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During red winemaking, diffusion of phenolic compounds from the grape berry cells into the liquid phase occurs simultaneously with the adsorption of the same compounds onto the pulp. In previous studies, we quantified the proportions of polyphenols diffusing from the skins and then assessed the amounts that can be fixed by the pulp. In this work, we added the impact of seeds, also present during vinification, by carrying out macerations in a model medium with the following berry compartments: skins, seeds, skins + seeds, skins + seeds + pulp.Interestingly, the seeds alone released a rather high amount of polyphenols. As soon as they were in the presence of cell walls of skin/flesh, and/or anthocyanins, the concentration of seed tannins in the solution dropped dramatically, due to a combined effect of adsorption and/or precipitation and/or chemical reactions. The pulp certainly adsorbed tannins, but they also tended to shift the extraction equilibria, and it seems that more tannins could be extracted from skins and seeds when pulp was present. Polyphenol amounts extracted in model systems with skins + seeds + pulp were close to what was extracted in microvinification.These model experiments reflect relatively well extraction during microvinification experiments and highlight the respective impact of the grape berry's different compartments in the wine's final phenolic composition as well as some of the mechanisms involved. © 2022 Society of Chemical Industry.

BACKGROUND During winemaking, after extraction from the skins, anthocyanins and tannins adsorb onto the pulp flesh cell walls. This study aims to quantify the amounts adsorbed and their impact on wine composition, the impact of variety and ethanol on adsorption, and whether the presence of anthocyanins plays a role and impacts tannin adsorption. RESULTS Anthocyanin and tannin fractions obtained by mimicking winemaking conditions were mixed with fresh flesh cell walls of two varieties: Carignan and Grenache. Adsorption isotherms were measured. Adsorption of tannins was higher with Carignan than with Grenache and decreased when the ethanol content increased. In comparison, anthocyanins were adsorbed in small amounts, and their mixing with tannins had no impact on their adsorption. The differences were related to differences in pulp cell wall composition, particularly in terms of extensins and arabinans. CONCLUSION Adsorption of tannins, which can reach 50% of the initial amount, depends on the pulp cell wall composition. This needs to be further investigated. This article is protected by copyright. All rights reserved.

Concentrations of anthocyanins and tannins after extraction from berries in wines and from skin macerations in model solutions have been studied for two grape varieties, two maturation levels and two vintages berries. Characterization of the cell wall polysaccharides has also been performed, the classical method based on the analysis of the neutral sugars after depolymerization being completed by a comprehensive microarray polymer profiling (CoMPP). Extraction was lower in model solutions than in wines, with the same ranking: non acylated anthocyanins> tannins > p-coumaroylated anthocyanins. The polysaccharidic composition suggested a role of homogalacturonans, rhamnogalacturonans and extensins in the extraction process. A global explanation of the interactions between anthocyanins, tannins and polysaccharides is proposed.

International audience; Phenolic compounds (anthocyanins, tannins), mainly present in the skin of the grape berry, play a decisive role in the sensory properties of red wine. They are partly extracted during the maceration step of the winemaking process and can undergo different structural changes., Their extraction is mostly related to their initial contents in skins, medium conditions and to their interactions with cell wall material, which modulate their diffusion. The aim of this work was to characterize the impact of grape variety, berry size and density on the extraction of skin polyphenols at maturity harvest, and to identify the main factors involved.Thus, grape heterogeneity was studied at technological maturity, for two contrasted varieties in terms of phenolic compositions (Grenache, Carignan). The berries were sorted according to their size (vol-, vol+) and then density (deg-, deg+). The grape skins were analyzed (polyphenol constituents, alcohol insoluble solids (AISs) polysaccharides and proteins). Wine-like maceration experiments were performed on fresh skins in model systems at constant parameters (22°C, under argon, without yeast), by increasing the percentage of ethanol from 0 to 15%. After the diffusion experiment, precipitates were recovered and skins were then successively washed with new 0 and 15% wine like solvents until total phenolic extraction. The Polyphenol concentration was determined by spectrophotometry and chromatography. Skin AISs differed between the two varieties by their carbohydrate composition and protein content. Fresh skins had similar contents in polymeric tannins, but strongly differed by their anthocyanin contents (higher in Carignan and in the ripest berries) and composition (higher proportions in coumaroylated anthocyanins in Carignan). During maceration, anthocyanin extraction differed between the two varieties and with the berry density, whereas berry size had no impact. The initial quantities of polyphenols in grape skins was not sufficient to predict their concentrations in wine. Both a selective precipitation of coumaroylated anthocyanins and chemical changes strongly modulated anthocyanin concentrations. Neither anthocyanin contents nor the AIS compositions had a decisive impact on tannin extraction. The analysis of residual polyphenols in skins evidenced a deficit in the mass balance due to different evolution mechanisms of anthocyanins and tannins. Further analyses are necessary to evaluate the composition of wines based on the composition of the skin and the pulp, which is a strong demand from the vine-wine sector, especially in the context of varietal selection in response to climate change.

