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This study investigated the feasibility of using hyperspectral imaging (HSI) to characterize the diffusion of acid and water within food structures during gastric digestion. Two different sweet potatoes (steamed and fried) and egg white gel (pH5 and pH9 EWGs) structures were exposed to in vitro gastric digestion before scanning by HSI. Afterward, the moisture or acid present in the digested sample was analyzed for calibration purposes. Calibration models were subsequently built using partial least-squares (PLS). The PLS models indicated that the full-wavelength spectral range (550–1700 nm) had a good ability to predict the spatial distribution of acid (Rcal2 > 0.82) and moisture (Rcal2 > 0.88). The spatiotemporal distributions of moisture and acid were mapped across the digested food, and they were shown to depend on the food composition and structure. The kinetic data revealed that the acid and moisture uptakes are governed by Fickian diffusion or by both diffusion and erosion-controlled mechanisms.

International audience; This study explores the ability of lactic acid bacteria (LAB) to ferment soy juice. The ability of 276 LAB strains from 25 species to ferment the principal soy carbohydrates, sucrose, raffinose or stachyose was tested in synthetic media and a soy juice. Fermented soy juices (FSJs) were characterized for their odor. Selected FSJs were characterized by targeted metabolomics. All Streptococcus, 83% of Leuconostoc and Lactobacillus and 41% of Lactococcus strains were sucrose-positive, while only 36% of all the LAB strains tested were raffinose-positive and 6% stachyose-positive. Nearly all (97%) the sucrose-positive strains fermented soy juice, indicating that an ability to use sucrose is a good criterion to select strains for soy juice fermentation. Among the most efficient acidifying strains, 46 FSJs had an odor deemed to be acceptable. FSJ composition was dependent on both species and strains: 17/46 strains deglycosylated soy juice isoflavones, the 27 S. thermophilus strains converted a mean 4.4 ± 0.1 g/L of sucrose into 3.0 ± 0.1 g/L of lactic acid versus 5.2 ± 0.1 g/L into 2.2 ± 0.1 g/L for the 18 Lactobacillus and one Lactococcus strains. This study highlights the diversity of the metabolic profiles of LAB strains in soy juice fermentation.

International audience; Le lait maternel est la référence en nutrition néonatale, en particulier pour les prématurés. Il pourrait réduire le risque de complications liées à la prématurité et serait bénéfique au neurodéveloppement de l’enfant. Le lait maternel de don, pasteurisé pour prévenir la transmission des pathogènes, est le premier choix pour nourrir les prématurés lorsque le lait de la mère n'est pas disponible. Cependant, la pasteurisation altère la qualité du lait en dénaturant certains composants biologiques. Le but de cette étude est d’évaluer in vitro l’impact de la pasteurisation du lait maternel sur la digestion gastro-intestinale chez l’enfant prématuré et sur l’absorption intestinale des lipides. Matériel et méthodes: Les cinétiques de digestion de lait maternel pasteurisé à 62,5°C pendant 30 min (LP) ou cru (LC) ont été réalisées dans un modèle de digestion in vitro statique que nous avons adapté pour simuler la capacité de digestion des prématurés. La protéolyse a été déterminée par électrophorèse en gel de polyacrylamide et la lipolyse par chromatographie sur couche mince. Puis, des cellules Caco-2/TC7, modèle d’absorption intestinale, ont été incubées avec le LP et le LC préalablement digérés. L’absorption lipidique a été quantifiée par analyse d’image numérique des gouttelettes lipidiques après coloration à l’Oil Red O dans les cellules et par mesure de la sécrétion de triglycérides dans le milieu extracellulaire. L’expression de certains gènes impliqués dans l’absorption intestinale des lipides a aussi été analysée. Résultats et Analyse statistique : A la fin de la phase intestinale de digestion in vitro du LP et du LC, la protéolyse de la lactoferrine, de la β-caséine et de l’α-lactalbumine comme la lipolyse n’étaient pas significativement différentes. Le nombre de pixels dans les gouttelettes lipidiques des cellules Caco-2/TC7 était diminué après 16h d’incubation avec le LP digéré par rapport à LC digéré (p=0,04). Le nombre de gouttelettes lipidiques par image était identique pour les 2 laits (p=0,26) mais l’aire moyenne des gouttelettes était plus petite dans les cellules Caco-2/TC7 incubées avec le LP digéré (p=0.01). La sécrétion des triglycérides dans le milieu baso-latéral après 16h d’incubation des cellules avec le LP ou le LC digérés n’était pas différente (36.1 vs 42.9 µmol/L respectivement, p=0.26). De plus, aucune différence dans l’expression de certains gènes impliqués dans le métabolisme des lipides n’a été mise en évidence. Conclusion: La pasteurisation du lait maternel n’entraine pas de modification importante de la protéolyse ni de la lipolyse en fin de digestion gastro-intestinale par rapport au lait cru. Dans les cellules Caco-2/TC7, les gouttelettes lipidiques étaient plus petites après incubation avec LP digéré qu'avec LC digéré mais la quantité de triglycérides sécrétés était similaire avec les 2 laits, suggérant que la pasteurisation n’a pas d’impact majeur sur l’absorption intestinale des lipides dans ces modèles in vitro. L’utilisation de lait maternel pasteurisé semble une bonne alternative par rapport au lait maternel cru d’un point de vue nutritionnel.

National audience; Introduction et but de l’étude Le processus de fabrication des préparations pour nourrissons (PPNs) implique des traitements thermiques, modifiant les propriétés physico-chimiques des protéines et éventuellement leur cinétique de protéolyse. L'objectif de l'étude consiste en l’analyse des effets de la composition et des structures protéiques thermo-induites des PPNs sur la cinétique de protéolyse. Matériel et méthodes Deux PPNs modèles ont été formulées à 1,3% de protéines. Elles se distinguent par la qualité des protéines du lactosérum (α-lactalbumine, β-lactoglobuline et lactoferrine) : la PPN « standard » mime la composition protéique de la majorité des PPNs 1er âge commercialisées et la PPN « LF+ ALA+ » celle du lait maternel. Les PPNs ont été traitées thermiquement à 67,5°C ou 80°C avec un taux de dénaturation des protéines du lactosérum identique de 65%. Les PPNs sans traitement thermique ont servies de référence. Les structures protéiques thermo-induites ont été caractérisées par électrophorèse, fractionnement d’écoulement de champ couplé à la diffusion de lumière multi-angle et microscopie électronique. D’autre part, les PPNs ont été soumises à la digestion gastro-intestinale en condition statique in vitro au stade nouveau-né à terme (n = 3). Le degré d’hydrolyse a été mesuré par dosage des amines primaires, la cinétique de protéolyse suivie par électrophorèse et l’évolution de la structure au cours de la digestion par granulométrie à diffraction laser. Résultats et analyse statistique A taux de dénaturation protéique équivalent, les caractéristiques morphologiques des structures protéiques thermo-induites diffèrent selon la composition protéique des PPNs et la température de traitement thermique. La formation d’agrégats solubles a été observée uniquement pour la PPN « standard », tandis que la fixation de protéines dénaturées sur les micelles de caséines a été constatée pour les deux PPNs. Les agrégats formés à 67,5°C ont une plus petite masse pour la PPN « standard » et un plus petit diamètre pour la PPN « LF+ ALA+ » que ceux formés à 80°C. Au cours de la phase gastrique, le traitement thermique accélère la cinétique de protéolyse des caséines de la PPN « standard » contrairement à la PPN « LF+ ALA+ ». La cinétique de protéolyse de l’α-lactalbumine dépend de la composition protéique des PPNs et de la température de chauffage de la PPN « LF+ ALA+ ». La protéolyse de la lactoferrine est fortement affectée par le traitement thermique. Les entités protéiques formées par agrégation en fin de phase gastrique sont affectées par la composition protéique des PPNs et le traitement thermique. Conclusion Notre étude a permis de mettre en évidence les effets de la composition protéique des PPNs et des structures protéiques thermo-induites sur les cinétiques de protéolyse. Ces deux paramètres sont donc à prendre en compte pour l’optimisation des PPNs en termes de stratégie nutritionnelle.

