Abstract:

This study aimed to obtain a diacylgcerol (DAG) product with high purity. Molecular distillation was used
in deacidification and purification of DAG prepared by enzymatic synthesis. The effects of dripping speed, distillation
temperature and rotation speed on the molecular distillation were investigated. Based on single factor experiments,
the molecular distillation conditions were optimized by orthogonal array design as follows: dripping speed, 2 mL/min;
distillation temperature, 170 ℃; and rotation speed, 300 r/min. Under these optimal conditions, the purity of DAG was
72.51%. After a two-step molecular distillation under the same conditions, the purity of DAG was 92.31% with an acid value
of 0.97 mg KOH/g. Compared with soybean salad oil, the purified DAG had some advantages including higher stearic acid
content, higher stability, and lower iodine value, saponification value and peroxide value.

Key words: diacylglycerol, molecular distillation, deacidification, purification