A randomised cross-over trial in healthy adults indicating improved absorption of omega-3 fatty acids by pre-emulsification

BACKGROUND: The health benefits of increased intakes of omega-3 fatty acids are well established but palatability often presents a problem. The process of emulsification is used in the food industry to provide a wider spectrum of use, often with the result of increased consumption. Moreover, as emulsification is an important step in the digestion and absorption of fats, the pre-emulsification process may enhance digestion and absorption. In this study the levels of plasma fatty acid and triacylglycerol (TAG) following the ingestion of either an oil mixture or an emulsified oil mixture have been compared. METHODS: In this randomised cross-over study, 13 volunteers received the oil mixture and 11 received the oil emulsion as part of an otherwise fat free meal. Blood samples were collected at 0, 1.5, 3, 4.5, 6, 7.5 and 9 hours after ingestion of oil, separated and stored at -20°C. Plasma triacylglycerols were assessed spectrophotometrically and fatty acids were determined by gas chromatography. Following a washout period of twenty days the procedure was repeated with the assignments reversed. RESULTS: The postprandial plasma TAG and the C18:3 (n-6), C18:3(n-3), C20:5(n-3) and C22:6 (n-3) polyunsaturated fatty acid (PUFA) levels for the emulsified oil group were increased significantly (P = 0.0182; P = 0.0493; P = 0.0137; P < 0.0001; P = 0.0355 respectively) compared with the non-emulsified oil group. The C16:0 and C18:0 saturated fatty acids, the C18:1 (n-9) monounsaturated fatty acid and the C18:2 PUFA were not significantly different for the oil and emulsified oil groups. CONCLUSION: Pre-emulsification of an oil mixture prior to ingestion increases the absorption of longer chain more highly unsaturated fatty acids (especially eicosapentaenoic acid and docosahexaenoic acid) but does not affect absorption of shorter chain less saturated fatty acids, suggesting that pre-emulsification of fish oils may be a useful means of boosting absorption of these beneficial fatty acids. Trial registration: Current Controlled Trials ISRCTN4320260

Wheat Bran Pretreatment by Room Temperature Ionic Liquid-Water Mixture: Optimization of Process Conditions by PLS-Surface Response Design

International audienceRoom Temperature Ionic Liquids (RTILs) pretreatment are well-recognized to improve the enzymatic production of platform molecules such as sugar monomers from lignocellulosic biomass (LCB). The conditions for implementing this key step requires henceforth optimization to reach a satisfactory compromise between energy saving, required RTIL amount and hydrolysis yields. Wheat bran (WB) and destarched wheat bran (DWB), which constitute relevant sugar-rich feedstocks were selected for this present study. Pretreatments of these two distinct biomasses with various 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc])-water mixtures prior to hydrolysis catalyzed by hemicellulolytic cocktail (Cellic CTec2) were finely investigated. The main operating conditions such as pretreatment temperature (25–150°C), time (40–180 min), WB and DWB loading (2–5% w/v) and concentration of [C2mim][OAc] in water [10–100% (v/v)] were screened through glucose and xylose yields and then optimized through a Partial Least Square (PLS)—Second Order Design. In an innovative way, the PLS results showed that the four factors and their interactions could be well-fitted by a second-order model (p < 0.05). The quadratic PLS models were used to predict optimal pretreatment conditions. Thus, maximum glucose (83%) and xylose (95%) yields were obtained from enzymatic hydrolysis of WB pretreated at 150°C for 40 min with 10% of [C2mim][OAc] in water and 5% of WB loading. For DWB, maximum glucose (100%) and xylose (57%) yields were achieved for pretreatment temperatures of 150°C and 25°C, respectively. The required duration was still 40 min, with 20% of [C2mim][OAc] in water and a 5% DWB loading. Then, Multiple Response Optimization (MRO) performed by Nelder-Mead Simplex Method displayed sugar yields similar to those obtained by individual PLS optimization. This complete statistical study confirmed that the established models were appropriate to predict the sugar yields achieved after different pretreatment conditions from WB and DWB biomasses. Finally, Scanning Electron microscopy (SEM) studies allowed us to establish clearer link between structural changes induced by pretreatment and the best enzymatic performances obtained

Le numérique éducatif à l'école élémentaire en tension entre politiques nationales, politiques locales et logiques d'appropriation par les enseignants

