Low-salt Meat Products Research Articles

Advances in Research on the Improvement of Low-Salt Meat Product Through Ultrasound Technology: Quality, Myofibrillar Proteins, and Gelation Properties.

The high sodium content in meat products poses health risks to consumers and does not align with modern green and healthy living standards. Current strategies for directly reducing the sodium content in meat products are limited by their negative impact on the sensory or quality attributes of the products. In recent years, there has been great interest in applying ultrasound technology to reduce sodium content. This paper discusses the advantages and disadvantages of current mainstream strategies for reducing the sodium content in meat products, as well as the potential mechanisms by which ultrasound-assisted marination improves the quality of low-salt meat products. The main findings indicate that ultrasound, through its cavitation and mechanical effects, facilitates the transition of proteins from stable insoluble aggregates to stable soluble complexes, exposing more hydrophilic groups and, thus, enhancing protein solubility. At the same time, ultrasound promotes a greater number of proteins to participate in the formation of interfacial layers, thereby increasing emulsifying activity. Furthermore, ultrasound treatment promotes the interaction between proteins and water, leading to partial unfolding of protein chains, which allows polar residues to more readily capture water in the gel, thereby improving the water-holding capacity of the gel. These effects will contribute to the formation of high-quality low-salt meat products. However, variations in the frequency, intensity, and duration of ultrasound treatment can lead to differing effects on the quality improvement of low-salt meat products.

Influence of NaCl and phosphate on gelation properties of chicken breast myofibrillar protein gels and its application to in vitro digestion model

To investigate the combination effect of sodium chloride and phosphates on chicken breast myofibrillar proteins, MP gels containing various molarity of NaCl (0.15, 0.30 and 0.45 M) and phosphate (0 and 0.05 M) were prepared, their rheological properties were characterized, and applied to an in vitro digestion model. MP mixture containing 0.45 M NaCl and 0.05 M phosphate had the highest viscosity. The gel strength and cooking yield of MP gels was improved by increasing of molarity of NaCl. As NaCl concentration in MP increased, sulfhydryl levels decreased, while disulfide levels increased. As NaCl and phosphate levels increase, MP gels become denser and porosity decreases, which may reduce protein digestibility. In SDS-PAGE, protein bands from MP gels containing low NaCl levels (≤ 0.30 M) degraded more rapidly during in vitro digestion. These results may support the need for the meat industry to develop low-salt meat products with improved digestibility. KeywordsChicken,Myofibrillar protein,NaCl,Phosphate,Rheological properties,In vitro digestion

Incorporation of cross-linked/acetylated tapioca starches on the gelling properties, rheological behaviour, and microstructure of low-salt myofibrillar protein gels: Perspective on phase transition.

This study investigated the gelling properties, rheological behaviour, and microstructure of heat-induced, low-salt myofibrillar protein (MP) gels containing different levels (2%, 4%, 6%, and 8%, w/w) of cross-linked (CTS) or acetylated (ATS) tapioca starch. The results indicated that either CTS or ATS significantly enhanced the gel strength and water-holding capacity of low-salt MP gels (P < 0.05), an outcome verified by the rheological behaviour test results under different modes. Furthermore, iodine-staining images indicated that the MP-dominated continuous phase gradually transited to a starch-dominated phase with increasing CTS or ATS levels, and 4% was the critical point for this phase transition. In addition, hydrophobic interactions and disulphide bonds constituted the major intermolecular forces of low-salt MP gels, effectively promoting phase transition. In brief, modified tapioca starches possess considerable potential application value in low-salt meat products.

