title: Following the compositional changes of fresh grape skin cell walls during the fermentation process in the presence and absence of maceration enzymes.
abstract: Cell wall profiling technologies were used to follow compositional changes that occurred in the skins of grape berries (from two different ripeness levels) during fermentation and enzyme maceration. Multivariate data analysis showed that the fermentation process yielded cell walls enriched in hemicellulose components because pectin was solubilized (and removed) with a reduction as well as exposure of cell wall proteins usually embedded within the cell wall structure. The addition of enzymes caused even more depectination, and the enzymes unravelled the cell walls enabling better access to, and extraction of, all cell wall polymers. Overripe grapes had cell walls that were extensively hydrolyzed and depolymerized, probably by natural grape-tissue-ripening enzymes, and this enhanced the impact that the maceration enzymes had on the cell wall monosaccharide profile. The combination of the techniques that were used is an effective direct measurement of the hydrolysis actions of maceration enzymes on the cell walls of grape berry skin.
authors.affiliation: †Institute for Wine Biotechnology, Department of Viticulture and Oenology, Faculty of AgriSciences, Stellenbosch University, Matieland 7602, South Africa.
authors.forename: Anscha J J
authors.initials: AJ
authors.lastname: Zietsman
authors.affiliation: †Institute for Wine Biotechnology, Department of Viticulture and Oenology, Faculty of AgriSciences, Stellenbosch University, Matieland 7602, South Africa.
authors.forename: John P
authors.initials: JP
authors.lastname: Moore
authors.affiliation: ‡Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, DK-1001 Copenhagen, Denmark.
authors.forename: Jonatan U
authors.initials: JU
authors.lastname: Fangel
authors.affiliation: ‡Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, DK-1001 Copenhagen, Denmark.
authors.forename: William G T
authors.initials: WG
authors.lastname: Willats
authors.affiliation: §Computational Life Science Cluster (CLiC), Department of Chemistry, Umeå University, Umeå 901 87, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Trygg
authors.affiliation: †Institute for Wine Biotechnology, Department of Viticulture and Oenology, Faculty of AgriSciences, Stellenbosch University, Matieland 7602, South Africa.
authors.forename: Melané A
authors.initials: MA
authors.lastname: Vivier
mesh_terms: D055162:Biocatalysis; D002473:Cell Wall / Q000737:chemistry* / Q000378:metabolism; D004798:Enzymes / Q000737:chemistry*; D005285:Fermentation; D005638:Fruit / Q000737:chemistry / Q000382:microbiology; D006868:Hydrolysis; D010368:Pectins / Q000737:chemistry* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D027843:Vitis / Q000737:chemistry* / Q000378:metabolism / Q000382:microbiology
chemical_list: D004798:Enzymes; D010368:Pectins
keywords: cell wall; grape maturity; grape skin; maceration enzymes; multivariate data analysis