Acyl Migration Kinetics of Vegetable Oil 1,2‐Diacylglycerols

Abstract

Abstract The acyl migration kinetics of long‐chain 1,2‐diacylglycerol (1,2‐DAG) to form 1,3‐diacylglycerol (1,3‐DAG) over the temperature range of 25–80 °C were examined using 1 H‐NMR spectroscopy. Lipase‐catalyzed ethanolysis of high‐oleic sunflower oil, followed by a series of solvent extraction steps, generated high purity 1,2‐DAG (0.93 mol fraction of the DAG content). The 1,2‐DAG mole fraction of 0.32 at equilibrium was found to be insensitive to temperature, indicating that long‐chain acyl group migration is neither endothermic nor exothermic. Determination of the temperature‐dependent, first‐order reaction kinetic parameters revealed a 1,2‐DAG half life ( t 1/2 ) of 3,425 h and 15.8 h at 25 and 80 °C, respectively. A comparison of 1,2‐DAG with 2‐monoacylglycerol indicated that there is no difference between the two in the potential energy state (Δ G ‡ ) of their respective transitions states or cyclic intermediates.