Optimization of the reaction conditions in the lipase-catalyzed synthesis of structured triglycerides

Structured triglycerides of the ABA-type, containing one type of fatty acid (A) in the sn-1 and sn-3 positions and a second type of fatty acid (B) in the sn-2 position of the glycerol, were synthesized using lipases. The high est yields and purities were achieved in a two-step process, where a trigly ceride of the B-type was subjected to an alcoholysis reaction in an organic solvent catalyzed by sn-1,3-regiospecific lipases yielding the correspondi ng 2-monoglyceride (2-MG). Using this strategy, e.g., 2-monopalmitin (2-MP) was obtained in up to 88% yield at >95% purity by crystallization. Esterif ication of 2-MP with oleic acid resulted in the formation of 1,3-oleyl-2-pa lmitoyl-glycerol in up to 72% yield containing 94% palmitic acid in the sn- 2 position. The best lipases were from Rhizomucor miehei, Rhizopus delemar, and Rhizopus javanicus. Water activity, sol vent, and carrier for lipase i mmobilization strongly influenced the yield and purity of the products in b oth steps. Futhermore, 2-MG from fish oil were produced by alcoholysis in u p to 84% yield at >95% purity.