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Poster De Conférence Année : 2015

How the physicochemical properties of egg white gel influence the in vivo gastric digestion process: Spatio-temporal mapping

Résumé

The ability of egg white proteins to form gels with very different structures means that egg white has considerable potential as a functional food with controlled delivery properties. This work aimed to investigate the links between the gastric digestion process and the structural properties of three different egg white matrices. The heat-induced egg white gels had the same composition, but different physicochemical properties; a smooth-rigid gel at pH 9, a granular-spongy gel at pH 5 and an intermediate gel at pH 7. Each gel was fed to pigs (n=33) as a single meal and gastric chyme samples were collected from 10 different stomach locations over a 6h-postprandial period in order to study digestion as a function of stomach location and postprandial time. At 20min postprandial, the pH of the chyme was similar to the pH of the gel ingested (Fig.1). Acidification of the chyme commenced near the pylorus, and 4h to 6h postprandial was required to uniformly acidify (pH < 3) the whole stomach. Up to 2h postprandial time, the pH 9 gel acidified more rapidly than the pH 7 gel even though the gastric emptying rate was not significantly different between these two gels. Thus, the acidification kinetics of the stomach contents was driven not only by the initial pH of the diet but also by the gels structural properties. Degree of hydrolysis measurements, as well as microscopic, rheological and particle size characterization of the gastric contents are currently in progress and will enable a better understanding of the gastric digestion process. This work gives insights into the heterogeneous nature of gastric chyme and the role food structure and pH may have on gastric pH behavior. These results question the relevance of static in vitro gastric digestion simulation models in which the incubation pH is typically set around 3.5-2.5, the optimum of pepsin activity.
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Dates et versions

hal-01209785 , version 1 (02-10-2015)

Identifiants

  • HAL Id : hal-01209785 , version 1
  • PRODINRA : 282601

Citer

Kéra Nyemb, S.M Rutherfurd, Catherine Guérin-Dubiard, Didier Dupont, Francoise Nau. How the physicochemical properties of egg white gel influence the in vivo gastric digestion process: Spatio-temporal mapping. 4th International Conference of Food Digestion, Mar 2015, Naples, Italy. , 2015. ⟨hal-01209785⟩
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