoding a key surface layer protein, suppressed this immunomodulatory effect and the resulting slpB mutant induced a rather proinflammatory response and failed to prevent mucositis. Accordingly, consumption of Lactococcus lactis NCDO 2118 harboring pXIES-SEC:slpB and expressing the propionibacterial SlpB reduced severity of colitis, lowered weight loss, disease activity index, shortening of the colon length, and histopathological score, compared with mice treated with L. lactis NCDO 2118 wild-type strain. P. freudenreichii was further shown to produce extracellular vesicles (EVs), which mimic the immunomodulatory features of propionibacteria in vitro by modulating NF-κB transcription factor activity and IL-8 release in cultured human intestinal epithelial cells (HIEC). Proteomic analysis revealed presence of surface layer (S-layer) proteins, including SlpB, in these EVs. Guanidine treatment of P. freudenreichii intact cells leads to extraction of surface proteins, which constitute the S-layer, the outmost structure of bacteria. These extracted proteins also mimic the effect of propionibacteria, inducing IL-10 in immune cells and modulating NF-κB and IL-8 in HIEC. This work emphasizes the importance of extractable surface proteins, including SlpB, and of EVs, in P. freudenreichii probiotic effects. It opens perspectives for the development of probiotic and postbiotic products aimed at decreasing inflammation. (Gwénaël Jan) 23 Nov 2023
  • [hal-04302652] Dairy starters as "2-in-1" probiotic microorganisms fermenting foods and modulating gut mucosal immunity

    The gut microbiota plays a crucial role in the regulation of mucosal immunity and of the function of the intestinal barrier. Dysbiosis is accordingly associated with rupture of mucosal immune homeostasis, leading to inflammatory intestinal diseases. In this context, probiotic bacteria, including a new generation of intestinal probiotics, can maintain intestinal homeostasis and promote health. Surprisingly, little is known about the impact of fermented dairy products in this context, while they represent our main source of live and active bacteria. Indeed, they provide, through our daily diet, a high number of bacteria whose effect on mucosal immunity deserves attention. Among bacteria ingested in fermented dairy products, Streptococcus thermophilus, Lactobacillus delbrueckii, Lactobacillus helveticus, Lactococcus lactis and Propionibacterium freudenreichii are on top, as they are ingested in high concentrations (close to 109 ufc per gram of product) in fermented milks or cheeses. (Nassima Illikoud) 23 Nov 2023

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Date de modification : 15 avril 2024 | Date de création : 25 octobre 2022 | Rédaction : stlo