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 gelcoated quartz rods). Comparison of cooked beef stored for 0, 4 and 7 d at 4°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 in lipid oxidation.