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

Research output: Contribution to journalArticle


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)S44-55
JournalMolecular Nutrition and Food Research
Volume55 Suppl 1
Publication statusPublished - May 2011


  • Adult
  • Antioxidants
  • Bacteria
  • Biological Availability
  • Biotransformation
  • Cacao
  • Digestion
  • Fermentation
  • Flavonoids
  • Gastrointestinal Tract
  • Humans
  • Hydroxybenzoates
  • Male
  • Metagenome
  • Phenols
  • Polyphenols
  • Propionates

Cite this

Fogliano, V., Corollaro, M. L., Vitaglione, P., Napolitano, A., Ferracane, R., Travaglia, F., Arlorio, M., Costabile, A., Klinder, A., & Gibson, G. (2011). In vitro bioaccessibility and gut biotransformation of polyphenols present in the water-insoluble cocoa fraction. Molecular Nutrition and Food Research, 55 Suppl 1, S44-55.