Structured lipids resembling human milk fat ( HMF) enriched with omega- 3 fatty acids were synthesized by enzymatic acidolysis reactions between tripalmitin, hazelnut oil fatty acids ( FA), and omega- 3 FA concentrate. Response surface methodology was used to model and optimize the incorporation of omega- 3 FA and oleic acid into tripalmitin, in hexane, using immobilized sn- 1,3- specific lipase, Lipozyme RM IM. The three factors chosen were substrate molar ratio, reaction temperature, and reaction time. Good quadratic models were obtained for the incorporation of eicosapentaenoic acid ( EPA) plus docosahexaenoic acid ( DHA) ( response 1) and oleic acid ( response 2) by multiple regression and backward elimination. The determination coefficient ( R 2) value for the models was 0.95. The adjusted R-2 values were 0.91 and 0.92 for responses 1 and 2, respectively. The optimal conditions generated from the models for the targeted total EPA and DHA ( 5%) and oleic acid ( 40%) incorporation were 12.4 mol/ mol, 55 degrees C, and 24 h for substrate ratio, temperature, and time, respectively. The model was verified, which led to the production of a HMF ingredient with 76.6% palmitic acid at the sn- 2 position.