# Evaluation of NO Synthase Activity in Meat-Brining Solutions: Implications for Meat Curing and Color Stability

## TL;DR

This study investigates whether nitric oxide synthase can replace nitrite in meat curing, but finds it ineffective for maintaining meat color and nitrite levels.

## Contribution

The study evaluates the feasibility of using nitric oxide synthase as a nitrite substitute in meat curing under various conditions.

## Key findings

- Nitric oxide synthase activity in meat solutions produced minimal nitrite, insufficient for effective curing.
- UV-Vis and Raman spectra showed no evidence of nitroso myoglobin formation.
- Meat samples with nitric oxide synthase had lower a* color values, indicating less redness.

## Abstract

L-arginine is a substrate for nitric oxide synthase, which, in its optimal conditions in a living organism, generates nitric oxide. In this presented research, we test the hypothesis that nitric oxide can be produced in a solution in which L-arginine, inducible nitric oxide synthase, and meat are present. We evaluate the effect of L-arginine concentration (0.0%/0.1%/0.2%), temperature (20/37 °C), and incubation time (1 h/2 h) on meat color. Nitrite, L-arginine, and citrulline concentrations are analyzed, as well as the UV-Vis and Raman spectra of meat extracts and meat, respectively. The results indicate that there is very weak evidence that at a pH level closer to the enzyme’s optimum, slightly higher concentrations of nitrite can be found. The decrease in L-arginine concentration after incubation of an enzyme with meat in water suggests enzyme activity. The UV-Vis and Raman spectra do not support the generation of nitroso myoglobin. Meat color analysis showed lower a* coordinate values in samples incubated with nitric oxide synthase compared to their analogs without the enzyme. The results indicate that in given conditions, nitric oxide synthase cannot be used as a nitrite replacer.