Myofibrillar Protein Solubility Research Articles

Insight into the mechanism of enhancing myofibrillar protein gel hardness by ultrasonic treatment combined with insoluble dietary fiber from oat

The present study investigated the effects of ultrasonic treatment combined with insoluble dietary fiber (IDF) from oat on gelation and structural characteristics of myofibrillar protein (MP). Ultrasonic treatment combined with IDF promoted the deployment of the MP chain and significantly increased (P < 0.05) the solubility of MP. The samples treated with 120 W of ultrasonic power combined with IDF (U120 + IDF) formed a more continuous and dense gel microstructure, resulting the water-holding capacity (WHC) reached maximun values of 0.88 g/g. Moreover, compared with the U80 and U120 groups, MP treated by 80 W of ultrasonic power combined with IDF (U80 + IDF) and U120 + IDF groups had a higher β-sheet content of 46% and 40%, respectively. The gel hardness and chewiness of the U120 + IDF group reached maximum values of 2.14 N and 7.09 mJ, respectively. Ultrasonic treatment combined with IDF enhanced the texture and WHC of MP gel by expanding the secondary structure and increasing protein solubility. In conclusion, the U120 + IDF group had the highest value of gel hardness, chewiness, and a three-dimensional network structure.

Combination of millet pepper and garlic water extracts improves the antioxidant capability of myofibrillar protein under malondialdehyde-induced oxidative modification

This study aimed to investigate the effect of millet pepper water extract (PWE) and garlic water extract (GWE) on the antioxidant capability of myofibrillar protein (MP) under malondialdehyde-induced oxidation. Mass spectrum analysis showed that the main antioxidant substances are dihydrocapsaicin, l-tryptophan, and 5-aminolevulinic acid in PWE, and l-tryptophan, 5-aminolevulinic acid and uridine in GWE. Compared with that in the control group, the addition of PWE and GWE inhibits the formation of carbonyl compounds and cross-linked polymers in MP, and inhibits the reduction in MP solubility, fluorescence spectral intensity, and UV spectral intensity. PWE increases the antioxidant capability of MP better than GWE due to its higher content of main antioxidant components. The differences in main antioxidant components between PWE and GWE provide them with a synergistic effect on enhancing the antioxidant capability of MP.

Influence of repeated freeze-thaw treatments on the oxidation and degradation of muscle proteins from mirror carp (Cyprinus carpio L.), based on myofibrillar protein structural changes

The effects of repeated freeze-thaw (F-T) treatments on the oxidation and degradation of muscle proteins from mirror carp (Cyprinus carpio L.) were investigated. The myofibrillar fragmentation index, trichloroacetic acid-soluble peptides, total volatile basic nitrogen, amino nitrogen, and carbonyl content of the samples significantly increased (P < 0.05). However, the samples showed a significant reduction in the fragmentation index, myofibrillar protein (MP) solubility, and total sulfhydryl content after five F-T cycles (P < 0.05). Moreover, the sodium dodecyl sulfate-polyacrylamide gel electrophoresis bands of the MP faded because of the oxidation and degradation of the protein with increasing F-T cycles. By the fifth F-T cycle, the α-helix and β-turn content significantly decreased by 10.41 % and 5.72 %, respectively (P < 0.05), whereas the β-sheet and random coil content significantly rose by 7.66 % and 8.47 %, respectively (P < 0.05). Furthermore, the intrinsic fluorescence of the MP showed a substantial decrease in intensity and a redshift. In summary, iterative F-T cycles destroyed the MP structure and caused the oxidation and degradation of muscle proteins from mirror carp.

Characteristics of pork emulsion gel manufactured with hot-boned pork and winter mushroom powder without phosphate

This study investigated the physicochemical characteristics of pork emulsion gels manufactured from hot-boned (HB) pork and winter mushroom powder in the absence of phosphate. It was found that compared to cold-boned (CB) pork, HB pork had a higher pH and exhibited a higher myofibrillar protein solubility with a lower actomyosin content (P < 0.05). Four types of pork gels were prepared, namely CB pork without phosphate, CB pork with phosphate (CBP), HB pork without phosphate, and HB pork with winter mushroom powder but without phosphate (HBW). The total exuded fluid was comparable for the CBP and HBW gels on all storage days. In addition, the HB and HBW gels had similar springiness and cohesiveness properties to the CBP gel (P > 0.05). These results indicate that the quality of pork gels manufactured in the absence of phosphate can be improved by the use of HB pork and with the incorporation of winter mushroom powder.

