Fatty acid, triaglycerol, tocopherol, sterol, phospholipid composition and oxidative stability of Egyptian Nigella sativa seed oil

Abstract

Fatty acid and triacylglycerol composition, fatty acid distribution among glycerol carbons -2 and -1 (3) tocopherol, sterol and phospholipid composition and autoxidative stability of crude Egyptian Nigella sativa seed oil were determined, Fatty acid composition of the triacylglycerol portion of the oil was: 59.6% linoleic, 23.8% oleic, 12.4% palmitic and 3.5% stearic with less than 1.0% linolenic acids. The major triacylglycerols were trilinoleoyl, 24.6%; oleoyldilinoleoyl, 39.6%; palmitoyldilinoleoyl, 17.5%; palmitoyloteoyllinoleoyl, 12.9%; and dioleoyllinoleoyl, 9.6%, glycerols. The distribution of linoleic acid among glycerol carbons -2 and -1(3) was about equal. Alpha, beta, gamma and delta-tocopherols were identified in the crude oil. Crude oil sterols were beta-sitosterol, campesterol and stigmastanol. Crude oil phospholipid composition was phosphatidylethanolamine, 94.3%; phosphatidylcholine, 5.4%, and phosphatidylinositol, 0.3%. Oxidation of crude Nigella sativa seed oil in the dark in oxygen at 60 degrees C showed an induction period of one day, followed by a rapid oxidation level increase to peroxide value 76 meg/Kg after 5 days.