SEPARATION AND CLASSIFICATION OF BROWN PIGMENTS OF AQUEOUS INFUSIONS OF BLACK TEA

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 (E450) 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 ‘SII 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. Copyright © 1969 John Wiley & Sons, Ltd