Fractionation of Grape Tannins by Affinity Chromatography and Partial Characterization of the Fractions

Fractionation of grape tannins was accomplished by chromatography on Sepharose‐immobilized bovine serum albumin. Tannin fractions emerged from the column sequentially according to an increasing molecular weight. Nine distinct fractions were obtained and were further partially characterized. Fractions that failed to bind or bound only weakly to the column material lacked the ability to precipitate gelatin and yielded no anthocyanidins when treated with acid. In contrast, all of the fractions that bound strongly to the column, were able to precipitate gelatin and yielded anthocyanidins with characteristic wavelength maxima.