SYNTHESIS OF STRUCTURED TRIGLYCERIDES BY LIPASE CATALYSIS

The synthesis of structured triglycerides containing medium chain fatt y acids (M) in sn1 and sn3-position and an unsaturated long-chain fatt y acid (L) in sn2-position of the glycerol backbone (MLM) with 1,3-reg iospecific lipases has been investigated. In an one-step synthesis (ac idolysis or transesterification) various commercial lipases were teste d. In all reaction systems, the recovered product contained considerab le amounts of undesired byproduct (e.g. MLL). A significantly higher c oncentration of MLM was obtained in a two-step process under the contr ol of the water activity: In the first step, the 2-monoglycerides (2-M G) were prepared by alcoholysis (e.g. with ethanol) of pure triglyceri des (triolein and trilinolein) or a natural oil (cottonseed oil) with lipase from Rhizopus delemar immobilized on Celite(R) in organic solve nts (e.g. methyl tert-butyl ether). The 2-MGs were purified by crystal lization and isolated in yields up to 71.8% (e.g. from triolein). The 2-MGs obtained from cottonseed oil was esterified in the second step w ith caprylic acid in n-hexane using lipase from Rhizomucor miehei (Lip ozyme). The final product contained more than 94% caprylic acid in sn1 - and sn3-position, whereas the sn2-position was composed of 78% of un saturated long-chain fatty acids.