Biosynthesis of structured lipids enriched with medium and long-chain triacylglycerols for human milk fat substitute

Human milk fat is rich in medium and long-chain triacylglycerol (MLCT), especially the triacylglycerol with one medium-chain fatty acid and two long-chain fatty acids (MLL type). To obtain human milk fat substitutes having similarity in medium and long-chain triacylglycerol (MLCT) composition to human milk, structured lipids (SLs) enriched with medium-chain fatty acid and high content of 16:0 at sn-2 position of glycerol backbone were synthesized from catfish oil and coconut oil through enzymatic interesterification. The different immobilized lipases and the reaction conditions (substrate ratio, temperature, enzyme load and reaction time) were investigated. Under the optimal conditions, the content of MLCT and MLL reached 62.14% and 39.85%, respectively. Moreover, the relative content of 16:0 at the sn-2 position was 46.14%, and the most abundant TAGs in the final SL were 12:0/16:0/18:1, 12:0/18:1/18:1, 12:0/14:0/18:1, 12:0/12:0/18:1. The novel SLs as human milk fat substitutes enriched with MLCTs was produced and have potential application in infant formulas.