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Updated: Jun 28, 2025

In vitro Digestion of Emulsions in a Single Droplet via Multi Subphase Exchange of Simulated Gastrointestinal Fluids
Published on: November 18, 2022
Interactions between Salivary Proteins and Apple Polyphenols and the Fate of Complexes during Gastric Digestion
Müzeyyen Berkel Kasikci1,2, Sophie Guilois-Dubois3, Kevin Billet3
1INRAE, Institut Agro, STLO, 35042 Rennes, France.
Abstract:
Beneficial polyphenols in apples can reach the stomach as complexes formed with salivary proteins. The present study aimed at documenting the interactions between salivary proteins and cider apple polyphenols and the fate of complexes during gastric digestion. A polyphenolic extract was mixed with human saliva, and interactions were characterized by analyzing proteins and polyphenols in the insoluble and soluble fractions of the mixtures, before and after in vitro gastric digestion. Results confirmed that proline-rich proteins can efficiently precipitate polyphenols and suggested that two zinc-binding proteins can also form insoluble complexes with polyphenols. The classes of polyphenols involved in such complexes depended on the polyphenol-to-protein ratio. In vitro gastric digestion led to extensive proteolysis of salivary proteins, and we formulate the hypothesis that the resulting peptides can interact with and precipitate some procyanidins. Saliva may therefore partly modulate the bioaccessibility of at least procyanidins in the gastric compartment.
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