Reduction and coordination properties of l-Lysine/l-arginine/l-cysteine for the improvement of the color of cured sausage

Effect of lysine-assisted ultrasonic and vacuum tumbling treatment on the quality of chicken breast meat in canned foods

Curing is a technological process that improves the tenderness, water retention, and overall quality of canned food. This study aimed to evaluate the effects of different exogenous additives, specifically sodium tripolyphosphate and lysine, on the quality of chicken breast meat in canned assorted vegetables and diced chicken using different curing methods: static curing, ultrasonic curing, vacuum tumbling curing, and ultrasonic combined with vacuum tumbling curing. The texture, moisture mobility and distribution, microstructure, and sensory acceptability of the chicken meat were evaluated. The results showed that lysine demonstrates better water retention than sodium tripolyphosphate, combining ultrasonic and vacuum tumbling treatments with 0.2% Lys (SL-UVT) significantly enhanced the texture characteristics and reduced the cooking loss of chicken breast meat. Additionally, SL-UVT treatment improved the texture, appearance, flavor, and overall acceptability scores. Nuclear magnetic resonance (NMR) analysis showed that SL-UVT treatment affected water distribution and flowability, increasing the retention of less mobile water in chicken breasts. In addition, the gap between myogenic fibers increased after SL-UVT treatment, trapping more water. In conclusion, SL-UVT treatment significantly improved the tenderness and water-holding capacity of the chicken breast from both macroscopic and microscopic perspectives. This study provided a theoretical foundation for refining and optimizing canned meat processing techniques.

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

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.

Effects of polyphenols in combination with L-cysteine/L-ascorbic acid: Myoglobin redox state, color and quality of refrigerated longtail tuna (Thunnus tonggol) slices

Effects of phenolic compounds in conjunction with L-cysteine/l-ascorbic acid on the redox state of myoglobin (Mb) and their efficacy to maintain the color and quality of refrigerated longtail tuna (Thunnus tonggol) slices were investigated. Purified metmyoglobin (metMb) and oxymyoglobin (oxyMb) samples were added with epigallocatechin-3-gallate (EGCG) or quercetin individually or in combination with L-cysteine (CT) or L-ascorbic acid (AA) at 4 °C. EGCG in combination with AA (EGCG+AA) and AA alone significantly reduced metMb and increased oxyMb levels (p < 0.05). Furthermore, the slices of tuna were treated with EGCG+AA (200 and 200 mg/kg, respectively) exhibited superior color retention (high a* value and a*/b*) and reduced lipid and protein oxidation more potentially, compared to other treated slices. AA alone was less effective in preserving color and quality of slices. Therefore, EGCG+AA effectively maintained the color and quality of tuna slices stored at 4 °C.

Effect of ultra-high pressure heat-assisted technology combined with L-cysteine on the color of ready-to-eat shrimp during storage

This study used ultra-high pressure processing (HPP) heat-assisted technology combined with L-cysteine (L-cys) to process ready-to-eat (RTE) shrimp. Subsequently, the effects of physical field and chemical modifications on the color of RTE shrimp were studied. The results showed that the RTE shrimp treated with HPP-Heat-L-cys showed better performance in terms of brightness value (65.25) and astaxanthin (AST) content (0.71 μg/g) during storage, maintaining the original color of RTE shrimp effectively. In addition, it was observed that the application of HPP-Heat-L-cys significantly delayed phenol oxidation, lipid oxidation, and Maillard reaction compared with traditional HPP or heat treatments. Specifically, the total phenolic content of RTE shrimp treated with HPP-Heat-L-cys was higher than that of other samples, but the TBARS and browning index were lower. Furthermore, HPP-Heat-L-cys could delay the production of dark products (such as 2-methylanthraquinone, p-benzoquinone, lipofuscin and melanin), ultimately safeguarding the color stability of RTE shrimp during storage.

