High temperature reduction of metmyoglobin in aqueous muscle extracts

• Published in: Meat science 2003-09, Vol.65 (1), p.631-637
• Main Authors: Osborn, H.M., Brown, H., Adams, J.B., Ledward, D.A.
• Format: Article
• Language: English
• Subjects: Beef colour; Biological and medical sciences; Cooked meat colour; Food industries; Fundamental and applied biological sciences. Psychology; Meat and meat product industries; Reducing enzymes
• ISSN: 0309-1740; 1873-4138
• DOI: 10.1016/S0309-1740(02)00258-9

Oxymyoglobin in aqueous extracts of fresh beef longissimus dorsi muscles was initially oxidised to metmyoglobin during heat treatments at temperatures in the range 50–70 °C. The metmyoglobin then underwent reduction to a red pigment that was shown spectrally to be identical to oxymyoglobin. The formation of oxymyoglobin involved a heat induced precipitate that when removed from the solution, allowed oxidation to metmyoglobin to occur. However, on re-addition of the precipitate further reduction to oxymyoglobin took place. Dialysis of the muscle extract prior to heating markedly inhibited the reduction but addition of NADH to the dialysate permitted further reduction. The precipitate plus NADH caused oxymyoglobin formation in the presence of metmyoglobin but neither the precipitate nor NADH alone induced this formation. It is concluded that the initial conversion of oxymyoglobin to metmyoglobin on heating fresh beef muscle extracts was reversible and that the reverse reaction depended on the presence of both NADH and a muscle protein.