Impact of extraction parameters and concentration by nanofiltration on the recovery of phenolic compounds from Cynara cardunculus var. altilis: Assessment of antioxidant activity

• Parameters of phenolic extraction from Cynara cardunculus were tested.
• Best total phenolic content was achieved with sequential extraction.
• High antioxidant activity was found with sequential extraction.
• Total phenols and chlorogenic acid were concentrated by nanofiltration.

Cynara cardunculus var. altilis has been reported to be an excellent source of phenolic compounds. Being extraction methodology a crucial step for final extract properties, batch solid–liquid extraction, the most commonly used method, was studied and parameters such as solvent concentration, stirring rate and sequential extraction were tested in order to understand their impact on: kinetic rate, total phenolic compounds concentration and extracts antioxidant activity. Profile of phenolic extraction of C. cardunculus appeared as a first order steady-state, being the kinetic rate influenced by solvent concentration, as well as by a lipophilic fraction removal, within a sequential extraction. Based on the high kinetic rate, and antioxidant activity, sequential extraction was therefore chosen as the best methodology for C. cardunculus phenolic compounds extraction. After extraction evaluation study, nanofiltration was used to concentrate phenolic extracts, having the results shown an increase on antioxidant activity, and on total phenolic compounds concentration, as well on chlorogenic acid levels.