International audienceCet article rend compte d'un travail de recherche réalisé par le laboratoire Techné de l'université de Poitiers portant sur le numérique éducatif à l'école élémentaire en France métropolitaine. Il découle d'une étude menée entre 2018 et 2019 et dont les principaux résultats ont été transmis à la Cour des comptes dans le cadre d'une contribution à ses travaux sur le sujet. Après une présentation des principaux résultats de l'étude centrale dans la première partie de l'article, les deux parties suivantes proposent d'aborder deux prolongements spécifiques identifiés : les liens entre équipements numériques disponibles et usages des enseignants et la confrontation entre politiques publiques et discours de terrain

Avulsions en parodontologie ? (critères de décision)

CLERMONT FD-BCIU Odontol. (631132226) / SudocCLERMONT FD-BCIU-Santé (631132104) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Etude des relations entre structures et propriétés de films d'arabinoxylanes isolés de co-produits agricoles

Plus de 40% des matériaux plastiques sont utilisés pour l emballage. Les principaux polymères sur le marché de l emballage alimentaire sont les polymères synthétiques d origine fossile. Du fait de la raréfaction des ressources fossiles, la valorisation des polymères issus de matières premières renouvelables d origine végétale représente une alternative à l utilisation des polymères pétro-sourcés. Les hémicelluloses, avec la cellulose et les lignines, sont un composant majeur des ressources lignocellulosiques. Les hémicelluloses constituent des réseaux macromoléculaires denses et peu mobiles qui leur confèrent intrinsèquement d excellentes propriétés barrières aux gaz. L objectif de cette thèse est d isoler les arabinoxylanes (AX) à partir de divers co-produits de céréales (son de blé, paille de blé, rafles de maïs) afin d étudier l impact de leurs compositions et de leurs structures sur certaines de leurs propriétés physico-chimiques, après mise en oeuvre sous forme de films pour des applications potentielles dans le domaine de l emballage alimentaire.Les arabinoxylanes ont été extraits par un procédé alcalin puis séparés en trois fractions en fonction de leur solubilité dans l eau et dans l éthanol 50% (v/v). Les trois fractions récupérées (i/ insoluble dans l eau, ii/soluble dans l eau et insoluble dans l éthanol, iii/soluble dans l eau et soluble dans l éthanol) présentent un rapport Ara/Xyl croissant avec leur solubilité dans l eau et dans l éthanol. Dans le cas du son de blé, les trois fractions présentent des masses moléculaires similaires mais se distinguent par différents degrés de substitution et divers types de substitutions de la chaîne principale de xylanes. L étude des propriétés physico-chimiques de films formés par ces trois fractions ont permis d établir une corrélation entre le degré de substitution et leurs propriétés sous forme de films. La morphologie cristalline, la mobilité des chaînes etl hydratation des films de xylanes sont corrélés avec les taux de substitution des AX. Lorsque le taux d Ara/Xyl diminue, le film est plus cristallin, la mobilité locale augmente alors que la mobilité globale diminue, la teneur en eau diminue à haute humidité relative (de 67% à 60% à 90%HR), la perméabilité et la diffusivité à l oxygène diminue. L étude des trois fractions insolubles dans l eau isolée à partir de son de blé,de paille de blé et de rafles de maïs a révélé que les propriétés des films sont également affectées par la longueur des chaînes de xylanes et par leur conformation moléculaire ainsi que par la teneur des substituants tels que les acides uroniques. Des nanocharges (nanocristaux de cellulose de linters de coton) sont utilisées(5 ou 10% p/p) pour renforcer les films formés par les fractions d AX de son de blé. L incorporation des nanocristaux au sein des films n a pas provoqué de modification du degré de cristallinité. Par contre, la teneur en eau à haute humidité relative est diminuée. La mobilité locale des chaînes d AX est réduite indiquant l existence d interactions entre les nanocristaux et les AX alors que la mobilité globale des chaînes n est pas modifiée. L effet du renforcement semble être plus intense pour la fraction AX la plus substituée par les groupements arabinosyl.There are more than 40% of plastics used for packaging. The main polymers in the food packaging market are synthetic polymers from fossil resource. Due to limited fossil resources on our planet, the development of renewable raw materials derived from plant is required to have an alternative to synthesized polymers from petroleum sources. Hemicelluloses, with cellulose and lignin, are a majorc omponent of lignocellulosic resources which display dense and low-mobility macromolecular networks making them have excellent gas barrier properties. The aim of this thesis is to isolate arabinoxylans (AX)from the various cereals co-products such as wheat bran, wheat straw and corn cob, in order to study the impact of their compositions and structures on several physicochemical properties of AX based films for potential food packaging application. The alkaline solution is used to extract arabinoxylans, and a step of fractionation is used to separate the different populations AX according to their solubility in water and in ethanol 50% (v/v). Three fractions were finally obtained (i) water insoluble, ii) water soluble-ethanol insoluble and iii) water ethanol soluble) displaying the increasing ratios Ara/Xyl with increasing solubility in water and in ethanol. The three fractions of wheat bran have similar molar masses, different substitution degrees and patterns. The results about the films physicochemical properties based on theset hree fractions could be established a relationship between the substitution degree and their films properties. The film morphology, the chain mobility, the water sorption behavior at high relative humidity and the coefficient permeability and diffusivity of oxygen could be correlated with the degree of substitution. When the Ara/Xyl ratio decreases, the film is more crystalline, the local chain mobilityincreases whereas the global chain mobility decreases, water content at high relative humidity decreases and the oxygen permeability and diffusivity decreases. The AX has different substitution patterns and molar masses according to their botanical origins. The study of three water-insoluble fractions isolated from three cereal co-products reveals that the film properties could be also affected by chain length, theamounts of other substituents such as uronic acids and their molecular conformations. The nanofillers(cellulose nanocrystals of cotton linters) are used in order to enhance the films properties based on threeAX fractions of wheat bran (5 or 10% w/w). The incorporation of nanocrystals in the films does not change in the crystalinity degree; whereas the water content at high relative humidity is decreased; the local chain mobility of AX is reduced indicating the existence of interactions between the nanocrystals and AX while the global chain mobility is almost unchanged. The reinforcement effect seems to be more intense for the most substituted AX by arabinosyl groups.REIMS-SCD-Bib. electronique (514549901) / SudocSudocFranceF

