Synthesis of structured triacylglycerols containing medium-chain and long-chain fatty acids by interesterification with a stereoespecific lipase from Mucor miehei.

Susana Nieto,Alfonso Valenzuela,Julio Sanhueza

doi:10.3989/gya.1999.v50.i3.656

Abstract

The preparation of structured triacylglycerols sn-1, sn-3 dilauryl, sn-2 eicosapentaenoyl glycerol and sn-1, sn-3 dilauryl, sn-2 docosahexaenoyl glycerol by enzymatic interesterification under restricted water availability is described. Laurie acid, one of the substrates for interesterification, was obtained by the controlled hydrolysis of coconut oil by a non-specific lipase obtained from Candida cylindracea . The fatty acid was separated from the hydrolysis products by silverresin column chromatography and converted to methyl ester, sn-2 Eicosapentaenoyl glycerol and sn-2 docosahexaenoyl glycerol were prepared by the hydrolysis of fish oil by the sn-1, sn-3 stereospecific immobilized lipase Lipozyme IM-20 obtained from Mucor miehei as described in the accompanying paper. The interesterification was carried out in a water jacketed glass reactor and the triacylglycerol products were separated and recovered through aluminum oxide column chromatography The interesterification procedure described allows to obtain In laboratory scale structured triacylglycerols containing medium-chain fatty acids at the sn-1 and sn-3 positions and long-chain polyunsaturated fatty acid from marine origin at the sn-2 glycerol position.

Highlights

Physical properties as well as nutritional value of triacylglycerols (TGs) are based on the fatty acid composition and on the positional distribution of the fatty acids bound to glycerol (Heird et al, 1986)
Ester hydrolysis is favored under high water availability, but ester synthesis may be conducted under restricted water availability where a minimum quantity of water is necessary for enzyme catalysis to take place (Lindfield et a/., 1984)
Laurie acid was converted to the methyl ester derivative which was used as substrate for the interesterification reaction

Summary

Introduction

Physical properties as well as nutritional value of triacylglycerols (TGs) are based on the fatty acid composition and on the positional distribution of the fatty acids bound to glycerol (Heird et al, 1986). In this paper we describe the lipase-catalyzed interesterification of two long-chain polyunsaturated acylglycerols, sn-2 eicosapentaenoyi glycerol and sn-2 docosahexaenoyi glycerol, with lauric acid, a saturated medium-chain fatty acid, to obtain two types of structured TGs of potential useful nutritional and/or pharmacological application.

Results

Conclusion