In vitro digestion of nitrite and nitrate preserved fermented sausages - New understandings of nitroso-compounds' chemical reactivity in the digestive tract

Abstract

In vitro digestions of dry-cured sausages formulated with four different rates of added sodium nitrite and sodium nitrate (NaNO₂ / NaNO₃, in ppm: 0/0; 80/80; 120/120; 0/200) were performed with a dynamic gastrointestinal digester (DIDGI®). The chemical reactivity of the potentially toxic nitroso-compounds (NOCs), oxidation reactions products and different iron types were evaluated over time. No nitrite nor nitrate dose effect was observed on NOCs' chemical reactivity. Nitrosothiols were scarce, and nitrosylheme was destabilized for every conditions, possibly leading to free iron release in the digestive tract. Total noN-volatile N-nitrosamines concentrations increased in the gastric compartment while residual nitrites and nitrates remained stable. The minimal rate of 80/80 ppm nitrite/nitrate was enough to protect against lipid oxidation in the digestive tract. The present results provide new insights into the digestive chemistry of dry sausages, and into new reasonable arguments to reduce the load of additives in formulations.

Keywords: Digestion; Dry-cured fermented sausages; Nitrate; Nitrite; Nitrosation; Nitroso-compounds; Nitrosylation; Oxidation; Processed meat.

Fig. 1

Proposed mechanism for the chemical reactivity of nitroso-compounds in the gastro-intestinal tract studied in the present paper. Legend: The dry-cured sausages formulation compounds are represented in orange, the nitroso-compounds in red-squared text (different sizes represent different proportions: major quantity with bigger text, minor quantity with smaller text) and the proteolysis with the thunderbolt symbol. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)