Effects of lysine and arginine addition combined with high-pressure microfluidization treatment on the structure, solubility, and stability of pork myofibrillar proteins

This study aims to investigate the effects of lysine (Lys) and arginine (Arg) addition combined with high-pressure microfluidization (HPM) treatment on the structure, solubility and stability of pork myofibrillar proteins (MPs). Results show that these treatments can lead to the structural unfolding of MPs, decreased particle size, and increased absolute value of zeta potential, thereby strengthening the interaction between MPs and the solution and significantly increasing solubility and stability. In addition, these treatments result in the production of some soluble polymers in MPs. The addition of Lys and Arg combined with HPM treatment can increase the solubility of MPs from 71.82% to 82.89% and from 71.82% to 85.17%, respectively. Besides, the MPs can still maintain high solubility of 70.43% and 71.84% after 5 day at 4 °C under adding Lys and Arg combined with HPM treatment, respectively. Comprehensive consideration, the method of adding Arg combined with HPM treatment can be considered in production to improve the solubility and stability of MPs.

Effect of different postmortem ageing conditions on physicochemical properties, structure and water‐holding capacity of pork

SummaryThis study aimed to determine the effects of postmortem ageing temperatures on protein–water interactions and muscle water‐holding capacity (WHC) of pork. The oxidation degree, solubility and secondary structure of myofibrillar protein (MP) were also studied. Porcine longissimus lumborum muscles were aged at −6 ± 1, 4 ± 1, and 10 ± 1°C for 3, 12, 24, 72, 120 and 168 h, respectively. The results showed the lower ageing temperature is conducive to decrease the protein oxidation and the transformation of protein conformation from ordered structures (α‐helices and β‐sheets) to disordered structures (β‐turns and random coils). These physicochemical changes favoured protein–water interactions, thus the muscle samples aged at −6 ± 1°C for 120 h had the highest protein solubility and WHC. This work revealed that ageing at sub‐freezing temperature (−6 ± 1°C) is beneficial to reduce protein oxidation and improve muscle water‐holding capacity.

Effect of Ultrasound-Assisted Sodium Bicarbonate Treatment on Aggregation and Conformation of Reduced-Salt Pork Myofibrillar Protein.

To study the effects of an ultrasound (0, 30, and 60 min) and sodium bicarbonate (0% and 0.2%) combination on the reduced-salt pork myofibrillar protein, the changes in pH, turbidity, aggregation, and conformation were investigated. After the ultrasound-assisted sodium bicarbonate treatment, the pH increased by 0.80 units, the absolute value of Zeta potential, hydrophobic force, and active sulfhydryl group significantly increased (p &lt; 0.05), and the turbidity and particle size significantly decreased (p &lt; 0.05). Meanwhile, the fluorescence intensity decreased from 894 to 623, and the fluorescence peak showed a significant redshift, which indicated that the ultrasound-assisted sodium bicarbonate treatment exposed the non-polarity of the microenvironment in which the fluorescence emission group was located, leading to the microenvironment and protein structure of myofibrillar tryptophan being changed. Overall, an ultrasound-assisted sodium bicarbonate treatment could significantly improve pork myofibrillar protein solubility and change the protein structure under a reduced-salt environment.

Effect of Grafted Insect Protein with Palatinose on Quality Properties of Phosphate-Free Meat Emulsion.

Due to concerns about the negative effects of phosphate on human health, the development of phosphate substitutes is an active area of research. Among the various methods, the structural modification of proteins has previously been established. In this study, we used grafting technology. Extracted insect protein was grafted with palatinose (GI), and 0.1 and 0.15% of GI were added to a phosphate-free meat emulsion mixed with 0.1% of eggshell powder (ES). The pH, myofibrillar protein solubility, and apparent viscosity increased with the addition of GI and ES (p < 0.05). Color values were also affected by GI and ES addition (decreased CIE L* and CIE a* and increased CIE b*; p < 0.05), while cooking loss was only improved by the addition of ES and not GI. Although the total fluid separated more than negative control (p < 0.05), the addition of ES improved emulsion stability and total expressible fluid separation and the fat separation reduced with addition of GI and ES (p < 0.05). Lipid oxidation was inhibited by the addition of GI and ES (p < 0.05). Moreover, the protein molecular weight distribution under 20 kDa was modified by the addition of GI, and the hardness and springiness of treatments decreased. In conclusion, the addition of GI and ES might be used to improve cooking loss, emulsion stability, and antioxidants, while the textural properties should be further researched.

