Preparation of structured lipids enriched with medium- and long-chain triacylglycerols by enzymatic interesterification for infant formula

•SLs enriched with medium and long-chain triacylglycerols by enzymatic interesterification were prepared.•The highest yield of MLCTs was achieved by Lipozyme 435 from Candida antarctica.•The optimized conditions produced MLCTs with a yield of 53.75%. Single cell oils (SCOs) are considered as important sources of the essential fatty acids (EFAs) such as arachidonic acid (ARA), which is of great importance for infant’s growth and development. Medium-chain triacylglycerols (MCTs) induce the residual glyceride lipolysis, which improve fat absorption, and thus reduce its deposition in infants. Medium- and long-chain triacylglycerols (MLCTs)-rich structured lipids (SLs) combine these benefits, and they can be delivered to infants in an easy way. In this study, MLCTs-rich SLs were synthesized by lipase-catalyzed interesterification of ARASCO with MCTs in a solvent-free system. Four commercial immobilized lipases from different sources were compared for their efficiency in the production of MLCTs yield. The results indicated that the highest yield of MLCTs was achieved by Lipozyme 435 from Candida antarctica as a biocatalyst. The best reaction conditions were as follows; enzyme load 8% (w/w), reaction temperature 90°C, reaction time of 3h, and substrates mole ratio 1:1. Under these conditions, MLCTs were obtained in a yield of 53.75%. Thermoprofile displayed that the MLCTs-rich SLs melted below body temperature of 37°C. The obtained MLCTs-rich SLs can be suggested as a nutritional and functional fat analogue with potential applications in infant formula industry.