National audience; La fortification du lait de femme (LF) est une pratique courante dans l’alimentation des prématurés, pour les aider à rattraper leur retard de croissance. Les fortifiants, généralement à base de protéines de lait de vache hydrolysées (FV), peuvent poser des problèmes d’intolérances alimentaires de par l’immaturité du système digestif du prématuré. Un nouveau fortifiant à base de protéines entières de lait d'ânesse (FA) a été mis au point et testé lors d’un essai clinique randomisé chez les prématurés. Il a été démontré que la fortification de LF par FA réduisait l'intolérance alimentaire, les résidus gastriques bilieux et les épisodes de vomissements par rapport à FV, contenant des protéines hydrolysées. Le but de ce travail était d’évaluer comment ces différents fortifiants (FA, FV) affectaient la digestion des macronutriments (protéines et lipides) du LF. Matériel et méthodes: Du LF d’enfant prématuré, enrichi avec FA ou FV en conditions isoprotéique et isocalorique, a été digéré à l’aide d’un modèle de digestion in vitro dynamique adapté aux conditions digestives du nouveau-né prématuré. Les échantillons ont été prélevés à différents temps de digestion gastro-intestinale et ont été caractérisés en termes de protéolyse par suivi en électrophorèse et par mesure du degré d’hydrolyse (technique OPA) et de lipolyse par chromatographie en couche mince. La microstructure a été suivi au cours de la digestion par granulométrie à diffraction laser (distribution de taille de particules) et microscopie confocale. Résultats et Analyse statistique : Les cinétiques d’hydrolyse des protéines majoritaires de LF ne différaient pas entre les laits au cours de la digestion. Concernant le degré d’hydrolyse global, il était plus élevé avant digestion pour LF+FV que pour LF+FA de par la présence de protéines hydrolysées dans FV. Cette différence était maintenue entre les deux laits au cours de la digestion, mais l’écart était réduit en fin de phase intestinale. Le degré de lipolyse augmentait de la même manière pour les deux types de fortifications au cours de la digestion. De gros agrégats étaient présent dans LF+FA avant et pendant la digestion gastrique. La taille de ces particules était réduite après 60 min de digestion gastrique. Dans la phase intestinale, l'évolution de la taille des particules était similaire entre LF+FA et LF+FV. Conclusion: La libération des peptides et acides aminés est ralentie pour le lait de femme fortifié avec les protéines entières de lait d’ânesse par rapport à celui fortifié aux protéines hydrolysées de lait bovin. Ceci sera compléter par le dosage des peptides et acides aminés libérés au cours de la digestion. Apporter des protéines entières au nouveau-né avec le FA pourrait d’apporter au prématuré les acides aminés de manière plus progressive, et pourrait ainsi avoir un intérêt physiologique bénéfique pour la maturation du système digestif et immunitaire

About one third of the world's population suffers from micronutrient deficiencies with short and long-term consequences on individual life.Food fortification is one of the solutions for nutritional optimization to overcome these deficiencies, but the conditions for its maximum effectiveness remain to be defined regarding the actual bioavailability of these micronutrients.The impact of food structure on the kinetics of macronutrient digestion has been widely documented. However, with regard to micronutrients, studies do not always distinguish the matrix structure effect from the composition effect on their bioavailability. The main objective of this thesis is to evaluate the impact of food structure only on the digestion process and on the bioavailability of micronutrients, using real complex foods.Four foods with identical composition but different structures and textures have been designed, and enriched with icronutrients (lutein and vitamins D, B9 and B12). The structure of the food matrix had actually an impact on the bioavailability of lutein, and vitamins D and B9 in adult healthy men, in both quantitative and kinetics terms, thus providing proof of concept. The in vitro studies confirmed the food structure effect observed in vivo and allowed to study in depth the degradation of the food matrix, the release of micronutrients from the matrix, and thus their bioaccessibility.This work highlights the importance of the matrix effect for food digestion. It also suggests that a deep understanding of the digestion mechanisms could enable, in the future, the control over the digestion process with a targeted food design.; Un tiers de la population mondiale souffrirait d’une carence en micronutriments entraînant des conséquences à court et long terme sur la vie des individus. L’enrichissement des aliments est une des pistes de l’optimisation nutritionnelle visant à lutter contre ces carences, mais les conditions de son efficacité maximale restent à définir au regard de la biodisponibilitéréelle de ces micronutriments. L’impact de la structure des aliments sur la cinétique de digestion des macronutriments a été largement démontré. En revanche, en ce qui concerne les micronutriments, les études ne permettent pas toujours de distinguer les effets composition et structure de la matrice sur leur biodisponibilité. L’objectif principal de cette thèse est d’évaluer l’impact de la seule structure d’aliments réels sur le processus de digestion et la biodisponibilité des micronutriments.Quatre aliments de même composition mais de structures et textures variables ont été conçus et enrichis en micronutriments (lutéine et vitamines D, B9 et B12). La structure de la matrice alimentaire a effectivement influencé la biodisponibilité de la lutéine et des vitamines D et B9 chez l’Homme, et ce de manière quantitative et cinétique, apportant ainsi une preuve de concept. Les études in vitro ont permis de confirmer l’effet structure observé in vivo et d’étudier en détail la dégradation de la matrice alimentaire, la libération des micronutriments et donc leur bioaccessibilité.Ce travail souligne l’importance de l’effet matrice dans la digestion des aliments. Il suggère aussi que la compréhension fine des mécanismes de digestion pourrait permettre, à terme, la maîtrise du déroulement de la digestion par un design ciblédes aliments.

International audience; Introduction: Donor human milk (DHM) represents the best alternative when mother’s own milk is not available, a common occurrence in Neonatal Intensive Care Units. Heat treatment of DHM is mandatory for safety reasons. Holder pasteurization (HoP, 62.5°C-30’) is recommended by all human milk bank guidelines. Recent studies have demonstrated that HoP affects the digestion profile and behavior of several human milk components. High Temperature-Short Time pasteurization (HTST, 71°C-15’’) is currently under evaluation as a promising alternative technology to limit the denaturation of some biological compounds of raw human milk. The aim of the present work was to assess whether the different types of pasteurization (HoP, HTST) impacted the digestive kinetics of human milk during in vitro dynamic digestion. Materials and Methods: pooled raw HM (RHM) was collected and processed by using the two pasteurization techniques. The pasteurized samples and RHM were digested in vitro using preterm gastrointestinal conditions. Samples were collected at different digestion times. Undigested and digested milks samples were characterized for their particle size distribution (PSD), triglyceride content, protein and amino acid (AA) profiles. Results: during gastric digestion, both pasteurization methods modified PSD, as compared to RHM. Caseins were rapidly hydrolyzed in the gastric phase unlike that for the whey proteins. Lactoferrin was hydrolyzed faster in the pasteurized samples in comparison to RHM, in which lactoferrin was resistant to gastro-intestinal digestion. Heat-treatments, consequently, affected the intestinal release of some AA, and a higher bioaccessibility of AA was found for HTST, as compared to HoP. Concerning lipolysis, at any time of the intestinal digestion phase, the lipolysis of HoP samples was significantly lower (p < 0.05) than in both RHM and HTST samples. Conclusions: this work provides the first important evidences on the differential impact of HoP and HTST pasteurization techniques on bioaccessibility of DHM nutrients and biological compounds, for preterm newborns.

