The properties of protein isolates prepared from slaughter animal blood

Abstract

Plasma and globin isolates were prepared form whole bovine blood. The powdered isolates were white, free-flowing and of high microbiological quality. The major nutrient was protein (90%) which contained all of the essential amino acids at levels greater than those specified by the Food and Agriculture Organization of the United Nations with the exception of isoleucine and methionine, which are limiting amino acids. Investigation of the solubility, emulsification capacity and the foaming properties of the plasma and globin isolates demonstrated that the isolates possess functional properties that may be useful in a variety of food processes. The functional properties of the globin isolate exhibited the least degree of change due to variations in processing conditions. The proteins of the plasma isolate, which were prepared in a manner to minimize processing effects, exhibited no change in identity in relation to the proteins of raw plasma. The globin isolate exhibited a change in both physical and chemical identify relative to native hemoglobin. The major physical difference was color which changed from red to white as a result of heme removal. Chemically, the globin isolate characteristically contained one major protein component which could be resolved electrophoretically under acidic conditions. Molecular weight analysis demonstrated the presence of one major protein having a molecular weight of 14,000 and two minor proteins with molecular weights of 29,700 and 55,000. The globin protein was resolved by gel isofocusing into six fractions with isoelectric points at pH 7.65, 7.48, 6.80, 6.64, 6.56 and 5.28.