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Livestock plays a major role in rural areas, where it provides economic, environmental and social services. There is a pressing need to assess the multiple positive contributions provided by livestock to society. This would be useful for society in general but constitutes a new scientific topic as well. The objective of this study was to develop a framework for the assessment of the social, economical and ecological services provided by livestock in France. Combining expert knowledge and literature review, we first defined the set of services provided by livestock. We then selected indicators to quantify the services considered at the department level considering the available databases on the French case-study. We finally assessed services and their relationships (synergies or tradeoffs) on a gradient of French departments. Four main classes of services were revealed: provisioning (e.g. food quantity and quality), environmental quality (e.g. biodiversity, diversified landscapes), rural vitality (e.g. employment, rural dynamism) and cultural heritage (e.g. gastronomy, landscape quality). Four major types of services were revealed, showing contrasted levels of services provided. The analysis of the spatial distribution of the types of services sets. The main socio-economic, ecological, political and geographical determinants of service provision will be identified in further study to inform policy makers and society.; L’élevage joue un rôle essentiel dans les territoires ruraux au sein desquels il assure de nombreux services économiques, environnementaux et sociaux. Appréhender la multiplicité des services rendus par l’élevage à la société représente donc un enjeu essentiel mais aussi un champ nouveau pour la recherche agronomique. L’objectif de cette étude est de réaliser une première quantification des services rendus par l’élevage en considérant les dimensions économiques, environnementales et sociales. Sur la base de réunions d’experts et de la revue de la littérature, nous avons d’abord proposé une qualification des services rendus par l’élevage pour définir le bouquet de services rendus par l’élevage en France. Nous avons ensuite sélectionné des indicateurs pour quantifier des bouquets de services départementaux à partir des bases de données mobilisables à l’échelle de la France. Nous avons analysé les services et leurs interrelations (synergies ou antagonismes) par une typologie de bouquets de services au niveau départemental. L’analyse met en évidence quatre catégories principales de services : approvisionnement (e.g. quantité et qualité d’aliments), qualité environnementale (e.g. biodiversité, hétérogénéité des paysages), vitalité territoriale (e.g. dynamisme rural et emploi) et identité culturelle (e.g. gastronomie, identité des terroirs). Quatre grands types de bouquets de service ont été mis en évidence présentant des niveaux contrastés d’expression des services. L’analyse de leur distribution géographique a montré une répartition non-aléatoire des types de bouquets. Une perspective de ce travail consistera à étudier les principaux leviers socio-économiques, politiques, écologiques et géographiques impliqués dans la fourniture de services pour informer les décideurs politiques et la société.

The fatty acid composition of milk triacylglycerols (TAGs) can be modified to improve their nutritional properties and the long-term health of consumers. However, the consequences of an increase in unsaturated fatty acid (UFA) content on the physical properties of milk TAGs remain to be elucidated. This study aimed at comparing the crystallisation properties and melting behaviour of control vs. UFA-enriched milk TAGs using the coupling of time-resolved synchrotron X-ray diffraction and differential scanning calorimetry on cooling and then heating at 3 °C/min. On cooling from the melt, high crystallisation temperature (HCT) TAGs solidify from 15.8 °C in α 2L (45–49 A) structures, then low crystallisation temperature (LCT) TAGs form α 3L structures with a higher thickness (75.5 A vs. 71.5 A) and a delay (8.5 °C vs. 12.1 °C) for UFA-enriched TAG. On heating, melting of TAGs crystals and formation of 3L 2 (64.7–80.1 A) and β′ 2L f (40–44 A) crystals associated with polymorphic reorganisations have been characterised. The organisation of TAG molecules in their liquid state revealed a higher thickness for UFA-enriched TAGs as compared to control TAGs. Such results improve the knowledge about the mechanisms of TAG crystallisation as a function of their FA composition and are important for the technological utilisation of UFA-enriched TAGs in food products.

Livestock plays a major role in rural areas, where it provides economic, environmental and social services. There is a pressing need to assess the multiple positive contributions provided by livestock to society. This would be useful for society in general but constitutes a new scientific topic as well. The objective of this study was to develop a framework for the assessment of the social, economical and ecological services provided by livestock in France. Combining expert knowledge and literature review, we first defined the set of services provided by livestock. We then selected indicators to quantify the services considered at the department level considering the available databases on the French case-study. We finally assessed services and their relationships (synergies or tradeoffs) on a gradient of French departments. Four main classes of services were revealed: provisioning (e.g. food quantity and quality), environmental quality (e.g. biodiversity, diversified landscapes), rural vitality (e.g. employment, rural dynamism) and cultural heritage (e.g. gastronomy, landscape quality). Four major types of services were revealed, showing contrasted levels of services provided. The analysis of the spatial distribution of the types of services sets. The main socio-economic, ecological, political and geographical determinants of service provision will be identified in further study to inform policy makers and society., L’élevage joue un rôle essentiel dans les territoires ruraux au sein desquels il assure de nombreux services économiques, environnementaux et sociaux. Appréhender la multiplicité des services rendus par l’élevage à la société représente donc un enjeu essentiel mais aussi un champ nouveau pour la recherche agronomique. L’objectif de cette étude est de réaliser une première quantification des services rendus par l’élevage en considérant les dimensions économiques, environnementales et sociales. Sur la base de réunions d’experts et de la revue de la littérature, nous avons d’abord proposé une qualification des services rendus par l’élevage pour définir le bouquet de services rendus par l’élevage en France. Nous avons ensuite sélectionné des indicateurs pour quantifier des bouquets de services départementaux à partir des bases de données mobilisables à l’échelle de la France. Nous avons analysé les services et leurs interrelations (synergies ou antagonismes) par une typologie de bouquets de services au niveau départemental. L’analyse met en évidence quatre catégories principales de services : approvisionnement (e.g. quantité et qualité d’aliments), qualité environnementale (e.g. biodiversité, hétérogénéité des paysages), vitalité territoriale (e.g. dynamisme rural et emploi) et identité culturelle (e.g. gastronomie, identité des terroirs). Quatre grands types de bouquets de service ont été mis en évidence présentant des niveaux contrastés d’expression des services. L’analyse de leur distribution géographique a montré une répartition non-aléatoire des types de bouquets. Une perspective de ce travail consistera à étudier les principaux leviers socio-économiques, politiques, écologiques et géographiques impliqués dans la fourniture de services pour informer les décideurs politiques et la société.

International audience; Dairy ingredients with highly concentrated protein contents are high added value products with expanding market. The manufacture of such ingredients includes a succession of unit operations of which heat treatment is a key step to guarantee the microbial safety, that induces major changes in protein structures and thus ingredients functionalities. However, due to an incomplete understanding of phenomena taking place at high protein concentrations, shedding light on their mechanisms is a scientific challenge as well as an industrial need. In this study, the influence of heat treatment (74 • C/ 30 s) of highly concentrated milk protein systems (up to 20 % w/ w) on protein denaturation/aggregation and enzymatic coagulation properties was studied using an original semi-industrial approach. 10 % w/w protein solutions constituted with whey protein and casein micelles at milk ratio, standardized in osmosed water or ultrafiltration permeate were used. These protein solutions were processed in different ways prior the manufacture of powders: heat treatment of the 10 % w/w protein solution before vacuum evaporation, heat treatment of the 20 % w/w protein solution after vacuum concentration, two consecutive heat treatments before and after vacuum evaporation. A fourth powder was prepared from unheated 10 % w/w protein solution. An increase in protein concentration led to a higher heat-induced protein denaturation. This phenomenon was reduced when increasing the lactose content. The effect of heat treatment on the extent of protein denaturation was not cumulative. At high protein concentration, interactions between κ-casein and whey protein were modified compared to milk, as mainly micelle-bound aggregates were formed at pH about 6.7. This phenomenon was enhanced at low ionic strength and lactose content. Our study showed that the enzymatic coagulation properties of reconstituted protein powders could be correlated with their physico-chemical compositions. An increase in protein denaturation disrupted the gel reorganization and led to the formation of weaker gels but did not interfere on the micelles aggregation phase and the early gelation. On the contrary, an increase in ionic strength and lactose content led to higher gel time.

National audience; Ce programme a pour objectif de mieux cerner les évolutions de structure et de propriétés fonctionnelles subies par les concentrés protéiques laitiers au cours de leur élaboration, en lien avec les paramètres de procédés appliqués. L’influence du schéma technologique defabrication, de la base de mélange (eau vs perméat d’ultrafiltration de lait) et de la formulation sur les caractéristiques physico-chimiques etles propriétés de réhydratation ont notamment été évaluées. Les résultats montrent qu’à teneur en lactose et force ionique plus élevées, ladénaturation des protéines est moins prononcée après concentration par évaporation. De plus, les poudres à caséines majoritaires traitéesthermiquement présentent une granulométrie plus élevée que celles sans traitement thermique. Pour ces formules, le traitement thermiqueinduit une augmentation significative de la fraction volumique occupée par les protéines dans les concentrés aqueux avant séchage. Enfin,quelle que soit la formulation, le traitement thermique facilite la réhydratation des particules : ce phénomène est d’autant plus marquélorsque le taux de protéines solubles dans le mélange est plus élevé.

