The invention discloses a method for preparing
diglyceride by enzymatically catalyzing
glycerol by a supercritical CO2
system.
Diglyceride (
Diglyceride, DAG) is a natural ingredient of oil, has the content of about 5 percent, is an ingredient with stronger function in natrual oil and can be divided into two kinds of 1, 2-DAG and 1, 3-DAG according to different combination positions of acyl and
glycerol hyroxyl, wherein the active function of the 1, 3-DAG is better. In recent years, by taking the natural oil as a
raw material, the method for preparing the DAG comprises a
glycerolysis method, a
hydrolysis method, a
hydrolysis-esterification
combined method and the like. At present, the
glycerolysis method is mainly adopted, but has low reaction yield and has little 1, 3-DAG content. In a supercritical state, a CO2 fluid simultaneously plays the roles of a
solvent and a catalyst and can efficiently avoid the phenomena of catalyst positioning, inactivation and the like. In addition, moreimportantly, the CO2 fluid can prevent
glycerolysis reverse reaction in the reaction environment. The
diglyceride content in a product generated through the method is 70.2 percent, wherein the content of the 1, 3-DAG can reach 48.8 percent.