Food is a complex combination of chemically diverse structures, influenced by composition andprocessing. The nutritional quality of food cannot be solely based on individual contents in nutrientsas food structure will strongly modulate the bioaccessibility of nutrients upon digestion. In previousstudies, the most common approach for measuring the extent of proteolysis and nutrient uptake wasto compare the initial macroscopic features of ingested food to final concentrations in thebloodstream. However, there is limited literature to the support underlying mechanisms of thedigestion of food in the stomach and enzyme diffusion in solid food substrates. In the present work,the influence of casein protein gel microstructure on enzymatic digestion was investigated for thefuture development of personalised foods. Casein gels with an identical composition, but differing bythe coagulation mode, were characterized and submitted to simulated gastric digestion. The changesin gel structure over time were studied using confocal microscopy and small angle x-ray scattering(SAXS). The molecular interactions that occur as a gel network is formed, and subsequently brokendown under digestive conditions will be discussed.

Les produits fermentés sont consommés dans le monde entier depuis des siècles. Les végétaux fermentés font l’objet d’un regain d’intérêt, suivant les tendances du végétarisme, de la recherche de naturalité et du développement durable. Le CTCPA et le pôle de compétitivité VEGEPOLYS vous proposent ce séminaire de formation, au cours duquel leurs intervenants feront le point sur les tendances de ce marché, sur l’état de l’art et les limites des connaissances techniques et scientifiques sur le sujet.

Unravelling the mechanisms of food digestion to improve our knowledge of the effect of food on human health. 4. Simposio de Alimentos e Nutriçao

Objectifs/ObjectivesThe study aims to improve knowledge over LAB characteristics to ferment a commercial soy juice. Matériels et Méthodes/Materials and methodsFirst 280 strains of LAB from 23 different species of Lactococcus, Streptococcus, Lactobacillus and Leuconostoc genera were tested for their abilities to ferment soy juice containing sucrose, raffinose or stachyose as carbon source and to acidify synthetic media containing sucrose, raffinose or stachyose as unique carbon source. Then, fermented soy juices (FSJ) were produced by 10 h of fermentation (inoculation level 1 %), followed by 14 days of storage at 4 °C. The scents of FSJ were sensorially characterized and FSJ’s primary and secondary metabolites were analyzed. Résultats principaux/Main ResultsWithin 48 h, 39 % of L. lactis strains, 82 % of Lactobacillus strains and all S. thermophilus strains could acidify the synthetic medium with sucrose, as previously described in fermentation patterns of these species. 101 strains representing 18 species could use raffinose and 12 strains representing 6 species could use stachyose. 94 % of the strains that could use sucrose could also ferment soy juice, whose sucrose is the major sugar. Interestingly, 3 strains from species never tested to ferment soy juice, L. kunkeei, L. xiangfangensis and L. pontis revealed abilities to ferment soy juice. Among the 280 strains, 116 strains could acidify soy juice below 6.0 pH units within 10 h. Among the 116 corresponding FSJs, the scents of 48 FSJs were judged as acceptable. The use of sucrose was species-dependent: less residual sucrose was present in FSJs from strains of L. plantarum, L. pentosus, L. lactis, L. delbrueckii and L. coryniformis species compared to S. thermophilus strains. None of the strains used raffinose nor stachyose. S. thermophilus strains produced more lactic acid and less acetic acid than the other strains, in agreement with their homolactic metabolism. Due to acetic acid, FSJs from L. plantarum were more frequently described as ‘sour’. In addition, some strains presented specific traits. For example, CIRM-BIA2115 of L. plantarum produced a floral scent in FSJ likely related to the production of phenylethan-1-ol observed. ConclusionThe present study is an advance on the knowledge of LAB diversity and their capacity to ferment soy juice. It shows that LAB capacity to use sucrose is important to ferment soy juice and highlights the importance of screening due to the diversity of LAB metabolism.

Mucositis, a common and often debilitating side effect of cancer chemotherapy, is a clinically important gastrointestinal inflammatory disease. It consists in a painful inflammation and ulceration of the mucosa lining the digestive tract, which may compromise proper nutrition of the patient, as well as termination of the treatment. It thus increases mortality and morbidity and contributes to rising health care costs. Its treatment is mainly supportive and often fails to relieve symptoms. Several studies indicate a role of the microbiota and suggest a healing effect of probiotic ingestion. Probiotic bacteria may maintain homeostasis and reduce side effects of chemotherapy toxicity. A major limit to probiotic bacteria anti-inflammatory effect is their susceptibility to digestive stresses and several studies indicate the key protective role of food matrices in increasing probiotics’ effect via the protection of bacteria against digestive constraints. In this study, we investigated the role of fermented milk, using Lactobacillus casei or Propionibacterium freudenreichii as probiotic starter, and of its fortification via addition of whey proteins.Matériels et Méthodes/Materials and methodsWe evaluated the role of whey protein isolate (WPI), when added to skim milk fermented by L. casei BL23 or by P. freudenreichii 138, as a protective matrix against in vitro stress challenges. In addition, we investigated in vivo the therapeutic effect of these fermented beverages in a murine model of mucositis induced by 5-Fluorouracil (5-FU). The monitored outcomes included weight loss, ileum histopathological score, villus height, crypt depth and number of mucus-producing goblet cells.Résultats principaux/Main ResultsThis study demonstrated that milk supplementation with 30% (w/v) of WPI increases the survival rate of both strains when challenged with acid, bile salts, high temperature and cold storage stresses, compared to fermented skim milk without the addition of WPI. Moreover, treatment with the probiotic beverages prevented weight loss and intestinal damages in mice receiving 5-FU. All symptoms of mucositis were drastically reduced by the consumption of developed probiotic fermented milks.ConclusionThis study evidenced the protective effect of selected strains of both lactic and propionic acid bacteria, in the context of induced mucositis. It confirmed that selected strains might be used bot as starter and probiotic. It opens new avenues for the development of fermented functional foods for target populations.

Artisanal fermented foods represent a cultural heritage that needs to be preserved and protected; this is particularly true in the context of industrial food standardization. The manufacture and unique sensorial properties of such products mainly relies on autochthonous complex microbiota and their activities. The present study focuses on Pélardon, a Protection Designation of Origin (PDO) French artisanal soft rind cheese, exclusively produced from raw goat’s milk using a back slopping method in mountainous areas in southern France. Pélardon microbial ecology and dynamics were studied by culture-dependent and -independent methods. A complete production was followed at an artisanal cheese-making factory and sampling was performed at different cheese-making steps from the raw milk to cheese ripened for 3 months. Different population were monitored on different media. Fungal and bacterial isolates were collected and identified. The achieved results were compared to metabarcoding analyses targeting ITS 2 region for Fungi and V3-V4 region of the 16S RNAr for Bacteria. Focusing on cultivable microorganisms, higher microbial populations were observed in whey used for inoculation compared to raw milk. Results also highlighted the importance of fungi. Despite the initial low inoculum, yeast growth began as early as milk acidification and during the renetting step. Metagenetic results outlined the differences in both fungal and bacterial communities between cheese rind and core samples. Bacterial diversity increased during the ripening specially in the rind compared to the curd stage. Although yeasts were present early in the processing, fungal diversity remained limited at the end of ripening. To better understand the origin of the observed microbial diversity, environmental and raw material samples were also investigated and ongoing work should provide new insights about the dynamics of these microbial communities.

