Production of Structured Lipids by Lipase-Catalyzed Acidolysis in Supercritical Carbon Dioxide:Effect on Acyl Migration

摘要

Structured lipids were synthesized by the acidoly-sis of corn oil by caprylic acid in supercritical carbon dioxide (SCCO_2)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 SCCO_2 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 SCCO_2.The overall incorporation of caprylic acid in the SCCO-,system remained higher than that in the solvent-free system at every temperature tested.This trend was observed more clearly at lower temperatures (35-55deg C)than at higher temperatures (65-75deg 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 SCCO_2 system.