Influence of meat source, pH and production time on zinc protoporphyrin IX formation as natural colouring agent in nitrite-free dry fermented sausages

Abstract

Nitrite is commonly used in meat products due to its plural technological advantages. However, it is controversial because of its detrimental side effects on health. Within the context of nitrite reduction, zinc protoporphyrin IX (Zn(II)PPIX) formation in meat products as natural red colouring agent has been suggested. This investigation presents the evaluation of naturally occurring pigments, namely Zn(II)PPIX, protoporphyrin IX (PPIX) and heme in nitrite-free dry fermented sausages in function of time, meat source (pork, horsemeat and a combination of both meat sources) and pH condition. In function of time, Zn(II)PPIX and PPIX were formed and heme content decreased. Higher pH conditions promoted Zn(II)PPIX and PPIX formation, whereas the influence of pH on heme was less clear. The use of horsemeat also promoted Zn(II)PPIX formation. Moreover, even similar amounts were formed when it was combined with pork. Product redness, however, could not be related to Zn(II)PPIX formation.

Overview of sodium nitrite as a multifunctional meat-curing ingredient

“…The main functions of NaNO2 in cured meat consist of the sensory characteristics development (color, flavor), as well as the protection against lipid and protein oxidation, and the microbiological safety of meat products. Improvement and fixation of the color Color is the most important indicator of meat product quality, and it is often considered an extremely important attribute for consumer acceptance (Carpenter et al, 2001;Krystallis and Chryssohoidis, 2005;Sindelar and Milkowski, 2012;Xu et al, 2016;De Maere et al, 2018). The development and fixation of a desirable red color is the most obvious effect of NaNO2 addition (Sindelar and Milkowski, 2012).…”

“…The reddish-pink color of thermally-processed cured meat products is the result of highly complex chemical processes, culminating in the formation of nitrosomyglobin ( Figure 1). The color manifests itself in many different shades, depending on the nature of the ligand attached to iron and the oxidation state of the iron (De Maere et al, 2018). Raw meat is primarily found as one of three colors depending on the Mb (myoglobin) state and the bound ligand.…”

“…Raw meat is primarily found as one of three colors depending on the Mb (myoglobin) state and the bound ligand. Deoxy-Mb (ferrous myoglobin) is present when iron is in the ferrous state (Fe2 + ), nothing is bound to the ligand, and the meat is purple-red (Mancini and Hunt, 2005;De Maere et al, 2018). Oxy-Mb is the state in which the iron is in the ferrous (Fe2 + ) state, O2 is bound to Mb, and the color is bright red (Mancini and Hunt, 2005;De Maere et al, 2018).…”

“…The consumers associate this bright red color with meat freshness. Finally, ferric met-Mb is present when the iron is in the ferric (Fe3 + ) state, nothing is bound to the ligand, and the meat is brown (Mancini and Hunt, 2005;De Maere et al, 2018). Met-Mb is generated by the removal of a superoxide anion from the hematin, and its replacement by a water molecule.…”

“…NaNO2 is considered the active curing ingredient responsible for the preservation of meat in combination with other ingredients like NaCl, and ascorbic acid or its derivatives. NaNO2 is commonly used in industrially processed meat because it contributes to the microbiological safety of meat products, to a superior control of color formation (unique reddish-pink meat color), color uniformity, and product flavour (Honikel, 2008;Sindelar and Milkowski, 2011;Parthasarathy and Bryan, 2012;Xu et al, 2016;Cantwell and Elliott, 2017;De Maere et al, 2018;Lee et al, 2018;Liu et al, 2019). NaNO2-curing is used in the manufacture of numerous processed meat products to extend their shelf-life by preventing microbiological spoilage and the growth of pathogens.…”