Potential mechanisms and effects of ultrasound treatment combined with pre- and post-addition of κ-carrageenan on the gelling properties and rheological behavior of myofibrillar proteins under low-salt condition

This study investigated the effect of ultrasound (US) combined with pre- and post-addition of κ-carrageenan (KC) on the gelling properties, structural characteristics and rheological behavior of myofibrillar proteins (MP) under low-salt conditions. The results showed that US combined with either pre- or post-addition of KC rendered higher gel strength and water holding capacity (WHC) of MP gels than those treated with US alone and added with KC alone (P < 0.05). US combined with pre-addition of KC facilitated the binding between MP and KC, which enhanced the gel strength and WHC of the mixed MP gels and significantly improved the rheological behavior of MP. This was also confirmed by the highest surface hydrophobicity, disulfide bonds and β-sheet content of the MP gels with US combined with pre-addition of KC. Moreover, microstructural results reflected a denser structure for the pre-addition of KC in combination with US. However, US combined with post-addition of KC resulted in limited MP unfolding and relatively weak hydrophobic interactions in the composite gels, which were less effective in improving the gel properties of the MP gels. This study provides potential strategies for enhancing the gelling properties of low-salt meat products via application of US and KC.

Modulation of sodium distribution and digestion properties in low salt myofibrillar protein gel incorporating γ-polyglutamic acid and transglutaminase: Conformation and microstructure

The weak gelling and poor digestion properties of myofibrillar protein (MP) under low-salt conditions constrain the development of functional sodium-reduced meat products. This study investigated how modification with γ-polyglutamic acid (γ-PGA) and transglutaminase (TG) cross-linking influences the conformation, gelation, and in vitro digestion of low-salt MPs pretreated with konjac glucomannan (KGM) and ultrasound. The results revealed that γ-PGA addition effectively facilitated the exposure of tryptophan and tyrosine residues in low salt MPs. The better dispersibility and slightly lower rheological properties of protein sols suggested the circumscribed effect of γ-PGA in augmenting protein gelation. TG crosslinking promoted moderate aggregation of MPs through different sites in myosin fragments, augmented the uniform distribution of sodium, and remarkably enhanced the gelling behavior of MPs. Importantly, the simultaneous incorporation of γ-PGA contributed to the refinement and uniformization of the TG cross-linked protein gel network, especially in the protein gel modified by pre-ultrasound treatment in combination with KGM. This result could also be corroborated by the augmented intermolecular interactions and enhanced digestibility observed in γ-PGA-modified TG crosslinked protein gel. Coupled with the identification of potentially bioactive peptides, it was confirmed that myosin light chain, actin, and myomesin account for the major contribution to the γ-PGA-induced changes in MP gels. Therefore, TG cross-linking combined with γ-PGA could be used to regulate the conformation and gelling properties of low-salt MPs, thus influencing the sodium distribution and digestion properties of low-salt meat products.

New insights into the cross-linking between myosin and alkali-treated pea protein by transglutaminase under low ionic conditions: Contribution of legumin and vicilin fractions

This study investigated the cross-linking of myosin with pH12-shifted legumin (11SpH) or vicilin (7SpH), and the gel properties of composite gels, with or without transglutaminase, in 0.3 M NaCl. The free sulfhydryl content of 7SpH/11SpH increased significantly (P < 0.05). The covalent cross-linking degree between 7SpH/11SpH and myosin was enhanced, with the vicilin of approximately 45 kDa showing more pronounced cross-linking. SDS–PAGE analysis of myosin subfragments revealed that S1 and light meromyosin were the primary cross-linking regions for 11SpH, reducing the Ca2+-ATPase activity of the myosin head, while S2 was an alternative cross-linking region for 7SpH. The cross-linking of 7SpH/11SpH enhanced the thermal aggregation of S1. The cross-linking degree of tails followed this order: myosin > myosin+7SpH > myosin+11SpH. Thus, the use of 7SpH/11SpH and transglutaminase offers a new approach to improving texture in low-salt meat products.

