Marjeta Stevanović1, Marjeta Šentjurc2
1University of Ljubljana, Biotechnical faculty, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
2J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
Sodium nitrite has a multifunctional role in the meat curing process: it imparts characteristic pink colour to cooked cured meat products, it gives the typical flavour to cured meats, it acts as an antioxidant and most importantly, it is a very effective antimicrobial agent. Unfortunately, nitrite can also react with amines, amides and amino acids in meats forming carcinogenic N-nitroso compounds. The residual nitrite present in cured meats may also lead to the formation of carcinogenic N-nitroso compounds in the gastrointestinal tract. Therefore, there is a need to develop an alternative to the use of nitrite. The cooked cured meat pigment (CCMP) was synthesized from bovine hemin chloride using nitrosating (NO) and reducing agent (Na-ascorbate). CCMP is a low spin (S=1/2) ferrous protoporphyrin complex with odd number of electrons. It was qualitatively analysed with electron paramagnetic resonance. The results showed that CCMP is a five-coordinate mononitrosylprotohaem complex. EPR spectra of CCMP obtained in our synthesis closely resembled those reported in the literature. Our results also indicated that freshly prepared CCMP is unstable: with longer time of storage the intensity of EPR spectra decreases. Accordingly, we could not detect the EPR spectrum of CCMP after 14 days of storage, suggesting that the iron ion in CCMP complex oxidized back to the ferric (3+) state.