Composition of Lipids in Some Beef Muscles

SUMMARY— The lipids extracted from five different muscles of four Angus steers were separated into phospholipids, free fatty acids, and a fraction containing the triglycerides. The phospholipid concentration for a given muscle was relatively constant in all four animals. The concentration of total lipids varied considerably more than that of phospholipids. The diaphragm had the highest total lipid and phospholipid content. The diaphragm also differed from the other muscles studied in the palmitic and steak acid concentration of the phospholipids. The free fatty acid concentration varied from muscle to muscle, however, two distinct patterns of free fatty acid distribution were observed in the four animals. The triglycerides and phospholipids differed in the qualitative composition of their fatty acids. Approximately 20% of the phospholipid fatty acids, but only a trace of triglyceride fatty acids, were above C₂₀. The phospholipids contained a much greater amount of polyunsaturated acids than the triglycerides.