Lipid analysis of baker's yeast

Abstract

Commercial baker's yeast was analysed for lipids by TLC and GC. The TLC system of a silica gel plate with n-hexane-diethyl ether-acetate acid (70:30:1, v/v/v) allowed the total lipids to be divided into sterol esters (ES), free fatty acids (FFA), triacylglycerols (TAG), diacylglycerols (DAG), free sterols (FS), monoacylglycerols (MAG) and phospholipids (PL). Phospholipids were separated by two-step chromatography with the systems SiO 2 with acetone and SiO 2 with chloroform-methanol-acetic acid-water (25:15:4:2, v/v). The following phospholipids were detected: phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI), phosphatidylcholine (PC) and lysophospholipids (LPL). The fatty acid composition of TAG, ES, FFA, DAG, MAG, PC, PE, PS and PI was investigated by using packed column (15% DEGJ + 3% H 3PO 4) and capillary column (SP 2340) GC, Twenty-two individual fatty acids with carbon chain lengths in the range 12–24 were detected by capillary GC. The presence of squalene, zymosterol, ergosterol and lanosterol in non-saponifiable lipid was proved and the compounds were determined by GC (SE-30).