Insight on the emulsifying mechanisms of low-salt type emulsions stabilized by Maillard conjugates: Myofibrillar protein peptide-dextrin with different degrees of hydrolysis

In this study, we investigated the emulsifying properties and stabilisation mechanisms of low-salt type emulsions stabilised by MP-base conjugates prepared via the Maillard reaction between DX and MP peptides (MPP). Mild hydrolysis by Alcalase promoted a well-controlled Maillard reaction in dry conditions. Combining hydrolysis and Maillard reaction caused the dissociation and unfolding of highly aggregated MP structures; the ordered secondary structure was lost and the hydrophobic residue was exposed. The MPP-DX conjugates greatly improved the emulsifying ability and stability in the low-salt system; the resulting emulsion exhibited a small droplet size and homogeneous microstructure with desirable storage stability. Further, the glycation products were found to effectively suppress gravity-induced creaming. The MPP-DX glycoconjugate developed with 5% DG, exhibiting strongest flocculation and creaming stability, was determined as the optimal emulsifying agent for low-salt type emulsions. These findings provide a theoretical basis for developing low-salt meat products and/or emulsion-based foods.

Modification of low-salt myofibrillar protein using combined ultrasound pre-treatment and konjac glucomannan for improving gelling properties: Intermolecular interaction and filling effect

The quality deterioration of low-salt meat products has been gained ongoing focus of researchers. In this study, konjac glucomannan (KGM) was used to alleviate the finiteness of ultrasound treatment on the quality improvement of low-salt myofibrillar protein (MP), and the modification sequence was also investigated. The results revealed that the single and double sequential modification by utilizing KGM and ultrasound significantly influenced the gelation behavior of low-salt MPs. The uniform MP-KGM mixture formed by a single ultrasound treatment had limited protein unfolding, resulting in relatively weak intermolecular forces in the composite gel. Importantly, ultrasound pre-treatment combined with KGM modification promoted the unfolding and moderate thermal aggregation of proteins and remarkably improved the rheological behaviors and gel strength of the composite gel. This result could also be corroborated by the highest percentage of trans-gauche-trans conformation of SS bridges and maximum β-sheet proportion. Furthermore, molecular dynamic simulation and molecular docking elucidated that the hydrogen bond length between protein and KGM was shortened after ultrasound pre-treatment, which was the molecular basis for the enhanced intermolecular interactions. Therefore, ultrasound pre-treatment combined with KGM can effectively improve the gelling properties of low-salt MPs, providing a practical method for the processing of low-salt meat products.

Quality improvement of prerigor salted ground chicken breast with basic amino acids at low NaCl level

The prerigor salting effect is known to provide superior meat processing quality. Based on the urgent need for low salt meat products, the present study was undertaken to evaluate the prerigor salting effect when basic amino acids were introduced at 1% NaCl level. Ground chicken breast meat was salted with NaCl and basic amino acids at 30 min, 60 min, and 90 min postmortem for prerigor treatments. Compared to the 1% NaCl (w/w) treatment, the introduction of 0.06% basic amino acids (w/w) in the prerigor significantly led to an increase in myofibril fragmentation, myofibrillar protein solubility, emulsion activity, storage modulus change rate, gel water-holding capacity and hardness (P < 0.05). Furthermore, smaller and more uniformly sized droplets were producedin emulsion by basic amino acids. Individual basic amino acids had different prerigor salting effects, and it was indicated that basic amino acids could play a positive role in the prerigor salting effect when NaCl was reduced.

Design and characterization of low salt myofibrillar protein-sugar beet pectin double-crosslinked gels pretreated by ultrasound and konjac glucomannan: Conformational and gelling properties

The purpose of this study was to investigate the influence of two-step sequential cross-linking induced by laccase and heat treatment on the conformation and gelling properties of low-salt myofibrillar proteins (MP) modified by konjac glucomannan (KGM) and ultrasound treatments. Adding sugar beet pectin (SBP), irrespective of laccase crosslinking, significantly decreased the fluorescence intensity of low-salt MPs (MP, UMP, UMP-KGM). Laccase crosslinking caused the exposure of hydrophobic and Tyr residues, induced moderate aggregation of MPs, and enhanced rheological properties and gel strength of composite MP gels, especially in the UMP-KGM sample. This result could also be corroborated by the highest WHC, improved textural characteristics, enhanced intermolecular interactions, and increased percentage in t-g-g conformation of S–S bridges in the SBP modified UMP-KGM gel after laccase crosslinking. Therefore, the dual crosslinking could be used to regulate the protein-protein and protein-polysaccharide interactions and improve the gel properties of low-salt meat products.