Investigating the Effects of Pink-Generating Ligands on Enhancing Color Stability and Pigment Properties in Pork Sausage Model Systems Cured with Sodium Nitrite or White Kimchi Powder

In this study, we investigated the effects of different nitrite sources (sodium nitrite or white kimchi powder) and pink-generating ligands (cysteine, histidine, or nicotinamide) on the development and stability of cured meat color in pork sausage model systems over 30 d of refrigerated storage. The samples were prepared in a 2 × 3 factorial design with two nitrite sources and three ligands, and their physicochemical properties were evaluated on days 0, 15, and 30. Although white kimchi powder induced cured color development similar to that of synthetic sodium nitrite, it resulted in higher cooking loss and lower residual nitrite content in cured pork sausages (p < 0.05). The addition of cysteine resulted in significantly higher CIE a* values, cured meat pigment, and curing efficiency than histidine and nicotinamide (p < 0.05), while yielding lower pH values, residual nitrite content, and total pigment content (p < 0.05). The storage duration significantly reduced the residual nitrite and total pigment contents of the products. These findings suggest that white kimchi powder can serve as a natural alternative to sodium nitrite in pork sausage models and that the incorporation of cysteine has a favorable impact on the development and enhancement of cured meat color.

Quality and Flavor Difference in Dry-Cured Meat Treated with Low-Sodium Salts: An Emphasis on Magnesium

The present study aimed to develop low-sodium curing agents for dry-cured meat products. Four low-sodium formulations (SPMA, SPM, SP, and SM) were used for dry-curing meat. The physicochemical properties and flavor of the dry-cured meat were investigated. The presence of Mg2+ ions hindered the penetration of Na+ into the meat. The weight loss, moisture content, and pH of all low-sodium salt groups were lower than those of S. Mg2+ addition increased the water activity (Aw) of SPMA, SPM, and SM. Dry-curing meat with low-sodium salts promoted the production of volatile flavor compounds, with Mg2+ playing a more prominent role. Furthermore, low-sodium salts also promoted protein degradation and increased the content of free amino acids in dry-cured meat, especially in SM. Principal component analysis (PCA) showed that the low-sodium salts containing Mg2+ were conducive to improving the quality of dry-cured meat products. Therefore, low-sodium salts enriched with Mg2+ become a desirable low-sodium curing agent for achieving salt reduction in dry-cured meat products.

Zinc protoporphyrin IX generation by Leuconostoc strains isolated from bulged pasteurized vacuum sliced hams

The colour of meat typically fades as it decays. However, it has been observed that certain vacuum-packaged spoiled hams can maintain a pink colour even when the packaging is bulged. A large amount of Zinc protoporphyrin IX (ZnPP) was found in these hams, compared to fresh red hams or spoiled and grey hams. Combined with high-throughput sequencing and cultural isolation, the potential cultures of Leuconostoc mesenteroides S-13 (LM), Leuconostoc citreum OCLC11 (LC), and Leuconostoc mesenteroides subsp. IMAU:80679 (LS) were selected based on their ability to produce ZnPP. Subsequently, these cultures were introduced into a fermented sausage model to assess their effect on colour conversion. The analysis of absorption and fluorescent spectra showed that Nitrite sausages contained nitrosyl heme pigment, while bacteria-inoculated sausages were predominantly composed of ZnPP. In addition, the a* value of the LS sausage was close to the Nitrite group at the end of fermentation, significantly higher than control, indicating the effect of bacterial metabolism on the redness. Meanwhile, the Ferrochelatase (FECH) activity of LM, LC and LS groups were 140 ± 13, 113 ± 16 and 201 ± 20 U/g sausage, respectively, providing a potential method on compensating for nitrite/nitrate substitution based on the presence of ZnPP in meat products.

Use of basic amino acids to improve gel properties of PSE-like chicken meat proteins isolated via ultrasound-assisted alkaline extraction