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The identification and validation of biomarkers of food intake (BFIs) is a promising approach to develop more objective and complementary tools to the traditional dietary assessment methods. Concerning dairy, their evaluation in terms of intake is not simple, given the variety of existing foods, making it difficult to establish the association between specific dairy products consumption and the effects on human health, which is also dependent on the study population. Here, we aimed at identifying BFI of both milk (M) and yogurt (Y) in 14 healthy young (20–35 years) and 14 older (65–80 years). After a 3-week run-in period of dairy exclusion from the diet, the subjects acutely consumed 600 ml of M or Y. Metabolomics analyses were conducted on serum samples during the following 6 h (LC-MS and GC-MS). Several metabolites showing increased iAUC after milk or yogurt intake were considered as potential BFI, including lactose (M > Y, 2-fold), galactitol (M > Y, 1.5-fold), galactonate (M > Y, 1.2-fold), sphingosine-1-phosphate (M > Y from 2.1-fold), as well as an annotated disaccharide (Y > M, 3.6-fold). Delayed serum kinetics were also observed after Y compared to M intake lysine (+22 min), phenylalanine (+45 min), tyrosine (+30min), threonine (+38 min) 3-phenyllactic acid (+30 min), lactose (+30 min), galactitol (+45min) and galactonate (+30 min). The statistical significance of certain discriminant metabolites, such as sphingosine-1-phosphate and several free fatty acids, was not maintained in the older group. This could be related to the physiological modifications induced by aging, like dysregulated lipid metabolism, including delayed appearance of dodecanoic acid (+60 min) or altered postprandial appearance of myristic acid (+70% Cmax), 3-dehydroxycarnitine (−26% Cmin), decanoylcarnitine (−51% Cmin) and dodecanoylcarnitine (−40% Cmin). In conclusion, candidate BFI of milk or yogurt could be identified based on the modified postprandial response resulting from the fermentation of milk to yogurt. Moreover, population specificities (e.g., aging) should also be considered in future studies to obtain more accurate and specific BFI.

International audience; Dairy ingredients with highly concentrated protein contents are high added value products with expanding market. They are known to have specific properties adapted for a multitude of applications (cheese, bakery, infant formulae, nutritional products for the elderly and sportspeople...). Fabricationof such dairy protein ingredients is conducted by a succession of unit operations where heat treatment is a key step that induces major changes in protein structures and thus ingredients functionalities. However, due to an incomplete understanding of phenomena taking place at these high proteinconcentrations, shedding light on these mechanisms is simultaneously a scientific challenge and an industrial need. For this purpose, we used an original approach to investigate the influence of heat treatment and mineral environment of concentrated milk protein system on viscosity and enzymatic coagulation properties. Experiments were conducted with fresh whey protein isolates (WPI) and native phosphocaseinates (NPC) according to the ratio 20:80 (WPI:NPC) using 4 different technological routes: without heat treatment (Control); with one heat treatment at 10% w/w protein; with one heat treatment at 20% w/w protein and with two heat treatments at 10% and 20% w/w protein. Interestingly, the protein concentration of the heat-treated solution greatly modulates the denaturation and aggregation process of whey proteins, which modifies the association mechanismsbetween WPI and NPC. Indeed, the increase of protein content leads to a higher particles collision probability and a shorter inter-protein distance modifying protein-protein interactions. Furthermore, the nature of complexes formed during the heat treatment and the amount of aggregates present in solution are two parameters that can modulate the rheological properties (here viscosity and enzymatic coagulation ie, gel time and gel strength) of the system. Influence of lactose and mineral environment is discussed in a second time.

International audience; Health effects of dairy fats (DF) are difficult to evaluate, as DF intakes are hard to assess epidemiologically and DF have heterogeneous compositions that influence biological responses. We set out to find biomarkers of DF intake and assess biological response to a summer DF diet (R2), a winter DF diet (R3), and a R3 supplemented with calcium (R4) compared to a plant-fat-based diet (R1) in a randomized clinical trial (n=173) and a 2-year study in mildly metabolically disturbed downsized pigs (n=32). Conventional clinical measures were completed by LC/MS plasma metabolomics/lipidomics. The measured effects were modeled as biological functions to facilitate interpretation.DF intakes in pigs specifically induced a U-shaped metabolic trajectory, reprogramming metabolism to close to its initial status after a one-year turnaround. Twelve lipid species repeatably predicted DF intakes in both pigs and humans (6.6% errors). More broadly, in pigs, quality of DF modulated the time-related biological response (R2: 30 regulated functions, primarily at 6 months; R3: 26 regulated functions, mostly at 6–12 months; R4: 43 regulated functions, mostly at 18 months). Despite this heterogeneity, 9 functions overlapped under all 3 DF diets in both studies, related to a restricted area of amino acids metabolism, cofactors, nucleotides and xenobiotic pathways and the microbiota. In conclusion, over the long-term, DF reprograms metabolism to close to its initial biological status in metabolically-disrupted pigs. Quality of the DF modulates its metabolic influence, although some effects were common to all DF. A resilient signature of DF consumption found in pigs was validated in humans.

International audience; The most abundant minerals in milk are calcium, potassium, chloride, phosphorus, sodium and magnesium. This article first discusses the composition and distribution of these elements and citrate between the soluble (serum) and micellar (casein micelle) phases of milk. Then, it describes how this distribution, named the salt equilibria, is affected by the main physico-chemical treatments applied to milk in dairy processing (heating, cooling, pH variation, milk concentration, calcium salt and calcium chelator additions). Finally, sample preparation and some analytical methods to determine the mineral and citrate content and distribution in dairy liquids are described.

International audience

International audience; L'authentification des pratiques d'élevage par des analyses rapides du lait et/ou du fromage est une préoccupation de nombreuses filières laitières depuis plusieurs années. Les techniques de spectroscopie dans le visible (VIS) et l’infrarouge (IR) ont été proposées comme outils d’authentification prometteurs en raison de leur rapidité et de leur faible coût qui permettent une application en routine. L’objectif de cette synthèse est de faire un point sur les connaissances concernant l’authentification de l’alimentation des vaches laitières en utilisant la spectroscopie (dans le VIS, le proche IR (SPIR) et le moyen IR (MIR)) sur le lait et le fromage. La spectroscopie IR permet de discriminer des laits ou des fromages issus de régimes contrastés avec une précision fréquemment supérieure à 90 %. Appliquée au lait, la SPIR seule présente des précisions légèrement inférieures à celles de la MIR lorsqu’elle ne tient pas compte du spectre VIS. La précision de la spectroscopie IR est largement réduite lorsqu’elle est utilisée pour discriminer des rations peu contrastées. Pour faire face à cette limite, des avancées récentes proposent d’utiliser la MIR sur le lait pour prédire des indicateurs de la proportion des différents aliments dans la ration des vaches. Des résultats prometteurs ont été obtenus, notamment pour prédire la proportion d’herbe pâturée dans la ration. Un exemple d’utilisation de la MIR pour authentifier, à l’échelle d’un territoire, la composition de la ration des troupeaux laitiers est fourni et les atouts et les faiblesses de cette application sont analysés.

The Covid-19 pandemic is a major global event. A reflection on the first implications of this sanitary crisis for the world agricultural economy and the animal sectors of three geographical areas is proposed in this article. The agri-food systems have been strongly affected by this crisis, whose global economic impacts (a 3.5% drop in world gross domestic product and a 5.3% drop in international trade in goods between 2019 and 2020) are affecting the purchasing power of final consumers. However, they have resisted the crisis well, both in terms of supply (stability or slight growth in the volumes of meat and milk produced on a global scale) and trade. In 2021, the sharp rise in international prices for agricultural products and the rapid resumption of economic growth, particularly in the three zones more specifically studied here (China, the United States and the European Union), suggest that agriculture should remain under pressure from sustained world demand. More than Covid-19, the impact of African swine fever in China has had a major impact on international meat trade flows for several years. In addition, the growing Chinese appetite for dairy products is playing a central role in the development of international dairy markets, to the benefit of exporting areas including the EU and the US., La pandémie de Covid-19 est un évènement mondial majeur. Une réflexion sur les premières implications de cette crise sanitaire pour l'économie agricole mondiale et les filières animales est proposée dans le cadre de cet article. Les secteurs agricole et agroalimentaire ont été fortement concernés par cette crise dont les impacts économiques globaux (baisse de 3,5 % du produit intérieur brut mondial et de 5,3 % des échanges internationaux de marchandises entre 2019 et 2020) affectent le pouvoir d'achat des consommateurs finaux. Ils ont cependant bien résisté à la crise, tant au niveau de l'offre (stabilité ou légère croissance des volumes produits de viandes et de lait à l'échelle mondiale) que du commerce. En 2021, la forte hausse des prix internationaux des produits agricoles et la reprise rapide de la croissance économique, notamment dans les trois zones plus spécifiquement étudiées ici (Chine, Etats-Unis et Union européenne), suggèrent que l'agriculture devrait rester sous la pression d'une demande mondiale soutenue. Plus que la Covid-19, l'impact de la peste porcine africaine en Chine a eu, depuis plusieurs années, des répercussions majeures sur les courants d'échanges internationaux de viandes. De plus, l'appétit croissant des chinois pour les produits laitiers joue un rôle central dans le développement des marchés laitiers internationaux, au bénéfice des zones exportatrices dont l'Union européenne et les Etats-Unis.

