Extraction conditions and moisture content of canola flakes as related to lipid composition of supercritical CO2 extracts

Canola flakes obtained before and after conventional cooking were extracted with supercritical carbon dioxide (SC-CO2) at 35-75 degrees C and 20.7-62.0 MPa. Moisture content was adjusted to 12.7-42.5% (why, moisture- and oil-free basis). Moisture content of residual flakes after extraction was monitored. Amount of extract recovered increased with increasing temperature and pressure, except at 20.7 MPa pressure it decreased with temperature indicating a crossover of the solubility isotherms. Some water was co-extracted with canola oil. Free fatty acid (FFA) concentration of the extracts increased with decreasing pressure due to a decrease in triglyceride (TG) solubility. Oleic and linolenic acids had highest concentrations in the FFA fractions of all extracts. The lowest TG content of extracts was attained at 20.7 MPa and 75 degrees C. The effect of extraction conditions was more pronounced than seed pre-treatments on yield and composition of SC-CO2 extracts.