To improve the gel quality of pale, soft, and exudative (PSE)-like chicken protein isolate (PPI) obtained via ultrasound-assisted alkaline extraction (UAE), l-lysine (l-Lys), l-arginine (l-Arg), or l-histidine (l-His) were used and the effects on the thermal gelling characteristics of PPI were studied. Compared with the nonbasic amino acid addition group, the addition of l-His/l-Arg/l-Lys significantly increased the solubility and absolute zeta potential of PPI, whereas reduced the particle size and turbidity (p < 0.05). They enhanced the gel strength and textural properties of PPI (p < 0.05) and reduced the cooking loss of PPI in the following order: l-Lys > l-Arg > l-His. The solubility, gel strength, and hardness of PPI with l-Lys were increased by 18.6%, 44.6%, and 57.6%, respectively, and cooking loss was decreased by 18.1%. Low-field nuclear magnetic resonance and magnetic resonance imaging revealed that basic amino acids addition decreased the water mobility in PPI gels with increasing immobile water content. Scanning electron microscopy revealed that the addition of basic amino acids promoted the formation of a more uniform and tight network microstructure in PPI gels. The α-helix content was decreased, whereas the β-sheet content was increased in PPI gels after basic amino acid addition. Therefore, addition of basic amino acids, especially l-Lys, enhances the gel properties of PPI. PRACTICAL APPLICATION: This study revealed that adding basic amino acids effectively improved the gel properties of PPI obtained via UAE method, with l-Lys exerting the best improvement effect. Our findings highlight the application value of PSE-like meat by the improvement of gel characteristics of PPI, providing a theoretical reference for the processing and utilization of PPI.

Investigating sensitization activity of azobenzene disperse dyes via the Direct Peptide Reactivity Assay (DPRA)

Azobenzene disperse dyes are the fastest-growing category of commercial dyestuffs and have been found in indoor house dust and in children's polyester apparel. Azobenzene disperse dyes are implicated as potentially allergenic; however, little experimental data is available on allergenicity of these dyes. Here, we examine the binding of azobenzene disperse dyes to nucleophilic peptide residues as a proxy for their potential reactivity as electrophilic allergenic sensitizers. The Direct Peptide Reactivity Assay (DPRA) was utilized via both a spectrophotometric method and a high-performance liquid chromatography (HPLC) method. We tested dyes purified from commercial dyestuffs as well as several known transformation products. All dyes were found to react with nucleophilic peptides in a dose-dependent manner with pseudo-first order kinetics (rate constants as high as 0.04 h-1). Rates of binding reactivity were also found to correlate to electrophilic properties of dyes as measured by Hammett constants and electrophilicity indices. Reactivities of polyester shirt extracts were also tested for DPRA activity and the shirt extracts with high measured abundances of azobenzene disperse dyes were observed to induce greater peptide reactivity. Results suggest that azobenzene disperse dyes may function as immune sensitizers, and that clothing containing these dyes may pose risks for skin sensitization.

Effects of replacement partial sodium chloride on characteristic flavor substances of bacon during storage based on GC×GC-MS and non-targeted metabolomics analyses

Comprehensive 2D gas chromatography-mass spectrometry (GC × GC-MS) and non-targeted metabolomics were employed to investigate the differences in key volatile flavor substances between bacon salted with alternative salt and traditional bacon during storage. The GC × GC-MS analysis revealed that among 146 volatile compounds in both types of bacon, alcohol, aldehydes, ketones, phenols, and alkenes were the most abundant. Additionally, non-targeted metabolomics indicated that the changes in amino acids and the oxidation degradation of lipids could be the main reasons for the flavor differences among the two kinds of bacon. Furthermore, the acceptability scores of both bacon types showed a general upward trend as the storage time increased, indicating that the metabolic of substances occurring during bacon storage significantly impact its overall quality. By partially substituting sodium chloride with 22% potassium chloride and 11% calcium ascorbate, coupled with appropriate storage conditions, the quality of bacon can be improved.

Additive Effects of L-Arginine with Potassium Carbonate on the Quality Profile Promotion of Phosphate-Free Frankfurters

The present study investigated the additive effects of L-Arginine (L-Arg) with potassium carbonate (PC) on the quality characteristics of phosphate-free frankfurters. The results showed that L-Arg combined with PC could act as a viable phosphate replacer by decreasing cooking loss and improving the textural properties of phosphate-free frankfurters (p < 0.05), mainly because of its pH-raising ability. Moreover, L-Arg could assist PC in effectively retarding lipid oxidation in phosphate-free frankfurters during storage (p < 0.05). Furthermore, 0.1% L-Arg combined with 0.15% PC was found to exhibit the best optimal phosphate-replacing effect. This combination could also overcome quality defects and promote the sensory attributes of phosphate-free frankfurters to the maximum extent. Therefore, our results suggest that L-Arg combined with PC can be considered a feasible alternative for the processing of phosphate-free frankfurters with an improved quality profile and superior health benefits.

