Isolation of Black Tea Pigments Using High-Speed Countercurrent Chromatography and Studies on Properties of Black Tea Polymers

Isolation of theaflavins and epitheaflavic acids from black tea using high-speed countercurrent chromatography (HSCCC) on a preparative scale is demonstrated. HSCCC also enabled the isolation of a polymeric fraction from black tea. According to Roberts' classification, the polymeric fraction mainly consisted of SII thearubigins (TR). HPLC analysis showed that the isolated material is free of any known chromatographically resolved tea constituents and eluted from reversed-phase packings as a convex “hump” (a broad signal). The antioxidant activity of the TR fraction was 3.6 mmol of Trolox equivalents per gram. The total phenolic content of this fraction was determined to be 34.7 g/100 g (as gallic acid equivalents). Keywords: Black tea; polymers; thearubigins; theaflavin; epitheaflavic acid; color; high-speed countercurrent chromatography; HSCCC; TEAC values; Folin−Ciocalteu; polyphenols; flavonoids; antioxidants