Influence of NaCl on lipid oxidation and endogenous pro-oxidants/antioxidants in chicken meat

The aim of this study was to investigate the effect of different content of sodium chloride (NaCl) on lipid oxidation of chicken breast meat and the endogenous pro-oxidants/antioxidants contributing to lipid oxidation. The results demonstrated that NaCl could promote lipid oxidation in chicken meat until NaCl content reached up to 4.5%. Generation of reactive oxygen species and H₂O₂ initiated by NaCl might be responsible for the increased lipid oxidation, and lipoxygenase activity was highly correlated with oxidative stability of meat. However, oxidation of lipid was not negatively correlated with superoxide dismutase, glutathione peroxidase and catalase activity. The sensory evaluation by electronic nose showed an increase in saltiness, richness and umami taste and a decrease in bitterness with increasing NaCl content, but there was no significant change in these sensory ratings when the NaCl content exceeded 3.0%. The volatile compounds obtained by gas chromatography-mass spectrometry (GC-MS) showed that NaCl increased the formation of most flavor components in chicken meat. This study could provide a reference for the control of lipid oxidation in meat and development of low salt meat products.

Methods to improve the quality of low-salt meat products: a meta-analysis

AbstractLow-salt meat (salt content &amp;lt;2%) is gaining popularity for its lower health risks, while the food industry faces technical challenges in improving its quality. Twenty-one studies involving meat quality improvement measures in low-salt meat products were included in this meta-analysis. The outcomes of these studies were assessed to derive conclusions about their effects on meat hardness and cooking losses. The results demonstrated that higher power ultrasound treatments (300–1500 W) significantly increased the hardness of low-salt meat, while a similar outcome was also achieved by low-strength (50–200 MPa) high-pressure processing (HPP) treatment, which was beneficial for alleviating the undesirable too-soft texture of the low-salt meat products. Furthermore, when salt reduction was greater than 50%, the application of ultrasonic treatment and HPP of 50–200 MPa significantly reduced the cooking losses, and the addition of hydrocolloids also increased the cooking yield of the salt-reduced meat products. Among all the interventions, HPP exhibited the most significant effects in low-salt meat quality improvement, which warrants future studies on the combination of this method with salt reduction strategies in the reduction of salt content in processed meat products.

Sous-vide cooking as a practical strategy to improve quality attributes and shelf stability of reduced-salt chicken breast ham

The objective of this study was to evaluate the general quality attributes and shelf stability of reduced-salt and sous-vide cooked chicken breast hams during 4 weeks of refrigerated storage (4°C). Four treatment groups of chicken breast ham were prepared using a 2 (salt level, 1.5% NaCl (regular) and 0.75% (reduced))×2 (cooking method, conventional and sous-vide) factorial arrangement. Based on each chicken breast weight, 20% NaCl solution was injected. Conventional cooking was done at 80°C until the core temperature reached 71°C, whereas sous-vide cooking was conducted at 60°C for 2 h. Sous-vide cooking could decrease cooking loss and shear force of reduced-salt chicken breast ham (P < 0.05). As a result, sensory scores for juiciness and tenderness of reduced-salt and sous-vide cooked chicken breast ham were similar to those of regular-salt and conventionally cooked chicken breast hams (P > 0.05). No adverse impacts on lipid oxidation and microbial safety were found in reduced-salt and sous-vide cooked chicken breast ham during 4 wk of refrigerated storage. Therefore, this study suggests that sous-vide cooking could be a practical thermal process for improving the water-holding capacity and texture of chicken breast ham without adverse impacts on shelf stability. Further studies on the combined application of sous-vide cooking with salt replacers would be warranted to improve the sensorial acceptance of saltiness of sous-vide cooked low-salt meat products.

