Journal of Zhejiang University SCIENCE
(ISSN 1009-3095, Monthly)

2005   Vol. 6B   No. 10   p.999-1004

Optimization of conditions for supercritical fluid extraction of flavonoids from hops (Humulus lupulus L.)

HE Guo-qing^†1, XIONG Hao-ping^†‡1, CHEN Qi-he¹, RUAN Hui¹, WANG Zhao-yue¹, TRAORÉ Lonseny²

(¹Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310029, China)
(²Department of Food Science and Nutrition, University of Conakry PB 1147, Guinea)
^†E-mail: gqhe@zju.edu.cn; hpxiong@126.com
Received Mar. 1, 2005; revision accepted June 9, 2005

Abstract: Waste hops are good sources of flavonoids. Extraction of flavonoids from waste hops (SC-CO₂ extracted hops) using supercritical fluids technology was investigated. Various temperatures, pressures and concentrations of ethanol (modifier) and the ratio (w/w) of solvent to material were tested in this study. The results of single factor and orthogonal experiments showed that at 50 °C, 25 MPa, the ratio of solvent to material (50%), ethanol concentration (80%) resulted in maximum extraction yield flavonoids (7.8 mg/g). HPLC-MS analysis of the extracts indicated that flavonoids obtained were xanthohumol, the principal prenylflavonoid in hops.

Key words: Optimization, Supercritical fluid extraction, Flavonoids, Xanthohumol, Hops (Humulus lupulus L.)
doi:10.1631/jzus.2005.B0999             CLC number: TS201

^‡ Corresponding Author