Fatty acid composition of milk thistle seed oil obtained with cold pressing

Abstract

Milk thistle seeds are a unique source of biologically active substances. The oilseed crop studied is used in various fields, both for food purposes, animal husbandry and in medicine. The characteristics of milk thistle oil were considered in the work. Milk thistle seeds are known to contain 35% vegetable oil (seed fat). The oil was obtained with cold pressing. Milk thistle seed oil was chosen as the object of study. Using an experimental extruder, the oil was obtained under the following modes: the annular gap of the grain chamber - 1.25 mm, the screw rotation speed - 190 rpm, the pressing temperature - 353 K. A comparative study of the fatty acid composition of milk thistle oil components with literary sources was carried out. Gas-liquid chromatography on a Chromotek 5000 device was used to determine the composition of the components according to the GOST 31665-2012 method. The calculation for the components of milk thistle oil  on the basis of which the chromatograms were obtained for the amount of fatty acids was made. It was found out that the characteristics of the test sample are comparable with the literature data, but they also have differences, since other fatty acids were found in the oil. 24 fatty acids were identified by gas chromatographic analysis. The following ratio of fatty acids was determined: linoleic - 53%, oleic - 26%, palmitic - 8%, stearic (5%), arachidic (3%) and behenic (2%). The sample under study contains saturated and unsaturated fatty acids. According to the results of the vitamin composition analysis  milk thistle oil contains vitamins A, E and K and minor β-carotene traces which are a valuable source for diet and preventive nutrition.