Evaluation of Physicochemical Properties and Fatty Acid Composition of Milk Thistle Seed Oil

Milk thistle plant (Silybum marianum) is one of the medicinal plants which possess important nutritional and medicinal applications. It is shown that extracts of its leaf and the oil extracted from its seeds can retard liver diseases; and promote antioxidant and anticancer effects. In this research, physicochemical properties and fatty acid composition of extracted oil from milk thistle seeds were studied. The total oil content of the seeds was 28.9% and physicochemical properties were as follow: refractive index 1.452, chlorophyll content 0.55 mg pheophytin/kg oil, acid value 0.25 mg NaOH/g Oil, peroxide value 0.7 meq O2/kg Oil, saponification value 181 mg KOH/g Oil and iodine value 105 g I2/100 g Oil. Fatty acid composition of milk thistle oil was also analysed by gas chromatography. Among determined fatty acids, linoleic acid (39%) and oleic acid (36.7%) were the highest, followed by palmitic acid (10.1%), stearic acid (6.8%), linolenic acid (3.6%), arachidic acid (2.9%) and behenic acid (0.57%). Based on the results obtained, milk thistle seeds were rich in oil and essential fatty acids and this is important from nutritional and medicinal points of view, therefore cultivation of this oilseed for production of edible oil can be studied for consumption.