High hydrostatic pressure extraction of flavonoids from propolis

A high hydrostatic pressure extraction (HHPE) method is presented for the extraction of flavonoids from propolis. Various experimental conditions of the HHPE process, such as solvents, ethanol concentration (35-95%, v/v), HHPE pressure (100-600 MPa), HHPE time (1-10 min) and solid/liquid ratio (1:5 - 1:45 g cm(-3)), were investigated to optimize the extraction process. The extraction yield with HHPE for 1 min was higher than those using extraction at room temperature for 7 days and heat reflux extraction for 4 h respectively. From the viewpoints of extraction time, the extraction efficiency and the extraction yield of flavonoids, HHPE was more effective than the conventional extraction methods studied. (C) 2004 Society of Chemical Industry.