Modeling lipase-catalyzed interesterification of flaxseed oil and tricaprylin for the synthesis of structured lipids

The biosynthesis of structured lipids (SLs) in organic solvent media (OSM) was carried out by the interesterification of flaxseed oil (FO) TAGs and tricaprylin (TC) using Lipozyme TL-IM from Thermomyces lanuginosus. The bioconversion yield (BY, %) of medium-long-medium type SLs (MLM-SLs), including CLnC (C-caprylic and Ln-linolenic acids), CLaC (La-linoleic acid) and COC (O-oleic acid), was monitored. Response surface methodology (RSM) was used to obtain significant models for the responses and to optimize the interesterification reaction, on the basis of a three level, five variable fractional factorial design (FFD) with center points. For the optimization of the interesterification reaction significant parameters, including reaction time (Rt), reaction temperature (Tr), TC to FO molar ratio (Mr), enzyme concentration (Ec), and agitation speed (As, 100–300 rpm), were considered. The optimal conditions generated for the maximum synthesis of CLnC, CLaC and COC, were found to be, 4.00–4.01 h for Rt, 41.49–50.00 °C for Tr, 1.5% for Ec, 5.00–5.13 mol/mol for Mr and 260–300 rpm for As. Under these optimal conditions, the BY of CLnC, CLaC and COC were predicted to be 35.34–35.45, 4.09–4.19 and 8.44–8.53%, respectively.