Efficiency of foam fractionation for the enrichment of nonpolar compounds from aqueous extracts of plant materials.

Biologically active compounds from several useful plants were enriched using foam fractionation, a separatory method belonging to the adsorptive bubble separation (ABS). Nonpolar humulones (1-6) from Pilsener beer, curcuminoids (7-9) from turmeric, and carotenoids (16 and 17) from carrot juice were enriched fast and quantitatively, depending on the process parameters, whereas more polar compounds such as catechins from green tea (11, 12, 14, and 15) and naringin (18) and hesperidin (19) from orange and grapefruit juices could not be enriched.