Investigation of nitrite alternatives for the color stabilization of heme–iron hydrolysates

Abstract

This study investigates the potential of novel heme-ligand complexes, derived from heme-iron isolated from porcine hemoglobin by enzymatic hydrolysis, to use as pigments for meat products. Five alternatives to sodium nitrite were identified as possible heme ligands and stabilizing agents of the red conformation of heme. The effects of 4-methylimidazole, methyl nicotinate, pyrrolidine, piperidine, pyrazine and sodium nitrite (as comparative benchmark) on the color of heme-iron extract and pure hemin standard were studied in solution. The ligand affinity and heme-ligand stability was assessed over time in solution by UV-Vis absorbance spectroscopy and CIELAB color space parameters. The CIE redness score * was used as a single measurement to propose a predictive model based on the following parameters: heme source (heme-iron extract or hemin standard), heme-to-ligand molar ratio (1:20 to 1:300), and storage time (up to 32 days). The optimal concentration at which each ligand can be added to either heme source, as well as the stability of the red color of the formed heme-ligand complexes in-solution was determined. Heme-iron extract-derived samples showed increased redness and color stability as compared to their hemin counterparts. No ligand showed as much affinity for heme as sodium nitrite. As the most promising ligand candidates, methyl nicotinate and 4-methylimidazole started to show color changes at a 1:50 molar ratio, but higher amounts (1:100 and 1:300, respectively) were required to attain the maximum redness possible with the highest stability.

Dietary Heme-Containing Proteins: Structures, Applications, and Challenges

“…But according to the results of He’s group, gallic acid and tea polyphenols exhibit tremendous effects to maintain the color stability by preventing oxidation of hemoglobin [ 47 , 48 ]. Chhem-Kieth and co-workers [ 49 ] established a novel method to encapsulate hemoglobin pigment by four ligands, including sodium nitrite, 4-methylimidazole, methyl nicotinate, and pyrazine. It is proved that the redness of the heme-pyrazine complex showed improvement upon heating.…”

Multiple Pulse Amperometry—An Antifouling Approach for Nitrite Determination Using Carbon Fiber Microelectrodes

“…Nitrite is widely used as a coloring agent [ 1 ], food additive [ 2 , 3 ], and preservative [ 4 , 5 ]. In the chemical industry, it is a major precursor to nitro-rubber production [ 6 ].…”