SOLID-PHASE EXTRACTION (SPE) - A COMPARISON OF 16 MATERIALS FOR THE PURIFICATION OF ANTHOCYANINS FROM ARONIA-MELANOCARPA VAR NERO

There is an increasing interest in anthocyanins, not only as natural f ood colourants but also for pharmaceutical products due to their antio xidative potential. Common extraction procedures of anthocyanins from plant material are non-selective and yield pigment solutions with larg e amounts of by-products such as sugars, sugar alcohols, organic acids , amino acids and proteins. Some of these impurities may accelerate an thocyanin degradation or cause problems in further processing steps su ch as spray drying. In order to obtain a highly concentrated and purif ied anthocyanin pigment from black chokeberry (Aronia melanocarpa var Nero), juices and skin extracts were purified by solid-phase extractio n (SPE). Sixteen solid-phase materials were tested on a laboratory sca le, whereby the anthocyanin and sugar content of collected fractions w ere determined to represent elution profiles. Among these, reversed-ph ase silica gels and macroreticular non-ionic acrylic polymer adsorbent s such as Serdolit PAD IV or Amberlite XAD-7 turned out to be most sui table. SPE was investigated with these materials in an enlarged scale, improving elution gradient and column purification. Amberlite XAD-7 w as successfully applied in a 36-litre-scale separation. (C) 1998 Socie ty of Chemical Industry.