International audience; The ability of mid-infrared spectroscopy (MIR) to predict indicators (i) of diet composition in dairy herds and (ii) forthe authentication of the cow-feeding restrictions included in the specification of two Protected Designation ofOrigin (PDO) cheeses (Cantal and Laguiole) was tested on 7607 bulk milk spectra from 1355 farms located in theFrench Massif Central. For each milk sample, the corresponding cow diet composition was obtained through onfarm surveys between April 2018 and March 2019. Cow diet composition varied largely (from full grazing forextensive farming systems to corn silage-based diets). The database was divided into a calibration (n = 6107) andvalidation (n = 1500) sets. Partial least square regression and discriminant analysis were used to predict theproportion of different feedstuffs in the cows’ diets and to authenticate the cow-feeding restrictions for the PDOcheese specifications, respectively. The pasture proportion in the cows’ diets was predicted by MIR with an R2 inexternal validation (R2V) = 0.81 and a standard error of prediction (SEP) of 11.7% dry matter. Pasture + hay, cornsilage, conserved herbage, fermented forage and total herbage proportions were predicted with a R2V > 0.61 and aSEP < 14.8%. The discrimination models for pasture presence, pasture ≥ 50% and pasture ≥ 57% in the cows’diets achieved an accuracy and specificity ≥ 90%. A sensitivity and precision > 80% were observed for all modelsincluding pasture proportion in cow diet. An accuracy ≥ 80% was also observed for pasture + hay ≥ 72%, herbage≥ 50%, pasture + hay ≥ 25%, absence of fermented herbage, absence of corn silage and corn silage ≤ 30% in thecows’ diets, but for several models, either the sensitivity or precision was lower than the accuracy. Models built withrespect to all the criteria of the feeding restrictions of PDO cheese specifications achieved an accuracy, specificity,sensitivity and precision > 90%. Both the regression and discriminant MIR models for bulk milk can provide usefulindicators of cow diet composition and PDO cheese specifications to producers and consumers; L’aptitude de la spectroscopie dans le moyen infrarouge (MIR) appliquée sur des laits de mélange pour 1) prédirela composition de la ration des troupeaux laitiers et 2) authentifier des pratiques des cahiers des charges desfromages AOP Cantal et Laguiole, a été testée. Les spectres MIR de 7607 laits de mélange AOP et non AOP de larégion ont été associés aux données d’enquêtes sur l’alimentation correspondantes (obtenues entre avril 2018 etmars 2019), afin de constituer la base des données. La composition de la ration était très variable, allant de rations100% pâturage, à des rations à base d’ensilage de maïs (jusqu’à 74%). La base de données a été divisée en deuxpour l’étalonnage (n = 6107) et la validation (n = 1500). Des modèles de régression « partial least squares » et desanalyses discriminantes ont été utilisés pour prédire la composition de la ration en pourcentage de matière sèche(MS) et pour authentifier les critères d’alimentation inclus dans les cahiers des charges des deux AOP,respectivement. La proportion d’herbe pâturée dans la ration a été prédite avec un modèle caractérisé par uncoefficient de détermination en validation externe (R2V) de 0,81 et une erreur standard de prédiction (SEP) de 11,7%. Les proportions de pâturage + foin, d’ensilage de maïs, d’herbe conservée, de fourrages fermentés et d’herbetotale ont été prédites par des modèles ayant des R2V > 0,61 et SEP < 14,8%. Les modèles d’analysesdiscriminantes pour la présence du pâturage, la proportion de pâturage ≥ 50% et ≥ 57% ont montré des valeursd’exactitude et de spécificité ≥ 90%. Des valeurs de sensibilité et de précision ≥ 80% ont été observées pour tousles modèles discriminants concernant la proportion du pâturage dans la ration. Les modèles discriminants pour laproportion de pâturage + foin ≥ 72%, herbe totale (fraiche et conservée) ≥ 50%, le pâturage + foin ≥ 25%, absenced’herbe fermentée, absence d’ensilage de maïs et ensilage de maïs ≤ 30% dans la ration ont montré des valeursd’exactitude ≥ 80%, mais pour ces modèles soit la sensibilité, soit la précision ont été moins performantes. Lesmodèles construits pour tester le respect de l’ensemble des critères des cahiers des charges de chaque AOP ontmontré des valeurs d’exactitude, spécificité, sensibilité et précision > 90%. Les modèles pour la prédiction du %des aliments dans la ration tout comme les modèles discriminants peuvent permettre de fournir, via la MIR, desindicateurs sur la composition de la ration des troupeaux laitiers utiles aux éleveurs, filières et aux consommateurs.

Few data are available regarding dietary habits of the elderly, especially about dairy products (DPs) (total DP and milk, fresh DP, and cheese), whereas these are part of healthy habits. The aim was to describe the socio-demographic characteristics, food, and nutritional intakes of elderly DP consumers. The sample consisted of 1584 participants from the Three-City-Bordeaux cohort (France), who answered a food frequency questionnaire and a 24-h dietary recall. Socio-demographic characteristics, practice of physical activity, Body Mass Index, and polymedication were registered. The sample was 76.2 years (SD 5.0 years) on average, 35% were in line with the French dietary guidelines for DP (3 or 4 servings of DP/day), while 49% were below, and 16% above. Women were significantly more likely to declare the highest total DP (&ge, 4 times/day), milk (&gt, 1 time/day), and fresh DP (&gt, 1.5 times/day) frequency consumption. The highest cheese frequency consumers (&gt, 1.5 times/day) were more likely men, married, and ex-smokers. The highest frequency of fresh DP intake was significantly associated with the lowest energy and lipid intakes, and that of cheese with the highest consumption of charcuteries, meat, and alcohol. This cross-sectional analysis confirmed that the socio-demographics and dietary characteristics varied across DP sub-types consumed, which encourages individual consideration of these confounders in further analyses.

International audience; Context: France has recently set up a new organization based on collaborative epidemiological platforms, strengthening the link between private and public stakeholders in charge of ensuring food safety. The first two years of work focused notably on prevention of Salmonella contamination, data sharing and data quality.

International audience

This study aimed at investigating the changes in skim camel milk (SCMP) and skim bovine milk (SBMP) powders produced by spray-drying. The physical (sorption isotherms at 25 °C and the glass transition temperature Tg at 0.13, 0.23 and 0.33 of water activities (aw)) and the biochemical (LC-MS, before and after drying) properties were assessed. Compared to SBMP, the results for SCMP indicated lower protein denaturation extent, lower critical aw for lactose crystallization (aw = 0.60 instead of 0.70), and lower Tg at 0.13 of aw (54.6 ± 1.4 °C instead of 57.8 ± 0.4 °C). Fitted to Guggenheim, Anderson and De Boer (GAB) model, the water sorption isotherms showed that both powders exhibited the same monolayer moisture content (Xm = 2.0 g 100 g−1, p > 0.05). These findings were linked to the absence of β-lactoglobulin, the high surface lactose content, the high initial lactose crystallization and the low size distribution (d50

Highlights • Trans-palmitoleic and trans-vaccenic acids are fatty acids of nutritional interest. • Doubts remain about the formal dietary sources of both fatty acids. • Foods available at retail in France were accurately analyzed. • Both fatty acids’ intakes are exclusively ensured by ruminant-derived foods., High circulating levels of trans-palmitoleic acid (TPA) are associated with a lower risk of type 2 diabetes in humans. Thus, the origin of circulating TPA matters. Direct intakes of TPA are ensured by dairy products, and perhaps by partially hydrogenated oils (PHOs). Indirect intakes of TPA rely on dietary trans-vaccenic acid (TVA), which occurs in ruminant-derived foods and PHOs. As it is usually assumed that PHOs are not used any longer, we analyzed here a wide range of foods currently available at retail in France. We report that TPA and TVA (1) do occur in ruminant milk and meat, dairy products and in foreign PHOs, (2) do occur in dairy fat-containing foods and (3) do not occur in dairy fat-free foods. Together, our findings demonstrate that ruminant fats are the only contributors to circulating levels of TPA in humans.