Ultrasound combined with carrageenan and curdlan addition improved the gelation properties of low-salt chicken meat paste

Excess Na+ intake can easily lead to chronic diseases, whereas the sodium salt plays very important role in maintaining meat product quality. To overcome the low-salt induced deterioration, the ultrasound treatment (UT) was coupled with polysaccharide addition (PS) to improve the gelation properties of low-salt chicken meat product. Carrageenan (CAR) and curdlan (CUD) were chosen as PS sources. The application of UT, CAR, CUD could all effectively decrease cooking loss, and CUD group showed lowest cooking loss. However, CUD and CUD-UT treatment both reduced the gel hardness significantly, while CAR and CAR-UT showed greatly positive effects on texture. CAR/CUD decreased the whiteness of gels, while the corporation with UT diminished the negative impact. UT could improve gel quality of CAR group by lowering the particle size, making polymers more evenly distributed and increasing viscosity. UT showed different influence on CAR and CUD samples, which is probably induced by various water distribution population in these groups. Overall, CAR-UT showed the best quality, which provides important information for development of low-salt meat products.

Study on saltiness sensing during oral processing of dry-cured pork base on salivary proteomics

Recently, the concept of low-salt and healthy diet has been widely accepted, while the market recognition of low-salt meat products is generally inferior due to their inability to satisfy the oral pleasure of consumers. Therefore, to investigate the role of saliva in saltiness during oral processing of chewing high-salt dry-cured pork, a subset of 3 male subjects with high salt-sensitivity were selected to partake this study. Cooked dry-cured pork (5% salt added) as chewed and held in the oral cavity without swallowing for four different chewing stages during oral processing. Saliva from the 3 subjects was collected and analyzed for salivary proteomics by Data Independent Acquisition (DIA) combined with food oral processing methods. According to the analysis of human proteome (H.sapiens, UP000005640), the abundance of RAC1(RAS-related C3 botulinum toxin substrate 1) and calmodulin-like 3 (CALML 3) was first found to be related to the change of saltiness sensing during oral processing. Moreover, oral chewing leads to upregulation of RAC1 protein, which leads to positive regulation of protein kinase B signaling, ultimately leading to increased serine-type endopeptidase activity and salt perception.

Konjac glucomannan improves the gel properties of low salt myofibrillar protein through modifying protein conformation

Improving the characteristics of low salt proteins is the key to the gel properties of low-salt meat products which are demanded by people nowadays. The present study focused on the effects of KGM concentrations on the changes in structure and gelling properties of low-salt myofibrillar protein (MP). KGM addition (≤0.75 %) irrespective of salt concentration modified secondary and tertiary structures of MPs, enhanced the binding capacity of Troponin-T and Tropomyosin, augmented the gelling behavior of proteins, and remarkably improved the storage modulus (G′) and gel strength of heat-induced MP gels. Interestingly, KGM addition in low salt condition showed the transformation of the all-gauche SS conformation into gauche-gauche-trans and trans-gauche-trans, and the partial transformation of α-helices into β-sheets. overall, KGM modified the structure of low salt MPs and thus improved the gel properties of low salt MPs. Therefore, KGM is recommended for low-salt meat processing to enhance the MP gelling potential.

Effect of partial substitution of NaCl by KCl , CaCl 2 , and MgCl 2 on properties of mixed gelation from myofibrillar protein and Flammulina velutipes protein

