Use of Echium oil fatty acids and tricaprylin as substrates of enzymatic interesterification for the production of structured lipids

Abstract

Structured lipids (SLs) were produced from the free fatty acids of Echium oil and tricaprylin by enzymatic acidolysis reactions. Lipozyme® RM IM, immobilized sn-1,3 specific lipase was used in the enzymatic reactions. In order to optimize the incorporation of stearidonic acid (SDA), three factors were chosen [Reaction temperature (50-60 ºC), reaction time (6-12 hour) and substrate molar ratio (3-6 mol/mol (total free fatty acids/ tricaprylin)] for the application of response surface methodology (RSM) using a central composite circumscribed design (CCC) with five levels. The optimum temperature, time and substrate molar ratio obtained from the models were 60 ºC; 6 h, 6 mol/mol, respectively. Furthermore, SLs with 6.2% SDA content at sn-2 position were produced by scaling up the process. SL was obtained with nearly 78-79% of long-chain fatty acids at the sn-2 position. According to the melting profile analysis, the melting peaks of tricaprylin and Echium oil were sharper and narrower while the SL had more broadened peaks.