Denaturation Of Myosin Research Articles

Effects of contact ultrasound coupled with infrared radiation on drying kinetics, water migration and physical properties of beef during hot air drying

Drying, as a critical step in the production of air-dried beef, has a direct impact on the quality of the final product. Innovatively, a composite system incorporating contact ultrasound (CU) and infrared radiation (IR) as auxiliary measures within a hot air drying (HAD) framework was built in this research, and the effects of these techniques on the drying kinetics, protein denaturation, and moisture transformation of air-dried beef were investigated. In comparison to HAD treatment, the integrated CU and IR (CU-IRD) system displayed marked enhancements in heat and moisture transport efficiency, thereby saving 36.84% of time expenditure and contributing favorably to the improved moisture distribution of the end-product. This was mainly ascribed to the denaturation of myosin induced by IR thermal effect and the micro-channel produced by CU sponge effect, thus increasing T2 relaxation time and the proportion of free water. In conclusion, the composite system solved the problem of surface hardening and reduces hardness and chewiness of air-dried beef by 40.42% and 45.25% respectively, but inevitably increased the energy burden by 41.60%.

Elucidate the molecular basis of ampholytic chitosan as a high-performance cryoprotectant to myosin denaturation: The importance of saccharide charges

The uses of charged poly/oligo-saccharides enable the retarding of protein denaturation against various environmental stresses during food storage and manufacturing. However, at subzero temperatures, the molecular basis of such stabilization behaviors, i.e., cryoprotections, remain less explored. In this study, we introduced an ampholytic saccharide, carboxymethyl chitooligosaccharide (CMCO) that effectively inhibited the freezing-induced myosin denaturation. The in-depth cryoprotective mechanism was systematically investigated by using molecular dynamic simulation and multispectral characterizations. Results showed that CMCO may interact with myosin through hydrogen bonding and electrostatic interactions, which caused the expelling of water at protein surfaces and the reduced conformational flexibility of myosin molecules. Due to this water replacement event, both secondary and ternary structures of myosin became freezing-resistant, leading to the inhibited protein aggregations and retained functionalities, such as solubility, Ca2+-ATPase activity, and gelling properties. Moreover, cryoprotective behaviors of CMCO were charge-dependent. CMCO with a higher degree of carboxymethyl substitution (DS: 1.2) was inclined to bind and stabilize myosin molecules better than the low-DS (DS: 0.8) one, even though both outperformed other cryoprotective saccharides. Therefore, this investigation not only introducing a high-performance myosin cryoprotectant, but also elaborated the cryoprotective mechanism of ampholytic saccharides.

Molecular modelling studies reveal cryoprotective mechanism of L-Proline during the frozen storage of shrimp (Litopenaeus vannamei)

This study aimed to investigate the cryoprotective properties of proline (1% and 3% (w/v)) on shrimp. The cryoprotective mechanism was studied using physico-chemical experiments and molecular simulations. Proline had a notable positive impact on the thawing loss and texture of shrimp in comparison to the control. The denaturation of myosin in frozen shrimp was delayed by proline. Microscopy analysis demonstrated that proline effectively lowered the harm caused by ice crystals to shrimp muscle. Molecular simulations indicated that proline potentially exerted a cryoprotective effect primarily through the “water substitution” and “glassy state” hypotheses. Proline formed hydrogen bonds with myosin to replace the water molecules around myosin. Additionally, proline interacted with water molecules to form a glassy state, impeding the growth of ice crystals. Consequently, the stability of shrimp myosin was enhanced during freezing. In conclusion, proline demonstrated promise as an efficacious cryoprotectant for aquatic products.

Effect of protein structure changes during different power ultrasound thawing on emulsification properties of common carp (Cyprinus carpio) myofibrillar protein

The impact of ultrasound thawing (UT) at different power (0 W, 100 W/0.132 W·cm−2, 300 W/1.077 W·cm−2, and 500 W/1.997 W·cm−2, namely WT, UT-100, UT-300, and UT-500) on protein structure, aggregation, and emulsifying properties of common carp (Cyprinus carpio) myofibrillar protein were investigated in the present study. The result showed that the reactive sulfhydryl content, total sulfhydryl content, protein solubility, and absolute potential of UT-300 samples were obviously higher than those of other thawed samples, while the turbidity of UT-300 samples was lower (P < 0.05), which indicated that proper UT power was beneficial to inhibit protein aggregation caused by thawing, while too low (100 W) or too high (500 W) ultrasonic power had poor effect. The Ca2+-ATPase activity and thermal stability of UT-300 samples were much higher than those of other thawed samples (P < 0.05), indicating that UT-300 inhibited myosin denaturation and thermal stability reduction of thawed products. The α-helix content of UT-300 samples was higher than that of other thawed samples, while the β-sheet content was significantly lower than that of other thawed samples (P < 0.05). The fluorescence intensity of UT-300 samples was higher than that of other thawed samples, and the λmax of UT-300 samples and UT-100 samples were lower than that of other thawed samples, which indicated that UT-300 could effectively inhibit the alteration of protein secondary structure and tertiary structure during thawing. The emulsifying activity of UT-300 samples was significantly higher than that of WT samples, and the droplet diameter of UT-300 samples was also lower than that of WT samples (P < 0.05), which indicated that UT-300 inhibited the decrease of emulsifying property during thawing. Overall, moderate ultrasonic power (300 W) could effectively inhibit the protein aggregation and structural changes during thawing, led to the decrease of emulsifying activity.

