The effects of lactate on nitrosylmyoglobin formation from nitrite and metmyoglobin in a cured meat system

1H NMR Reveals the Mechanism of Potassium Lactate on Proteolysis and Taste Metabolites of Rugao Ham

To deepen the understanding of the effect of potassium lactate on the taste of Rugao ham, proteolysis index, enzyme activities and protein degradation of Rugao ham salted with potassium lactate (0%, 0.5%, 1%, 2%) were investigated. Metabolites of Rugao ham were identified by 1H nuclear magnetic resonance (NMR) spectroscopy and the metabolic pathways of the key metabolites were enriched by the Kyoto Encyclopedia of Genes and Genomes (KEGG); the relationship between taste and metabolites was assessed by partial least square discriminant analysis (PLS-DA). The hams with 2% potassium lactate showed lower cathepsin B and L activities, and higher aminopeptidase activities than that of the control group. The contents of free amino acids and organic acids significantly increased from the control to the treatment of 2% potassium lactate. PLS-DA further demonstrated that aspartate, glutamate, alanine, serine, threonine, acetate, lactate, succinate, carnosine, β-glucose and glycerol were the key metabolites to improve the taste of Rugao ham in the treatment of 2% potassium lactate. Metabolic pathways analysis further demonstrated that amino acids metabolism was the main pathway for the taste development of Rugao ham.

Nitrites in Cured Meats, Health Risk Issues, Alternatives to Nitrites: A Review

Nitrite is one of the most widely used curing ingredients in meat industries. Nitrites have numerous useful applications in cured meats and a vital component in giving cured meats their unique characteristics, such as their pink color and savory flavor. Nitrites are used to suppress the oxidation of lipid and protein in meat products and to limit the growth of pathogenic microorganisms such as Clostridium botulinum. Synthetic nitrite is frequently utilized for curing due to its low expenses and easier applications to meat. However, it is linked to the production of nitrosamines, which has raised several health concerns among consumers regarding its usage in meat products. Consumer desire for healthier meat products prepared with natural nitrite sources has increased due to a rising awareness regarding the application of synthetic nitrites. However, it is important to understand the various activities of nitrite in meat curing for developing novel substitutes of nitrites. This review emphasizes on the effects of nitrite usage in meat and highlights the role of nitrite in the production of carcinogenic nitrosamines as well as possible nitrite substitutes from natural resources explored also.

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

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.

The effect of potassium lactate on the free amino acid composition, lipid oxidation, colour, microbiological, and sensory properties of ready-to-eat pastırma, a dry-cured and dried meat product

In this study, the effects of potassium lactate (PL, Potassium-L-2-hydroxy-propionate, Potassium-L-Lactate) usage (0%, 0.5%, 1.0%, 2.0% PL of curing mixture) in addition to NaCl and sodium nitrite as curing agent on the physico-chemical, microbiological and sensory properties of ready-to-eat pastırma were investigated. The usage of PL affected pastırma properties as pH (P < 0.01), TBARS (P < 0.01), salt (P < 0.01), residual nitrite content (P < 0.01), a* value (P < 0.01), microbial properties (P < 0.01) (total aerobic mesophylic bacteria, lactic acid bacteria, Micrococcus/Staphylococcus, yeast-mould count) and amino acid levels [lysine (P < 0.01), isoleucine (P < 0.01), leucine (P < 0.01), methionine (P < 0.05), phenylalanine (P < 0.01), valine (P < 0.05), threonine (P < 0.01), tryptophan (P < 0.05), aspartic acid (P < 0.05), glutamic acid (P < 0.05), asparagine (P < 0.05), serine (P < 0.01), histidine (P < 0.01), glycine (P < 0.01), alanine (P < 0.01), proline (P < 0.01), cystine (P < 0.05) and norvaline (P < 0.01)]. According to results of sensory analysis, the difference among pastırma samples including PL was not significant (P > 0.05).

High ZnPP-forming food-grade lactic acid bacteria as a potential substitute for nitrite/nitrate to improve the color of meat products

Zinc protoporphyrin IX (ZnPP)-forming food-grade lactic acid bacteria (LAB) were screened from various sources for their ability to improve the color of meat products. The effects of salt and nitrite on the ZnPP-forming ability of these bacteria were also investigated. Finally, these bacteria were applied in salt-added minced meat to assess their ability to improve the color. Twenty-five LAB were screened for their ZnPP-forming ability in pork. Most of the strains exhibited maximum growth anaerobically in 3% salt at 30 °C and grew well at pH 5.5 and 6.5. Moreover, 3% salt slightly retarded ZnPP formation; however, nitrite completely inhibited ZnPP formation in all the ZnPP-forming LAB. Thirteen LAB (avoiding duplication and non-food-grade) could form ZnPP in salt-added minced meat, resulting in improvement of the bright red color, high ZnPP autofluorescence, and increased fluorescence intensity. Finally, considering the safety, Lactobacillus plantarum, Lactococcus lactis subsp. cremoris, and Leuconostoc lactis were suggested as promising candidates to improve the color of meat products.

Effects of the Use of Staphylococcus carnosus in the Curing Process of Meat with a Reduced Amount of Sodium Nitrite on Colour, Residue Nitrite and Nitrate, Content of Nitrosyl Pigments, and Microbiological and the Sensory Quality of Cooked Meat Product

The aim of the work was to apply the bacteria Staphylococcus carnosus ATCC 51365 in the meat curing process with the use of a reduced amount of sodium nitrite and to evaluate the effects of bacteria on residual nitrites and nitrates, the content of nitrosyl pigments, colour, pH, oxidation-reduction potential, microbiological, and the sensory quality of a cooked meat product. Three meat batters in cans were prepared: (C) a control batter cured with NaNO2—100 mg/kg, (L) a batter cured with NaNO2—15 mg/kg, and (LS) a batter cured with NaNO2—15 mg/kg and S. carnosus (107 CFU/g). The cans were stored at a temperature of 4°C for 24 h (curing time) and cooked. The analysis was carried out after production and after 4 and 8 weeks of storage. The use of denitrifying bacteria in the curing process with a reduced amount of sodium nitrite increased the availability of nitrite in the meat, by reducing nitrates formed as a result of a dismutation reaction. The reaction contributed to the formation of nitrosyl pigments in a larger quantity than in the treatment in which the denitrifying bacteria were not used. The LS treatment was characterized by the greatest redness. The colour of the LS treatment was stable during storage. No negative effect of S. carnosus on the sensory quality of the meat product was found. The use of S. carnosus had no influence on the microbiological quality of meat product during storage.

The investigation of the use of beetroot powder in Turkish fermented beef sausage (sucuk) as nitrite alternative

The objective of this study was to examine the effects of reformulation of Turkish dry fermented beef sausage (sucuk) by replacing nitrite with beetroot powder (BP), which has high nitrate content, on some quality characteristics of the product during storage at 4 °C for 84 days. Four different sausage formulations were produced containing C:150 mg/kg sodium nitrite; BS1:100 mg/kg sodium nitrite and 0.12% BP; BS2:50 mg/kg sodium nitrite and 0.24% BP and BS3: 0.35% BP. The inclusion of BP increased a* value of samples and resulted in the protection of the desired red color during storage. There was no significant difference between the residual nitrite contents of the samples at the end of the storage period. The lactic acid bacteria count was highest in BS3. Suggested storage periods for BS2 and BS3 samples were 56 days by taking into consideration the TBARS value. Sensory evaluation scores of samples with BP were comparable to those of C during storage.

The role of monoxide hemoglobin in color improvement of chicken sausage

The role of monoxide hemoglobin (COHb) in improvement of chicken sausage color was investigated. COHb and NaNO₂ synergistically increased a* values. Addition of 0.1% COHb decreased the residual nitrite content in the presence of 0.001% NaNO₂. Compared with controls, the combined treatment resulted in significantly higher nitroso pigment contents while the single treatment resulted in slightly higher nitroso pigment contents. Visible spectrometry indicated that both nitrosohemochrome (NH) and hematin were the main ingredients of pigments extracted from chicken sausage treated with a combination of 0.006% NaNO₂ and 0.6% COHb. Formation of NH and hematin caused an increase in a* values and a decrease in L* values, respectively. COHb showed potential for use in meat product formulations.

Effect of sodium lactate /sodium diacetate in combination with sodium nitrite on physiochemical, microbial properties and sensory evaluation of cow sausage

Sodium nitrite has been always considered as one of the common additives due to its antibacterial effects on Clostridium botulinum and meat products' color, however it produces cancer creating nitrosamine. Recently, organic acids and their salts such as lactates have been employed as antimicrobial compounds. Lactates also improve organileptic properties including color, texture and taste and antioxidant properties. Sodium lactate causes to more reduction of anaerobic spore former bacteria than nitrite, inhibits botulin produced by Clostridium botulinum. Sodium lactate produces a permanent reddish pink color through reduction of deoxymygloboline and producing deoxymyoglobuline. In this study, the decrease of sodium nitrite amount from 120ppm to 15ppm by adding sodium lactate / sodium diacetate led to achieve an acceptable product. The best results revealed through adding 3.0625% of sodium lactate / sodium diacetate in combination with 30ppm sodium nitrite. Results also exhibited more reduction of pathogens' growth than nitrite, enhanced flavor slightly, but unable to produce reddish pink color as produced by nitrite. Results also exhibited  that sodium lactate / diacetate cause to retard in microbial growth, reducing chemical change, enhance sensory properties, partially improvement in taste and texture. Although inappropriate color demonstrated sodium lactate / diacetate's inability in red pink color production in 4th sample (contains 15 ppm nitrite), its synergy effect in combination with sodium nitrite on nitroso myoglobuline production has been proven, led to sodium nitrite reduction in sausages.

