Figure 3: IFT isotherms in canola oil/aqueous solution of STEOL®CS-270 surfactant Downward shift of SLES CMC in the presence of permanent concentration of CF yeast exo-protein 1,200 ppm) is observed. After CF was ca. five times concentrated using membrane filtration, this solution of concentrated protein synergist, CCF, was added to surfactant in the amount of 233 ppm. Isotherms with CF and CCF at these settings practically coincided, as expected.