Recovery of antioxidants from industrial waste liquors using membranes and polymeric resins

Liquors obtained by pressing distilled grape pomace were assayed for composition and antioxidant activity, and refined by different methods (adsorption–desorption or processing by ultrafiltration (UF) and nanofiltration (NF) membranes, followed by solvent extraction of concentrates and adsorption–desorption of permeates). Commercial polymeric resins (Sepabeads SP700) were employed in the adsorption step, and desorption was carried out with aqueous ethanol solutions. The final products presented ABTS radical scavenging capacities equivalent to 1.5–9.9 g of Trolox per gram of desorbed product, and DPPH radical scavenging capacities comparable to that of BHA, with reducing powers corresponding to 1.94–2.97 mM ascorbic acid.