Journal of Food Research; Vol. 2, No. 6; 2013 ISSN 1927-0887 E-ISSN 1927-0895 Published by Canadian Center of Science and Education 97 Optimization of the Lipase Catalyzed Production of Structured Acylglycerols With Polyunsaturated Fatty Acids Isolated From Sardine Oil Juan Antonio Noriega-Rodríguez 1 , Esther Carrillo-Perez 1 , Nohemí Gámez-Meza 2 , Luis A. Medina-Juárez 2 , Ramiro Baeza-Jiménez 3 & Hugo S. García 4 1 Departamento de Ingeniería Química y Metalurgia, Universidad de Sonora, Hermosillo Sonora, México 2 Departamento de Investigaciones Científicas y Tecnológicas, Universidad de Sonora, Hermosillo Sonora, México 3 Centro Conjunto de Investigación en Química Sustentable. Universidad Autónoma del Estado de México. Toluca, Estado de México, México 4 Unidad de Investigación y Desarrollo en Alimentos, Instituto Tecnológico de Veracruz, Veracruz México Correspondence: Juan Antonio Noriega-Rodríguez, Departamento de Ingeniería Química y Metalurgia, Universidad de Sonora, Hermosillo Sonora, México. Tel: 52-662-259-2106. E-mail: janoriega@guayacan.uson.mx Received: August 26, 2013 Accepted: October 30, 2013 Online Published: November 19, 2013 doi:10.5539/jfr.v2n6p97 URL: http://dx.doi.org/10.5539/jfr.v2n6p97 Abstract In the present work, direct enzyme-catalyzed esterification of n-3 polyunsaturated fatty acids (n-3 PUFA) isolated from sardine oil was optimized to obtain structured acyglycerols. A n-3 PUFA concentrate was prepared by urea crystallization of refined sardine oil and esterification was carried out mixing free fatty acids and glycerol at different molar ratios (M = 0.48, 1.5, 3.0, 4.5 and 5.52 mol/mol), using an immobilized lipase preparation from Candida antarctica (NV-435) at different temperatures (T = 38, 45, 55, 65 and 72 °C) and reaction times (t = 0.7, 2.75, 5.75, 8.75 and 10.8 h) in a rotatable central composition design. The degree of esterification was determined by analysis of the acylglycerides produced, using liquid chromatography (HPLC-ELSD). Optimization by response surface methodology (RSM) showed that in order to obtain higher esterification levels of n-3 PUFA to glycerol (99.5%), a molar ratio of 1.3 mol n-3 PUFA/mol glycerol, time 8.3 h and temperature 38 °C, are required. However, results of this work show that it is possible to drive the reaction to any determined product (MAG, DAG or TAG) by modifying the reaction conditions. Keywords: acylglycerides, enzymatic esterification, polyunsaturated fatty acids, response surface methodology, sardine oil, hplc-elsd 1. Introduction N-3 polyunsaturated fatty acids (n-3 PUFA) are essential fatty acids because they cannot be synthesized by humans and animals; their tissues lack the enzymatic mechanism to insert double bonds before carbon nine from the end methyl group (Makrides, Neumann, & Gibson, 1996). The well documented health beneficial effects of n-3 PUFA for cardiovascular disease, rheumatoid arthritis, immune function and cancer (Mantzioris, Cleland, & Gibson, 2000; Li, Bode, Drummond, & Sinclair, 2003; Cleland, Caughey, James, & Proudman, 2006) have promoted the rapid development of the nutraceutical and pharmaceutical markets (Young, 2003). One of the most important effects of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids is the prevention of arrhythmias (Sellmayer & Koletzco, 1999); furthermore, researchers have concluded that n-3 PUFA can reduce the amount of triacylglycerides (TAG) in 25 and 30%, with a dose of 2 and 3 g/day (Harris & Isley, 2001). Fish oil is well known for its high content of n-3 fatty acids (FA), with documented benefits on human health (Nettleton, 1994). DHA has proven capable to reduce the risk of heart disease and inflammatory cytokines (Simopoulos, 2002; Von Schacky, 2007). Additionally, DHA inhibits tumour cells growth (Zhang, Long, Zhang, & Wang, 2007) and it can be consumed as acylglycerol for its moderate absorption and less oxidation compared to the free fatty acid form (Valenzuela, Valenzuela, Sanhueza, & Nieto, 2005). Different methods have been