JUSTIFICATION OF THE TEMPERATURE REGIME OF THE MECHANICAL EXTRACTION PROCESS OF OIL FROM MILK THISTLE SEEDS

Abstract

The aim of the study was to determine the effect of pressing temperature regimes of milk thistle seeds on the yield and quality of oil. Particular attention was paid to identifying the optimal temperature conditions that ensure the maximum yield of unfiltered and filtered oil while preserving its oxidative stability. The object of the research was seeds of spotted milk thistle (Silybum marianum L.), a domestic variety “Boikivchanka”. The study covered the process of mechanical pressing of milk thistle seeds within a temperature range of 40–130°C, subsequent oil filtration, and quality evaluation. A set of methods was applied: seed pressing under laboratory conditions with controlled temperature regimes; analytical techniques for determining moisture, acid and peroxide values; ethanol extraction; and statistical analysis of results using analysis of variance (ANOVA). Particular attention was given to assessing the relationship between seed pressing temperature and the quantitative and qualitative characteristics of the obtained oil. The research confirmed the existence of optimal temperature intervals for the pressing process: 60°C – optimum for the yield of unfiltered and filtered oil; 40°C – minimum acid and peroxide values. The obtained data have the following significance: theoretical – expanded scientific understanding of the influence of temperature regimes on the yield and physicochemical characteristics of oil from spotted milk thistle seeds. Practical – the results can be used to optimize technological pressing regimes on an industrial scale in order to obtain high-quality food and pharmaceutical products with minimal losses. Further research should be focused on detailing the processes occurring at temperatures above 100°C, particularly pigment degradation and the formation of secondary oxidation products; studying the potential of combined oil extraction technologies (e.g., pressing followed by ethanol extraction) to increase overall yield; determining sensory characteristics and consumer appeal of oil obtained at different pressing temperatures; and examining antioxidant activity depending on pressing temperature.