Separation of Proanthocyanidins into Oligomeric and Polymeric Components Using a Novel Collagen Fiber Adsorbent

Abstract A novel collagen fiber adsorbent (CFA) was prepared by modification of natural collagen fiber using glutaraldehyde, and its adsorption behaviors to proanthocyanidins were investigated. Both batch and column adsorption experiments indicated that CFA has high adsorption selectivity to polymeric proanthocyanidins because of the stronger trend of these polymers to combine with collagen fiber through hydrophobic and hydrogen bonds. Based on this character of CFA, the purified oligomeric proanthocyanidins was obtained by using CFA as adsorbent. Meanwhile, it was found that the polymeric proanthocyanidins adsorbed on CFA can be easily desorbed by 50% (v/v) acetone-water solution. Thus, as a cost effective approach, CFA can be used to separate proanthocyanidins extracts into two parts, oligomeric proanthocyanidins and polymeric proanthocyanidins, which would favor the fine uses of proanthocyanidins extracts. Column adsorption studies showed that CFA used can be regenerated by using acetone-water solution as eluant, and its adsorption selectivity to polymeric proanthocyanidins was almost unchanged in 6 cycles.