Establishment of a model experiment system to elucidate the mechanism by which Zn-protoporphyrin IX is formed in nitrite-free dry-cured ham.

The aim of this study was to establish a model experiment system to elucidate the mechanism by which Zn-protoporphyrin IX (ZPP) is formed in Parma ham. The established model consisted of myoglobin, meat and antibiotics, and incubation under anaerobic conditions resulted in a greater yield of ZPP. Formation of ZPP was observed even in the presence of various antiseptics. The amount of ZPP formed increased as the period of incubation increased. ZPP formation was inhibited by heating meat homogenate depending on the heating temperature. Our results show that anaerobic conditions are suitable for the formation of ZPP in meat products without nitrate or nitrite and that endogenous enzymes as well as microorganisms may be involved in ZPP formation.