International audience

[Epub ahead of print]; BACKGROUND & AIMS: Metabolic syndrome (MetS) induces major disturbances in plasma metabolome, reflecting abnormalities of several metabolic pathways. Recent evidences have demonstrated that the consumption of dairy products may protect from MetS, but the mechanisms remains unknown. The present study aimed at identify how the consumption of different types of dairy products could modify the changes in plasma metabolome during MetS. METHODS: In this observational study, we analyzed how the consumption of dairy products could modify the perturbations in the plasma metabolome induced by MetS in a sample of 298 participants (61 with MetS) from the French MONA LISA survey. Metabolomic profiling was analyzed with UPLC-MS/MS. RESULTS: Subjects with MetS exhibited major changes in plasma metabolome. Significant differences in plasma levels of branched chain amino acids, gamma-glutamyl amino acids, and metabolites from arginine and proline metabolism were observed between healthy control and Mets subjects. Plasma levels of many lipid species were increased with MetS (mono- and diacylglycerols, eicosanoids, lysophospholipids and lysoplasmalogens), with corresponding decreases in short chain fatty acids and plasmalogens. The consumption of dairy products, notably with a low fat content (milk and fresh dairy products), altered metabolite profiles in plasma from MetS subjects. Specifically, increasing consumption of dairy products promoted accumulation of plasma C15:0 fatty acid and was inversely associated to some circulating lysophospholipids, sphingolipids, gamma-glutamyl amino acids, leukotriene B4 and lysoplasmalogens. CONCLUSIONS: the consumption of low fat dairy products could mitigate some of the variations induced by MetS.

Dairy products (DP) are part of a food group that may contribute to the prevention of physical frailty. We aimed to investigate DP exposure, including total DP, milk, fresh DP and cheese, and their cross-sectional and prospective associations with physical frailty in community-dwelling older adults. The cross-sectional analysis was carried out on 1490 participants from the Three-City Bordeaux cohort. The 10-year frailty risk was examined in 823 initially non-frail participants. A food frequency questionnaire was used to assess DP exposure. Physical frailty was defined as the presence of at least 3 out of 5 criteria of the frailty phenotype: weight loss, exhaustion, slowness, weakness, and low physical activity. Among others, diet quality and protein intake were considered as confounders. The baseline mean age of participants was 74.1 y and 61% were females. Frailty prevalence and incidence were 4.2% and 18.2%, respectively. No significant associations were observed between consumption of total DP or DP sub-types and frailty prevalence or incidence (OR = 1.40, 95%CI 0.65–3.01 and OR = 1.75, 95%CI 0.42–1.32, for a total DP consumption &gt, 4 times/d, respectively). Despite the absence of beneficial associations of higher DP consumption on frailty, older adults are encouraged to follow the national recommendations regarding DP.

International audience; Storage is an unavoidable critical phase regarding dairy powder reconstitution abilities, particularly for high casein content powders, which generally present a poor rehydration behavior. The ability of micellar casein powders to completely rehydrate can thus be particularly affected by storage time and temperature. To implement best practices for the optimization of storage conditions, understanding changes occurring is a crucial point. For the first time, biophysical techniques were used to investigate powder surface at the nanoscale. Atomic force microscopy revealed that particle surface became rougher during storage, associated with the formation of hollow zones (around 500 nm) holes when stored for 10 months at 40 degrees C. Mechanical properties of micellar casein particle surface during powder storage was quantified using AFM nanoindentation. Spatially-resolved force/indentation curves evidenced a significant stiffer surface for aged powder (Young modulus of similar to 20 GPa) in comparison with the fresh one (similar to 0.2 GPa). These findings were fully consistent with the formation of a crust at the powder surface observed by high-resolution field-emission scanning electron microscopy during powder rehydration. Finally, alterations of the rehydration process can be related to modifications occurring at the particle surface during storage.

International audience

International audience

International audience; Along the cold chain, cheese product temperatures need to be maintained below 6 degrees C. However, cheese generates heat via the metabolism of the micro-organisms. Therefore, to ensure the uniformity of temperature within a pallet of cheese, it is important to take into account this amount of heat. This work aimed to study the influences of different parameters on the heat transfer for which forced convection around the pallet interacts with free/mixed convection inside it. An experimental device was used in which cheese was replaced by plaster blocks; each block being equipped with a heating resistance to simulate the product heat generation. Two upwind air velocities were selected: 0.31 m s(-1) and 0.73 m s(-1); the heat generating varied between 0.05 W and 0.30 W per product of 0.25 kg; two pallet orientations were studied. The results of the present study can also benefit fresh horticultural products which generate heat and require temperature-controlled equipment.

The surface of milk fat globules consists of a biological membrane rich in polar lipids and glycoproteins. However, high shear stress applied upon homogenization disrupts the membrane and leads to the adsorption of casein micelles, as the major protein fraction of milk. These changes in the interface properties could affect the interactions between native or homogenized milk fat globules and the surrounding protein matrix, at neutral pH and upon acidification. In this study, macroscale rheometry, microscopic observations, nanoscale AFM-based force spectroscopy and physico-chemical analysis were combined to examine the interfacial composition and structure of milk fat globules and to evaluate their interactions with casein micelles. We showed that the surface properties of milk fat globules (biological membrane vs. caseins) and pH govern their interactions with casein micelles. The adhesion between individual fat globules and casein micelles was higher upon homogenization, especially at acid pH where the work of adhesion increased from 3.3 x 10-18 to 14 x 10-18 J for native and homogenized fat globules, respectively. Consequently, casein-coated homogenized fat globules yield stiffer milk acid gels. These findings cast light on the importance of colloidal particle’s surface properties and pH on their connectivity with the surrounding matrix, which modulates the bulk microstructure and rheological properties with potential functional consequences, such as milk lipid digestion.

International audience; This work aimed to investigate the airflow and temperature levels within a pallet of heat-generating product under steady-state conditions. A cheese product was simulated. An experimental device was used in which cheese was replaced by plaster camembert cheeses; each simulated camembert was equipped with a heating resistance to simulate heat generation by the product. The pallet was placed in an experimental room with controlled upwind temperature and air velocity. The air velocity within the pallet was measured by LDV (Laser Doppler Velocimetry). Two pallet orientations, two upwind velocities of 0.31 m s −1 and 0.73 m s −1 and two heat fluxes of 0.05 W and 0.30 W per product item with a mass of 0.25 kg were investigated and compared. This study provides a better understanding of the complexity of the airflow pattern related to natural and forced convection flows as well as the dynamic interactions under mixed convection. It can be applied to other living products such as fruit or vegetables that generate heat via respiration.

International audience; TNF-Related Apoptosis-Inducing Ligand (TRAIL) is a well-known apoptosis inducer, which activates the extrinsic death pathway. TRAIL is pro-apoptotic on colon cancer cells, while not cytotoxic towards normal healthy cells. However, its clinical use is limited by cell resistance to cell death which occurs in approximately 50% of cancer cells. Short Chain Fatty Acids (SCFA) are also known to specifically induce apoptosis of cancer cells. In accordance, we have shown that food grade dairy propionibacteria induce intrinsic apoptosis of colon cancer cells, via the production and release of SCFA (propionate and acetate) acting on mitochondria. Here, we investigated possible synergistic effect between Propionibacterium freudenreichii and TRAIL. Indeed, we hypothesized that acting on both extrinsic and intrinsic death pathways may exert a synergistic pro-apoptotic effect. Whole transcriptomic analysis demonstrated that propionibacterial supernatant or propionibacterial metabolites (propionate and acetate), in combination with TRAIL, increased pro-apoptotic gene expression (TRAIL-R2/DR5) and decreased anti-apoptotic gene expression (FLIP, XIAP) in HT29 human colon cancer cells. The revealed synergistic pro-apoptotic effect, depending on both death receptors (TRAIL-R1/DR4, TRAIL-R2/DR5) and caspases (caspase-8, -9 and -3) activation, was lethal on cancer cells but not on normal human intestinal epithelial cells (HIEC), and was inhibited by Bcl-2 expression. Finally, milk fermented by P. freudenreichii induced HT29 cells apoptosis and enhanced TRAIL cytotoxic activity, as did P. freudenreichii DMEM culture supernatants or its SCFA metabolites. These results open new perspectives for food grade P. freudenreichii-containing products in order to potentiate TRAIL-based cancer therapy in colorectal cancer.

