title: Influence of solvents on the composition of condensed tannins in grape pomace seed extracts.
abstract: The extracting effectiveness of some solvents (water, ethanol, acetone, ethyl acetate), used as pure or in binary and ternary mixtures, was studied for the extraction of seeds from the fermented pomace of Nebbiolo cv. The aqueous mixtures of acetone provided the highest extraction yields in total polyphenols and total flavonoids. Polyphenolic extracts were also obtained with aqueous mixtures of ethanol or acetone at variable concentrations, and the condensed tannins were quantified with the phloroglucinolysis method. The aqueous mixtures of acetone were more effective than the corresponding aqueous mixtures of ethanol. The solvent influenced the extraction yield and the composition of the extracts: with the increase of the yield, the mean degree of polymerization (mDP) of the condensed tannins increased. A significant correlation was noticed between mDP and the molar percentages of (+)-catechin as terminal unit (negative correlation), and of (-)-epicatechin and (-)-epicatechin-3O-gallate as extension units (positive correlation).
authors.affiliation: Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria - Centro di Ricerca per l'Enologia, via P. Micca 35, 14100 Asti, Italy. Electronic address: antonella.bosso@entecra.it.
authors.forename: Antonella
authors.initials: A
authors.lastname: Bosso
authors.affiliation: Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria - Centro di Ricerca per l'Enologia, via P. Micca 35, 14100 Asti, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Guaita
authors.affiliation: Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria - Centro di Ricerca per l'Enologia, via P. Micca 35, 14100 Asti, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Petrozziello
mesh_terms: D000085:Acetates / Q000737:chemistry; D000096:Acetone / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry; D005285:Fermentation; D056604:Grape Seed Extract / Q000737:chemistry* / Q000378:metabolism; D044945:Proanthocyanidins / Q000032:analysis / Q000302:isolation & purification*; D052616:Solid Phase Extraction / Q000379:methods*; D012997:Solvents / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D000085:Acetates; D056604:Grape Seed Extract; D044945:Proanthocyanidins; D012997:Solvents; D014867:Water; D000096:Acetone; D000431:Ethanol; C007650:ethyl acetate
keywords: Condensed tannins; Grape pomace; Phloroglucinolysis; Solvent extraction; Ultrasound assisted extraction