Quantitation of acyl migration during lipase-catalyzed acidolysis, and of the regioisomers of structured triacylglycerols formed

Various MLM-type (M, medium-chain fatty acids; L, long-chain fatty acids) s tructured triacylglycerols were produced in pilot- or small-scale packed-be d reactors by lipase-catalyzed acidolysis. The incorporation and acyl migra tion of octanoic acid were measured by gas chromatography and Grignard degr adation, and ranged from 39.0 to 48.7% and 0.6 to 9.3%, respectively. Quant itation of triacylglycerol molecular species was performed by ammonia negat ive ion chemical ionization (NICI) mass spectrometry (MS). The proportion o f ACN (acyl carbon number) 34 species that contained one C-18 fatty acid an d two C-8:0, in samples analyzed, varied from 12.5 to 23.2%. The selected r egioisomers MLM and MML within the ACN 34 species group were quantified by NICI tandem MS (MS/MS) and were in the range of 97.1 to 98.4% and 1.6 to 2. 9%, respectively. There was no correlation between the level of acyl migrat ion during lipase-catalyzed esterification and the level of regioisomers of the selected MLM-type triacylglycerols in the structured lipid samples.