Ultrasound-assisted freezing retards the deterioration of functional properties of myofibrillar protein in chicken breast during long-term frozen storage

Ultrasound-assisted freezing (UF) is a novel and fast freezing technology that has attracted much attention in the food processing industry in recent years. The objective of this study was to investigate the influence of UF, immersion freezing (IF), and air freezing (AF) on the functional properties (solubility, emulsification, and gelation) of myofibrillar protein (MP) in chicken breast during frozen storage (0–180 days). Compared to AF and IF samples, UF samples showed higher solubility, absolute potential, and emulsifying activity index, and lower turbidity and particle size during frozen storage (P < 0.05). Furthermore, UF treatment could better delay the deterioration of gel structure during storage. The gel water holding capacity and gel strength of MP in UF samples were higher than those in IF and AF samples during frozen storage (P < 0.05). The results of a hierarchical cluster analysis revealed that MP in the UF, IF, and AF samples had similar functional properties at 180, 90, and 60 days, respectively. Overall, UF retarded the decrease in functional properties of MP usually seen during frozen storage.

Improvement of solubility, gelation and emulsifying properties of myofibrillar protein from mantis shrimp (Oratosquilla oratoria) by phosphorylation modification under low ionic strength of KCl

The objective of this study was to investigate the mechanisms of phosphates coupled with KCl (at 0, 0.01 and 0.03 M) affecting gel and emulsifying properties of myofibrillar protein (MP) from mantis shrimp. 31P NMR showed that phosphate groups were introduced to MP after treatment with sodium pyrophosphate (SPP) or sodium tripolyphosphate (STPP). The incorporation of phosphates enhanced electronegativity and solubility of MP, leading to exposure of hydrophobic groups, especially in the presence of 0.03 M KCl. These changes resulted in increased gel strength, water-holding capacity and elasticity of MP, mainly due to the improved cross-linking of proteins via ionic interaction, hydrophobic interaction and disulfide bonds. Furthermore, the combination of phosphate and KCl contributed to formation of more stable emulsions stabilized by MP with higher emulsifying activity and smaller droplet size. These results indicated that phosphates and low-dose sodium substitutes synergistically improved the processing properties of muscle food.

Improved water solubility of myofibrillar proteins by ultrasound combined with glycation: A study of myosin molecular behavior

The poor water solubility of myofibrillar proteins (MPs) limits their application in food industry, and is directly related to the molecular behavior associated with myosin assembly into filaments. This study aims to explore the effect of high-intensity ultrasound (HIU) combined with nonenzymatic glycation on the solubility, structural characteristics, and filament-forming behavior of MPs in low ionic strength media. The results showed that the HIU (200–400 W) application could promote the subsequent glycation reaction between MPs and dextran (DX) and interfere with the electrostatic balance between myosin rods, suppressing the formation of filamentous myosin polymers. Glycated MPs pretreated by 400 W HIU had the highest solubility, which corresponded to the smallest particle size, highest zeta potential, and optimum storage stability (P < 0.05). Structure analysis and microscopic morphology observations suggested that the loss of the MP superhelix and the depolymerization of filamentous polymers were the main mechanisms for MP solubilization. In conclusion, HIU combined with glycation can effectively improve the water solubility of MPs by destroying or suppressing the assembly of myosin molecules.

Improving the solubility of myofibrillar proteins in water by destroying and suppressing myosin molecular assembly via glycation

Filamentous myosin is a self-assembling polymer that prevents myofibrillar proteins (MPs) from functioning in low ionic strength media. This study was aimed at investigating if glycation has the potential to improve the solubility of MPs in water. MPs were conjugated with monosaccharides, oligosaccharides, and polysaccharides under wet reaction conditions at 37 °C. The conjugation was verified by SDS-PAGE, FT-IR and amino acid analyses. MPs conjugated with dextran (DX) exhibited a higher solubility and dispersion stability in water, which corresponded to smaller particle size and more uniform distribution (P < 0.05). According to secondary and tertiary structure analyses, the loss of α-helix structures and unfolding of the MPs appear to be the main reasons for MP solubilization. Additionally, according to the zeta-potential, confocal laser scanning microscopy, and atomic force microscopy observation results, glycation can provide electrostatic repulsion or steric hindrance to disintegrate existing filamentous myosin aggregates and inhibit further self-assembly behavior.

