Evaluation of s-nitrosothiols as a nitritesubstitute in meat products

Abstract

This study aimed to evaluate the effects of adding S-nitrosothiols (RSNOs) as a complete substitute for the sodium nitrite additive in cooked cured products (ham-like products). In the first article, a review was made on the use of non-thermal technologies for nitrite reduction in meat products.In the second and third articles, the equivalence of replacement (5 to 300 mg of nitrite equivalent, NEq/kg) of the RSNOs S-nitroso-N-acetylcysteine (NAC-SNO) and S-nitroso-N-acetylcysteine ethyl ester (NACET-SNO) was evaluated, as well as their effects on the technological and sensory characteristics of the products. In the fourth article, the sensory descriptive profile and the stability of the technological characteristics of the products reformulated with NAC-SNO (50 to 300 mg NEq/kg) during vacuum storage for 60 days (at 4°C) were assessed. In the fifth article, a kinetic study of solutions (NAC-SNOS) and freeze-dried powder (NAC-SNOP) of NAC-SNO was conducted, at different concentrations (200 to 400 mM) and storage temperatures (-18 to 30°C). The RSNOs did not differ from each other, producing low levels of residual nitrite (0-10 mg/kg) and not affecting the pH of the product. In the TBARS index, higher values were observed for RSNOs at concentrations up to 50 mg NEq/kg and values similar to nitrite from 75 mg NEq/kg. Concentrations above 50 mg NEq/kg of RSNOs resulted in an instrumental cured color index within the ideal range, but similarity to nitrite in sensory perception was only observed from the addition of 150 mg NEq/kg. During storage, higher TBARS values were observed in samples containing 50 mg NEq/kg of the curing agent (RSNOs or nitrite) than at 150 and 300 mg NEq/kg, with slightly higher values in samples with added NAC-SNO. The loss of cured color during storage in samples containing NAC-SNO was similar to those with nitrite. The perceived intensity of characteristic flavor and aroma and the sensory acceptance notes of products added with NAC-SNO were higher than in products containing nitrite. The decomposition of NAC-SNO followed a first-order reaction in non-stabilized solutions and zero-order in stabilized solutions, with the half-life (t1/2)increasing from 1.1 days to 9.9 days, but reducing in more concentrated solutions. The decomposition of NAC-SNOP followed a second-order decay, with an average activation energy of 92 kJ/mol and a Q10 of 4.0. The stability of the powders increased with concentration, with t1/2 values reaching up to 100 days at the highest concentration at 2°C. Thus, the results suggest the addition of 150 mg NEq/kg of NAC-SNO to obtain and maintain the technological characteristics of cooked products during processing and storage. It is also concluded that the stabilization and freeze-drying process of NAC-SNO at higher concentrations and its refrigerated or frozen storage is an interesting optimization strategy for industrial use, as it presents good yield, stability, and ease of use.