International audience; Trans-palmitoleic acid (trans-C16:1 n-7, TPA) and trans-vaccenic acid (trans-C18:1 n-7, TVA) are usually found in dairy products: both are associated with improvements regarding risk of metabolic syndrome. However, partially hydrogenated oils (PHOs) were reported to contain TVA as well, while their TPA content was never assessed. Because there is no official ban on PHOs in Europe, the relative contribution of dairy products to trans fatty acids intake is not accurately known. The study aimed at assessing the most reliable sources of both TPA and TVA at the current time in France. Two hypotheses were made: (1) TPA and TVA are found in dairy products, (2) partially hydrogenated oils are not used anymore, and (3) current blends of vegetable oils are free of trans fatty acids. Foods were purchased in local stores in France. Trans fatty acids were isolated by silver-ion thin-layer chromatography and analyzed by gas chromatography-mass spectroscopy with appropriate conditions, to separate as much positional isomers (trans-C16:1 and trans-C18:1) as possible. Both TPA and TVA were found in dairy products, and in foods which fatty acid composition relied on both dairy lipids and vegetable oils. Conversely, blends of vegetable oils were free of TPA and TVA. Sources of both TPA and TVA are on the side of dairy products. In strong connection with dairy technology and farm management, the impact of processes and ruminant nutrition on TPA and TVA content in dairy fat should be understood.

IDF-WDS 2018 Best Poster Award; International audience; Trans-palmitoleic acid (trans-C16:1 n-7, TPA) is commonly found in dairy products. Previous epidemiological work associated TPA with lower risk of metabolic syndrome. To date however, no nutritional study exists to verify such hypothesis, mostly due to the low availability of TPA. Tackling the TPA availability issue, this work aimed at assessing for the first time the nutritional impact of TPA in straight relationship with metabolic syndrome. TPA was chemically synthesized starting from its cis isomer and purified by Flash HPLC. C57BL/6N mice were taken at 5 weeks of age and fed with a high-fat high-sucrose diet for 7 weeks to induce metabolic syndrome, while being TPA-supplemented (4% of total energy). A negative control (i.e., without disorders) and a positive one (supplementation with palmitic acid, C16:0) were also used. Approximately 70 g of 99%-purity TPA were obtained. TPA and its metabolites (e.g., trans-vaccenic acid) were found in the liver, red blood cells, muscle and adipose tissue (visceral and subcutaneous) of mice fed with TPA. Compared with the positive control, TPA supplementation reduced adipose tissue weights and adipocyte size, in both visceral and subcutaneous fat; these parameters did not differ with the negative control. Free fatty acids levels with TPA supplementation also differed with that of positive control but did not with the negative one. Our first results support beneficial effects of TPA, that might act on adipose tissue. Other parameters such as insulin or leptin are to be measured soon, to enable further statements about TPA and metabolic syndrome.

International audience; Trans-palmitoleic acid (trans-C16:1 n-7, TPA) is commonly found in dairy products, accounting for 0.03% of total fatty acids. Previous epidemiological work associated TPA with lower risk of metabolic syndrome. To date however, no nutritional study exists to verify such hypothesis, mostly due to the low availability of TPA. Tackling the TPA availability issue, this work aimed at assessing for the first time the nutritional impact of TPA in straight relationship with metabolic syndrome. TPA was chemically synthesized starting from its cis isomer and purified by Flash HPLC. C57BL/6N mice were taken at 5 weeks of age and fed with a high-fat high-sucrose diet for 7 weeks to induce metabolic syndrome, while being TPA-supplemented (4% of total energy). A negative control (i.e., without disorders) and a positive one (supplementation with palmitic acid, C16:0) were also used. Approximately 70 g of 99%-purity TPA were obtained. TPA and its metabolites were found in the liver, red blood cells, muscle and adipose tissue (visceral and subcutaneous) of mice fed with TPA. Compared with the positive control, TPA supplementation reduced adipose tissue weights and adipocyte size, in both visceral and subcutaneous fat; these parameters did not differ with the negative control. Free fatty acids levels with TPA supplementation also differed with that of positive control but did not with the negative one. So far, our results support epidemiological findings regarding TPA ability to prevent from key components of metabolic syndrome. Other key parameters are to be measured soon to enable further statements about TPA health effects.

International audience; In vitro, the rat Fatty Acid Desaturase 3 (FADS3) gene was shown to code for an enzyme able to catalyze the unexpected Δ13-desaturation of trans-vaccenic acid, producing the trans11,cis13-conjugated linoleic acid (CLA) isomer. FADS3 may therefore be the first methyl-end trans-vaccenate Δ13-desaturase functionally characterized in mammals, but the proof of this concept is so far lacking in vivo. The present study therefore aimed at investigating further the putative in vivo synthesis of trans11,cis13-CLA from dietary trans-vaccenic acid in rodents. During one week of pregnancy and two weeks post-partum, Sprague-Dawley female rats were fed two diets either high (10.0% of fatty acids and 3.8% of energy intake) or low (0.4% of fatty acids and 0.2% of energy intake) in trans-vaccenic acid. The trans11,cis13-CLA was specifically detected, formally identified and reproducibly quantified (0.06% of total fatty acids) in the mammary gland phospholipids of lactating female rats fed the high trans-vaccenic acid-enriched diet. This result was consistent with FADS3 mRNA expression being significantly higher in the lactating mammary gland than in the liver. Although the apparent metabolic conversion is low, this physiological evidence demonstrates the existence of this new pathway described in the lactating mammary gland and establishes the FADS3 enzyme as a reliable mammalian trans-vaccenate Δ13-desaturase in vivo.

International audience; Trans-palmitoleic acid (trans-C16:1 n-7, or trans Δ9-C16:1, TPA) is believed to improve several metabolic parameters according to epidemiological data. TPA may mainly come from direct intakes: however, data is inconsistent due to its very low amount in foods. Instead, TPA might arise from dietary trans-vaccenic acid (trans-C18:1 n-7, TVA), which is more abundant in foods. TVA chain-shortening would be involved, but formal proof of concept is still lacking to our knowledge. Therefore, the present study aimed at providing in vitro and in vivo evidence of TVA retroconversion to TPA. First, fresh rat hepatocytes cultured with growing doses of TVA were able to synthesise growing amounts of TPA, according to a 10%-conversion rate. In addition, TPA was found in secreted triacylglycerols (TAG). Inhibiting peroxisomal β-oxidation significantly reduced TPA synthesis, whereas no effect was observed when mitochondrial β-oxidation was blocked. Second, pregnant female rats fed a TVA-supplemented diet free of TPA did metabolise dietary TVA, leading to detectable amounts of TPA in the liver. Apart from the brain, TPA was also found in all analysed tissues, including the mammary gland. Hepatic peroxisomal β-oxidation of dietary TVA, combined with exportation of TPA under VLDL-TAG may explain amounts of TPA in other tissues. In conclusion, dietary TVA undergoes peroxisomal β-oxydation and yields TPA. Thus, not only TPA circulating levels in humans can be explained by dietary TPA itself, but dietary TVA is also of importance.

International audience; Trans-octadecenoic acids (trans-C18:1) intakes during pregnancy were previously shown to threaten polyunsaturated fatty acid (PUFAs) status in new-borns. However, a distinction should be made between trans-C18:1 positional isomers regarding their impact on human health. If industrial trans fatty acids are known to be harmful, less is known about dairy trans fatty acids such as trans-vaccenic acid (trans-C18:1 n-7, TVA). Studying one isomer at a time remains indeed a technical issue in terms of both purity and elevated amount. Overcoming such a challenge, this study aimed at focusing only on TVA, studying the impact of its supplementation during pregnancy on PUFAs status in new-borns. We first chemically synthesised cis-vaccenic acid (cis-C18:1 n-7, CVA), then isomerised it to yield TVA. Liquid Chromatography Flash, an innovative means, enabled the separation between TVA and CVA, according to a 95%-purity. Second, pregnant Sprague-Dawley (day 14) were used and fed with either a TVA-supplemented diet (2% of total energy), or a CVA-supplemented diet (2% of total energy, control) for three weeks. The linoleic acid/α-linolenic acid ratio was settled at 5 in both diets. Regarding pups, their diet relied exclusively on maternal milk for two weeks. Fatty acid composition of plasma, red blood cells, muscle, adipose tissue, liver and brain of pups was assessed by GC-MS. Data analysis relied on both univariate statistics and a recently developed multiblock procedure that modelled lipid metabolism and interaction between tissues. First, chemical synthesis of TVA was successful, yielding high amounts of pure TVA almost without any other trans-C18:1 isomer. Second, TVA was incorporated in all tissues analysed in the pups fed the TVA diet, including the brain (0.19% of total fatty acids). Compared to control, univariate analyses only revealed a significant decrease in C22:4 n-6 in the brain of pups fed the TVA diet; otherwise, non-significant decreases in arachidonic acid and DHA were found in these pups. In key tissues such as plasma and red blood cells, non-significant increases in both n-6 and n-3 PUFAs in the TVA group were highlighted. The multi-block procedure unravelled a discrimination between both groups, but consistently with univariate outcomes, PUFAs played a weak role in this separation. This study focused on one accurate trans-C18:1 isomer, namely TVA. Its supplementation during pregnancy may not jeopardise PUFAs status in new-borns, but other studies are needed to both draw accurate conclusions and understand the physiological impacts of TVA. As the current consumption of partially hydrogenated oil decreases in developed countries, dairy trans fatty acids will account for a larger part of trans fatty intakes in the forthcoming period. Their impact on human health in general should be properly assessed. Our study underline that solutions do exist to obtain one very pure isomer in high amounts. Our outcomes call for more studies about the relationship between dairy trans fatty acids intakes during pregnancy and PUFAs' status of new-borns.

