title: Polyphenol, antioxidant and antimicrobial potential of six different white and red wine grape processing leftovers.
abstract: BACKGROUND
  During winemaking, grape polyphenols are only partly extracted, and consequently unexploited. The main aim was to characterize the phenolic content of freeze-dried grape skin and seed (FDSS) extracts obtained from Slovenian and international grape varieties and to evaluate their antioxidant, antimicrobial and anti-adhesive activities.
  
  
  RESULTS
  FDSS of six Vitis vinifera L. grapevine cultivars from Vipava Valley region (Slovenia) underwent extraction and sonification under different conditions. Flavonols were the predominant content of extracts from white 'Zelen' and 'Sauvignon Blanc' grape varieties, with strong antimicrobial activities against Gram-negative bacteria. 'Pinot Noir' FDSS extracted with 50% aqueous ethanol extraction produced a high phenolic content in the final extract, which was further associated with strong antioxidant and antimicrobial activities against all tested bacteria. Bacterial adhesion to stainless steel surfaces with minimal and maximal surface roughness was significantly inhibited (up to 60%) across a wide FDSS concentration range, with lower concentrations also effective with two types of stainless steel surfaces.
  
  
  CONCLUSIONS
  FDSS extracts from winery by-products show interesting phenolic profiles that include flavonols, catechins, anthocyanins and hydroxycinnamic acids, with yields influenced by grapevine cultivar and extraction conditions. The antioxidant, antimicrobial and anti-adhesive activities of 50% aqueous ethanol 'Pinot Noir' FDSS extract reveals potential applications in food, pharmaceutical and cosmetic industries for these bioactive residues. © 2016 Society of Chemical Industry.
authors.affiliation: Wine Research Centre, University of Nova Gorica, Vipava, Slovenia.
authors.forename: Kajetan
authors.initials: K
authors.lastname: Trošt
authors.affiliation: Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Anja
authors.initials: A
authors.lastname: Klančnik
authors.affiliation: Wine Research Centre, University of Nova Gorica, Vipava, Slovenia.
authors.forename: Branka
authors.initials: B
authors.lastname: Mozetič Vodopivec
authors.affiliation: Wine Research Centre, University of Nova Gorica, Vipava, Slovenia.
authors.forename: Melita
authors.initials: M
authors.lastname: Sternad Lemut
authors.affiliation: Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Katja
authors.initials: K
authors.lastname: Jug Novšak
authors.affiliation: Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Peter
authors.initials: P
authors.lastname: Raspor
authors.affiliation: Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia. Sonja.Smole@bf.uni-lj.si.
authors.forename: Sonja
authors.initials: S
authors.lastname: Smole Možina
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology*; D005511:Food Handling; D007220:Industrial Waste; D059808:Polyphenols / Q000737:chemistry / Q000494:pharmacology*; D027843:Vitis / Q000737:chemistry* / Q000145:classification; D014920:Wine / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D000975:Antioxidants; D007220:Industrial Waste; D059808:Polyphenols
keywords: anti-adhesion activity to stainless steel; antimicrobial activity; antioxidant activity; extraction solvents; grape skins and seeds; phenolic profile