Влияние продолжительности сухого созревания и состава посолочных веществ на белки высококачественной говядины

Meat quality largely depends on the maturation conditions and natural biochemical processes that affect its taste, aroma, tenderness, and technological properties. Dry maturation and technological processing attract a lot of scientific attention. The research objective was to study the effect of dry maturation time on the physicochemical parameters of high-quality beef, as well as the effect of a new curing mix on the properties of raw materials.&#x0D; The research featured dorsal-lumbar cuts of high-quality beef on maturation days 21 and 40. Matured meat was tested for the main components, the solubility of sarcoplasmic and myofibrillar proteins, the hydrophobicity of myofibrillar proteins, protein oxidation products, and the activity of catalase and peroxidase. The chemical composition was evaluated depending on the dry maturation time using the arbitration method. The solubility of proteins was determined by the calorimetric method with a biuret reagent. The hydrophobicity of myofibrillar proteins was determined by bromophenol blue reaction, and the activity of catalase and peroxidase was determined by standard methods. Proteins were extracted with potassium phosphate buffer (pH 7.2), while myofibrillar proteins were extracted with Tris-HCl and KCl buffers at pH 7.5 and 7.0. &#x0D; The meat samples were deboned and salted using sodium chloride and a combined mix of 70% magnesium chloride and 30% sodium chloride. The solubility of myofibrillar proteins on day 21 increased by 23.95% but decreased by 14.1% by day 40. The solubility of sarcoplasmic proteins decreased continuously (22.10 and 31.12%, respectively). The obtained data matched the hydrophobicity of proteins. Dry maturation initiated protein oxidation, as demonstrated by carbonyl and sulfhydryl groups of myofibrillar proteins on maturation day 40 (27.85 nmol/L and 27.3 µmol/g of protein, respectively). Sodium chloride and its mix increased the extractability of proteins by 5.2 and 6.9% on day 21 and by 6.8 and 10.6% on day 40 but triggered protein oxidation.&#x0D; Muscle proteins of high-quality beef proved functional after 21 days of dry maturation. The new mix with reduced sodium content can be recommended for high-quality dry-aged beef production.

Effects of different curing methods on edible quality and myofibrillar protein characteristics of pork

This study aimed to investigate the effects of standing curing (SC), tumbling curing (TC), vacuum tumbling curing (VTC) and ultrasonic-assisted curing (UAC) on the edible quality of black pork and property of myofibrillar proteins (MPs) extracted from black pork. The results showed that all curing methods could improve the marinating absorptivity and the gel water retention of black pork, the solubility and surface hydrophobicity of myofibrillar proteins, and reduce the cooking loss and shear force of black pork, the hydrogen bond content of myofibrillar proteins and the gel whiteness compared with the control group (SC). The result of sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) showed that the concentration of protein bands by VTC treatment was decreased obviously. In addition, the result of the scanning electron microscope (SEM) presented that tumbling and ultrasound treatment would destroy the structure of muscle fibers and make them loose and disordered.

The Solubility and Structures of Porcine Myofibrillar Proteins under Low-Salt Processing Conditions as Affected by the Presence of L-Lysine.

This study aimed to investigate the presence of L-lysine (Lys) on the solubility and structures of myofibrillar proteins (MFPs) at different ionic strengths. Porcine MFPs were incubated at 4 °C with various levels of ionic strengths (0.15, 0.3, or 0.6 M NaCl) with or without the presence of 20 or 40 mM Lys. After 24 h of incubation, MFP solubility and turbidity were determined, and the particle size distribution, circular dichroism spectra, and intrinsic tryptophan fluorescence of MFP were analyzed to obtain their secondary and tertiary structure. Results showed that the solubilization effects of Lys on MFPs are dependent on the ionic strength. Particularly, the presence of Lys could improve MFP solubility at 0.3 M, which resembles salt-reducing processing conditions. Concomitantly, the secondary and tertiary structures were observed to change as a result of the varying ionic strengths and the addition of Lys, including myofibril swelling, dissociation of myosin filaments, uncoiling of α-helix, and unfolding of the tertiary structure. The possible mechanisms underlying the solubilization effects of Lys on MFPs at low ionic strengths are discussed from the perspective of protein structural changes.

Effect of sodium bicarbonate on solubility, conformation and emulsion properties of pale, soft and exudative meat myofibrillar proteins

To investigate the effects of sodium bicarbonate on aggregation and emulsion properties of pale, soft and exudative (PSE) meat myofibrillar proteins, the changes in pH, turbidity, particle size, free sulfhydryl, surface hydrophobicity, emulsifying ability, and emulsion stability were studied. The pH, solubility, proportion of free sulfhydryl groups, surface hydrophobicity, emulsifying ability, and emulsion stability significantly increased (P < 0.05) with an increase in sodium bicarbonate concentration from 0 g/kg to 6 g/kg. In contrast, zeta potential, turbidity, and particle size significantly decreased (P < 0.05). In summary, the addition of sodium bicarbonate increased the pH of PSE meat myofibrillar proteins and enhanced the electrostatic repulsion between the proteins, causing the absolute value of zeta potential to increase, leading to greater exposure of sulfhydryl and hydrophobic groups and formation of smaller aggregations, enhancing its solubility, emulsifying ability and emulsion stability. Thus, sodium bicarbonate could improve the processing performance of PSE meat.

