Developing an on-line extraction -reaction process for lipids using supercritical carbon dioxide

Lipase-catalyzed hydrolysis of canola oil in supercritical CO2 (SCCO2) was used as a model reaction to develop an on-line extraction-reaction system to extract oil from oilseeds and to convert them to high-value products in a supercritical fluid (SCF). The optimum reaction conditions (24 MPa and 35°C) were obtained by investigating the effect of pressure, temperature and CO2 flow rate on the continuous hydrolysis of a commercially refined canola oil. Although, overall enzyme performance was not affected by a change in the CO2 flow rate, a higher triglyceride (TG) and free fatty acid (FFA) fraction and a lower monoglyceride (MG) and diglyceride (DG) fraction were observed at a lower CO2 flow rate.;The diffusion coefficient (D12) is a fundamental parameter in the mass transfer of lipids during supercritical extraction and reactions. D12 of several lipid classes was determined in SCCO2 applying the Taylor-Aris peak broadening technique. Presence of a secondary solvent as well as an increase in temperature or a decrease in pressure led to an increase in D12 of oleic acid. D12 of FFA was reduced by an increase in the number of double bonds or a change in the position of double bound from o-3 to o-6. D12 of lipid classes decreased in the following order: methyl ester > ethyl ester > FFA > TG.;An on-line extraction-reaction process using SCCO2 as developed in this study shows great potential for new process design in the production of high-value products from agricultural commodities, which will be used as ingredients in food and various other industries.;The effect of enzyme load, CO2 flow rate and oil content on the product composition and total production of products was investigated in the on-line extraction-reaction of oil from canola flakes at 24 MPa and 35°C. A higher extent of hydrolysis was observed with an increase in the enzyme load, a decrease in CO2 flow rate or a decrease in canola load. Scanning electron microscopy (SEM) did not demonstrate any apparent structural changes on the immobilized enzyme.