In vitro bioaccessibility and gut biotransformation of polyphenols present in the water-insoluble cocoa fraction

Vincenzo Fogliano*, Maria Laura Corollaro, Paola Vitaglione, Aurora Napolitano, Rosalia Ferracane, Fabiano Travaglia, Marco Arlorio, Adele Costabile, Annett Klinder, Glenn Gibson

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

84 Citations (Scopus)


Scope: Cocoa, especially the water-insoluble cocoa fraction (WICF), is a rich source of polyphenols. In this study, sequential in vitro digestion of the WICF with gastrointestinal enzymes as well as its bacterial fermentation in a human colonic model system were carried out to investigate bioaccessibility and biotransformation of WICF polyphenols, respectively. Methods and results: The yield of each enzymatic digestion step and the total antioxidant capacity (TAC) were measured and solubilized phenols were characterized by MS/MS. Fermentation of WICF and the effect on the gut microbiota, SCFA production and metabolism of polyphenols was analyzed. In vitro digestion solubilized 38.6% of WICF with pronase and Viscozyme L treatments releasing 51% of the total phenols from the insoluble material. This release of phenols does not determine a reduction in the total antioxidant capacity of the digestion-resistant material. In the colonic model WICF significantly increased of bifidobacteria and lactobacilli as well as butyrate production. Flavanols were converted into phenolic acids by the microbiota following a concentration gradient resulting in high concentrations of 3-hydroxyphenylpropionic acid (3-HPP) in the last gut compartment. Conclusion: Data showed that WICF may exert antioxidant action through the gastrointestinal tract despite its polyphenols being still bound to macromolecules and having prebiotic activity.

Original languageEnglish
Pages (from-to)S44-S55
JournalMolecular Nutrition and Food Research
Issue numberSUPPL. 1
Publication statusPublished - May 2011
Externally publishedYes


  • Digestion
  • Flavanols
  • Phloroglucinolysis
  • Prebiotic
  • SCFA

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