title: Influence of juice pressing conditions on polyphenols, antioxidants, and varietal aroma of Sauvignon blanc microferments.
abstract: The impact of juice press fractions upon the content of varietal thiols in Sauvignon blanc has been examined for wines fermented at the laboratory scale (750 mL). Wines made from pressed juices (taken at 0.25 and 1.0 bar) contained less than half the concentration of 3-mercaptohexan-1-ol (3MH) and 3-mercaptohexyl acetate (3MHA), important contributors to the tropical and passion fruit character of Sauvignon blanc wines, compared to wines made from free run juices. The pressed juices and wines exhibited lower acidity values, more rapid decline in glutathione content, and more advanced polyphenol oxidation. Supplementation of the juices with glutathione (at 67 mg/L) prior to fermentation led to lower varietal thiol concentrations in the finished wines, typically by several percent, whereas treatment with polyvinylpolypyrrolidone (PVPP) made no impact on wine parameters. Pasteurization of pressed juices increased 3MHA content in the finished wines, but also led to a decline in 3MH concentrations.
authors.affiliation: Wine Science Programme, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Parimal
authors.initials: P
authors.lastname: Patel
authors.forename: Mandy
authors.initials: M
authors.lastname: Herbst-Johnstone
authors.forename: Soon A
authors.initials: SA
authors.lastname: Lee
authors.forename: Richard C
authors.initials: RC
authors.lastname: Gardner
authors.forename: Randy
authors.initials: R
authors.lastname: Weaver
authors.forename: Laura
authors.initials: L
authors.lastname: Nicolau
authors.forename: Paul A
authors.initials: PA
authors.lastname: Kilmartin
mesh_terms: D000975:Antioxidants / Q000032:analysis* / Q000378:metabolism; D001628:Beverages / Q000032:analysis* / Q000382:microbiology; D005285:Fermentation; D005419:Flavonoids / Q000032:analysis* / Q000378:metabolism; D005511:Food Handling / Q000379:methods*; D010636:Phenols / Q000032:analysis* / Q000378:metabolism; D059808:Polyphenols; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D027843:Vitis / Q000737:chemistry* / Q000382:microbiology; D014920:Wine / Q000032:analysis* / Q000382:microbiology
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols