In the context of impact on human health, nitrite/nitrate and related nitrogen species such as nitric oxide (NO) are a matter of increasing scientific controversy. An increase in the content of reactive nitrogen species may result in nitrosative stress—a deleterious process, which can be an important mediator of damage to cell structures, including lipids, membranes, proteins and DNA. Nitrates and nitrites are widespread in the environment and occur naturally in foods of plant origin as a part of the nitrogen cycle. Additionally, these compounds are used as additives to improve food quality and protect against microbial contamination and chemical changes. Some vegetables such as raw spinach, beets, celery and lettuce are considered to contain high concentrations of nitrates. Due to the high consumption of vegetables, they have been identified as the primary source of nitrates in the human diet. Processed meats are another source of nitrites in our diet because the meat industry uses nitrates/nitrites as additives in the meat curing process. Although the vast majority of consumed nitrates and nitrites come from natural vegetables and fruits rather than food additives, there is currently a great deal of consumer pressure for the production of meat products free of or with reduced quantities of these compounds. This is because, for years, the cancer risks of nitrates/nitrites have been considered, since they potentially convert into the nitrosamines that have carcinogenic effects. This has resulted in the development and rapid expansion of meat products processed with plant-derived nitrates as nitrite alternatives in meat products. On the other hand, recently, these two ions have been discussed as essential nutrients which allow nitric oxide production and thus help cardiovascular health. Thus, this manuscript reviews the main sources of dietary exposure to nitrates and nitrites, metabolism of nitrites/nitrates, and health concerns related to dietary nitrites/nitrates, with particular emphasis on the effect on nitrosative stress, the role of nitrites/nitrates in meat products and alternatives to these additives used in meat products.

Oxidation processes are responsible for reduction of the sensory and nutritional quality of meat and meat products, thus affecting consumer acceptance. The use of sodium nitrite in meat processing is an important factor limiting these changes. Therefore, eliminating this substance from the recipe of meat products to increase their nutritional value is not an easy challenge. The aim of this study was to determine the effect of sodium nitrite reduction on the lipid oxidation (peroxide value, thiobarbituric acid reactive substances), and color parameters (CIE L*a*b*, total heme pigment and heme iron, nitrosylmyoglobin) in cooked meat products during 15 days of vacuum storage. The antioxidant properties of products and isolated peptides (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS•), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric-reducing antioxidant power) were also evaluated. Experimental material included four different sample groups of cooked meat products produced with various percentages of sodium nitrite (0, 50, 100, and 150 mg kg⁻¹). It was shown that the sodium nitrite dose had no statistically significant effect on lightness (L*) and redness (a*) values, as well as nitrosylmyoglobin content. Along with decreasing the share of sodium nitrite in the samples, the thiobarbituric acid reactive substances (TBARS) value increased from 0.43 mg kg⁻¹ for samples with 150 mg kg⁻¹ at day 0 to 3.14 mg kg⁻¹ for samples without nitrite at day 15. The total ABTS scavenging capacity of the cooked meat samples was in the range 2.48 to 4.31 eqv. mM Trolox per g of product throughout the entire storage period. During storage, the ferric-reducing antioxidant power of samples with nitrite increased from 0.25 to 0.38 eqv. mg/mL ascorbic acid per g of product. In conclusion, reduction of nitrite to the level of 50 mg kg⁻¹ seemed to be comparable with the traditional use of nitrite in meat products in terms of the physicochemical properties and properties related to lipid oxidation, as well as total antioxidant capacity and peptide antioxidant capacity.

The present study examined the effect of the type of meat (beef and fallow deer) and the addition of freeze-dried acid whey on nutritional values and the content of bioactive compounds (peptides, L-carnitine, glutathione, and conjugated linoleic acid (CLA)) in uncured fermented sausages. The antioxidant properties of isolated peptides (ABTS, DPPH radical scavenging activity, and ferric-reducing antioxidant power) were also evaluated. The results showed that fallow deer sausages had higher peptide content than beef products. The addition of acid whey caused a decrease in the content of peptides, especially in fallow deer sausages. The glutathione content in beef sausages (22.91–25.28 mg 100 g⁻¹ of sausage) was quite higher than that of fallow deer sausages (10.04–11.59 mg 100 g⁻¹ of sausage). The obtained results showed a significantly higher content of CLA in beef sausages than in products from fallow deer meat. In conclusion, products prepared from fallow deer meat have generally higher nutritional value because of the content of peptides, their antioxidant properties, and the content of L-carnitine, while beef products have higher levels of CLA and glutathione.

This study aims to improve knowledge on fermented beef and fallow deer sausages and the effect of nitrite elimination and the addition of freeze dried acid whey on the fatty acid profile and volatile compounds. Three different formulations within each of the two product groups, made of beef and fallow deer meat, respectively, were prepared: control sample with sodium nitrite, sample without nitrite, and sample without nitrite and with the addition of freeze-dried acid whey powder (0.7%). After production, the sausages were subjected to analysis including proximate chemical composition, pH and water activity, Thiobarbituric Acid Reactive Substance (TBARS), fatty acid profile, and volatile compound determination. The fermented sausages were characterized by an average pH and water activity in the range of 5.23–5.79 and 0.910–0.918, respectively. Fallow deer sausages were characterized by a higher content of saturated and polyunsaturated fatty acids in comparison to beef sausages. The elimination of nitrite did not significantly affect the amount of volatile compounds in fermented sausages. However, the effect of the freeze-dried acid whey powder addition on the amount of some volatile compounds in uncured sausages was observed, in particular, that derived from bacterial metabolism.