Mechanism on the Synergistic Gelation of the Myofibrillar Protein Composite Gel Enhanced by "Clean-Label" Skin Functional Protein Powders.

The concept of healthiness and sustainability has promoted the innovation and development of "clean-label" products. Herein, this study aims to explore the influence mechanism of "clean label" skin protein powder (FPP) on the gelation properties of myofibrillar proteins (MPs). Specifically, the addition of FPP (0.2-4.0%) can improve the water holding capability and texture properties of MP composite gels. When the FPP concentration is over 1.0%, the composite gels exhibit no significant water loss during centrifugation. Dynamic rheology and sodium-dodecyl sulfate-polyacrylamide gel electrophoresis results revealed that FPP can slow the aggregation and denaturation of myosin and promote the formation of disulfide bonds between myofibril proteins, thus forming a stable network structure. Structural observation revealed that FPP can fill into the MP gel and lead to the formation of compact gel structures. Besides, with the increase of FPP concentration, the chemical forces involved in structural stabilization change significantly. Specifically, hydrophobic interaction and hydrogen bonding are the dominant forces at a lower FPP concentration (0.2 and 0.4%), while the ionic bond and disulfide bond are the dominant forces at a higher concentration. Overall, this work demonstrated that FPP can significantly improve the gel functionality of MP by altering the gel structure and strengthening the molecular forces.

Influence of pyrophosphate (PPi) and adenosine 5`-triphosphate (ATP) on the conformational stability and ultrastructure of silver carp myofibrillar proteins at low salinity

The effect of pyrophosphate (PPi) in comparison with adenosine 5`-triphosphate (ATP) on the thermal and ultrastructural properties of silver carp myofibrillar protein (SMf) was studied. The temperatures for 50 % denaturation (T1/2) of PPi-treated myosin and actin were 38 °C and 41 °C, respectively, lower than those for control SMf (43 °C and 48 °C, respectively). In comparison, T1/2 of myosin in ATP-treated SMf was 42 °C, while T1/2 of actin cannot be detected because no changes in actin digestion pattern. The ultrastructural change of PPi-treated and control SMf differed considerably from that of ATP-treated SMf in which the typical striated structural pattern disappeared, replaced by an aggregated form. In contrast, PPi-treated SMf retained the striated structure with lengthened sarcomere. Therefore, while both PPi and ATP can dissociate actomyosin, the presence of ATP hinders the chymotryptic digestion of actin.

Elucidating the molecular mechanism of water migration in myosin gels of Nemipterus virgatus during low pressure coupled with heat treatment

The relationship between myosin denaturation, aggregation and water migration in Nemipterus virgatus myosin gels with different treatment processes under optimal low pressure coupled with heat treatment was investigated to clarify the molecular mechanism of water migration. With the different treatment processes, the proportion of bound water of the myosin gels increased significantly (P < 0.05). Denaturation of myosin S1 sub-fragments and α-helical unfolding during different treatment processes led to an increase in β-sheets content. These promote increased exposure of Try residues and hydrophobic groups of myosin, formation of clathrate hydrates, and reduced mobility of bound water. Furthermore, hydrophobic interactions and disulfide bonds caused the head-head and head-hinge to coalesce into a 3D honeycomb network with greater fractal dimension, less lacunarity, smaller water hole diameter and more water holes. This increased the capillary pressure experienced by the bound water, causing immobile water to migrate towards the bound water. The present study may be necessary to improve the mechanism of water migration in protein gel systems and to promote the industrial application of high pressure processing technology in surimi-based foods.

Effects of polyphenols on the gel and digestive properties of Penaeus vannamei myosin after freezing.

Polyphenols could inhibit the freezing-induced denaturation of myosin, and affect its nutritional and functional properties, which have rarely been studied to date. Therefore, the effects of interactions between polyphenols and myosin after freezing on myosin gel and digestive properties were investigated using low field NMR, a texture analyzer, a dynamic rheometer, ultraviolet-visible spectra, scanning electron microscopy, LC-MS/MS, an automatic amino acid analyzer, etc. Hesperetin (HE), dihydroquercetin (DI), salidroside (SA), and mangiferin (MA) increased the water-holding capacity, non-flowable water content, gel strength, texture, storage modulus, and fractal dimensions of the myosin gel, while modifying its leading force. The results of scanning electron microscopy revealed that the surfaces of polyphenol groups were relatively smoother than those of the control group. Meanwhile, the four types of polyphenols under study significantly improved the gastric and gastrointestinal digestibility of myosin. Furthermore, they significantly increased the contents of essential, flavor, and total free amino acids, as well as the unique peptide numbers in myosin digestion products. This work provides reliable guidance for polyphenols to improve protein function and nutritional properties.

