SUPERCRITICAL-FLUID FRACTIONATION OF THERMALLY OXIDIZED CANOLA OIL

Supercritical fluid extraction procedures were developed to fractionat e thermally oxidized canola oil. Canola oil was heated in a sealed gla ss ampoule for 72 h at 200 degrees C in a forced convection oven. Afte r heating, the percentages of triacylglycerol (TAG) trimer, dimer, mon omer and lower-molecular weight (LMW) compounds in the heated oil samp le (as determined by high-performance size-exclusion chromatography) w ere 3.0, 8.4, 81.3 and 7.3%, respectively. The LMW compounds included diacylglycerols, monoacylglycerols and free fatty acids. Fractions of TAG monomer of approximately 98% purity were isolated after extraction at 408 atm for 45 min. After a second extraction at 442 atm for 45 mi n, a TAG dimer fraction of 95% purity was isolated. Recoveries of TAG monomer and dimer were 96 and 87%, respectively.