Purification of artichoke polyphenols by using membrane filtration and polymeric resins

• Phenolic compounds were recovered, concentrated and purified from artichoke wastewaters.
• Artichoke wastewaters were clarified by UF with tubular ceramic membranes.
• The UF permeate was concentrated by NF with a spiral-wound polymeric membrane.
• Macroporous resins were tested to produce purified phenolics from the NF retentate.
• Samples were analyzed for total antioxidant activity, sugars and phenolic compounds.

The present study aimed at evaluating the potential of an integrated process based on the use of membrane technology and adsorbent resins for the recovery, concentration and purification of phenolic compounds from artichoke wastewaters.In particular, artichoke wastewaters coming from the blanching step were pre-treated by ultrafiltration (UF) in order to remove suspended solids and macromolecular compounds. The UF permeate was submitted to a nanofiltration (NF) process producing a concentrated fraction enriched in phenolic and sugar compounds.Three different macroporous resins were tested through adsorption/desorption methods to produce purified phenolic fractions with high antioxidant activity. Samples produced in UF, NF and adsorption–desorption tests were assayed for phenolic composition (chlorogenic acid and apigenin 7-O-glucoside), sugar composition (fructose, glucose and sucrose) and antioxidant activity.Among the three different tested resins, the S 7968 offered the best performance in terms of adsorption/desorption ratio for chlorogenic acid, with a total adsorption/desorption yield (TADY) of 63.39%; for the apigenin 7-O-glucoside the S 7968 and the S 2328 resins showed a TADY in the range 68.31–78.45%.