The Fate of Nitrite: Reaction With Protein

This paper presents results showing that one of the major pathways for loss of nitrite in cured meats may be through reaction with nonheme protein. Incorporation of the stable isotope 15 N from nitrite is shown to occur in both bovine serum albumin and the muscle protein myosin, at pH's below and at those found in cured meat. In bovine serum albumin solution at pH 5.5 and at 20°C, 60% loss of added nitrite (200 ppm) occurred within 1 wk and almost half of the lost nitrite nitrogen was recovered as 15 N chemically bound to the protein. Analysis of the reaction products of nitrite and myosin showed that, under the conditions used, 10–20% of the incorporated nitrogen was present as 3‐nitrotyrosine. Several other products were found in acid hydrolysates of protein containing bound nitrite, but these did not appear to quantitatively account for the remainder of the incorporated nitrite.