Preparation and Oxidation Prevention of Functional Polyunsaturated Lipids

Abstract

The paper is based on the article that qualified for the 1999 Japan Oil Chemists' Society Award. Novel methods for obtaining triacylglycerols (PUFA-TG) and glycerophospholipids (PUFA-PL) having functional polyunsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are first reviewed. Physiologically beneficial PUFA-TG with 90% PUFA was prepared through triplicate transacylation of tuna orbital oil with PUFA at 60°C for 7.5h with immobilized lipase from Rhizomucor miehei in combination with ethyleneglycol or propyleneglycol as alternatives for essential water indispensable for enzyme activation. PL with 38% PUFA content was prepared with 83% recovery by 4 repeated transacylations of soy PL with polyunsaturated monoacylglycerol (PUFA-MG) using microbial lipase from Candida cylindracea. PUFA-MG could be used in place of essential water for inducing enzyme activity and also as a polyunsaturated acyl donor.Study was made of the antioxidative and synergistic effects of amino compounds for autoxidation of PUFA-TG. Amino compounds such as nitrogen-containing PLs, alkylamines and spermine were found to possess but little antioxidative activity compared to the tocopherol mixture. The remarkable synergistic activity of primary amino group toward tocopherols was detected in the autoxidation of PUFA-TG in non-aqueous or emulsifying systems. Primary amino hydrogen in amino compounds may possibly function quite well as hydrogen radical donors for regenerating tocopherols.