Consumer's demand for naturally preserved food products is growing and the use of bioprotective cultures is an alternative to chemical preservatives or a complementary tool to hurdle technologies to avoid or delay fungal spoilage of dairy products. To develop antifungal cultures for the dairy product biopreservation, experiments were conducted both in vitro and in situ. Firstly, the antifungal activity of 32 strains of lactic acid bacteria (LAB) and propionibacteria was screened alone, and then on combinations based on 5 selected lactobacilli strains. This screening was performed in yogurt and cheese models against four major spoilage fungi previously isolated from contaminated dairy products (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Selected combinations were then tested as adjunct cultures in sour cream and semi-hard cheeses produced at a pilot scale to evaluate their antifungal activity during challenge tests against selected fungal targets (P. commune, M. racemosus, and Rhodotorula mucilaginosa) and shelf life tests; and their impact on product organoleptic properties. The screening step allowed selecting two binary combinations, A1 and A3 composed of Lactobacillus plantarum L244 and either Lactobacillus harbinensis L172 or Lactobacillus rhamnosus CIRM-BIA1113, respectively. In situ assays showed that the A1 combination delayed the growth of P. commune, M. racemosus and R. mucilaginosa for 2-24 days on sour cream depending of the antifungal culture inoculum, without effect on organoleptic properties at low inoculum (106 colony-forming units (CFU)/mL). Moreover, the A1 and A3 combinations also delayed the growth of P. commune in semi-hard cheese for 1-6 days and 1 day, respectively. Antifungal cultures neither impacted the growth of starter cultures in both sour cream and cheese nor the products' pH, although post acidification was observed in sour cream supplemented with these combinations at the highest concentrations (2.107 CFU/mL). The combination of both in vitro and in situ screening assays allowed developing 2 antifungal combinations exhibiting significant antifungal activity and providing future prospects for use as bioprotective cultures in dairy products.

Objectifs Le microbiote intestinal humain est un écosystème complexe et dynamique. Il exerce de nombreuses fonctions biologiques et métaboliques. Le maintien de son équilibre (composition, activité) est important pour la santé et le bien-être de l’hôte et peut être influencé par de nombreux facteurs, comme l’alimentation. Les produits laitiers fermentés, qui contiennent une grande quantité de bactéries lactiques vivantes, peuvent contribuer à cet équilibre mais la compréhension de leur impact reste encore limitée. Ce travail a pour objectif de mieux comprendre, à partir de l’utilisation d’outils métaomiques, l’impact de la consommation de lait fermenté et de bactéries lactiques vivantes sur la composition et l’activité du microbiote intestinal. De plus, il vise à évaluer l’état physiologique et métabolique des bactéries lactiques en transit dans le tractus digestif. Matériels et Méthodes Trois groupes de 8 souris à flore humanisée (ie transplantation d’un microbiote fécal d’un individu sain à des souris axéniques) ont été alimentées avec (i) un régime contrôle sans lait (alimentation traditionnelle des souris + tampon PBS), (ii) un régime avec lait fermenté (alimentation traditionnelle des souris + un lait fermenté par les 2 bactéries du yaourt, Streptococcus thermophilus et Lactobacillus bulgaricus), ou (iii) un régime avec lait fermenté thermisé (alimentation traditionnelle des souris + un lait fermenté par les 2 bactéries du yaourt puis thermisé à 95°C pendant 25 min). La composition et l’activité du microbiote humain transplanté chez les souris ont été évaluées respectivement par métagénomique shotgun et métatranscriptomique à partir d’échantillons fécaux. Résultats principaux L’analyse quantitative et le suivi de l’activité du microbiote intestinal de souris à flore humanisée est réalisable grâce à des approches métaomiques. La consommation de lait fermenté (thermisé ou pas) ne modifie pas la composition du microbiote intestinal humain chez la souris mais a un impact significatif sur son activité. L’expression des gènes est modifiée pour la plupart des genres bactériens dominants, et modulant par conséquent leurs fonctions. Cet impact est d’autant plus important que la consommation de lait fermenté est régulière et prolongée dans le temps. En revanche, il n’a pas été possible de suivre l’activité des bactéries lactiques en transit qui sont minoritaires. Conclusion Ce travail met en évidence l’intérêt des méthodes métaomiques pour suivre l’impact de l’alimentation et ouvre des perspectives sur l’exploration des effets bénéfiques potentiels des laits fermentés sur le microbiote intestinal humain.

Comprendre la digestion pour proposer les aliments de demain. 1ère matinale thématique Sodiaal : la digestion, clé de l’innovation

The use of probiotic bacteria derived from fermented foods has been explored by the scientific community as alternative strategies for the treatment of several diseases, mainly regarding intestinal dysfunction. One of the most relevant inflammatory diseases affecting the alimentary tract, for which no current intervention is entirely successful, is mucositis. In this review article, we summarize the most recent proof-of-concept studies dealing with the therapeutic use of dairy origin probiotics, for the treatment of gastrointestinal mucositis. Furthermore, we discuss several approaches for the improvement of the classical therapeutic rationale, such as supplementation with prebiotics and genetic engineering along with the respective translational issues, which may be crucial for the successful transposition of these therapeutic strategies for clinical use.

Donor human milk (DHM) represents the best alternative when mother’s own milk is not available,a common occurrence in Neonatal Intensive Care Units. Heat treatment of DHM is mandatory forsafety reasons. Holder pasteurization (HoP, 62.5°C-30’) is recommended by all human milk bankguidelines. Recent studies have demonstrated that HoP affects the digestion profile and behavior ofseveral human milk components. High Temperature-Short Time pasteurization (HTST, 71°C-15’’)is currently under evaluation as a promising alternative technology to limit the denaturation of somebiological compounds of raw human milk.ObjectiveThe aim of the present work was to assess whether the different types of pasteurization (HoP,HTST) impacted the digestive kinetics of human milk during in vitro dynamic digestion.MethodologyPooled raw HM (RHM) was collected and processed by using the two pasteurization techniques.The pasteurized samples and RHM were digested in vitro using preterm gastrointestinal conditions.Samples were collected at different digestion times. Undigested and digested milks samples werecharacterized for their particle size distribution (PSD), triglyceride content, protein and amino acid(AA) profiles.Main findingsDuring gastric digestion, both pasteurization methods modified PSD, as compared to RHM. Caseinswere rapidly hydrolyzed in the gastric phase unlike that for the whey proteins. Lactoferrin was hydrolyzedfaster in the pasteurized samples in comparison to RHM, in which lactoferrin was resistantto gastro-intestinal digestion. Heat-treatments, consequently, affected the intestinal release of someAA, and a higher bioaccessibility of AA was found for HTST, as compared to HoP. Concerning lipolysis,at any time of the intestinal digestion phase, the lipolysis of HoP samples was significantlylower (p < 0.05) than in both RHM and HTST samples.ConclusionThis work provides the first evidences about the differential impact of HoP and HTST pasteurizationtechniques on bioaccessibility of DHM nutrients and biological compounds, for preterm newborns.

IntroductionIn order to minimize the denaturation of bioactive compounds, which is known to affect donor humanmilk (HM) after the mandatory heat treatment (Holder pasteurization at 62.5°C, 30min – HoP), anumber of alternative processing techniques are currently being investigated. Recently, High Temperature-Short Time pasteurization (HTST, 72°C-15s) was found to limit the denaturation of somebioactive components of human milk.ObjectiveThe aim of the study was to investigate whether different types of pasteurization (HoP and HTST)may differently affect peptide release from human milk during preterm infant gastrointestinal digestion,by using a dynamic in vitro systemMethodologyPooled raw HM (RHM) from 5 donors was collected and processed in triplicate according to HoP andHTST. The pasteurized milks and RHM were digested in triplicate using a dynamic in vitro digestionsystem, mimicking the preterm physiology conditions. Samples were collected at different digestiontimes. Peptides from undigested and digested samples were analysed using a Q-Exactive massspectrometer and peptide abundance was subjected to multivariate statistics to unravel specificprofile trends.Main findingsPre-proteolysis occurred mostly on β-casein, from which originated more than 82% of the peptidesfound in undigested milk. During digestion, a differential behaviour between gastric and intestinalpeptide release was found by multivariate statistics. In particular, whereas in the gastric phase thepeptide pattern was more similar for HTST and RHM with respect to HoP, the opposite was found atthe beginning of the intestinal phase, while at the end of digestion no difference was found. Thesedifferences were mostly due to peptides released from β-casein, especially in the gastric phase.Some bioactive peptides from bile salt-stimulated lipase, caseins and lactoferrin presented significantlydifferent abundances between the different samples during intestinal digestion.ConclusionThe results indicate possible consequences of the different pasteurizations on the biological activityof donor’s human milk.

