Separation of diacylglycerols from enzymatically hydrolyzed soybean oil by molecular distillation

Soybean oil was partially hydrolyzed by phospholipase A1 (Lecitase Ultra) to produce a mixture of water, diacylglycerols, free fatty acids and unreacted triacylglycerols. The non-polar upper layer (NPUL) composed of acylglycerols and free fatty acids, was treated with a two-step molecular distillation (MD) to separate and purify diacylglycerols. The free fatty acids in the NPUL were removed by the first-step MD at 150 degrees C to obtain the diacylglycerols-enriched soybean oil (DESO) with diacylglycerols purity of 42.64 wt%. Soybean diacylglycerols oil (SDO) with purity more than 80 wt% diacylglycerols was obtained when the DESO from the first-step MD was molecularly distilled at the evaporate temperature of over 220 degrees C at the second-step MD. The changes of antioxidants content in the oils have been investigated and acyl migration of 1,2-DAG to 1,3-DAG during MD has been observed during MD. (C) 2010 Elsevier B.V. All rights reserved.