title: Chemical characterization and in vitro colonic fermentation of grape pomace extracts.
abstract: BACKGROUND
  Currently, there is growing interest in extracts derived from winery by-products because of their beneficial health properties, which are associated with the presence of bioactive compounds. In this paper, we have carried out the chemical characterization and in vitro colonic fermentation of four grape pomace (GP) extracts rich in polyphenols and dietary fibre.
  
  
  RESULTS
  Firstly, phenolic and dietary fibre composition of the GP extracts was determined. The highest individual phenolic concentrations corresponded to gallic and ellagic acids, followed by catechins and flavonols. The non-digestible fibre fraction ranged from 66% to 83% of the GP extracts, which indicated that they mainly contained non-digestible cell wall components. Secondly, when GP extracts were subjected to fermentation by faecal microbiota, a total of 16 bacterial phenolic metabolites were found in the fermented samples, confirming that polyphenols contained in the GP extracts were metabolized to different active metabolites by microbiota. In addition, the GP extracts tended to promote the growth of intestinal microbiota, although it was only significant for the Enterococcus group.
  
  
  CONCLUSIONS
  These findings, together with other information available in the literature, support the high added value of products obtained from winery by-products. © 2016 Society of Chemical Industry.
authors.affiliation: Institute of Food Science Research (CIAL), CSIC-UAM, Madrid, Spain.
authors.forename: Irene
authors.initials: I
authors.lastname: Gil-Sánchez
authors.affiliation: Grupo de Investigación en Polifenoles, Universidad de Salamanca, Salamanca, Spain.
authors.forename: Begoña
authors.initials: B
authors.lastname: Ayuda-Durán
authors.affiliation: Grupo de Investigación en Polifenoles, Universidad de Salamanca, Salamanca, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: González-Manzano
authors.affiliation: Grupo de Investigación en Polifenoles, Universidad de Salamanca, Salamanca, Spain.
authors.forename: Celestino
authors.initials: C
authors.lastname: Santos-Buelga
authors.affiliation: Institute of Food Science Research (CIAL), CSIC-UAM, Madrid, Spain.
authors.forename: Carolina
authors.initials: C
authors.lastname: Cueva
authors.affiliation: Institute of Food Science Research (CIAL), CSIC-UAM, Madrid, Spain.
authors.forename: M Angeles
authors.initials: MA
authors.lastname: Martín-Cabrejas
authors.affiliation: Bodega Matarromera, Valladolid, Spain.
authors.forename: Marisa
authors.initials: M
authors.lastname: Sanz-Buenhombre
authors.affiliation: Bodega Matarromera, Valladolid, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Guadarrama
authors.affiliation: Institute of Food Science Research (CIAL), CSIC-UAM, Madrid, Spain.
authors.forename: M Victoria
authors.initials: MV
authors.lastname: Moreno-Arribas
authors.affiliation: Institute of Food Science Research (CIAL), CSIC-UAM, Madrid, Spain.
authors.forename: Begoña
authors.initials: B
authors.lastname: Bartolomé
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D003106:Colon / Q000378:metabolism* / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D005285:Fermentation; D005638:Fruit / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism; D027843:Vitis / Q000737:chemistry / Q000378:metabolism*; D014866:Waste Products / Q000032:analysis*
chemical_list: D010936:Plant Extracts; D014866:Waste Products
keywords: colonic fermentation; fibre; grape pomace extracts; polyphenols