Valorization of coffee bean husk via pressurized liquid extraction for production of physicochemical extract

BACKGROUND In this study, obtaining phytochemical compounds from coffee bean husk (Arabica variety) under pressurized conditions (PLE) was investigated. For this, an experimental design was applied to evaluate the efficiency of the extraction in different conditions of temperature, solvent to husk ratio, and composition of the hydroethanolic solvent, and to determine the maximum extraction conditions of total phenolic acids (TPA). The dry extract obtained under different conditions and by Soxhlet extraction was characterized.RESULTS The conditions evaluated in the PLE showed that the composition of the hydroethanolic solvent had a greater influence on the results and the maximum extraction of TPA in the liquid extract (3.61 mg CAE 100 g(husk)(-1)) was achieved with 50% (v/v) ethanol in solvent, 45 mL g(-1) and 80 degrees C. Under these operational conditions, the extract obtained showed high mass yield (G(Y)) and antioxidant activity (AA). Under pressurized conditions, synergism between operational variables and the presence of phytochemical compounds could be observed. Comparing the techniques, PLE provided a higher G(Y) and AA, demonstrating the efficiency and selectivity of this technique in obtaining biologically active compounds. The main phenolic acids identified in the dry extract were gallic and chlorogenic, indicating an important role as an antioxidant and suggesting potential for its use.CONCLUSION PLE is a potential method for green extraction to obtain a phytochemical extract from coffee bean husk; when associated with the recovery of compounds by obtaining the dry extract, PLE presents advantages related to storage and handling, thus representing a starting point for the development of nutraceuticals that can be easily used as ingredients or additives in the chemical industry. (c) 2023 Society of Chemical Industry (SCI).