CONTEXT

Polyphenols and carotenoids are abundant in fruit, vegetables and their derived products. They play important roles in the sensorial properties of foods, in particular through their impact on color, a key-factor in the consumer’s choice. These phytomicronutrients are also susceptible to take part in the prevention of cardiovascular disease, cancers and age-related disorders by a combination of mechanisms: direct antioxidant effects, enzyme inhibition, regulation of gene expression… These biological effects can occur as early as in the upper digestive tract where native forms accumulate after a meal. After intestinal absorption, they strongly involve the micronutrients’ metabolites, i.e. phase II conjugates, oxidation products, products from the catabolism by the intestinal microbiota.

OUR RESEARCH THEMES

The reactivity of polyphenols and carotenoids in the gastrointestinal tract with a focus on the bioaccessibility bioavailability and antioxidant	The mechanisms of color expression by anthocyanins with a focus on the transformation and chenical synthesis of anthocyanins.	Emerging fields - Encapsulation of micronutrients for stabilization and controlled release - Mathematical modeling of the reactivity in complex media (food, digestion)

EXPERTISE

The Team is partner of:

• the Carnot Institute Qualiment® and thus provides scientific and technological resources to support companies in their projects on sensory and nutritional quality of food.
• the local network of competitivity Innov'Alliance promoting innovation between academia and companies.

Also for support of its main research objectives, the team has developed specific expertise and know-how in:

• Structural analyses of complex mixtures (plant extracts, biological samples) by UHPLC with detection by UV-visible absorption, fluorescence and mass spectrometry
• Antioxidant tests (ORAC, TRAP, FRAP…)
• Mechanisms of the antioxidant activity and oxidative degradation of polyphenols and carotenoids
• Quantification of the interactions between micronutrients and biomolecules (proteins, polysaccharides, lipids) or transition metal ions

Theme 1: The reactivity of polyphenols and carotenoids in the gastrointestinal tract

The bioavailability of polyphenols and carotenoids is low with typically less than 10% of these micronutrients crossing the upper intestinal barrier and entering the blood circulation. Hence, polyphenols and carotenoids could exert part of their nutritional effects (e.g., the inhibition of postprandial oxidative stress) directly in the digestive tract where they can accumulate in high concentration after a meal rich in plant products. However, the release of phytomicronutrients from the plant matrix (bioaccessibility) is the first mandatory step prior to intestinal absorption and bioactivity.

Aims

-  To uncover the impact of the food matrix on the bioaccessibility and bioavailability of polyphenols and carotenoids.

- To evaluate the capacity of these micronutrients to inhibit the oxidation of dietary polyunsaturated lipids initiated by dietary iron in gastric and intestinal conditions.

These topics are investigated using in vitro static and dynamic digestion models and in vivo models (minipig, rat, human).

Main publications

Goupy, P.; Carail, M.; Giuliani, A.; Duflot, D.; Dangles, O.; Caris-Veyrat, C. (2018). Carotenoids: Experimental Ionization Energies and Capacity at Inhibiting Lipid Peroxidation in a Chemical Model of Dietary Oxidative Stress. Journal of Physical Chemistry B, 122, 5860-5869.

Dufour C. Loonis M., Delosière M., Buffière C., Hafnaoui N., Santé-Lhoutellier V., Rémond D. (2018). The matrix of fruit & vegetables modulates the gastrointestinal bioaccessibility of polyphenols and their impact on dietary protein digestibility, Food Chemistry, 240, 314-322.

Kopec RE, Gleize B, Borel P, Desmarchelier C, Caris-Veyrat C. (2017) Are lutein, lycopene, and β-carotene lost throughthe digestive process? Food & Function, 8, 1494-1503. DOI: 10.1039/c7fo00021a

Dangles, O. ; Dufour, C. ; Tonnele, C. ; Trouillas, P. (2016) The physical chemistry of polyphenols: insights into the activity of polyphenols in humans at the molecular level; In Recent Advances in Polyphenol Research, Vol 5; Eds: Yoshida, K.; Cheynier, V. ; Quideau, S., WILEY-BLACKWELL.

Sy, C., Dangles, O., Borel, P., Caris-Veyrat, C. (2015). Stability of bacterial carotenoids in the presence of iron in a model of the gastric compartment – Comparison with dietary reference carotenoids. Archives of Biochemistry and Biophysics, 572, 89-100. DOI : 10.1016/j.abb.2014.12.030

Gobert, M., Rémond, D., Loonis, M., Buffière, C., Sante-Lhoutellier, V., Dufour, C. (2014). Fruits, vegetables and their polyphenols protect dietary lipids from oxidation during gastric digestion. Food and Function, 5, 2166-2174. DOI : 10.1039/c4fo00269e

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Theme 2: The mechanisms of color expression by anthocyanins

Anthocyanins are responsible for the red, purple and blue colors of many fruit, vegetables, cereals and their products. Anthocyanins and their natural derivatives are now regarded as credible alternatives for artificial food colorants, whose innocuous character is increasingly questioned. However, anthocyanins have specific physicochemical properties and a reputation of chemical instability limiting their industrial development.

Aims   - To quantitatively investigate their reversible transformations in water, their degradation mechanisms, their affinity for metal ions and colorless phenols (natural mechanisms of color variation and stabilization) as well as for biopolymers for the purpose of encapsulation   - To chemically synthetize anthocyanins and analogs as a viable alternative to extraction, provided that simple structures (e.g., 3-deoxyanthocyanins and their glucosides) be targeted

Trouillas, P.; Sancho-Garcia, J. C.; De Freitas, V.; Gierschner, J. ; Otyepka, M.; Dangles, O. (2016) Stabilizing and Modulating Color by Copigmentation: Insights from Review Theory and Experiment, Chemical Reviews, 116, 4937-4982.

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Emerging fields

• Encapsulation of micronutrients for stabilization and controlled release
• Mathematical modelling of the reactivity in complex media (food, digestion)

Publication

Aksamija, A., Polidori, A., Plasson, R., Dangles, O., Tomao, V. (2016). The inclusion complex of rosmarinic acid into beta-cyclodextrin: A thermodynamic and structural analysis by NMR and capillary electrophoresis. Food Chemistry, 208, 258-263. DOI : 10.1016/j.foodchem.2016.04.008

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Team Staff

Claire Dufour (RS, HDR), Olivier Dangles (PR), Pascale Goupy (RE), Béatrice Gleize (E), Nathalie Mora (AP), Raphaël Plasson (AP), Valérie Tomao (AP, HDR), Christian Ginies (AE), Marie-José Vallier (TR), Maxence Rosa (AT)

Post-docs and PhDs: Emmanuelle Richard, Charlène Sirvins

National collaborations

C2VN Marseille, UNH Clermont-Ferrand, BIA Nantes, Genial Massy,  SPO Montpellier, Qualisud Montpellier, STLO Rennes, Limoges University, Bordeaux University, CTCPA

International collaborations

 - Universities of Porto (Portugal), Lisbon (Portugal), Salamanca (Spain), Madrid (IMDEA, Spain), Parma (Italy), Naples (Italy), Gand (Belgium), Iasi (Romania), Bucharest (Romania), Bejaia (Algeria), Rabat (Morocco), London (Royal Holloway, UK), Campinas (Brazil)

 - Organic Waste System (Gand), Prodigest (Gand), Bioactor (Maastricht), Holloway Immunology Ltd. (London, UK)