The effects of substitution of sodium chloride (NaCl) by chloride salt mixtures (KCl, CaCl2, and MgCl2) with different formulas on quality characteristics of mixed protein system containing 80% myofibrillar protein (MP) and 20% Flammulina velutipes protein (FVP) were investigated in this study. The addition of chloride salts (KCl, CaCl2, and MgCl2) into a reduced-sodium (0.3 M NaCl) mixed gel system, increased the gel properties, and network structure of the MP-FVP gel, which might be attributed to the increase in protein solubility and rheological properties. The examination of the turbidity, particle size, zeta potential, UV spectroscopy, and Fourier transform infrared spectroscopy indicated that the protein molecules were obviously aggregated, that the electrostatic interaction was weakened, that the hydrophobic interaction and β-sheet content was increased. The results showed that when KCl, CaCl2, and MgCl2 were used to replace NaCl at 35, 10, and 5%, respectively, the gel properties reached the maximum. Practical applications This study evaluated the effects of different types of sodium salt substitution on the structural properties of proteins and the structural properties of mixed myofibrillar protein and Flammulina velutipes protein gels. The results revealed that the mixed protein molecules apparently aggregated under different replacement of KCl, CaCl2, and MgCl2 (i.e., 35, 10, and 5%). The hydrophobicity and β-sheet content significantly increased, while the electrostatic interaction decreased, leading to enhanced mixed gel properties. The results indicated the different replacements of sodium salts could improve the gels characteristics, which may be a guide for the future production of low-salt meat products.

Development of strategies to manufacture low-salt meat products - a review.

Urbanization is usually followed by changes in eating habits, with a specific trend toward the consumption of ready-to-eat products, such as processed foods. Among the latter, meat products are known contributors to high dietary sodium owing to salt addition. Salt plays an essential role in maintaining the quality of meat products in terms of acceptability and safety. However, an excessive salt intake is linked to high blood pressure and cardiovascular diseases. Hence, several studies have been competing for the discovery of salt alternatives performing in a similar way as common salt. A number of replacements have been proposed to reduce salt consumption in meat products while taking into account consumer preferences. Unfortunately, these have resulted in poorer product quality, followed by new adverse effects on health. This review addresses these recent issues by illustrating some established approaches and providing insight into further challenges in developing low-salt meat products.

Effects of micro-/nano-scaled chicken bones on heat-induced gel properties of low-salt pork batter: Physicochemical characteristics, water distribution, texture, and microstructure

The effect and mechanism of micro-/nano-scaled (MCB/NCB) chicken bones on improved gel properties of low-salt (0.5%) pork batters (LSPB) were investigated. Results showed that the Ca2+ released from MCB/NCB induced protein conformational transition of LSPB from α-helix and β-turn to random coil, which facilitated the orderly protein aggregation, resulting in the formation of denser and more uniform gel network. The better-organized gel network not only improved the textural properties and gel strength, but also contributed to the cooking loss reduction, water release decline, water state transition from free water into more immobilized water, and proton density increase, resulting in better sensory attributes. NCB showed more preferable effects on the property improvement of LSPB gels than MCB, because of its smaller particle size, less redness and yellowness, higher dispersibility, and higher Ca2+ release. This study could help promote the high-value utilization of poultry by-product bones and development of low-salt meat products.

Combined Effect of High-Pressure Processing with Spice Extracts on Quality of Low-Salt Sausage during Refrigerated Storage.

The study evaluated the combined effect of high-pressure processing (HPP) and spice extracts on low-salt sausages during refrigerated storage. Physicochemical and microbiological characteristics of the sausages were determined. HPP treatment increased the thiobarbituric acid reactive substances (TBARS) value and the carbonyl content of the samples (p < 0.05), which meant lipid and protein oxidation was accelerated. Adding clove and cinnamon extracts can retard the oxidation caused by HPP (p < 0.05). The pH of the sausages treated with both the spice extracts and HPP maintained a higher pH value during the storage (p > 0.05). Compared with the samples treated with HPP or with the spice extracts alone, the combined treatment observably inhibited the growth of spoilage bacteria (p < 0.05) and improved the microbial community. The results demonstrated that the use of clove and cinnamon extracts in conjunction with HPP improved the storage quality and prolonged the shelf-life of the low-salt sausages. Thus, the combined use of spice extracts and HPP can be developed as a promising way to preserve low-salt meat products.