Effect of Oyster Shell Calcium Powder on the Quality of Restructured Pork Ham

This study was conducted to evaluate the effects of oyster shell calcium powder (OSCP) as a substitute for phosphates in curing agent, on the quality of restructured pork ham. Restructured pork ham was processed under six treatment conditions: T1 (no additives), T2 (0.3% sodium tripolyphosphate), T3 (1.5% NaCl+0.5% whey protein), T4 (1.5% NaCl+0.5% whey protein+0.15% OSCP), T5 (1.5% NaCl+0.5% whey protein+0.3% OSCP), and T6 (1.5% NaCl+0.5% whey protein+0.5% OSCP). Addition of OSCP significantly increased the ash content and pH of restructured pork ham (p<0.05), but did not affect the cooking loss and water holding capacity values of restructured pork ham. Addition of OSCP had no effect on Hunter a and b surface color values of restructured pork ham, but did decrease the Hunter L surface color value (p<0.05). The addition of 0.5% OSCP showed significantly higher chewiness and springiness values of restructured pork ham, compared with the addition of phosphates (p<0.05). In conclusion, the addition of OSCP combined with low NaCl and 0.5% whey protein can be considered a viable substitute for phosphates in the curing agent, when processing restructured pork ham.

Effect of forage and retail packaging types on meat quality of long-term chilled lamb loins

The objectives of this study were to determine the effects of different forage regimes and modified atmosphere packaging (MAP) systems [high oxygen (HiOx-MAP): 80% O2 and 20% CO2; and CO2-MAP: 20% CO2 and 80% N2] on color and lipid oxidation stability and sensory attributes of long-term chilled lamb loins during retail display. Lambs (n = 124) were randomly assigned to several pasture-feeding regimes for 12 wk before slaughter. Some had ryegrass (n = 18), lucerne (n = 18), chicory (n = 19), plantain (n = 16), or red clover (Clover 12; n = 17) for all 12 wk. Some were assigned a regime of red clover for 11 wk and pasture for 1 wk (Clover 11; n = 18), with others on red clover for 9 wk and pasture for 3 wk (Clover 9; n = 18). After the lambs were slaughtered, the paired loins (M. longissimus dorsi) were excised at 24 h postmortem, vacuum-packed and stored at -1.5 °C for 9 wk. Cuts were then made from each loin and randomly allocated to either HiOx-MAP or CO2-MAP, and displayed for 7 d at 4 °C under light. Chemical attributes including lipid oxidation, surface color-reversing ability, oxygen consumption, and meat quality attributes (color stability and sensory characteristics) were determined. Among the different forage types, the loins from lambs finished on ryegrass appeared to have greater color stability and less lipid oxidation than the loins from lambs finished on other forage types (P < 0.05). On the other hand, the loins from lambs finished on lucerne had the least color and lipid oxidation stabilities and least color-reversing ability (P < 0.05). The loins from lambs finished on chicory had higher aroma and flavor scores than other pasture types in general (P < 0.05). HiOx-MAP negatively influenced meat quality attributes of lamb loins during display, as substantial increases in surface discoloration and lipid oxidation were observed, along with significant decreases in aroma and flavor during retail display compared with the loins in CO2-MAP. These results suggest that different forage types and packaging conditions could result in substantial impacts on meat quality attributes of long-term chilled lamb loins by affecting oxidation stability. Furthermore, the present study suggests that CO2-MAP could provide beneficial effects on the eating quality of long-term chilled lamb loins by suppressing oxidation-related defects during display without compromising the ability of blooming for meat display.

Formation and identification of nitrosylmyoglobin by Staphylococcus xylosus in raw meat batters: a potential solution for nitrite substitution in meat products

Staphylococcus xylosus and Pediococcus pentosaceus isolated from Chinese dried sausage were assessed for their ability to convert metmyoglobin into nitrosylmyoglobin in Mann-Rogosa-Sharp broth model systems and raw pork meat batters without the addition of nitrite. The results showed that samples in model systems with S. xylosus cultures had an absorption spectra that is typical of nitrosylmyoglobin, an obvious pink colour (judged by visual inspection) and a significantly higher a-value than the control samples or samples inoculated with P. pentosaceus. In raw meat batters, the a-values of the S. xylosus samples were almost the same as those for the meat with nitrite added. The complementary analysis of meat batter samples by photochemical information from UV-vis, electron spin resonance and resonance Raman spectroscopy revealed that the existing status of the myoglobin in meat batters inoculated with S. xylosus was mainly pentacoordinate nitrosylmyoglobin. This study provides a potential solution for nitrite substitute in meat products.