Iron and zinc compounds in the muscle meats of beef, lamb, pork and chicken

Beef, lamb, pork and chicken leg muscles were extracted with distilled water and the soluble iron and zinc compounds separated by gel filtration and dialysis. Iron was distributed between five main components: an insoluble fraction, ferritin, haemoglobin, myoglobin and a low molecular weight fraction. In beef and lamb, myoglobin was the predominant iron compound but in pork and chicken, most of the iron was associated with the insoluble fraction. Whereas more than 70% of beef iron was associated with the haemoproteins, haemoglobin and myoglobin, less than 30% of chicken iron was in this form. Even so, in all meats most of the soluble iron was associated with the haemoproteins. Zinc was present mainly in the insoluble fraction. The soluble zinc was distributed between five main components. Over 70% of soluble zinc was associated with two components having molecular weights of 65 000 and 35 000. The nature and availability of zinc and iron in the various meat fractions is discussed.