Extraction of value-added compounds from spent coffee grounds using supercritical fluid

Abstract

In this work, supercritical fluid extraction (SFE) using carbon dioxide (CO2) as solvent was used for the recovery of antioxidant phenolic compounds and proteins from spent coffee grounds (SCG). Extraction assays were carried out under different conditions of temperature and pressure. The highest contents of flavonoids (164.57 mg QE/g extract), protein (160.97 mg BSA/g extract), and antioxidant activity (FRAP = 0.5843 mM Fe (II)/g extract; and total antioxidant capacity = 272.26 mg α-tocopherol/g extract) were obtained when using 250 bar and 333.15k. On the other hand, SFE at 200 bar and 313.15k was the best condition to recover phenolic compounds from SCG (33.63 mg GAE/g extract).