Influence of sodium nitrite on protein oxidation and nitrosation of sausages subjected to processing and storage

The influence of NaNO 2 content on protein oxidation and nitrosation was investigated in cooked sausages at different concentrations (0, 50, 100, 200 and 400   mg NaNO 2 /kg). Dependent on concentration, NaNO 2 had both anti- and pro-oxidant effects on protein oxidation. The antioxidant effects of NaNO 2 on the protein oxidation were evidenced by significantly lower carbonyl contents, higher free amines and lower surface hydrophobicities. The pro-oxidant effects of NaNO 2 on protein oxidation resulted in a decrease of sulfhydryls and an increase of disulfide bonds. NaNO 2 also improved the protein nitrosation inducing the formation of 3-nitrotyrosine (3-NT). Moreover, 3-NT had significant correlations with parameters of protein oxidation, indicating that 3-NT may be a possible marker for protein oxidation. Results of this study contribute to an understanding of the impact of NaNO 2 on food quality and help to identify optimal formulations of cured meat products .