Structured lipids were successfully synthesized by lipase-catalyzed transesterifcation (acidolysis) of caprylic acid and triolein in nonaqueous medium.Twelve commercially available lipases (I 0% , w/w substrates) were screened for their ability to form structured lipid by incubating 100 mg triolein and 65.3 mg caprylic acid in 3 ml hexane at 55C for 24 h. 7he products were analyzed by reverse-phase high pe$ormunce liquid chromatography (HPLC) with evaporative light scattering detection. Monocapryloolein was the major component of the products (57.4 mol %) and IM60 lipase from Rhizomucor miehei was the best biocatalyst. Dicapryloolein and triolein contents were 35.4% and 5.3 %, respectively. Temperature, mole ratio, time course, incubation media, added water, enzyme load, and substrate concentration were also investigated in this study. The results suggest that it is possible to synthesize structured lipids with lipase as biocatalyst.

The ability of immobilized lipases IM60 fromMucor miehei and SP435 fromCandida antarctica to modify the fatty acid composition of selected vegetable oils by incorporation of n−3 polyunsaturated fatty acids into the vegetable oils was studied. The transesterification was carried out in organic solvent with free acid and ethyl esters of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) as acyl donors. With free EPA as acyl donor, IM60 gave higher incorporation of EPA than SP435. However, when ethyl esters of EPA and DHA were the acyl donors, SP435 gave higher incorporation of EPA and DHA than IM60. When IM60 and free acid were used, the addition of 5 μL water increased EPA incorporation into soybean oil by 4.9%. With ethyl ester of EPA as acyl donor, addition of 2 μL water increased EPA incorporation by 3.9%. For SP435, addition of water up to 2μL resulted in increased EPA incorporation, but the incorporation declined when the added water exceeded this amount. The addition of water increased the EPA incorporation into Trisun 90 after 24 h reaction but not the reaction rate at early stages of the reaction.

Structured lipids were successfully synthesized by lipase-catalyzed transesterification (ester interchange) of caprylic acid ethyl ester and triolein. The transesterification reaction was carried out in organic solvent as reaction media. Eight commercially-available lipases (10% w/w substrates) were screened for their ability to synthesize structured lipid by incubating with 100 mg triolein and 78.0 mg caprylic acid ethyl ester in 3 mL hexane at 45~ for 24 h. The products were analyzed by reverse-phase high-performance liquid chromatography with evaporative light-scattering detector. Immobilized lipase IM60 from Rhizomucor miehei converted most triolein into structured lipids (41.7% dicapryloolein, 46.0% monocapryloolein, and 12.3% unreacted triolein). However, lipase SP435 from Candida antarctica had a higher activity at higher temperature. The reaction catalyzed by lipase SP435 yielded 62.0% dicapryloolein, 33.5% monocapryloolein, and 4.5% unreacted triolein at 55~ Time course, incubation media, added water, and substrate concentration were also investigated in this study. The results suggest that lipase-catalyzed transesterification of long-chain triglycerides and medium-chain fatty acid ethyl ester is feasible to synthesize structured lipids. JAOCS 73, 245-250 (1996).

Two immobilized lipases, IM60 from Mucor miehei and SP435 from Candida antárctica, were used as biocatalysts for the modification of the fatty acid composition of crude melon seed (Citrullus colocynthis L) oil by incorporating n-3 polyunsaturated fatty acid (PUFA). Higher eicosapentaenoic acid (EPA) incorporation was obtained by using EPA ethyl ester (97% pure) than by using EPA free acid (45% pure) for both enzyme-catalyzed reactions. IM60 required additional water to optimize the reaction condition, but any added water inhibited the catalytic activity of SP435. Increasing the molar ratio of acid or ester to triacylglycerol (TAG) significantly increased EPA incorporation, especially when EPA ethyl ester was used. The n-6 fatty acid content of melon seed oil was significantly lowered by using a high molar ratio of EPA ethyl ester to TAG. Incorporation of EPA into melon seed oil by immobilized lipase can increase the n-3 PUFA content, can help control the level of n-6 fatty acid, and may improve the nutritional quality of melon seed oil.