Supercritical fluid fractionation of thermally oxidized canola oil

Supercritical fluid extraction procedures were developed to fractionate thermally oxidized canola oil. Canola oil was heated in a sealed glass ampoule for 72 h at 200°C in a forced‐convection oven. After heating, the percentages of triacylglycerol (TAG) trimer, dimer, monomer and lowermolecular weight (LMW) compounds in the heated oil sample (as determined by high‐performance size‐exclusion chromatography) were 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 min, a TAG dimer fraction of 95% purity was isolated. Recoveries of TAG monomer and dimer were 96 and 87%, respectively.