During aging, the sensory capacities and the mastication efficacy decrease, limiting both qualitatively and quantitatively the food intake of the elderly. However, protein and calcium requirements increase with age. In this context, the formulation of foods adapted to the nutritional and sensory needs of the elderly is a challenge for the next years. Objective The main objective of this work was to develop a series of cheeses of variable texture made of whey proteins and enriched with different sources of calcium and test their performances on the oral comfort of elderly people, the bioavailability of amino acids and the calcium bioaccessibility. Methodology The model cheeses developed had the same composition (24% of proteins including 23% of whey proteins, and 20% of lipids) and the different textures were generated by modulating the manufacturing process. Sensory analysis were performed on a panel of people over 65, and in vitro digestion performed using the INFOGEST model whereas in vivo digestion experiments were conducted on a conventional pig model. Main findings The results of the digestion studies highlighted the relevance of integrating whey proteins as a major protein source in dairy products, in order to maximize the bioavailability of essential amino acids. In addition, the bioaccessibility of calcium was mainly related to intra-gastric and intraintestinal pH, rather than to the initial chemical form of its source of enrichment. Finally, the sensory study showed that only the textures perceived as “dry” were linked to a significant decrease in the oral comfort of the elderly. Conclusion This work highlights the opportunity to develop sensory and nutritionally adapted dairy products for the elderly. Based on this work, it would be interesting to carry out clinical studies to know the physiological impact of these products on the prevention of osteoporosis and sarcopenia.

IntroductionLuminal pH is a key determinant of food disintegration in the stomach, acting both on their biochemicalstructures and on the activity of digestive enzymes.ObjectiveThe present study aimed at monitoring postprandial intragastric pH variation after ingestion of fourplant-based meals having the same macronutrients content: two liquids (soymilk and a pea emulsion)and two solids (seitan and tofu).MethodologyFour mini-pigs fitted with a gastric cannula located on the stomach greater curve were used. Threerecording methods were compared: chyme sampling from cannula, a classic pH meter-catheterequipped with two probes or a wireless pH sensor directly put inside the stomach through the canula.Gastric emptying was also investigated using indigestible markers sampled from duodenal cannulaon six other mini-pigs. In vitro multi-scale characterization in gastric condition were assessed inin vitro conditions in order to explain intragastric pH differences observed in vivo.Main findingsDistribution of variation coefficients allowed us to detect the method inducing the less interindividualvariability. The average values obtained from the catheter system and the wireless sensor wereconsistent with each other, while sampling method gave less meaningful results. Food effect washighlighted: an exponential decrease occurred with solids while liquids observed a plateau at pH 7that lasted about 2h before a sigmoid-type decrease. The seitan appeared to empty faster from thestomach than the other foods, that could explain the quick pH decrease observed in the stomach. Itwas not the case for tofu explained probably by aggregation, buffering capacity or nitrogen solubility.Finally, entire gastric pH curves were modeled for each meal, that will be useful for implementing invitro dynamic digestion in relevant conditions.ConclusionIn conclusion, pH recording with catheter remained better than other methods and food macrostructureappeared to impact significantly gastric pH.

Introduction A major challenge in the next years will consist in producing healthy and sustainable foods with optimized nutritional quality. Food fortification to increase micronutrient intakes is a strategy currently used to overcome deficiencies. Objective Since the structural characteristics of food influence disintegration process during digestion, it appears relevant to assess the impact of food structure on micronutrient bioavailability. Methodology Four model foods have been developed and enriched in lutein and vitamin D. These products were designed such as their composition was identical but their structures and textures were different. Custard, pudding, sponge cake and biscuit were thus produced by modulating the production process. A clinical trial has been set up, involving twelve healthy male subjects for a monocentric, controlled and randomized study, in a cross experimental design. After an overnight fast, kinetics of plasma micronutrient levels were recorded for 8 hours following each product consumption. In a second phase, the model foods have been digested using the INFOGEST in vitro model. Kinetics of matrix disintegration and micronutrients release have been recorded. Main findings The micronutrient absorption curves depended on the matrix. Especially, the biscuit resulted in a significantly later peak of maximal absorption for both micronutrients, and a lower total bioavailability for vitamin D. In vitro, digestion might enable to determine which food characteristics influence matrix disintegration, thereby affecting micronutrient bioaccessibility. Indeed, markers of matrix disintegration, namely proteolysis and lipolysis kinetics, suggested differences amongst the four model foods. Conclusion The in vivo results highlight that food structure modulates the kinetics of micronutrient appearance in plasma. Correspondences might be established between the kinetics of food matrix disintegration during in vitro digestion and the kinetics of micronutrient absorption during the clinical study. Using the DIDGI, a dynamic in vitro digestion model, further studies will aim to refine the quality of the model and the results obtained.

Introduction Human milk is a complex biological fluid recognized as the gold standard in neonatal nutrition, especially for preterm infants since it supports growth and brain development. Donor human milk, pasteurized for safety reasons, is the first option to feed preterm infants when mothers’ own milk is not available. Objective The aim of the present study was to determine the impact of breastmilk pasteurization on preterm gastrointestinal digestion and to evaluate its effect on lipid absorption. Methodology Kinetics of digestion and structural desintegration of pasteurized human milk (PHM) and raw human milk (RHM) were evaluated using a static in vitro digestion model that we adapted to simulate preterm digestion ability. Caco-2 /TC7 cells, an intestinal absorption model, were subsequently incubated with diluted PHM vs RHM-digestion media. Main findings During in vitro digestion, proteolysis was evaluated by SDS-PAGE followed by densitometry. Lactoferrin proteolysis was significantly (p

Introduction Because folate deficiency has been associated with an increased risk of development of neural tube defect, depression… folate fortification is recommended for populations at risk (pregnant, frail population), including supplementation within food-matrix. However, this hydrosoluble vitamin is known to interact with food matrix components. This could ultimately impact on bioavailability of folates in plasma. Objective The aim of the present work is to measure folate plasma levels of volunteers following ingestion of different matrices (Custard, pudding, sponge cake and biscuit) similar in terms of macronutrients and overall folate content but different in texture and potentially digestibility rate. Methodology Twelve healthy young volunteers were offered the matrices according to a randomized, controlled cross over design. Plasma folate concentrations were determined before and up to 8 hours post matrix ingestion. Results for folate overall bioavailability (corrected for ingested folate) correspond to area under the curve (AUC) and expressed in arbitrary units (UA). Main findings Folate bioavailability over the entire post prandial period was significantly (P

