Evaluation of 3-monochloropropanol esters and glycidyl esters during the production and concentration of diacylglycerol by two-stage short-path molecular distillation

Abstract Diacylglycerol (DAG) has been drawing increased global attention due to its health benefits; however, there is a biggest challenge raised by 3-monochloropropyl esters (3-MCPDEs) and glycidyl esters (GEs) during its preparation and concentration. Herein, a model firstly was clarified and evaluated for the preparation of 48.9% DAG achieved by enzymatic glycerolysis of soybean oil in a solvent-free system though Response Surface Methodology. Subsequently, the resulted DAG was concentrated to 79.7%, involving 75.1% 1,3-diacylglycerol and 24.9% 1,2-diacylglycerol due to the steric effect and/or acyl migration, thought two-stage short path molecular distillation (SPD), and 3-MCPDEs and GEs were concomitantly evaluated during the concentration. Comparative investigation of various SPD parameters (e.g., temperature, scraping speed and feed rate), temperature was dominant and dependency in both 3-MCPDEs and GEs formation during the primary molecular distillation. However, it has a less effect on the formation of 3-MCPDEs and more effect on levels of GEs during the secondary molecular distillation process. Nonetheless, the DAG and chloride increases the probability of formation of both 3-MCPDEs and GEs. The results may promote the engineering production of DAG with high purity and quality.