International audience; High levels of circulating trans-palmitoleic acid (TPA, C16:1 n-7 trans) are associated with a lower risk of metabolic syndrome. It was actually assumed that TPA arises from dietary transvaccenic acid (TVA, C18:1 n-7 trans) through the β-oxydation pathway. This study aimed at providing evidence of such retroconversion. Fresh rat hepatocytes were incubated with growing amounts of TVA to assess the conversion rate. Inhibitors of mitochondrial and peroxisomal β-oxydation were also used. Sprague-Dawley pregnant rats were fed during the last week of pregnancy plus two weeks of lactation, either with a TVA-diet or with the corresponding cis isomer (2% of total energy). Pups were exclusively fed with maternal milk for two weeks. TPA content was assessed in the main organs of both dams and pups. TPA was properly identified in hepatocytes. The conversion rate was estimated at 10%. Triacylglycerols secreted by hepatocytes did contain TPA. Blocking peroxisomal β-oxydation significantly decreased the conversion rate. TPA was quantified in the dams fed the TVA-supplemented diet and their pups, excepted in the brain. Importantly, TPA was found in the maternal milk. Liver ensures the retroconversion of dietary TVA to TPA, which can be exported to other tissues. Circulating levels of TPA are explained by dietary intakes of TVA. Given epidemiological data about TPA, future research is needed to assess dietary intakes of TVA.

International audience; Separation and analysis of positional isomers of trans-C16:1 and trans-C18:1 fatty acids usually rely on gas chromatography (GC), with flame-ionization detector (FID) and hydrogen as gas vector. Because hydrogen results in good peak resolution, it is unclear whether the use of mass spectroscopy (MS) and helium as gas vector would yield worse outcomes. Therefore, this study aimed at showing the abilities of GC-MS when dealing with positional isomers of trans-C16:1 and trans-C18:1 fatty acids. GC-MS in combination with helium was used. Both partially hydrogenated fish oil (PHFO) and dairy products, derivatized as fatty acid methyl esters (FAME), were considered because of differences of trans-C16:1 and trans-C18:1 isomer distribution. To rule out the effect of stationary phase, two different GC columns were used. Optimized conditions determined in each case. Using optimized conditions, GC-MS and helium led to decent resolution of trans-C16:1 and trans-C18:1 positional isomers, in respect with what can be obtained with hydrogen and FID. This held true for both dairy products and PHFO for which differences in profiles were clearly highlighted. Both GC columns provided similar resolutions. GC-MS in combination with helium is suitable for analysis of positional isomers of trans-C16:1 and trans-C18:1 fatty acids.

International audience; Growing evidence suggests that natural trans fatty acids should be distinguished from industrial ones, regarding their impact on human health. One trans isomer at a time should therefore be considered in nutritional studies. However, a high amount combined with an excellent purity of the corresponding isomer remains a challenge. This study aimed at providing means to overcome such issues. The purification of several grams of trans-palmitoleic acid (C16:1 n-7 trans, TPA) was considered in this study, starting from the cis-palmitoleic acid (C16:1 n-7 cis, CPA). Fatty acids were used as ethyl esters. Several sources of CPA were evaluated. The following means were critically assessed: Flash HPLC, urea complexation, and crystallization in solvent. Within each step, the purity was checked by GC-MS, and the best means was chosen. Macadamia nut was deemed as a reliable source of CPA, the other cis-C16:1 isomers being present in low amounts. Purification of CPA was best carried out using Flash HPLC. The isomerization of CPA to TPA was easily done. Removing as much CPA as possible from the CPA-TPA mix was best performed by crystallization in solvent, ensuring a 99%-purity of the final TPA product. Complementary means were used to get high amounts of highly purified-TPA. Not only ethyl esters were suitable for purification purposes, but they made the purity control by GC-MS easy. Provided the availability of the corresponding cis-isomer, our purification strategy can be applied to any trans monounsaturated fatty acid.

International audience; L’acide trans-vaccénique (TVA, C18:1 n-7 trans) est principalement retrouvé dans les produits issus de ruminants (e.g.,lait, viande). Du fait de sa présence naturelle, la question de son impact sur la santé se pose, à l’heure où les acides gras trans dans leur ensemble sont considérés comme délétères. Sur le plan de la gestation, les acides gras trans sont en effet associés à un moindre statut en acides gras polyinsaturés (AGPI) n-6 et n-3 chez le nouveau-né. Plusieurs études plaident cependant pour une différenciation entre acides gras trans naturels et industriels, introduisant par-là une nouvelle exigence pour les études de supplémentation : un seul acide trans doit être désormais considéré, au lieu d’un mélange de plusieurs isomères de position comme cela a souvent été le cas. Le TVA étant associé à des bénéfices au regard de la santé, cette étude se propose de regarder avec attention l’impact d’une supplémentation en seul TVA chez des rates gestantes, sur le statut en polyinsaturés des ratons. L’acide cis-vaccénique (CVA) a d’abord été synthétisé chimiquement par la réaction de Wittig, puis isomérisé en TVA. Le mélange cis/trans a été purifié par HPLC préparative (PuriFlash® 4250). Pour chaque acide gras, le degré de pureté a été supérieur à 95%. Des rattes Sprague-Dawley gestantes (14e jour) ont été réparties en deux groupes, selon le régime donné ad libitum : supplémenté soit en TVA (2% de l’énergie totale, n=4), soit en CVA (2% de l’énergie totale, n=4). Les ratons (n=12 dans chaque groupe) ont été exclusivement nourris au lait maternel, pendant deux semaines. Les compositions en acides gras de plusieurs organes des ratons ont été déterminées (cerveau, foie, plasma, globules rouges, muscle, tissu adipeux), par GC-MS. Les résultats ont été analysés d'une part par analyse univariée (ANOVA). D'autre part, une procédure innovante dite "multiblock" a été effectuée, modélisant les relations globales entre organes, et les liens existant entre acides acides gras au sein d'un même organe. A l’exception du C22:4 n-6 dans le cerveau (en baisse) et du DHA plasmatique (en hausse), la supplémentation en TVA n’impacte pas significativement la composition en AGPI des tissus chez les ratons. Les analyses « multiblock » vont également dans le sens d’un faible impact de la supplémentation en TVA sur le statut en AGPI : les AGPI ne contribuent que très faiblement à la discrimination entre les groupes CVA et TVA. Une supplémentation pendant la gestation avec un seul acide gras trans naturel, le TVA, ne semble pas significativement perturber le statut en polyinsaturés chez les ratons. De plus amples investigations sont requises pour évaluer l’impact précis du TVA sur les activités et les expressions des désaturases et des élongases.

International audience; La question d’une différence d’impact entre acides gras trans d’origine naturelle et industrielle fait débat. L’acide trans-palmitoléique (C16:1 n-7 trans, TPA), retrouvé exclusivement dans les produits laitiers (0,03% des acides gras totaux), est ainsi associé à des bénéfices vis-à-vis du syndrome métabolique. La difficulté pour des études d’impacts du TPA consiste à ne supplémenter que cet acide gras, et non plus un mélange d’isomères de position comme cela a souvent été le cas. Cette exigence de pureté se heurte à la quantité de TPA nécessaire pour une étude de supplémentation, d’autant plus que cette quantité (plusieurs dizaines de grammes pour un modèle rongeur) n’est pas disponible commercialement. Si la collaboration avec des industries chimiques peut être envisagée, des solutions à l’échelle du laboratoire peuvent également être mises en place. Dès lors, cette étude propose d’examiner les étapes successives de synthèse et de purification du TPA, en partant de son isomère de configuration cis (C16:1 n-7 cis, CPA), pour n’en retenir que les plus efficaces.Le travail a systématiquement porté sur des esters éthyliques d’acides gras. La comparaison entre la noix de macadamia et le complément alimentaire Provinal®, sources de CPA, a été effectuée. La purification du CPA, pour enlever tous les acides gras isomérisables, a été effectuée avec le système PuriFlash® 4250 et deux colonnes successives PuriFlash® C18-HP. Une fois l’isomérisation effectuée, deux méthodes ont été comparées pour séparer le CPA du TPA : système PuriFlash® 4250 et colonnes PuriFlash® C18-HP, et cristallisation différentielle dans le solvant à basse température. La composition en esters éthyliques à chaque étape a été évaluée par GC-MS, avec une colonne capillaire de haute polarité (BPX90). Des standards C16:1 cis et C16:1 trans authentiques ont été utilisés pour confirmer l'identité des pics.Malgré un fort taux de CPA (supérieur à 50% des acides gras totaux), le Provinal® comporte des isomères C16:1 trans ainsi que des C16:1 cis isomérisables. La noix de macadamia est plus avantageuse de ce point de vue, malgré un moindre taux de CPA (15%). Le système PuriFlash® 4250 s’avère efficace pour purifier le CPA des autres acides gras isomérisables (monoènes, diènes). Purifier de grandes quantités d’un mélange cis/trans est un défi, résolu très aisément par cristallisation différentielle dans le méthanol à -80°C : trois étapes de cristallisation suffisent pour obtenir des dizaines de grammes de TPA selon une pureté supérieure à 99%.Des solutions à l’échelle du laboratoire existent pour synthétiser et purifier de grandes quantités d’acides gras trans monoènes comme le TPA. Ces principes peuvent tout aussi bien être adaptés à des acides gras plus classiques (oméga-3), toujours en vue d’études de supplémentation/d’intervention.