IntroductionPlant proteins have recently gained attention in research and industrial areas by their relatively modestenvironmental, ethical and economic impact.ObjectiveFood structure associated to food processing are known to generally impact sensitivity of proteinsto digestive enzymes.MethodologyFour plant-based foods produced from different protein sources (soy, pea or wheat) and offeringdifferent structure and their corresponding concentrate or isolate were digested following the INFOGESTprotocol. Since tofu and seitan cannot be stored without structure degradation, the impact offreeze drying on protein digestion was also studied. Proteolysis progress was followed by monitoringthe release of free amino-groups and proteolysis degree was assessed. Multi-scale characterizationof foods was performed to allow data interpretation.Main findingsPea emulsion exhibited similar droplet size and lipid content than soymilk, only the protein sourcechanged. Final proteolysis degree was higher with pea (60 %) than soy (45 %). When comparingthe same source, protein digestion of tofu was more extensive than that of soymilk. This could beexplained by differences in macrostructure since tofu is obtained through soy protein coagulation,but also by differences in the origin of beans. Indeed, proteolysis degrees at the end of the intestinalphase were different between protein isolates created from beans used for tofu vs soymilk (15% vs 40 %). Proteins of tofu isolate were less hydrolyzed than tofu (15 % vs 26 %), that could beexplained by different protein denaturation levels. Comparing a simple solubilization of commercialpea isolate with its emulsion with soy lipids, proteolysis was twice higher for the emulsion (60 % vs30 %).ConclusionUltimately, freeze-drying effect of protein digestion was highlighted for seitan, increasing final proteolysisrate from 9 % to 22 %, but not for tofu explained through enzymatic accessibility improvedafter freeze drying in the case of seitan.

Infant formulas (IF) are the key nutritional source for infants who cannot be breastfed. There is currently a growing interest for these sensitive products, in order to control their quality and to design their composition with regard to nutritional balance and sustainable development concerns.This work aimed to study how plant proteins influence the digestibility of IF.Five infant formulas were developed with identical composition except that the protein source were whey proteins in the “reference IF”, pea, faba bean, rice or potato proteins in the four “plant IF” tested. The five IF were first evaluated using an in vitro static gastrointestinal model simulating infant conditions. Protein hydrolysis rate (PHR) and amino acid bioaccessibility (AAB) were measured using free amino group and free amino acid analyses, respectively. The pea and faba bean IF were then submitted to an in vitro dynamic digestion model closer to the physiological conditions, and compared to the reference IF. Protein digestibility (PHR and AAB) as well as the digesta microstructure were followed.Results showed that both PHR and AAB were very similar between the reference IF and pea and faba bean IF, but significantly lower for rice and potato IF. In dynamic conditions, the structure disintegration and the PHR showed differences among the reference, pea and faba bean IF. These differences were more pronounced during the gastric phase compared to the end of the intestinal digestion. This could result from the structure of proteins obtained from the processing steps that is known to influence the protein hydrolysis.This study provides new insights on the impact of protein source on the digestibility of IF. It especially showed that some plant proteins could be appropriate candidates for the composition of IF from a nutritional point of view.

Mathematical modelling of food digestion. STLOpendays

NativIF: Conception of an infant formula by filtration : nutritional ,physiological and sensory impacts. STLOpendays

Bioactivity & Nutrition. STLOpendays

Effect of technological treatment of the mechanisms of infant food digestion . STLOpendays

Smart design of functional fermented dairy foods . STLOpendays

An overview of the models available for simulating human food digestion : mythe or reality?. STLOpendays

Optimizing lactic fermentation of soy juice. STLOpendays

Infant formulas & New protein sources . STLOpendays

Food microstructure and gastric digestion: the egg white gel model. STLOpendays

Part of special issue: The 5th International Conference on Food Digestion - Edited by Didier Dupont, Pasquale Ferranti, Alan Mackie 5. International Conference on Food Digestion (INFOGEST) ; Rennes (France) - (2017-04-04 - 2017-04-06) / Conférence; In the frame of the COST action INFOGEST, a static in vitro digestion protocol has been elaborated aiming at the improvement of data comparability by harmonizing the experimental conditions. The success in harmonization was confirmed with inter-laboratory trials using skim milk powder as a standardized model food. Moreover, the physiological relevance of the gastric and intestinal endpoints of the static digestion protocol was demonstrated in a pig in vivo trial, with the same skim milk powder and samples collected from different sections of the digestive tract, as well as in a human study with from jejunal effluents. In vivo, digestion is a dynamic process influenced by peristalsis and by the gradual secretion of enzymes and juices and the dwell time of the food. To mimic these physiological mechanisms, dynamic in vitro digestion protocols are widely used. Until now, the differences of protein hydrolysis taking place during dynamic and static in vitro digestion have not been investigated.In this study, the gradual hydrolysis of the main milk proteins present in skim milk powder was digested with the dynamic DIDGI®-system using adult digestion protocol and the static harmonized INFOGEST method. Protein hydrolysis was analyzed by gel electrophoresis, peptide patterns were measured with mass spectrometry, and free amino acids with high pressure liquid chromatography. The peptide patterns at the gastric and intestinal endpoints of in vitro digestion showed a good approximation to the in vivo results from pigs. Moreover, gradual peptide generation was comparable in both in vitro digestion conditions. However, the dynamic protocol reflected the physiological situation better at the level of free amino acid release. Nonetheless, in both in vitro digestion protocols, absorption of free amino acids is not simulated, and they are therefore limited in reflecting the in vivo situation at this level.

Soleil Synchrotron illuminates our knowledge on gastric digestion. STLOpendays

communication orale et poster présentés aux Journées francophone de nutrition de Nice, du 28 au 30 novembre 2018; Introduction et but de l’étudeDes perturbations du métabolisme lipidique à jeun et en phase postprandiale constituent des facteurs de risque cardiovasculaire. La nutrition joue un rôle majeur dans leur modulation, notamment chez les femmes ménopausées qui constituent une population à risque. Un intérêt s’est récemment développé sur les effets bénéfiques potentiels des lipides polaires (LP) laitiers, qui sont riches en sphingomyéline. A ce jour, leurs effets chez l’Homme restent cependant à clarifier, car les rares études cliniques ont jusqu’à présent été réalisées chez des sujets sains et par supplémentation, augmentant ainsi l’apport énergétique. Nous avons donc testé l’hypothèse qu’un enrichissement isolipidique de l’alimentation avec des LP laitiers apportés par un produit laitier réaliste pourrait améliorer le profil cardiovasculaire de femmes ménopausées à risque.Matériel et méthodesUn essai clinique contrôlé aléatoire en double aveugle chez 58 femmes ménopausées en surpoids a été réalisé. Les volontaires ont été soumises à (i) 4 semaines d’intervention avec consommation quotidienne d’un fromage à tartiner contenant 12g de matière grasse laitière incluant aléatoirement soit 0g (contrôle, n=19), 3g (n=19) ou 5g (n=20) de LP laitiers, et (ii) des tests d’exploration métabolique sur 8h, avant et après intervention (2 visites). Des marqueurs lipidiques ont été mesurés dans le sérum et dans la fraction riche en chylomicrons. L’effet de la dose de LP laitiers a été testé par un modèle linéaire mixte (SAS®) recherchant les différences entre visites et entre groupes d’intervention.Résultats et analyse statistiqueLa consommation du fromage à 5g-LP diminue les concentrations sériques à jeun et postprandiales du cholestérol total (−0,33±0,03mM, p