International audience; Vitamin E membrane transport has been shown to involve the cholesterol transporters SR-BI, ABCA1 and NPC1L1. Our aim was to investigate the possible participation of another cholesterol transporter in cellular vitamin E efflux: ABCG1. In Abcg1-deficient mice, vitamin E concentration was reduced in plasma lipoproteins whereas most tissues displayed a higher vitamin E content compared to wild-type mice. alpha- and gamma-tocopherol efflux was increased in CHO cells overexpressing human ABCG1 compared to control cells. Conversely, alpha- and gamma-tocopherol efflux was decreased in ABCG1-knockdown human cells (Hep3B hepatocytes and THP-1 macrophages). Interestingly, alpha- and gamma-tocopherol significantly downregulated ABCG1 and ABCA1 expression levels in Hep3B and THP-1, an effect confirmed in vivo in rats given vitamin E for 5 days. This was likely due to reduced LXR activation by oxysterols, as Hep3B cells and rat liver treated with vitamin E displayed a significantly reduced content in oxysterols compared to their respective controls. Overall, the present study reveals for the first time that ABCG1 is involved in cellular vitamin E efflux. (C) 2014 Elsevier B.V. All rights reserved.

International audience; Scope: A single nucleotide polymorphism in the cluster determinant 36 (CD36) gene has recently been associated with plasma alpha-tocopherol concentration, suggesting a possible role of this protein in vitamin E intestinal absorption or tissue uptake. Methods and results: To investigate the involvement of CD36 in vitamin E transport, we first evaluated the effect of CD36 on alpha- and gamma-tocopherol transmembrane uptake and efflux using transfected HEK cells. gamma-Tocopherol postprandial response was then assessed in CD36-deficient mice compared with wild-type mice, after the mice had been fully characterized for their alpha -tocopherol, vitamin A and lipid plasma, and tissue contents. Both alpha- and gamma-tocopherol uptake was significantly increased in cells overexpressing CD36 compared with control cells. Compared with wild-typemice, CD36-deficient mice displayed a significantly decreased cholesterol hepatic concentration, and males exhibited significantly higher triacylglycerol contents in liver, brain, heart, and muscle. Although tissue alpha -tocopherol concentration after adjustment for lipid content was not modified, gamma-tocopherol postprandial response was significantly increased in CD36-deficient mice compared with controls, likely reflecting the postprandial hypertriglyceridemia observed in these mice. Conclusion: Our findings show for the first time that CD36 participates-directly or indirectly-in vitamin E uptake, and that CD36 effect on postprandial lipid metabolism in turn modifies vitamin E postprandial response.

International audience; Polymerization-induced self-assembly (PISA) is an efficient approach to synthesize self-assembled core–shell nanofibers in water, made of amphiphilic block copolymers. We demonstrate here for the first time that such anisotropic and high Tg nanofibers can be used as reinforcing fillers for water-based acrylic materials. This strategy opens the way for strong all-organic aqueous coatings.

Some applications coming from a new method to concentrate proteins. Macrowine 2016

Knowledge of porcine astrovirus diversity and epidemiology remains limited. We used a broad range PCR approach to investigate the presence and diversity of astroviruses in healthy pigs of different ages on 20 farms and in 3 slaughterhouses situated in the province of Quebec, Canada between 2005 and 2007. Our study unexpectedly revealed remarkable levels of genetic diversity and high prevalence of astroviruses in pigs of this province. Astroviruses were detected on every farm investigated and in all age groups of pigs, from suckling piglets to adults. In addition, we found that nearly 80% of healthy finisher pigs harbour astroviruses in their intestine at slaughter. Phylogenetic evidence based on partial polymerase and complete capsid sequences, suggests that porcine astroviruses do not form a monophyletic group but are rather found on separate branches across the mamastrovirus tree. In addition to type species strains, we found highly divergent strains that form two additional lineages, one of which falls outside existing taxonomic groups. The presence of diverse astroviruses in a majority of healthy pigs likely represents a continuous source of infection to piglets and possibly to other animal species including humans. Porcine astrovirus strains appeared phylogenetically related not only to prototypical human astroviruses, as was already known, but also to novel human strains recently discovered suggesting multiple cross species transmission events between these hosts and other animal species. Overall, the findings reported in this study suggest an active role of pigs in the evolution and ecology of the Astroviridae.

International audience; The interactions occurring at the intestinal level between the fat-soluble vitamins A, D, E and K (FSVs) are poorly documented. We first determined each FSV absorption profile along the duodenal-colonic axis of mouse intestine to clarify their respective absorption sites. We then investigated the interactions between FSVs during their uptake by Caco-2 cells. Our data show that vitamin A was mostly absorbed in the mouse proximal intestine, while vitamin D was absorbed in the median intestine, and vitamin E and K in the distal intestine. Significant competitive interactions for uptake were then elucidated among vitamin D, E and K, supporting the hypothesis of common absorption pathways. Vitamin A also significantly decreased the uptake of the other FSVs but, conversely, its uptake was not impaired by vitamins D and K and even promoted by vitamin E. These results should be taken into account, especially for supplement formulation, to optimise FSV absorption.