Assessment of the effect of marination with broccoli (Brassica oleracea var. italica) juice and balsamic vinegar on tenderness and quality of beefsteak.

Due to the increasing demand for natural foods with fewer artificial additives, broccoli is considered by the consumers and researchers due to its taste, nutritional values and biochemical components. Therefore, this research was conducted to investigate the effect of broccoli juice and balsamic vinegar on the physicochemical and textural attributes of the beefsteak aimed at tenderizing it and decreasing the ageing period. Experiments were carried out through marinating the beefsteak with three different treatments containing 3.00 units protease g-1 beefsteak of broccoli juice and 10.00% (v/w) of balsamic vinegar during 48 hr storage at 4.00˚C. A significant reduction in pH and Warner-Bratzler shear force as well as the increase in myofibrillar fragmentation index and myofibrillar protein solubility were obtained showing that the beefsteak was tendered in the presence of broccoli juice and broccoli juice+balsamic vinegar. Scanning electron microscopy images showed the destruction of endomysium collagen and sarcolemma areas of muscle filaments in the above-mentioned treatments. The electrophoretic analysis of isolated myofibrillar proteins indicated that the rate of troponin-T breakdown was quicker in all treatments compared to the control and its degradation was progressively obvious with 20.00 and 28.00 kDa protein bands in mentioned treatments. Based on the results, marinades of broccoli juice and balsamic vinegar could be utilized as a beneficial additive for improving beefsteak tenderness.

Improved Water Solubility of Myofibrillar Proteins by Ultrasound Combined with Glycation: A Study of Myosin Molecular Behavior

Improved Water Solubility of Myofibrillar Proteins by Ultrasound Combined with Glycation: A Study of Myosin Molecular Behavior

Effects of Maturation after Slaughter on Physicochemical Properties and Proteins Expression of Goats Meat

In order to investigate the physical and chemical properties of goats during maturation process within 48 h after death, longissimus dorsi muscle of goats at 0, 12, 24 and 48 h after slaughter was taken respectively. The TPA, pH, water retention rate, sarcoplasmic protein solubility and differential expression proteins (DEPs) level were measured respectively to study the change of meat quality at different maturation stages. The results showed as follows: With the extension of post-mortem time point, the pH of goats meat decreased significantly within 48 h (P 0.05). Within 12 h after slaughter, the solubility of myofibrillar proteins in goat meat samples decreased significantly (P<0.05), and then increased gradually (P<0.05), solubility of sarcoplasmic fibers protein increased gradually with the prolongation of post-slaughter time (P<0.05). The glycogen content of Xinjiang goats within 48 h after slaughter was significantly decreased (P<0.05). Compared with 0 h, there were 13 DEPs in the 12 h group, 26 DEPs in the 24 h group, and 69 DEPs in the 48 h group. The expression of enzymes related to energy metabolism was up-regulated from 0 to 48 h, and the expression of proteins related to lamb odor was up-regulated from 24 to 48 h. The tenderness, color and taste of Xinjiang goat meat were superior during the maturation period of 24~48 h after slaughter, the processing and storage during this period could provide basic guarantee for the quality of Xinjiang goats.

Processing Characteristics of Freeze-Dried Pork Powder for Meat Emulsion Gel.

The processing characteristics of freeze-dried pork powder as raw meat for comminuted meat products were compared with those of freeze-thawed pork. The tertiary structural properties, oxidation, and solubility of proteins in the freeze-dried pork powder were investigated. In addition, the properties of the emulsion gels manufactured with freeze-dried pork powder (GFD) and freeze-thawed pork (GFT) at 1.5% and 2.0% NaCl were evaluated. The surface hydrophobicity and intrinsic tryptophan fluorescence intensity of myofibrillar proteins between the freeze-dried pork powder and freeze-thawed pork were similar. However, freeze-dried pork powder had higher carbonyl compounds and lower solubility of sarcoplasmic and myofibrillar proteins than freeze-thawed pork (p<0.05). GFD had higher cooking loss than GFT in 2.0% NaCl, and lower hardness and a* value of GFD were observed regardless of NaCl level (p<0.05). Moreover, GFD had higher malondialdehyde content than GFT at the two NaCl concentrations (p<0.05). Therefore, our study demonstrated that freeze-dried pork powder has lower functional properties than freeze-thawed pork as raw meat for comminuted meat products.