Characterization of enzymatically synthesized structured lipids containing eicosapentaenoic, docosahexaenoic, and caprylic acids

Structured lipids (SL) containing n-3 polyunsaturated (eicosapentaenoic or docosahexaenoic) and mediumchain (caprylic) fatty acids were synthesized in gram quantities and characterized. Tricaprylin was mixed with n-3-rich polyunsaturated fatty acids in a 1:2 molar ratio and transesterified by incubating at 55°C in hexane with SP 435 lipase (10% by wt of total substrates) in a 125-mL Erlenmeyer flask as the bioreactor. After several batches of reaction, the products were pooled and hexane was evaporated. Short-path distillation was used for purification of synthesized SL. The distillation conditions were 1.1 Torr and 170°C at a feed flow rate of 3 mL/min. Up to 240 g of SL was isolated and deacidified by alkaline extraction or ethanol-water solvents. The fatty acid profile, free fatty acid value, saponification number, iodine value, peroxide value, thiobarbituric acid, and conjugated diene contents were determined. Oxidation stability, with α-tocopherol as antioxidant, and the oxidative stability index were also determined.