A comparative study of zinc protoporphyrin IX‐forming properties of animal by‐products as sources for improving the color of meat products

Abstract

The objective of this study was to obtain fundamental data for improving the color of meat products by using animal by-products. We investigated zinc protoporphyrin IX (ZnPP)-forming properties of various internal organs from pigs and chickens. ZnPP was formed in the liver, heart and kidney, whereas the porcine spleen and bile, which are involved in the metabolism of heme, did not have ZnPP-forming properties. The optimum pH values were different among the internal organs and the ZnPP-forming properties of porcine organs were better than those of chicken organs. The porcine liver showed the greatest ZnPP-forming properties among all of the internal organs investigated in this study. The optimum pH value for ZnPP formation in the liver was lower than that of skeletal muscle. Oxygen did not inhibit the formation of ZnPP in the liver, unlike in skeletal muscle. Animal by-products such as the liver have good ability for the formation of ZnPP and might be useful for improving the color of meat products.

Effects of post mortem pH and salting time on Zinc-protoporphyrin content in nitrite-free Serrano dry-cured hams

“…The ability of ferrochelatase to remove and insert the ions is regulated by pH (Chau et al, 2010). The ability of porcine ferrochelatase to form ZnPP is reported to be maximum at a pH of ≤ 6 in in vitro studies (Benedini et al, 2008;Ishikawa et al, 2006;Wakamatsu et al, 2019;Wakamatsu, Murakami, & Nishimura, 2015). It has recently been reported that the optimal pH values for ZnPP formation in porcine skeletal muscles are 5.5 and 4.75 depending on muscle fiber type (Wakamatsu et al, 2019).…”

Zinc-protoporphyrin content in commercial Parma hams is affected by proteolysis index and marbling

“…As shown in Table 2, heme is also correlated with pH (r = 0.517; P = 0.010). The Zn-chelatase enzyme has been reported to be affected by pH and takes part in the heme iron demetallation (Chau et al 2011;Wakamatsu et al 2015;Ishikawa et al 2006;Benedini et al 2008). Indeed, Chau et al, (2010) reported that insertion and removal of metal ions by Zn-chelatase is affected by various factors, but the optimal pH for the iron removal from the porphyrin can be set between 5.5-6.0 whereas that for the zinc-ion insertion can be set at pH 7.5-8.0.…”

Airborne ultrasonic application on hot air-drying of pork liver. Intensification of moisture transport and impact on protein solubility

“…Furthermore, pork liver contains a high concentration of Ferrochelatase, which is an enzyme that catalyzes the formation of Zinc protoporphyrin IX (ZnPP). ZnPP is a natural red pigment that, due to its stability to light and heat, might be useful as a means of improving the color of meat products, avoiding or minimizing the controversial use of nitrites/nitrates [8] , [9] , [10] .…”