Investigation of high-pressure phase transitions in DAG (diacylglycerol) oil using the Bleustein-Gulyaev ultrasonic wave method

In this paper, phase transitions in diacylglycerol (DAG) oil are investigated by using an ultrasonic method for measuring viscosity. Viscosity of diacylglycerol (DAG) oil is measured over a wide range of hydrostatic pressures up to 500 MPa, and at temperatures ranging from 10 to 40 °C. The observed discontinuities in the viscosity versus pressure curves (isotherms) indicate phase transitions. An original ultrasonic method that uses the surface acoustic Bleustein-Gulyaev (B-G) wave was employed to measure the viscosity of DAG oil at high pressure range. This method allows for fast and reliable measurement of DAG oil viscosity along various isotherms. Moreover, the kinetics of the observed phase transformations at various temperatures was analyzed. The results of the study are a novelty, and can be helpful in evaluating the physicochemical properties of edible oils.

► Viscosity of DAG oil was measured using the Bleustein-Gulyaev surface acoustic wave. ► Viscosity of DAG oil was measured up to 500 MPa, and at various temperatures. ► High-pressure phase transition in diacylglycerol oil was studied. ► Kinetics of high-pressure phase transition in diacylglycerol oil was investigated.