分子蒸馏技术纯化甘油二酯工艺优化及产品分析

为得到高纯度的甘油二酯产品，利用分子蒸馏技术对酶催化合成的甘油二酯进行脱酸和纯化。在分别考察进料速率、蒸发面温度和刮板转速对分子蒸馏效果影响的基础上，正交试验得到最佳工艺条件及结果为一级分子蒸馏进料速率2 mL/min、蒸发面温度170 ℃、刮板转速300 r/min，此时纯度达72.51%；经二级分子蒸馏后产品纯度92.31%、酸值0.97 mg KOH/g。与大豆色拉油相比，蒸馏后甘油二酯的硬脂肪酸含量升高，稳定性好，碘值、皂化值和过氧化值降低。

Optimization of Purification of Diacylglycerol by Molecular Distillation and Characterization of Purified Product

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.