Dairy food consumption is important for children as it contributes to the intake of key nutrients, especially calcium. The aim of the present paper is to provide an overview of dairy products consumption for French children, according to age, sex and type of dairy products. Adequacy of dairy and calcium intakes in line with French national guidelines “3 portions of dairy products per day” were also evaluated. Data were extracted and analyzed from the CCAF—Comportementet Consommations Alimentairesen France-study. Seven-day questionnaires were administered to free-living individuals from autumn 2009 to summer 2010. Subjects were children (n = 1171) aged 3 - 17 years. Dairy products contributed substantially to the intake of calcium, phosphorus, potassium, zinc, vitamin B2 and vitamin B12. A general decrease in DP consumption has been observed since 2003. This is most notably due to a lower milk intake which is not compensated by increased cheese or fresh dairy products. Most of children (67%), and up to 73% of adolescents (15 - 17 y), did not reach the recommended “3 servings of dairy products per day”. Twenty percent of children from the age of 6 and nearly 2/3 of female adolescents did not reach their estimated average requirement for calcium. The overview of French dairy food consumption during childhood, of particular Public Health concern, emphasizes the need to encourage dairy consumption and particularly milk consumption at breakfast in order to maintain a nutrient adequacy in children and adolescents.

International audience; The casein micelle is a highly aggregated colloid consisting of phosphoproteins and minerals, in particular calcium and phosphate. Its properties are affected by physico-chemical changes which provide possibilities for the development of new casein aggregates (CAs) with novel functionalities. The aim of this study was to investigate the emulsifying and emulsion-stabilizing capacity of gradually demineralized CAs in model dairy emulsions. Tri sodium citrate (TSC) was used to remove calcium and inorganic phosphate from pure casein micelles in order to produce four suspensions of differently demineralized CAs. Two types of milkfat-in-suspension (30:70 v/v) emulsions were then prepared to study the emulsifying and emulsion-stabilizing capacity of these CAs separately. Casein micelles were progressively demineralized (from 24 to 81% calcium reduction) and dissociated with the increase in TSC concentration. Three distinct populations of particles (micelle-like aggregates, sodium caseinate-like aggregates and casein monomers) were present in every suspension in different proportions. The smaller CAs had better emulsifying capacity and similar surface activity according to interfacial studies. The state of aggregation of the CAs was thus the main factor that controlled their emulsifying capacity. However, the emulsions formed with these smaller aggregates were less stable against creaming and flocculation, but still resisted coalescence under our storage conditions (21 days at 50 °C). The properties of the interfacial casein layers did not depend on the aggregation state of the CAs used to form the emulsions. The differences in instability were attributed to the nature of the non-adsorbed CAs and storage conditions.

International audience; Scope: TNF-Related Apoptosis-Inducing Ligand (TRAIL) induces apoptosis via the extrinsic death pathway in human colon cancer cells. Short Chain Fatty Acids (SCFA) by contrast induce apoptosis of cancer cells via the intrinsic death pathway. We have previously shown that food-grade dairy propionibacteria induce intrinsic apoptosis of colon cancer cells, via SCFA metabolites (propionate and acetate) acting on mitochondria. We investigate here the possible synergistic pro-apoptotic effect between Propionibacterium freudenreichii and TRAIL. Methods and results: Whole transcriptomic analysis demonstrated that propionibacterial supernatant or propionibacterial SCFA, in combination with TRAIL, increased pro-apoptotic gene expression (TRAIL-R2/DR5) and decreased anti-apoptotic gene expression (FLIPL, XIAP) in HT29 human colon cancer cells. The revealed synergistic pro-apoptotic effect, depending on both death receptors (TRAIL-R1/DR4, TRAIL-R2/DR5) and caspases (caspase-8, -9 and -3) activation, was lethal on cancer cells but not on normal human intestinal epithelial cells (HIEC), and was inhibited by Bcl-2 expression. Finally, milk fermented by P. freudenreichii induced HT29 cells apoptosis and enhanced TRAIL cytotoxic activity, as did P. freudenreichii culture supernatants or its SCFA metabolites. Conclusion: The revealed synergy opens new applications for food-grade P. freudenreichii-containing products as new adjuvants to potentiate TRAIL-based cancer therapy in colorectal cancer.

Supported by high added value products, the market of dairy protein powders has shown a continuous increase over the past decade. During powder manufacture, precautionary measures are taken to ensure optimal technological and nutritional functionalities regarding their use requirements. However, changes in physico-chemical and functional properties of whey protein isolates (WPI) powders appear during storage, which is not as well mastered as previous processing. It is therefore of high interest to understand the mechanisms and identify the structural markers involved in WPI powders ageing in order to control their end use properties. This study was performed to determine the effects of different storage conditions applied to WPI powders on heat induced aggregation of whey proteins, and simultaneously on both protein denaturation and lactosylation. Therefore, two different storage conditions regarding temperature (20 and 40 °C) have been carried out for periods of up to 15 months. On the one hand, our results showed that protein lactosylation occurred in WPI powders at 20 °C, but heat induced aggregation did not significantly differ from non-aged whey protein isolates. On the other hand, powders presented a high level of denaturation and aggregation at 40 °C, involving first protein lactosylation and then aggregation in the dry state. These evolutions were correlated with an increasing Browning Index starting from the first month of storage, and with a decrease in aggregate size after heat treatment at pH ≥ 5.8. A change in the shapes of heat induced aggregates was concomitantly observed. These results pave the route for a better control of functional properties of WPI powders during ageing, and for recommendations about optimal storage conditions.

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Thanks to PhenoFinlait program many knowledge and applications were developed regarding fine milk composition analysis, links between milk composition and farming systems, genetic determinism of milk fatty acids and proteins. Those results are based on a large scale data collection covering about 1,500 commercial farms. French dairy cattle, sheep and goat industries have now access to estimation equations for fatty acids and proteins based on mid infra-red spectra (MIR); very precise qualitative and quantitative analyzing method for milk proteins; references and tools to control milk composition by monitoring dairy females and animal feeding; reference populations for genomic selection and knowledge on genetic determinism of milk fatty acids and proteins profiles. Moreover, thanks to PhenoFinlait program, French research and dairy industries get a huge experience on MIR spectral data; large data-base and sample banks (milk and DNA) available for new developments both to go further on fine milk composition, or to investigate new topics (milk production traceability, animal health and reproduction monitoring, enteric methane emission ...). Appropriation and valorization by the different French dairy industries stakeholders is going on, but a lot of work and efforts still has to be done for accompanying field actors in relevant implementation improving competitiveness of their process. Besides, many new research projects come directly from PhenoFinlait program or are partially based on its data, samples and know-how. It is very likely that it will generate new knowledge, references and applications of interest for French researchers, farmers and dairy industries., Le programme PhénoFinlait a permis de nombreux développements en matière d’analyse du lait, de mise en relation des facteurs d’élevage et d’alimentation avec la composition fine du lait, et de déterminisme génétique des acides gras et protéines. Cela a été permis, en particulier, par un suivi de quelques 1500 fermes privées. Les filières laitières françaises, bovines, caprines et ovines, disposent, à l’issu de ce programme d’équations d’estimation en routine à partir des données spectrales MIR de la composition fine du lait en acides gras et protéines ; d’une nouvelle méthode hautement résolutive d’analyse qualitative et quantitative des protéines du lait ; de référentiels sur les liens entre les systèmes d’élevage et d’alimentation et la composition fine du lait, allant jusqu’à un outil de prédiction de sa composition en quelques acides gras d’un mois sur l’autre ; de populations de référence pour l’évaluation génomique et plus généralement d’une connaissance du déterminisme génétique de ces caractères. Au-delà de ces résultats, le programme PhénoFinlait est également à l’origine de méthodologies relatives à l’exploitation des spectres MIR éprouvées ainsi que de bases de données et de banques d’échantillons (lait et ADN) conséquentes, aisément mobilisables pour aller plus loin dans la caractérisation fine du lait ou pour explorer d’autres domaines (traçabilité des modes de production, suivi des animaux - santé, reproduction -, rejets de méthane entérique…). L’appropriation et la valorisation de ces acquis par les différentes filières est en cours, mais elle est encore très partielle car un travail conséquent d’explication et d’analyse cas par cas des modalités de valorisation les plus adaptées est nécessaire. Par ailleurs, plusieurs nouveaux projets sont issus ou s’appuient en partie sur l’investissement initial PhénoFinlait. Gageons que cela génère encore pendant plusieurs années des connaissances, références et outils nouveaux pour la recherche, les éleveurs et les filières françaises.

