Production of structured lipids by lipase-catalyzed acidolysis in supercritical carbon dioxide: Effect on acyl migration

摘要

Structured lipids were synthesized by the acidolysis of corn oil by caprylic acid in supercritical carbon dioxide (SCCO2) with Lipozyme RM IM from Rhizomucor miehei. The effects of pressure and temperature on the reaction were studied. To compare the degrees of acyl migration in the SCCO2 and solvent-free reaction systems, the effects of reaction time on the degree of acyl migration were also studied. The highest mole percentage incorporation of caprylic acid (62.2 mol%) occurred at 24.13 MPa in SCCO2. The overall incorporation of caprylic acid in the SCCO2 system remained higher than that in the solvent-free system at every temperature tested. This trend was observed more clearly at lower temperatures (35–55°C) than at higher temperatures (65–75°C). Acyl migration with both reaction systems was low, with a negligible difference between them up to 12 h, after which the degree of acyl migration in the solvent-free system increased rapidly with time up to 24 h compared with the SCCO2 system.