Enzymatic production of low-calorie structured lipid from Echium seed oil and lauric acid: Optimisation by response surface methodology

Low-calorie structured lipids (SLs) were produced from Echium seed oil and lauric acid by enzymatic acidolysis reactions. Lipozyme^® RM IM, commercially immobilised sn-1,3 specific lipase derived from Rhizomucor miehei, was used in the reactions. The effects of substrate molar ratio and reaction time on incorporation of lauric acid were investigated and optimised by response surface technology (RSM) with five-level, two-factor central composite design. Good quadratic model was obtained for the response [lauric acid (%) incorporation]. Highest lauric acid incorporation into Echium oil was obtained at 5:1 lauric acid/Echium oil molar ratio and at 4-h reaction time. The model was verified at these conditions and furthermore scale-up synthesis of SLs was performed. At these conditions, SL contained predominantly lauric acid (42.8%), oleic acid (9.9%), linoleic acid (10.8%), α-linolenic acid (15.1%), γ-linolenic acid (7.5%) and stearidonic acid (8.5%) with% 64.4 of PUFA at sn-2 position in gram-scale synthesis.