The elastin content of various muscles of beef animals

Abstract The elastin content of various muscles of beef animals has been measured by a technique designed to remove the last traces of collagen and myofibrillar proteins. Amino acid analysis of the elastin prepared in this way is almost identical with that of purified elastin from ox ligamentum nuchae. In particular, the hydroxyproline values of each are less than 2% of the dry weight. Most of the choice cuts of meat from the hindquarter and loin contain less than 0.2% elastin on the dry weight basis, i.e. less than 5% of the total connective tissue. The M. semitendinosus is the chief exception found. It contains about 2% dry fat free solids (DFFS), i.e. about 40% of the connective tissue. In the forequarter, the latissimus dorsi is the only muscle which contains as much elastin as the semitendinosus , i.e. about 2.0% DFFS. Muscles of intermediate elastin content are the trapezius, rhomboideus and pectoralis superficilias (about 0.4 to 0.8% DFFS). The muscle of the skin, panniculus , has a somewhat higher content of about 1.2% DFFS. Elastin appears to contribute to the toughness of a cooked muscle to about the same extent as denatured collagen. Thus the semitendinosus and biceps femoris have similar total connective tissue contents, and are about equally tough, but the former contains 15 times more elastin than the latter.