Viscosity Measurement of Olive Oil under Pressure

Abstract

This article presents changes in the viscosity of olive oil during compression. The test was carried out indirectly by measuring the dependence of the resonance frequency of the piezoelectric immersed in olive oil on pressure. For this purpose, for successive pressures, the resonance curves were read and the values of the characteristic frequencies were determined. Viscosity changes were analysed and related to the compression and crystallization taking place in the tested substance. During this research, a phase transition from the liquid phase to the alpha crystalline phase was detected, during which the resonant frequency of the tested piezoelectric reached a minimum and the viscosity related to this frequency reached a maximum. The measurement method developed in this paper can be used to detect the phase transitions of oils subjected to pressure. This may find application in the oil production and high-pressure food preservation industries for which this knowledge is essential for the safe and trouble-free use of their machines.