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Separation and classification of the brown pigments of aqueous infusions of black tea
Author(s) -
Millin D. J.,
Swaine D.,
Dix P. L.
Publication year - 1969
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740200511
Subject(s) - polyphenol , chemistry , sephadex , chromatography , aqueous solution , pigment , black tea , solvent , fraction (chemistry) , extraction (chemistry) , polysaccharide , dialysis , organic chemistry , food science , medicine , enzyme , antioxidant
Rapid thin‐film counter‐current dialysis of a typical infusion of black tea indicates that 10–12% of the soluble solids are non‐dialysable. the major components of this fraction are polysaccharides and a complex mixture which could not be separated into its protein and polyphenolic constituents. This latter complex accounts for 30–40% of the colour ( E 450 ) of the infusion. Solvent extraction of the infusion followed by dialysis of the various extracts reveals that the polyphenol‐protein complex may be approximately equated with ‘S II thearubigins’. Chromatography of infusions and various extracts thereof on alkylated Sephadex allows a partial separation of the coloured components largely owing to differences in molecular size. At least 7 distinct zones can be recognised.