High-pressure phases of vegetable oils (biological aspects)

The article presents the results of the authors' work on pressure-induced phase transformations in the group of vegetable oils. The results of previous and recent studies performed on a number of oils, mainly edibles, are presented. The methodology for generating the pressures necessary to carry out phase transformations in the tested oils and the system for measuring the pressure-volume characteristics are described. Two methods for achieving phase transformations are presented (isobaric method and quasi isochoric method). Research was carried out on less known oils due to the much smaller scale of their production compared to classic edible oils. They are characterized by several parameters that allowed us to assume that the obtained pressure phases would be stable after the pressure was reduced. These are: hazelnut oil, jojoba oil, and hemp oil. The work presents photographs of the obtained quasi-stable high-pressure phases taken immediately after leaving the pressure chamber. The fatty acid composition of the oils was tested by gaseous chromatography method both before the transformation and after the end of the cycle, without detecting any noticeable changes. The aim of the study, apart from the obvious cognitive ones, was to demonstrate the possibility of studying high-pressure phases from the point of view of food technology - improving the quality (properties) of edible oils.