The effect of nitric oxide synthase and arginine on the color of cooked meat

In previous studies, it has been suggested that the NO-synthase enzyme may be responsible for color formation in fermented sausages. Thus, this is the first study in which the aim was to analyze the effects of direct NO-synthase and arginine application to meat on its color after heating. Myoglobin forms as well as the presence of NO-myoglobin were investigated. The color of the meat and myoglobin forms present in the samples were mainly affected by pH differences, caused by a HEPES buffer or arginine. None of the variants demonstrated a bright pink color as in the case of the heated nitrite-cured sample. Based on analysis of the absorption spectra, it can be concluded that there is some evidence of nitroso-complex formation. Therefore, it is probable that optimizing the pH/time/temperature conditions for NO-synthase activity would allow to obtain a desirable color effect. NO-synthase could be used as an alternative curing ingredient.

The Physicochemical and Sensory Properties of Whey-Fed Pork Loin after Salting, Dry Aging, and Sous Vide Cooking

This study was conducted to evaluate the physicochemical properties of whey-fed pork loin subjected to salting, dry aging, and sous vide cooking. We compared raw and treated pork loin from pigs fed a basal diet (control) and those fed a diet supplemented with whey powder. Treated pork was salted, dry aged for 0–30 d, and then cooked using sous vide. The crude fat, total lipid, and cholesterol content and shear force of raw whey powder-fed pork loin were significantly lower than those of the control, while the crude protein content was higher. Cooking loss, hardness, and gumminess were found to decrease with the aging period in sous vide-treated pork. Dietary supplementation with whey had positive effects on pork color stability, texture, and sensory evaluation, and it significantly inhibited the growth of bacteria. The results suggest that supplementing the diet of pigs with whey powder can enhance meat quality, especially when combined with salting, dry aging, and sous vide cooking.

Identification and Quantitation of Hydroxy Fatty Acids in Fermented Sausage Samples

The quality of fermented sausage is strongly influenced by its fatty acid (FA). However, the role of a defined starter culture in modifying sausage FA composition, and especially in the production of hydroxy FAs (HFAs), has not been determined. In this study, the FA compositions of sausages fermented with Latilactobacillus sakei, with L. sakei plus Staphylococcus carnosus, and with an aseptic control were characterized by liquid chromatography-mass spectrometry (MS)/MS and gas chromatography-MS. The sausages fermented with L. sakei, and with L. sakei plus S. carnosus, showed a reduced accumulation of poly and/or diunsaturated FAs and distinct composition of HFAs compared to the aseptic control. 2-HFAs were enriched via high-speed counter-current chromatography and identified uniquely in the L. sakei plus S. carnosus fermented sausage. Through lipid analyses, this study illustrated how the choice of a defined starter culture affected the observed FA metabolism in fermented sausages, facilitating the development of starter cultures or additives that impart desirable characteristics to sausage.

Effect of L-cysteine, Boswellia serrata, and Whey Protein on the Antioxidant and Physicochemical Properties of Pork Patties

This study investigated the effects of L-cysteine (C) combined with Boswellia serrata (B) and whey protein (W) on the antioxidant and physicochemical properties of pork patties. Proximate composition, water holding capacity (WHC), pH, texture profile analysis, sensory evaluation, thiobarbituric acid-reactive substances (TBARS), DPPH radical-scavenging activity, volatile basic nitrogen (VBN), and color stability were assessed. Patty VBN gradually increased throughout the storage period. However, VBN for the C treatment increased relatively slowly, indicating that cysteine can delay spoilage and extend the shelf life of patties. The protein content of the whey powder treatment group increased to a greater extent than that of the C and control (CON) groups. Pork patties supplemented with antioxidants showed significantly higher WHC and significantly lower cooking loss and hardness than the CON. Moreover, the addition of 2% whey, 1% B. serrata, and 0.25% cysteine (WBC) significantly enhanced the relative DPPH radical-scavenging activity and sensory characteristics of the patties. After 7-day storage, the MetMb and TBARS values of all treatments were significantly lower than those of the untreated. The results indicated that there was synergy among the cysteine, B. serrata, and whey protein. This finding is of great importance to the production of high-quality pork patties with enhanced shelf life.