ANALYSIS OF LIPIDS FROM COOKED BEEF BY THIN-LAYER CHROMATOGRAPHY WITH FLAME-IONIZATION DETECTION

Lipids were extracted from cooked ground beef with methylene chloride/methanol (2:1). The lipids were separated on a silicic acid column, into neutral and polar fractions by elution with methylene chloride, followed by methanol. These fractions were analyzed by Iatroscan thin-layer chromatography with flame-ionization detection instrumentation on Chromarods S-III (silica gel-coated quartz rods). Comparison of cooked beef stored for 0, 4 and 7 d at 4 degrees C indicated that storage caused a decrease in total lipids, an increase in neutral lipids and a decrease in polar lipids, specifically in phosphatidylcholine. These changes in the lipid fraction were associated with meat flavor deterioration and an increase is lipid oxidation.