Inactivated yeast fractions (IYFs) can be used in enology to improve the stability and mouthfeel of red wines. However, information concerning the mechanisms involved and the impact of the IYF characteristics is scarce. Adsorption isotherms were used to investigate interactions between grape proanthocyanidin fractions (PAs) or wine polyphenols (WP) and a commercial yeast strain (Y), the inactivated yeast (IY), the yeast submitted to autolyzis and inactivation (A-IY), and the cell walls obtained by mechanical disruption (CW). High affinity isotherms and high adsorption capacities were observed for grape PAs and whole cells (Y, IY, and A-IY). Affinity and adsorbed amount were lower with wine PAs, due to chemical changes occurring during winemaking. By contrast to whole cells, grape PAs and WP adsorption on CW remained very low. This raises the issue of the part played by cell walls in the interactions between yeast and proanthocyanidins and suggests the passage of the latter through the wall pores and their interaction with the plasma membrane.

Interactions of grape proanthocyanidins and wine polyphenols with yeast extract. Macrowine 2014

International audience; Food fortification is a strategy to overcome vitamin A deficiency in developing countries. Our aim was to investigate the involvement of the bovine milk protein beta-lactoglobulin (beta-Lg), a potential retinoid carrier, in vitamin A absorption. In vivo experiments were conducted by force-feeding mice with retinol or beta-carotene associated with either beta-Lg or oil-in-water emulsion, with subsequent determination of both vitamin A intestinal mucosa and plasma contents. Caco-2 cells were then used to investigate the mechanisms of vitamin A uptake when delivered by either beta-Lg or mixed micelles. We showed that beta-Lg was as efficient as emulsion to promote beta-carotene, but not retinol, absorption in mice. Similar results were obtained in vitro. Interestingly, an inhibitor of the Scavenger Receptor Class B Type I significantly decreased the uptake of micellar beta-carotene but not that of beta-carotene bound to beta-Lg. Overall, we showed that beta-Lg would be a good vector for beta-carotene food fortification.

International audience; Vitamin K-1 (phylloquinone) intestinal absorption is thought to be mediated by a carrier protein that still remains to be identified. Apical transport of vitamin K-1 was examined using Caco-2 TC-7 cell monolayers as a model of human intestinal epithelium and in transfected HEK cells. Phylloquinone uptake was then measured ex vivo using mouse intestinal explants. Finally, vitamin K-1 absorption was compared between wild-type mice and mice overexpressing scavenger receptor class B type I (SR-BI) in the intestine and mice deficient in cluster determinant 36 (CD36). Phylloquinone uptake by Caco-2 cells was saturable and was significantly impaired by co-incubation with alpha-tocopherol (and vice versa). Anti-human SR-BI antibodies and BLT1 (a chemical inhibitor of lipid transport via SR-BI) blocked up to 85% of vitamin K-1 uptake. BLT1 also decreased phylloquinone apical efflux by similar to 80%. Transfection of HEK cells with SR-BI and CD36 significantly enhanced vitamin K-1 uptake, which was subsequently decreased by the addition of BLT1 or sulfo-N-succinimidyl oleate (CD36 inhibitor), respectively. Similar results were obtained in mouse intestinal explants. In vivo, the phylloquinone postprandial response was significantly higher, and the proximal intestine mucosa phylloquinone content 4 h after gavage was increased in mice overexpressing SR-BI compared with controls. Phylloquinone postprandial response was also significantly increased in CD36-deficient mice compared with wild-type mice, but their vitamin K-1 intestinal content remained unchanged. Overall, the present data demonstrate for the first time that intestinal scavenger receptors participate in the absorption of dietary phylloquinone.

International audience; We have recently shown that vitamin D-3 (cholecalciferol) absorption is not a simple passive diffusion but involves cholesterol transporters. As free fatty acids (FAs) modulate cholesterol intestinal absorption and metabolism, we hypothesized that FAs may also interact with vitamin D absorption. Effects of FAs were evaluated at different levels of cholecalciferol intestinal absorption. First, the physicochemical properties of micelles formed with different FAs were analyzed. The micelles were then administered to human Caco-2 cells in culture to evaluate FA effects on (i) cholecalciferol uptake and basolateral efflux and (ii) the regulation of genes coding proteins involved in lipid absorption process. Micellar electric charge was correlated with both FA chain length and degree of unsaturation. Long-chain FAs at 500 mu M in mixed micelles decreased cholecalciferol uptake in Caco-2 cells. This decrease was annihilated as soon as the long-chain FAs were mixed with other FAs. Oleic acid significantly improved cholecalciferol basolateral efflux compared to other FAs. These results were partly explained by a modulation of genes coding for lipid transport proteins such as Niemann-pick C1-like 1 and scavenger receptor class B type I. The data reported here show for the first time that FAs can interact with cholecalciferol intestinal absorption at different key steps of the absorption process. Cholecalciferol intestinal absorption may thus be optimized according to oil FA composition. (c) 2013 Elsevier Inc. All rights reserved.