Skip to Main content Skip to Navigation
Theses

Les tannins du vins et les lipides de la bouche et du bol alimentaire : vers une modification des marqueurs du goût. Une approche moléculaire et sensorielle.

Abstract : Tannins are polyphenol polymers present in significant amounts in red wine responsible for astringency and bitterness. The former is a tactile perception involving dryness and roughness in the mouth due to the interaction between tannins and saliva proteins and the latter is a primary taste due to the interaction between tannins and taste receptors in taste buds. Tannins are now known to also interact with lipids. Although not present in wine, lipids are yet present during tasting in the oral membranes of tasters and in fatty foods when wine is consumed during a meal. However, although the influence of lipids is well known to wine tasters through food pairing, there is no scientific evidence to support this hedonic feeling. The aim of the thesis is to study tannin-lipid interactions at molecular level in order to better understand their implication in wine gustative properties. The present work describes the effect of the main representative grape tannin subunits, the catechin monomer and the B1 dimer, both on a model of oral membranes and food fat globules. They are represented by a dispersion of POPC/cholesterol multilamellar vesicles and a olive oil in water emulsion stabilized by DMPC as emulsifier, respectively. The organization and dynamics of the lipids composing these two models were investigated by solid-state NMR spectroscopy (1H, 2H, and 13C) in the absence and the presence of the two tannin subunits. The affinity of tannins for lipids was also explored by the determination of the thermodynamic association constant. The results pointed out a fluidizing effect of tannins both on the membrane model, as previously shown on a simpler membrane model, and on the emulsion lipid droplets. The disorder caused by tannins was shown to be related to their location in the lipid structure depending on the tannin chemical nature. Moreover, the strength of the interaction between tannins and membrane lipids was revealed to be in the same order of magnitude of that between tannins and saliva proteins. In addition, the biophysical results were in accordance with those of a sensory analysis led in parallel that revealed that fatty foods are prone to decrease wine astringency. These pioneering works shows the impact of phenolic compound on membrane order and highlight for the first time the potential role of the tannin-lipid interactions on wine taste. On the one hand, by disrupting the lipid environment of taste receptors embedded in oral membranes, tannin-lipid interactions could affect the receptor functionnality and therefore the interaction with tannin molecules, so bitterness. On the other hand, the existence of a possible competition between lipids and saliva proteins for interacting with tannins during tasting could reduce astringency.
Document type :
Theses
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-01767457
Contributor : Abes Star :  Contact
Submitted on : Monday, April 16, 2018 - 11:32:20 AM
Last modification on : Monday, June 29, 2020 - 10:16:11 AM

File

SAAD_AHMAD_2017.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01767457, version 1

Collections

Citation

Ahmad Saad. Les tannins du vins et les lipides de la bouche et du bol alimentaire : vers une modification des marqueurs du goût. Une approche moléculaire et sensorielle.. Autre. Université de Bordeaux, 2017. Français. ⟨NNT : 2017BORD0879⟩. ⟨tel-01767457⟩

Share

Metrics

Record views

1353

Files downloads

288