Recovery of anthocyanins from grape pomace extracts (Vitis vinifera L. cv. Cabernet Mitos) using a polymeric adsorber resin

Anthocyanins from a Cabernet Mitos grape pomace were extracted without sulfitation, purified and concentrated on a laboratory scale by adsorption to a styrene - divinylbenzene copolymerisate. The pigment loss during sample loading and washing of the column with water was negligible. Elution was performed with acidified methanol, ethanol and 2- propanol, respectively. The recovery rates ranged from 96 to 100% of anthocyanins when methanol was used, from 86 to 96% for ethanol and from 78 to 88% when pigments were eluted with 2- propanol. The temperature during adsorption and desorption ( 25 and 50 degrees C) did not significantly influence the pigment binding capacity. The recovery rates were not affected by the scale- up from laboratory to pilot- plant adsorption experiments. The use of polymeric resins facilitates nonthermal anthocyanin concentration since highly pigmented alcoholic eluates were obtained which can further be concentrated under mild conditions. The present study provides systematic data on adsorber technology increasingly used for the recovery of plant secondary metabolites.