International audience; In 2018, about 60% of world’s newborns received cow milk-based infant formulas (IF) instead of human milk (UNICEF). The process of manufacturing IF involves heat treatments altering the physicochemical properties of milk components, especially whey proteins (WP). The objective of the study was to investigate the impacts of thermal treatments on the denaturation of WP of IF, particularly for those mimicking the protein profile of human milk, and to characterize the heat-induced protein structures. Methods: Three model IF were produced with a caseins:WP ratio of 40:60 at 1.3% and 5.5% of total proteins, differing in the quality of WP. The kinetic of heat-induced denaturation of each WP was investigated between 67.5°C and 80°C by quantification of the residual native proteins by RP-HPLC. The heat-induced protein structures were studied by dynamic light scattering, electrophoresis and asymmetric flow field flow fractionation coupled with MALLS. Results: The quantification of native WP fractions revealed an enhanced denaturation of α-lactalbumin in presence of both β-lactoglobulin and lactoferrin, an increased denaturation of β-lactoglobulin in presence of lactoferrin, and an increased denaturation lactoferrin in presence of β-lactoglobulin. At similar rate of total WP denaturation at 67.5°C and 80°C, the protein composition of the heat-induced aggregates changed between formulas, protein concentrations and heating temperatures but disulfide bonds were the main intermolecular links. The aggregates were larger and of fractal shape (apparent fractal dimension dfapp = 2.1) in formulas at 5.5% proteins whereas they were of spherical shape (dfapp = 2.9) in formulas at 1.3% proteins. Discussion: Effets of heat treatment on the denaturation of α-lactalbumin, β-lactoglobulin and lactoferrin and the protein structure are influenced by the WP quality of IF. These results will give to industrials reliable data on the protein structures formed during the heat treatments of IF. The impact on digestibility will be subsequently investigated

Comment lutter contre les pertes musculaires

Design of functional foods based on encapsulated long chain omega-3 PUFA. STLOpendays

WOS: 000462482100001, PubMed ID: 30886367, Developing a mechanistic understanding of the impact of food structure and composition on human health has increasingly involved simulating digestion in the upper gastrointestinal tract. These simulations have used a wide range of different conditions that often have very little physiological relevance, and this impedes the meaningful comparison of results. The standardized protocol presented here is based on an international consensus developed by the COST INFOGEST network. The method is designed to be used with standard laboratory equipment and requires limited experience to encourage a wide range of researchers to adopt it. It is a static digestion method that uses constant ratios of meal to digestive fluids and a constant pH for each step of digestion. This makes the method simple to use but not suitable for simulating digestion kinetics. Using this method, food samples are subjected to sequential oral, gastric and intestinal digestion while parameters such as electrolytes, enzymes, bile, dilution, pH and time of digestion are based on available physiological data. This amended and improved digestion method (INFOGEST 2.0) avoids challenges associated with the original method, such as the inclusion of the oral phase and the use of gastric lipase. The method can be used to assess the endpoints resulting from digestion of foods by analyzing the digestion products (e.g., peptides/amino acids, fatty acids, simple sugars) and evaluating the release of micronutrients from the food matrix. The whole protocol can be completed in similar to 7 d, including similar to 5 d required for the determination of enzyme activities., COST actionEuropean Cooperation in Science and Technology (COST) [FA1005 INFOGEST26]; French National Institute for Agricultural Research (INRA)Institut National de la Recherche Agronomique (INRA), We acknowledge COST action FA1005 INFOGEST26 (http://www.cost-infogest.eu/) for providing funding for travel, meetings and conferences (2011-2015). We acknowledge the French National Institute for Agricultural Research (INRA, http://www.inra.fr) for its continuous support of the INFOGEST network by organizing and co-funding the International Conference on Food Digestion and workgroup meetings. We thank A.G.F. Lopes (Universidade de Lisboa, Portugal) and V.S.N. Mishra (Teagasc Food Research Centre, Moorepark, Ireland) for their help in the final preparation of the videos. We also acknowledge the many other researchers, mostly associated with the above COST action and subsequent events, who have contributed to the discussion of digestion parameters.

Dans un contexte réglementaire contraint et une demande sociale et sociétale en pleine évolution, une refonte complète de l’ouvrage « Aliments fonctionnels » voit le jour. Grâce à la contribution de plus d’une cinquantaine d’experts aux compétences complémentaires, « Aliments fonctionnels » s’enrichit d’approches nouvelles en lien avec la durabilité des systèmes alimentaires.Ainsi cet ouvrage fournit de multiples pistes de réflexion et de nombreux axes de recherche pour l’innovation alimentaire.Aux chapitres des précédentes éditions entièrement réactualisés, s’ajoutent des volets illustrant les comportements, les inégalités sociales, la compréhension des messages, l’acceptabilité des innovations et les enjeux de la durabilité.Ce livre présente donc des questions nouvelles en lien avec la sécurité alimentaire du consommateur et les perspectives d’évolution de la démographie mondiale.« Aliments fonctionnels » s’adresse aux ingénieurs en R&D agroalimentaire, aux professionnels de la nutrition et de l’alimentation, de la santé, aux spécialistes du marketing, de l’innovation et de la communication et à tous les acteurs de la sécurité alimentaire.; Les dernières décennies ont vu une augmentation spectaculaire, à l’échelle internationale,des pathologies liées à l’aliment et à l’alimentation. Le surpoids et ses conséquences tellesque les maladies cardiovasculaires ou le diabète de type 2 touchent environ 1,5 milliard d’adultes dans le monde et la plupart des prévisions prévoient que ce chiffre atteindra 3 milliards d’individus à l’horizon 2030. On estime à près de 3 millions le nombre de personnes décédant chaque année du fait de leur surpoids ou de leur obésité. En France, 6,5 millions de personnes sont considérées comme obèses. La proportion des personnes obèses est ainsi passée de 8,5 % à 14,5 % entre 1997 et 2009. L’augmentation de la prévalence est observée dans toutes les tranches d’âge de la population, y compris chez les séniors, avec une exacerbation chez les femmes (15,1 %) par rapport aux hommes (13,9 %). L’augmentation de l’obésité est majoritairement liée à (1) une plus grande consommationd’aliments très caloriques riches en graisses et (2) un manque croissant d’activité physique en raison de la nature de plus en plus sédentaire de nombreuses formes de travail, de l’évolution des modes de transport et de l’urbanisation. Malgré de multiples campagnes de sensibilisation, force est de constater qu’il est difficile de contraindre les personnes en surpoids à accroître leur activité physique. Une des solutions possibles serait donc de proposer au consommateur une offre alimentaire moins calorique, tout en présentant lesmêmes propriétés de rassasiement et de satiété.

International audience; Infant formulas (IF) are the only source of nutrition for infants who cannot be breastfed from their mothers. There is currently a growing interest for these sensitive products, in order to control more carefully their quality and design their composition with regard to sustainable development concern. The aim of this work was to study how a partial substitution of dairy proteins by plant proteins influenced the functionality and the digestibility of IF. Three IF were developed with identical composition, except that 50% of the proteins were whey proteins in the “reference IF”, and pea or faba bean proteins in the “plant IF”. Homogenization and drying steps parameters were investigated at a semi-industrial scale (IF flow rate around 100 kg.h-1). The process influence was assessed through the IF microstructure using confocal microscopy, and the protein digestibility using a dynamic in vitro digestion model. The results showed that the emulsion structure differed depending on the protein type source that did not lead to the same stabilization of the fat droplets. It simultaneously affected the viscosity of the IF and consequently the drying parameters. Last, differences in terms of protein hydrolysis rate were observed mainly during the gastric phase compared to the end of the digestion. This study provides new insights on the impact of the substitution of protein source in IF. It showed that plant protein sources could be good candidates for dairy proteins substitution in IF, both from a processing and nutritional point of view.