Définition des critères d'efficacité d'une hémicellulase pour l'hydrolyse de substrats lignocellulosiques complexes et insolubles

REIMS-BU Sciences (514542101) / SudocSudocFranceF

Synthesis and desaturation of cis9, trans11 CLA in adipose tissue of Charolais steers and cull cows

National audienc

Les tissus adipeux, notamment intermusculaires, sont le siège de la synthèse et de la bioconversion du 9CIS,11TRANS CLA chez le bouvillon

National audienc

Un nouvel aliment protéique possédant une forte digestibilité

National audienc

9cis, 11trans conjugated linoleic acid (CLA) is synthesised and desaturated into conjugated 18 : 3 in bovine adipose tissues

International audienceAlthough endogenous synthesis of conjugated linoleic acid (CLA) in the mammary gland of lactating cows has been already well documented, no study has determined so far as to which tissue and/or organ is involved in CLA synthesis in the growing ruminant except one study showing that CLA synthesis does not occur in ruminant liver. In this context, adipose tissue appears to be a good candidate for endogenous synthesis of CLA in the growing ruminant. The aim of this study was to compare the respective metabolisms of 11trans 18:1 (vaccenic acid, VA) and 9cis,11trans 18:2 (rumenic acid) to that of stearic acid (the preferential substrate of Δ9 desaturase) in adipose tissues (subcutaneous, SC and intermuscular, IM) of six Charolais steers by using the in vitromethod of incubated tissue slices. Samples of SC and IM adipose tissues were incubated at 37°C for 16 h under an atmosphere of 95% O2/5% CO2 in a medium supplemented with 0.75 mM of fatty acid (FA) mixture (representative of circulating non-esterified FA) and 186 μM [1-14C]-18:0 or 58.6 μM [1-14C]-VA or 56 μM [1-14C]-9cis,11trans CLA. Viability of explants was verified by measuring metabolic functions (glucose uptake and glucose-6-phosphate dehydrogenase activity). After 16 h of incubation, FA uptake was similar for all FA (18:0, VA and 9cis,11trans 18:2) in both SC and IM adipose tissues (around 40%). Once in adipose tissue, all FA were preferentially esterified (>80% of cell FA) favouring neutral lipid synthesis (around 90% of esterified FA). Stearic acid was highly (27%) desaturated into oleic acid in SC adipose tissue whereas this desaturation was much lower (6.8%) in IM adipose tissue (P < 0.0001). VA was desaturated into 9cis,11trans CLA at a low extent of about 2.5% to 4.4% in both adipose tissues probably because of a limited affinity of Δ9 desaturase for VA. 9cis,11trans CLA was itself converted by desaturation into 6cis, 9cis,11trans 18:3 at the intensity of 10.8% and 14.5% of cell 9cis,11trans CLA in SC and IM adipose tissues, respectively. In conclusion, bovine adipose tissues of the growing ruminant were especially involved in the endogenous synthesis of CLA from VA and in its desaturation into conjugated derivative, mainly 6cis, 9cis,11trans 18:3, of which biological properties need to be elucidated