Viscosity and compressibility of diacylglycerol under high pressure

Abstract

The influence of high pressure on viscosity and compressibility of diacylglycerol (DAG) oil has been presented in this paper. The investigated DAG oil was composed of 82% of DAGs and 18% TAGs (triacylglycerols). The dynamic viscosity of DAG was investigated as a function of the pressure up to 400 MPa. The viscosity was measured by means of the surface acoustic wave method, where the acoustic waveguides were used as sensing elements. As the pressure was rising, the larger ultrasonic wave attenuation was observed, whereas amplitude decreased with the liquid viscosity augmentation. Measured changes of physical properties were most significant in the pressure range near the phase transition. Deeper understanding of DAG viscosity and compressibility changes versus pressure could shed more light on thermodynamic properties of edible oils.

Keywords:

• DAG viscosity
• compressibility
• phase transitions
• transmitted and scattered light

Notes

^†This paper was presented at the Lth European High Pressure Research Group (EHPRG 50) Meeting at Thessaloniki (Greece), 16–21 September 2012.