title: Sorption of grape proanthocyanidins and wine polyphenols by yeasts, inactivated yeasts, and yeast cell walls.
abstract: Inactivated yeast fractions (IYFs) can be used in enology to improve the stability and mouthfeel of red wines. However, information concerning the mechanisms involved and the impact of the IYF characteristics is scarce. Adsorption isotherms were used to investigate interactions between grape proanthocyanidin fractions (PAs) or wine polyphenols (WP) and a commercial yeast strain (Y), the inactivated yeast (IY), the yeast submitted to autolyzis and inactivation (A-IY), and the cell walls obtained by mechanical disruption (CW). High affinity isotherms and high adsorption capacities were observed for grape PAs and whole cells (Y, IY, and A-IY). Affinity and adsorbed amount were lower with wine PAs, due to chemical changes occurring during winemaking. By contrast to whole cells, grape PAs and WP adsorption on CW remained very low. This raises the issue of the part played by cell walls in the interactions between yeast and proanthocyanidins and suggests the passage of the latter through the wall pores and their interaction with the plasma membrane.
authors.affiliation: INRA, UMR 1083 SPO , F-34060 Montpellier, France.
authors.forename: J
authors.initials: J
authors.lastname: Mekoue Nguela
authors.forename: N
authors.initials: N
authors.lastname: Sieczkowski
authors.forename: S
authors.initials: S
authors.lastname: Roi
authors.forename: A
authors.initials: A
authors.lastname: Vernhet
mesh_terms: D000327:Adsorption; D002473:Cell Wall / Q000737:chemistry*; D005421:Flavoring Agents / Q000737:chemistry; D005511:Food Handling; D059808:Polyphenols / Q000737:chemistry*; D044945:Proanthocyanidins / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000254:growth & development; D027843:Vitis / Q000737:chemistry / Q000382:microbiology*; D014920:Wine / Q000032:analysis* / Q000382:microbiology
chemical_list: D005421:Flavoring Agents; D059808:Polyphenols; D044945:Proanthocyanidins; C013221:proanthocyanidin
keywords: inactivated yeast fractions; physicochemical properties; polyphenols; sorption isotherms