The non-polar and low-polar compounds whose extraction was examined were b- carotene from leaves and b-sitosterol from roots. Thus, cuticular waxes dissolved in carbon dioxide act as b-carotene entrainer. When the extraction of b-carotene is finished, the extraction of oleoresin slowly continues, especially at higher ethanol concentrations in the solvent, but this fraction of oleoresin may be composed of different compounds than cuticular waxes.

Figure 52 : Corelation of b-carotene and oleoresin yields from stinging nettle leaves.

(+) Experimental data, 20-28 MPa, 25-60 °C, 0-7.1 wt.% ethanol in CO2; (——) fitted curve

of the slope 9.3 mg/g.