Use of haemoglobin in foods-A review.

Blood from domestic meat animals contains biologically valuable protein equivalent to 6-7% of the lean meat content in the carcass. The major part of the protein is haemoglobin in the erythrocytes which even in minute concentrations imparts a dark brownish colour to foods. Large scale use of haemoglobin in foods consequently requires that the protein is made colourless unless attempts are made to hide the colour by technological manipulation in processing. The haem pigment can be removed from the globin by extraction with acidified organic solvents, usually acetone, or absorption on certain agents like carboxymethylcellulose. Alternatively, the globin may be digested by proteolytic enzymes and the liberated amino acids separated from the haem by ultrafiltration or centrifugation. Another approach is oxidative destruction of the haem after inactivation of the catalase activity of the erythrocytes. Hydrogen peroxide is preferred as oxidative agent but care must be taken to limit its impairment of protein quality. Because of its high lysine content globin should be suitable for fortification of cereals. Together with the blood plasma globin it may be used to replace meat in cured meat products. Use of blood proteins in foods may, however, sometimes be opposed for psychological reasons.