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Poster De Conférence Année : 2017

Exploring in vivo gastric digestion of egg white gels: impact of the initial gel structure and texture

Résumé

Food structure is an important factor in the nutritional quality of foods. With regard to dietary protein, it may have an impact on protein digestibility, proteolysis kinetics, gastric emptying and amino acid bioavailability, all with potential metabolic consequences. Egg white is an appropriate food model to investigate these issues, since very different structures and textures can be produced while keeping the chemical composition constant. Recently, we established that protein matrix structure impacts the extent of proteolysis and the nature of the peptides generated during in vitro digestion of egg white protein aggregates and gels. Our question here is “do such differences also exist in vivo, and do they have any biological consequences?” To address these questions, a smooth-rigid egg white gel, a granular-spongy gel and an intermediate gel were prepared. Each gel was fed to pigs (n=33) as a single meal, and gastric chyme samples were collected over a 6h-postprandial period in order to measure pH, proteolysis and particle size along digestion at 10 different stomach locations. Blood samples were also collected for plasma amino acid analyses.Acidification of the chyme started in the pylorus regin regardless of the type of gel, but acidification kinetics depended on the gel type, which suggested that gel structure impacts on HCl distribution in the chyme. In contrast, proteolysis commenced in the proximal region, consistent with the location of pepsinogen secretory cells. But from 1h-postprandial, proteolysis profiles greatly differed depending on the gels: the higher proteolysis was 2 observed in the pyloric region for the granular-spongy gel (acidity and proteolysis gradients were consistent), while maximum proteolysis was observed in the proximal region for the smooth-rigid and intermediate gels (acidity and proteolysis gradients were opposite), suggesting that pepsin diffusion profiles depend on the type of gel. Proteolysis kinetics were more rapid with granular-spongy gel than with intermediate gel, while the smooth-rigid gel was the most resistant to proteolysis, which was consistent with the particle size observed during digestion. Finally, amino acid absorption was faster for the granular-spongy gel than for the two other gels.
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Dates et versions

hal-01603787 , version 1 (02-10-2017)

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Paternité - Partage selon les Conditions Initiales

Identifiants

  • HAL Id : hal-01603787 , version 1
  • PRODINRA : 389077

Citer

Francoise Nau, Kéra Nyemb, T Boucher, Catherine Guérin-Dubiard, M. Ferrua, et al.. Exploring in vivo gastric digestion of egg white gels: impact of the initial gel structure and texture. 5. International Conference on Food Digestion, Apr 2017, Rennes, France. , 2017. ⟨hal-01603787⟩
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