Aims: To investigate the effects of fermentation parameters on the cell growth and on the resistance to each step of the freeze-drying process of Lactococcus lactis subsp. lactis TOMSC161, a natural cheese isolate, using a response surface methodology. Methods and Results: Cells were cultivated at different temperatures (22, 30 and 38 degrees C) and pH (5.6, 6.2 and 6.8) and were harvested at different growth phases (0, 3 and 6 h of stationary phase). Cultivability and acidification activity losses of Lc. lactis were quantified after freezing, drying, 1 and 3 months of storage at 4 and 25 degrees C. Lactococcus lactis was not damaged by freezing but was sensitive to drying and to ambient temperature storage. Moreover, the fermentation temperature and the harvesting time influenced the drying resistance of Lc. lactis. Conclusions: Lactococcus lactis cells grown in a whey-based medium at 32 degrees C, pH 6.2 and harvested at late stationary phase exhibited both an optimal growth and the highest resistance to freeze-drying and storage. Significance and Impact of the Study: A better insight on the individual and interaction effects of fermentation parameters made it possible the freeze-drying and storage preservation of a sensitive strain of technological interest. Evidence on the particularly damaging effect of the drying step and the high-temperature storage is presented.

This review is respectfully dedicated to the memory of Michel Ollivon, Research Director at CNRS (Châtenay-Malabry, France), outstanding physico-chemist specialist of lipid organization, recipient of the Hilditch Memorial Lecture award, who was the initiator of the network RMT LISTRAL. We are also sadly paying tribute to Jean-Luc Vendeuvre, Food Engineer at the French Pork and Pig Institute (IFIP, Maisons-Alfort, France), outstanding expert in meat products who participated actively in RMT LISTRAL and provided unpublished data for figures in the present review, who passed away during review submission. RMT LISTRAL: Mixed Technological Network combining academic and industrial partners, devoted to the enhancement and divulgation of knowledge regarding structured dietary lipids.; International audience; On a nutritional standpoint, lipids are now being studied beyond their energy content and fatty acid (FA) profiles. Dietary FA are building blocks of a huge diversity of more complex molecules such as triacylglycerols (TAG) and phospholipids (PL), themselves organised in supramolecular structures presenting different thermal behaviours. They are generally embedded in complex food matrixes. Recent reports have revealed that molecular and supramolecular structures of lipids and their liquid or solid state at the body temperature influence both the digestibility and metabolism of dietary FA. The aim of the present review is to highlight recent knowledge on the impact on FA digestion, absorption and metabolism of: (i) the intramolecular structure of TAG; (ii) the nature of the lipid molecules carrying FA; (iii) the supramolecular organization and physical state of lipids in native and formulated food products and (iv) the food matrix. Further work should be accomplished now to obtain a more reliable body of evidence and integrate these data in future dietary recommendations. Additionally, innovative lipid formulations in which the health beneficial effects of either native or recomposed structures of lipids will be taken into account can be foreseen.

We read with great interest the recent study by Dewulf and coworkers1 reporting encouraging results on a prebiotic-based dietary intervention trial in obese patients. This work enlightens that even subtle changes in the gut microbiota may influence the metabolomic signature both inside and outside the gut. Interplay among diet, immunity and microbial and host metabolism results in a complex multidirectional signalling that is critical in the maintenance of a healthy gut functionality, reducing risks for inflammatory bowel diseases and metabo-inflammation states associated with obesity.2 ,3 In parallel, the ‘omics’ era has produced many observations associated with disease states,4 and the correlation among the presence, absence or specific ratios of certain bacterial phyla, orders or genera can be considered as a strategy to directly or indirectly manipulate the microbiome. However, a clear causal molecular link between a specific microbial community and a specific metabolic or immune profile is …

Cette étude présente les principaux résultats d’estimation de paramètres génétiques et de détection de QTL obtenus dans le cadre du projet PhenoFinlaitsur les caractères de composition en acides gras (AG) du lait dans les trois races bovines Holstein, Montbéliarde et Normande. Les paramètres génétiques sont estimés à partir de 101 858 contrôles élémentaires de 21 947 vaches en première lactation. Chaque contrôle est caractérisé par son profil en AG, estimé par spectrométrie moyen infra rouge. Les paramètres génétiques dépendent beaucoup du mode d’expression des caractères : acides gras exprimés en proportion du lait ou de la matière grasse. Exprimés en teneur dans le lait, les AG saturés (SAT) présentent une héritabilité plus élevée que les insaturés (INSAT) mais l’écart est plus faible quand ils sont exprimés en pourcentage d’AG totaux. Les mesures d’AG sont fortement corrélées entre stades de lactation, à l’exception du premier mois qui apparait comme un caractère assez différent. Les corrélations génétiques sont positives entre SAT, positives entre INSAT. Entre SAT et INSAT, le signe des corrélations diffère selon le mode d’expression. Les SAT sont très fortement corrélés au taux butyreux du lait. 7500 vaches ont été génotypées avec la puce SNP Bovine 50k Beadchip et 500 autres ont été imputées depuis un génotypage sur la puce SNP bovine 7k, permettant une recherche de QTL par LDLA (analyse combinant liaison intra famille et déséquilibre de liaison). Au total, sur 31 caractères, 544 QTL ont été détectés dans l’ensemble des trois races, soit environ 9 par caractère et par race. Les QTL les plus importants ont été trouvés sur les chromosomes 14 (gène DGAT1), 26 (gène SCD), 13, 16, 17, 19 et 27. Les QTL les plus significatifs sont observés sur le chromosome 5 dans les 3 races, une région non décrite jusqu’à présent. On observe une forte colocalisation de QTL entre caractères, en particulier entre acides gras du même type, reflétant leur origine métabolique commune. Une fraction notable, au moins un tiers, de ces QTL semble partagée entre races. Ces résultats favorables ouvrent la voie à la prise en compte du profil en AG en sélection mais aussi à la recherche des mutations responsables de ces variations., This study presents the main genetic results obtained in the PhenoFinlait projects with regards to genetic parameters and QTL detection for milk composition in fatty acids (FA) in the French Montbeliarde (MO), Normande (NO) and Holstein (HO) cattle breeds. Genetic parameters were estimated from 101,858 test-day records from 21,947 cows in first lactation. Each test-day was characterized by its profile in FA in milk, as estimated from Mid-Infrared spectrometry. Genetic parameters were found to be very sensitive to the mode of expression of the traits, in % of milk or in % of fat. Expressed in % of milk, test-day saturated FA (SAT) had higher heritability estimates than unsaturated FA (UNSAT) but this difference was smaller when the traits were in % of fat. FA measurements were highly genetically correlated across different stages of lactation except in the beginning of lactation. Genetic correlations between FA in milk were positive across SAT, and also positive across UNSAT. Between SAT and UNSAT, their sign changed according to the mode of expression. SAT were strongly and positively correlated to fat content in milk. Seven-thousand five-hundred cows were genotyped with the Bovine 50k Beadchip and 500 other cow genotypes were imputed from their Bovine LD Beadchip (7k). A QTL detection analysis was carried out by Linkage and Linkage Disequilibrium Analysis (LDLA). For 31 traits, 544 QTL were detected in the three breeds, corresponding to an average of 9 per trait and breed. The most important QTL were found on chromosomes 14 (DGAT1 gene), 26 (SCD gene), 13, 16, 17,19 and 27. The most significant QTL were found on chromosome 5, a region not yet described until now. QTL often colocalized across traits, especially for fatty acids of the same type, reflecting their common metabolic origin. A relatively high fraction of the QTL, more than one third, was found to be shared across breeds. These results pave the way for including FA in selection and also for the discovery of the underlying causative mutations.