title: In vitro bioaccessibility and gut biotransformation of polyphenols present in the water-insoluble cocoa fraction.
abstract: METHODS
  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.
  
  
  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.
  
  
  CONCLUSIONS
  Data showed that WICF may exert antioxidant action through the gastrointestinal tract despite its polyphenols being still bound to macromolecules and having prebiotic activity.
authors.affiliation: Department of Food Science, University of Naples, via Università 100, Portici, Naples, Italy. fogliano@unina.it
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Fogliano
authors.forename: Maria Laura
authors.initials: ML
authors.lastname: Corollaro
authors.forename: Paola
authors.initials: P
authors.lastname: Vitaglione
authors.forename: Aurora
authors.initials: A
authors.lastname: Napolitano
authors.forename: Rosalia
authors.initials: R
authors.lastname: Ferracane
authors.forename: Fabiano
authors.initials: F
authors.lastname: Travaglia
authors.forename: Marco
authors.initials: M
authors.lastname: Arlorio
authors.forename: Adele
authors.initials: A
authors.lastname: Costabile
authors.forename: Annett
authors.initials: A
authors.lastname: Klinder
authors.forename: Glenn
authors.initials: G
authors.lastname: Gibson
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000032:analysis; D001419:Bacteria / Q000187:drug effects / Q000378:metabolism; D001682:Biological Availability; D001711:Biotransformation; D002099:Cacao / Q000737:chemistry*; D004063:Digestion; D005285:Fermentation; D005419:Flavonoids / Q000493:pharmacokinetics*; D041981:Gastrointestinal Tract / Q000378:metabolism* / Q000382:microbiology; D006801:Humans; D062385:Hydroxybenzoates / Q000378:metabolism; D008297:Male; D054892:Metagenome; D010636:Phenols / Q000493:pharmacokinetics*; D059808:Polyphenols; D011422:Propionates / Q000032:analysis
chemical_list: C491266:3-hydroxyphenylpropionic acid; D000975:Antioxidants; D005419:Flavonoids; D062385:Hydroxybenzoates; D010636:Phenols; D059808:Polyphenols; D011422:Propionates; C017616:phenolic acid