119 Bulgarian Journal of Agricultural Science, 15 (No 2) 2009, 119-122 Agricultural Academy STEROL COMPOSITION OF RAPESEED VARIETIES INTRODUCED IN BULGARIA I. MAREKOV 1 , B. DAMYANOVA 1 , S. MOMCHILOVA 1 , M. ZLATANOV 2 , G. ANTOVA 2 , M. ANGELOVA-ROMOVA 2 and T. NENKOVA 2 1 Bulgarian Academy of Sciences, Institute of Organic Chemistry with Centre of Phytochemistry, BG – 1113Sofia, Bulgaria 2 University of Plovdiv “P. Hilendarski”, Department of Chemical Technology, BG – 4000 Plovdiv, Bulgaria Abstract MAREKOV, I., B. DAMYANOVA, S. MOMCHILOVA, M. ZLATANOV, G. ANTOVA, M. ANGELOVA- ROMOVA and T. NENKOVA, 2009. Sterol composition of rapeseed varieties introduced in Bulgaria. Bulg. J. Agric. Sci., 15: 119-122 The composition of glyceride oils isolated from the seeds of 6 rapeseed varieties introduced in Bulgaria was investigated focusing on the biologically active substances: sterols and sterol esters. Sterols in the glyceride oils were found to be totally 3 g.kg -1 including 2 g.kg -1 free sterols and 1 g.kg -1 esterified sterols. β-Sitosterol predomi- nated in both free and esterified sterols, being respectively 658–790 g.kg -1 and 471–700 g.kg -1 , followed by campesterol and stigmasterol. Oleic acid (609–768 g.kg -1 ) was the main component among the fatty acids of the sterol esters, followed by palmitic acid (72–144 g.kg -1 ). Key words: rapeseed oil, sterols, biologically active substances, fatty acids e-mail: magzlat@uni-plovdiv.bg Introduction Rapeseed oil is one of the most important veg- etable oils concerning both its industrial application and nutritional consumption. The high nutritional value of the rapeseed oil is due to the high levels of unsatur- ated fatty acids including the biologically active linoleic (cis 9, cis 12-18:2) and linolenic (cis 9, cis 12, cis 15-18:3) acids, and the low level of saturated fatty acids. The oil is rich in sterols and tocopherols which are natural antioxidants and synergists preventing to some extent the autoxidation of lipids at ambient tem- perature. The sterol composition is an important indi- cator for the quality of the oil. However, knowledge about the sterols in the rapeseed oils of new varieties is still fragmentary and when it is available it concerns only the total sterols. No data is available about the content and composition of the two sterol fractions – free sterols and sterol esters. The objective of the present research is to investigate the oil of 6 rapeseed varieties introduced in Bulgaria about the content and composition of the sterols in both fractions – free ste- rols and sterol esters, as well as to determine the fatty acid composition of the sterol esters.