Production of diacylglycerols through low-temperature chemical glycerolysis

The aim of this study was to produce diacylglycerols (DAG) by chemical glycerolysis of soybean oil at low temperatures. Solvents and low-frequency ultrasonic irradiation were introduced to enhance the reaction. Three operation modes, namely mechanical stirring, magnetic stirring and ultrasonic irradiation, were compared. In the solvent-free system, DAG formation was not observed in any of the three operation systems. DAG were formed when reactions were incubated in tertiary alcohols for all of the three operation systems. Interesting observations were found in the acetone system. Although DAG formation was negligible under mechanical stirring with classical propeller, a total of 52.0 ± 2.2% DAG was obtained when ultrasonic irradiation was used. The same content of DAG can also be obtained under magnetic stirring; however, a 4-h reaction was required. Acetone dosage (solvent:oil, wt:wt) 3:1 and 40 W ultrasonic power were suitable for the reaction system under the conditions studied.