title: Characterization of macromolecular complexes in red wine: Composition, molecular mass distribution and particle size.
abstract: Precipitates were prepared from two compositionally different Pinot noir wines with addition of excess ethanol, and contained primarily polysaccharide, tannin and protein. The ethanol-soluble material was further fractionated into polymeric (tannin) and monomeric phenolics. Tannin associated with precipitates was of a higher molecular mass than that remaining in ethanolic solution. Wine fractions were reconstituted at the ratios of the original wine and analyzed using nanoparticle tracking analysis. The average particle size of the tannin fraction was 75-89 nm, and increased when combined with the precipitate (≅ 200 nm). Addition of the monomeric fraction to the tannin-precipitate complex increased both the incidence and concentration of smaller particles, reducing the average particle size. The formation of aggregates occurred in all fractions and only minor differences in particle size distribution were found between wines. Differences in particle concentration between wines appear to be due to differences in the total concentration of macromolecules rather than compositional differences.
authors.affiliation: The Australian Wine Research Institute, Hartley Grove, Urrbrae, 5064 Adelaide, SA, Australia. Electronic address: keren.bindon@awri.com.au.
authors.forename: Keren A
authors.initials: KA
authors.lastname: Bindon
authors.affiliation: Perennial Horticulture Centre, Tasmanian Institute of Agriculture, University of Tasmania, 165 Westbury Road, Prospect, Tasmania 7250, Australia.
authors.forename: Anna L
authors.initials: AL
authors.lastname: Carew
authors.affiliation: The Australian Wine Research Institute, Hartley Grove, Urrbrae, 5064 Adelaide, SA, Australia.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Mierczynska-Vasilev
authors.affiliation: The Australian Wine Research Institute, Hartley Grove, Urrbrae, 5064 Adelaide, SA, Australia.
authors.forename: Stella
authors.initials: S
authors.lastname: Kassara
authors.affiliation: Perennial Horticulture Centre, Tasmanian Institute of Agriculture, University of Tasmania, 165 Westbury Road, Prospect, Tasmania 7250, Australia.
authors.forename: Fiona
authors.initials: F
authors.lastname: Kerslake
authors.affiliation: The Australian Wine Research Institute, Hartley Grove, Urrbrae, 5064 Adelaide, SA, Australia; Centre for Marine Bioproducts Development, Flinders University, Level 4, Health Sciences Building, Flinders University Registry Road, Bedford Park, SA 5042, Australia.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Smith
mesh_terms: D000431:Ethanol / Q000032:analysis*; D010316:Particle Size; D010636:Phenols / Q000032:analysis; D014920:Wine / Q000032:analysis*
chemical_list: D010636:Phenols; D000431:Ethanol
keywords: Maceration; Molecular mass; Nanoparticle tracking analysis; Particle size; Pinot noir; Polysaccharide; Proanthocyanidin; Protein; Size exclusion chromatography