2003 Volume 52 Issue 7 Pages 367-374
It was attempted to prepare cis-9, trans-11 conjugated linoleic acid (c9,t11-CLA) and t10,c12-CLA concentrates that can be used as foods. A free fatty acid mixture (FFA-CLA) containing almost equal amounts of c9,t11- and t10,c12-CLAs was esterified with glycerol using immobilized Rhizomucor miehei lipase, and the resulting acylglycerols (Gly-CLA) were purified by molecular distillation. Contents of c9,t11- and t10,c12-CLAs in Gly-CLA were the same as those in FFA-CLA: c9,t11-CLA, 33.7 wt%; t10,c12-CLA, 34.5 wt%. Gly-CLA was first hydrolyzed with an equal weight of water and 1.0 U/g-mixture of Candida rugosa lipase, and c9,t11-CLA-rich FFAs were prepared by molecular distillation: purity of c9,t11-CLA based on the total content of c9,t11- and t10,c12-CLAs, 72.9%. Meanwhile, purity of t10,c12-CLA in acylglycerols was 65.0%. To further increase the purity, the acylglycerols were hydrolyzed again with 15 U/g-mixture of C. rugosa lipase, resulting in enrichment of t10,c12-CLA in acylglycerols (purity of t10,c12-CLA, 80.4%). Non-selective hydrolysis of t10,c12-CLA-rich acylglycerols with 200 U/g-mixture of C. rugosa lipase produced t10,c12-CLA-rich FFAs (purity of t10,c12-CLA, 81.5%). In addition, c9,t11-CLA-rich FFAs were successfully esterified with glycerol using immobilized R. miehei lipase, and c9,t11-CLA-rich acylglycerols can be synthesized (purity of c9,t11-CLA, 73.0%). The process was composed of reactions with C. rugosa and R. miehei lipases, which can be used for production of foods, and molecular distillation. Hence, the c9,t11- and t10,c12-CLA concentrates can be used as foods.
