Optimization of Bioactive Lipid Synthesis by Enzymatic Acidolysis Using EPA + DHA Concentrate from Rainbow Trout and Tocopherols from Maqui Seed Oil

A novel optimized bioactive lipid (OBL) rich in long-chain polyunsaturated omega-3 fatty acids (n-3 LCPUFA) was synthesized through enzymatic acidolysis using concentrated belly oil from rainbow trout (Oncorhynchus mykiss) (CB) and tocopherols obtained from cold-pressed maqui seed oil (Aristotelia chilensis (Mol.) Stuntz) (MSO) under supercritical CO2 conditions. The reaction was catalyzed by Candida antarctica lipase B (CALB) and optimized using a 32 response surface design with 12 experimental runs and three central points, considering pressure (100–300 bar) and temperature (50–80 °C) as independent variables. The response variables included the concentrations of EPA, DHA, α-, β-, γ-, and δ-tocopherols, as well as β- and γ-tocotrienols. MSO contained 10.63, 25.62, and 53.55 g·100 g−1 total fatty acids (TFAs) of α-linolenic, oleic, and linoleic acids, respectively, together with 280.95 mg α-tocopherol·kg−1 and 89.75 mg β-tocotrienol·kg−1. The CB contained 49.57 g EPA + DHA·100 g−1 TFAs. Optimal conditions (72.7 °C and 248.9 bar), experimentally validated at the RSM-predicted point, yielded an OBL containing 41.28 g EPA + DHA·100 g−1 TFAs, 0.39 mg α-tocopherol·kg−1, 3.54 mg β-tocopherol·kg−1, 18.48 mg β-tocotrienol·kg−1, 6.92 mg γ-tocopherol·kg−1, and 16.36 mg γ-tocotrienol·kg−1. Oil quality evaluation using official AOCS methods showed that the OBL exhibited an acceptable oxidative status within international regulatory limits while retaining a measurable phenolic content and intermediate antioxidant capacity derived from MSO. This study demonstrates the successful synthesis of a stable OBL from agro-industrial by-products as a sustainable source of functional ingredients for food, nutraceutical, and cosmetic applications.