cause a channeling effect, where the solvent is forced
through the sample at such a high rate that it passes only around
the solid matrix and is not able to diffuse through the pores within
the sample. The increased CO2 flow also could cause the sample to
compact and restrict CO2 movement into and out of the sample,
reducing the amount of CO2 that comes in contact with the sample
(Tonthubthimthong et al., 2001). Based on the contrary reasons
above, it is clear that the extraction process was limited by the solubility
of solute in the supercritical CO2.