Fibre Composition of Tough and Tender Muscles of Meat Animals

Abstract

THE connective tissue content of muscles has been considered to be the principal biochemical entity responsible for toughness in meat. Little attention seems to have been given to the contribution which differences in the composition of muscle fibres themselves might make in rendering a muscle tough. I have examined the distribution of nitrogen within characteristically tough (semitendinosus) and tender (longissimus dorsi) muscles of different species (cattle, lambs, and pigs). The nitrogen components estimated were sarcoplasmic protein nitrogen, myofibril protein nitrogen, stroma nitrogen (by difference) and non-protein soluble nitrogen. The analytical technique used was essentially that of Lawrie's modification¹ of Helander's extraction technique².