A Zn–porphyrin complex contributes to bright red color in Parma ham

The Italian traditional dry-cured ham (Parma ham) shows a stable bright red color that is achieved without the use of nitrite and/or nitrate. In this study we examined the pigment spectroscopically, fluoroscopically and by using HPLC and ESI-HR-MASS analysis. Porphyrin derivative other than acid hematin were contained in the HCl-containing acetone extract from Parma ham. A strong fluorescence peak at 588 nm and a weak fluorescence peak at 641 nm were observed. By HPLC analysis the acetone extract of Parma ham was observed at the single peak, which eluted at the same time as Zn-protoporphyrin IX and emitted fluorescence. The results of ESI-HR-MS analysis showed both agreement with the molecular weight of Zn-protoporphyrin IX and the characteristic isotope pattern caused by Zn isotopes. These results suggest that the bright red color in Parma ham is caused by Zn-protoporphyrin IX.