est destinée au dépôt

  Oxidative fate of emulsified Lipids during in vitro digestion of model emulsions depends on the composition of the medium and digestive characteristics of the emulsion Hernan Kenmogne Domguia, Anne Meynier, Claude Genot To cite this version: Hernan Kenmogne Domguia, Anne Meynier, Claude Genot. Oxidative fate of emulsified Lipids during in vitro digestion of model emulsions depends on the composition of the medium and digestive characteristics of the emulsion. 12. Eurofed Lipid Congress, Sep 2014, Montpellier, France. , 2014. hal-02795666 Oxidative Fate of Emulsified Lipids during in vitro Digestion of Model Emulsions depends on the Composition of the Medium and Digestive Characteristics of the Emulsion H.B. Kenmogne-Domguia, A. Meynier, C. Genot INRA, UR1268 Biopolymères Interactions Assemblages, BP 71627 Nantes, France hernan.kenmogne-domguia@nantes.inra.fr The characteristics of emulsified lipids (lipid composition, droplet size, emulsifiers nature, pH) can modulate their oxidation. Recently, issues related to the impact on the health of the consumption of lipid oxidation products have been raised and are subject to debate. Data related to oxidative fate of lipid during digestion are limited. However, some data highlight the potential pro-oxidant effect of the gastric environment and show that primary and secondary (aldehydes) products of lipid oxidation can be absorbed into the intestine. The aim of this work was to study the relative impact of the composition of digestive media and the characteristics of the emulsion on lipid oxidation in simulated gastrointestinal conditions. Emulsions stabilized by a protein or surfactants, with different compositions in polyunsaturated fatty acids (PUFA) and with well characterized droplets size, have been submitted to in vitro simulated gastrointestinal digestive conditions, with or without metmyoglobin. Lipid oxidation was followed by the consumption of oxygen and tocopherols, and by the formation of primary (hydroperoxides) and secondary (MDA, 4-hydroxy-nonenal, 4-hydroxy-hexenal) products. The results show that the physicochemical conditions of the digestive tract promote lipid oxidation in the presence of metmyoglobin. When emulsion is stabilized with the protein (1 µm), no effect of digestive juices is observed on the oxidation. When stabilized by surfactants (200 nm), the pancreatico-biliary juices have a protective effect on oxidation. For this emulsion, tocopherols are almost completely consumed in the first minutes of the intestinal phase in which an increased formation of MDA, 4-HNE and 4-HHE is observed. At the end of the intestinal phase, the amounts of these products are about fifty times lower when PUFA is ALA rather than EPA and DHA. At the end of the digestion of emulsions containing long chain FA, the quantities of oxidation products are identical and could induce toxic effects. The in vitro oxidation data were compared with results obtained in vivo in the gut contents and plasma of mice fed with the proteinstabilized emulsion containing long chain PUFA.


Alejandra Morán-Ordóñez
email: alejandra.moran@ctfc.essciencesconf.org

Kaori Otsu

Lluis Coll

Francois Lefèvre

Llui´s Brotons

Lluís Coll

François Lefevre

Lluís Brotons

Scenario-based modelling for management of Mediterranean forests

Keywords: Integrated Assessment Models, Mediterranean Forests, Modelling biodiversity and ecosystem services, Scenarios

come

Recherche Agronomique -INRA (FRANCE) -France

Abstract

The number of studies aimed at understanding the complexity of ecological patterns and processes and their interaction with human societies has dramatically increased in the last two decades, but especially since the publication of the Millennium Ecosystem Assessment reports in 2003 and 2005. Integrative models and scenarios are key tools to disentangle this complexity, forecast the ecological consequences of current and future states of societal development and support well-informed decision making. But, what's the state of the art in the development and application of these tools? We are conducting a review of the methods and scenarios in use for evaluating the future of biodiversity and ecosystem services provision in the context of forest systems across the Mediterranean basin. The review is framed within the international ERA-net Foresterra INFORMED project (INtegrated research on FOrest Resilience and Management in the MEDiterranean) that seeks to foster forest system resilience through biodiversity management (from genes to communities). Mediterranean forests represent a good example of biodiversity-rich and complex ecological systems, with a long history of human perturbations and management and currently threatened by ongoing global change. With our review, we aim to know which types of models are more widely used (correlative vs process-based) and how widespread is the implementation of integrated modelling approaches -those accounting for feedbacks across sectors (e.g. agriculture and forestry) and spatial scales within a single modelling framework. We also evaluate the prevalence of the use of multi-driver scenarios -those accounting for the simultaneous impacts of multiple direct and indirect drivers (e.g. climatic, land use, management) -and single-driver scenarios in literature. The overall goal is to understand the state of the art in how indicators of the state of Mediterranean forests are being developed/modelled, and to identify priority areas for future research.

Preliminary results show that the number of studies that focus on a single biodiversity or ecosystem service indicator, use a single model or scenarios based on a single-driver outnumber the more integrative studies. Our study will directly inform the currently-in-progress