Infant milk formulas: effect of heat treatments on the protein physicochemical properties and the nutritional quality. STLOpendays

The current allergenicity assessment of novel proteins is based on the EFSA GMO guidance. Recently, EFSA launched a new guidance document on allergenicity assessment of GM plants (2017). This document describes, amongst other topics, the new scientific and regulatory developments on in vitro protein digestibility tests. The EFSA GMO Panel stated that for in vitro protein digestibility tests, additional investigations are needed before any additional recommendation in the form of guidance can be provided. To this end, an interim phase is considered necessary to evaluate the revisions to the in vitro gastrointestinal digestion test, proposed by EFSA. This prompted the establishment of a joint workshop through two COST Action networks: COST Action ImpARAS and COST Acton INFOGEST. In 2017, a workshop was organised to discuss the relevance of digestion in allergenicity risk assessment and how to potentially improve the current methods and readouts. The outcome of the workshop is that there is no rationale for a clear readout that is predictive for allergenicity and we suggest to omit the digestion test from the allergenicity assessment strategy for now, and put an effort into filling the knowledge gaps as summarized in this paper first. © 2019 The Authors. Chemicals / CAS protein, 67254-75-5

Unravelling the fate of food in the gastrointestinal tract is essential to better understand the health effects of the food and to fight against diet-related pathologies such as cardiovascular diseases and type-2 diabetes. Digestion is the process that transforms food into nutrients. The first step of digestion occurs in the mouth, where mastication transforms solid and semi-solid foods into particles while mixing with saliva allows bolus formation and initiates digestion of carbohydrates.Then the bolus is transferred into the stomach, where acid conditions and specific enzymes (pepsin, gastric lipase) start hydrolyzing macronutrients like proteins and triglycerides. The next step occurs in the small intestine, where other digestive enzymes further degrade macronutrients allowing their absorption. In the small intestine, proteins are hydrolyzed by trypsin, chymotrypsin, elastase, carboxypeptidase etc, lipids by pancreatic lipases, and carbohydrates by pancreaticamylase. Small intestinal digestion is completed by the enzymes of the brush border membrane that release macronutrients, which can be absorbed by enterocytes to reach the bloodstream. Undigested material,fiber for example, reaches the large intestine where it is further metabolized by the intestinal microbiota.Investigating food digestion requires the use of models and a myriad of in vitro (static and dynamic), animal and human models have been described in the literature with the objectives of understanding the fateof food in the gastrointestinal tract. In particular, static in vitro digestion simulations are extremely popular because they are very easy to use and do not require sophisticated equipment. They have been shown to beadapted for screening large series of similar samples in identical conditions or to understand interactions at the molecular scale (Bohn et al.,2017). However, they are too simple to study more complex phenomenaand the kinetics of food digestion for which dynamic in vitro models are more appropriate (Dupont et al., 2018).There was a high heterogeneity between the different static in vitro digestion models that were used by the research groups all around the world. Models were differing in the pH used in the different phases(gastric and intestinal), their duration, the digestive enzyme/substrate ratio, etc For that reason, comparing results obtained from one study to another was impossible and there was a crucial need for a harmonizedmethod that could be used by everyone allowing comparison between studies. This was one of the main objectives of the INFOGEST COST Action.

Objectives: Nutritional strategies can play a major role in the management of cholesterolemia, notably in postmenopausal women at risk of CVD. Interest has recently grown on the potential health benefitsof milk polar lipids (MPL).We showed that isolipidic enrichment of the diet with MPL improved several lipid CV risk factors but underlying mechanisms remained unclear. We hypothesized that MPL reduceintestinal cholesterol absorption in humans.Methods:We performed a double-blind randomized controlled trial in 58 postmenopausal women with fasting HDL-cholesterol < 1.6 mM.They were subjected to a 4-week dietary intervention with daily consumption of a cream-cheese containing 12 g of milk fat including either 0 g (control, n = 19), 3 g (n = 19) or 5 g (n = 20) of MPL. Before and after each intervention, blood lipids were measured in the whole cohortwhereas fecal lipids and coprostanol were analyzed in a subgroup (n = 7–9 per group). A proof-of-concept mechanistic crossover study was also carried out in 4 ileostomized subjects who performed 8hpostprandial tests after consuming 0g-, 3g- or 5g-MPL enriched cheese labelled with 2H-cholesterol tracer. Plasma, chylomicrons and ilealefflux were analyzed.Results: Milk fat enriched with 3 to 5 g MPL induced doseresponse reductions in serum total cholesterol (up to −6.8% in 5 g group, p < 0.05), LDL-cholesterol (−8.7%, p < 0.05) and HDL/total-cholesterol ratio (p < 0.001), compared to the control that had no effect. Fecal excretion of coprostanol increased after MPL supplementation (p < 0.05, 3g- and 5g-MPL vs control), and the fecal coprostanol/cholesterol ratio was inversely correlated with serum total- and LDL-cholesterol after intervention (r = −0.5, p < 0.05). In ileostomized subjects, postprandial accumulation of 2Hcholesterol in plasma and chylomicrons was reduced after 3 to 5 g MPL consumption (p < 0.05, vs control). Both cholesterol and milk sphingomyelin increased in ileal efflux after MPL enriched cheeses (p < 0.05).Conclusions: Present results suggest that milk polar lipids decrease cholesterol absorption in humans through interactions with sphingomyelin and by increasing conversion of cholesterol to coprostanol.Funding Sources: ANR (French National Research Agency, VALOBAB project, ANR-11-ALID-007–01), PHRC-I (French Clinical Research Program, 14–007), CNIEL (French Dairy Interbranch Organization).

Do bacterial strains in cheese have an impact on the protein hydrolysis during human digestion, and if so, does a higher microbial diversity lead to the generation of a higher number of different peptides after digestion? Cheese bacteria are responsible for the hydrolysis of proteins already during cheese ripening. These bacterial cultures are introduced at different steps of the cheese manufacturing process. First, the raw milk flora that is dependent on the milk heat treatment before the cheese manufacturing process, is a major source of a variety of bacteria. Second, starter cultures, needed for a successful acidification of the cheese curd are added to prevent side fermentations. Third, addition of cultures is made for improving flavor or accelerating the ripening process, depending on the type of cheese. Because of bacterial proteolytic activity, proteins in cheese are partially hydrolyzed, depending on the ripening time and are further digested by gastric and pancreatic proteases, after consumption, to the level of small peptides and free amino acids. In order to elucidate possible differences in proteolysis depending on the presence of different bacteria, Swiss Raclette cheeses were produced either from raw or pasteurized milk with or without addition of a proteolytic bacterial strains (Lactobacillus helveticus) and ripened during 120 days. The microbial diversity and the relative abundance of specific strains in the different cheeses was assessed after 24 hours, 80 and 120 days of cheese ripening by sequencing the hypervariable regions V1-V2 of the 16S rRNA genes. Moreover, protein hydrolysis in the different cheeses was analyzed with gel electrophoresis, mass spectrometry, and HPLC after in vitro digestion, applying a static (Infogest) and a dynamic (DIDGI®) oro-gastrointestinal in vitro digestion protocol. In order to gain information on the influence of bacterial strains on protein hydrolysis, the 16s meta-genomic and 16s meta-transcriptomic results were correlated with protein and peptide patterns.

The process of manufacturing infant milk formulas (IMFs) involves heat treatments that can lead to whey protein denaturation. The objective of the study was to determine how protein composition affects the denaturation kinetics of the whey proteins within IMFs. Three model IMFs (1.3% of cow’s milk protein) were produced with a caseins: whey proteins ratio of 40:60, differing only by the whey protein composition. The kinetics of heat-induced denaturation of α-lactalbumin, β-lactoglobulin and lactoferrin were investigated between 67.5 °C and 80 °C by chromatographic quantification of the residual native proteins. Results showed that the heat-denaturation of α-lactalbumin was reduced when β-lactoglobulin was absent. The heat-denaturation of lactoferrin was not affected by the composition of the IMFs but its presence enhanced the heat-denaturation of β-lactoglobulin. This study revealed that, for higher heat treatments (90 °C/15 s, 75 °C/15 min), IMF containing α-lactalbumin and lactoferrin preserved a higher proportion of native whey proteins than IMFs containing β-lactoglobulin.