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The examined polar compounds were lutein and chlorophylls a and b from the leaves and scopoletin from the roots of stinging nettle. The extraction of any of them was not synchronised with the extraction of oleoresin; the transition from the faster extraction of free solute to the slower extraction of the solute interacting with matrix occurred much later for polar compounds than for oleoresin. Besides, the equilibrium relationship was, except for lutein, of a more complicated form than direct proportionality.
Figure 53 : Effect of the solvent modifier on the extraction of lutein at 40 ºC and 28 MPa.
Ethanol conc. in CO2: (u) 0 wt.%; (n) 3.0 wt.%; (ê) 4.4 wt.%; (5) 5.7 wt.%; (m) 7.1 wt.%.
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