Salting in the preparation of jerked beef meat with pork

Food processing allows a wide variation in the final quality of the product, which directly depends on the quality of the raw material used, the processing conditions, storage and commercialization. Salting, for example, is one of the oldest methods used to preserve meat. In the meat industry, the incorporation of salts into products is commonly used to improve dietary functionality and ensure food safety. Thus, the objective of this review was to understand that the discarded matrix meat can be used to make jerky meat, adding value to the final product. The processing of jerked beef is based on the osmotic dehydration process in counter flow, promoted by the penetration of salt with consequent exit of water from the inter and extra fibrillar compartments to the surface, with subsequent drying. At the same time, myosin denaturation occurs as a result of high temperatures, as well as myoglobin oxidation, promoted by salt, increasing the susceptibility to protein oxidation. The use of discarded animal meat to make jerky adds value to the by-product, improving sensory quality.

Understanding the Performance of Plant Protein Concentrates as Partial Meat Substitutes in Hybrid Meat Emulsions.

Hybrid meat products are an excellent strategy to incorporate plant proteins into traditional meat formulations considering recent market trends focusing on the partial reduction in red meat content. In this work, we evaluated the effects of different concentrated plant proteins (soy, pea, fava bean, rice, and sunflower) in partially replacing meat in meat emulsion model systems. Soy, pea, and sunflower proteins showed great compatibility with the meat matrix, giving excellent emulsion stability and a cohesive protein network with good fat distribution. Otherwise, adding rice and fava bean proteins resulted in poor emulsion stability. Color parameters were affected by the intrinsic color of plant proteins and due to the reduction in myoglobin content. Both viscoelastic moduli, G' and G″ decreased with the incorporation of plant proteins, especially for rice and fava bean. The temperature sweep showed that myosin denaturation was the dominant effect on the G' increase. The water mobility was affected by plant proteins and the proportion between immobilized and intermyofibrillar water was quite different among treatments, especially those with fava bean and rice proteins. In vitro protein digestibility was lower for hybrid meat emulsion elaborated with rice protein. It is concluded that soy, pea, and mainly sunflower proteins have suitable compatibility with the meat matrix in emulsified products.

Hybrid Meat Products: Incorporation of White Bean Flour in Lean Pork Burgers

The effect of partial lean pork-meat replacement by white Phaseolus vulgaris L. flour in hybrid burgers was studied. A multivariate regression model was used to test different bean flour levels (BF: 8–15 g/100 g) and water/bean flour ratios (W/BF: 1.2, 1.6, and 1.8 g/g). Process yield, texture profile analysis, color parameters, thermal transitions, and microstructure of the systems were analyzed. Respond Surface Methodology was used to model the response behaviors and optimization. Burgers with BF showed yields higher than 88%. Hardness and cohesiveness decreased as the BF level increased, with a more noticeable effect when the W/BF ratio became larger. Regarding color, the higher the BF and the W/BF ratio in burgers, the higher the L* obtained. The desirability optimization predicted an optimum formulation consisting of 15 g BF/100 g and 1.36 g/g W/BF with similar attributes to a commercial pork burger. The thermal analysis showed an increase in the enthalpy associated with the myosin denaturation and the interactions between meat proteins and BF led to higher temperatures for the starch gelatinization and protein denaturation. The microstructure of BF burgers presented a more stable coarse gel matrix derived from coagulated meat proteins combined with the flour components. The mathematical procedure adequately predicted the hybrid burger quality attributes.

Optimization of beef heat treatment using CFD simulation: Modeling of protein denaturation degree

AbstractBeef meat is most often eaten after heat treatment, but the quality of the final product is not always satisfactory. In this study, based on CFD modeling and simulation, optimization of the heat treatment process of beef was performed using RSM. The aim of the research was to select the parameters of thermal treatment in order to achieve the highest degree of denaturation of myosin and collagen proteins, and the lowest degree of actin denaturation and weight loss of the final product. The obtained results were verified by experimental studies, which showed statistically significant similarities with those predicted. Depending on the composition of the basic beef meat, heat treatment parameters should be selected individually in order to obtain a product characterized by the highest quality and, consequently, the highest acceptance among consumers. CFD modeling and RSM forecasting was a useful approach to study the unstable heat transfer in the combi steamer and also mapped the temperature distribution over the whole beef load, thus, optimizing the roasting process.Practical ApplicationThe use of CFD simulations and the RSM model in the meat industry will optimize the process of heat treatment of beef. This innovative method of predicting protein denaturation and thermal leakage will reduce mass losses caused by heat treatment. The consequence of using this model will be the delivery of an optimal dose of heat to the raw material, which will ensure the denaturation of myoglobin and collagen, and the actin will be left undenatured. As a result, the product will be characterized by the highest quality and acceptance of sensory features among consumers. As a result, energy consumption in the production of roast beef will be reduced and the demand for these products among demanding customers will increase.

Effects of microbial transglutaminase on textural, water distribution, and microstructure of frozen-stored longtail southern cod (Patagonotothen ramsayi) fish mince gel.

Frozen-stored fish mince tend to have poor gelling ability due to significant myosin denaturation caused by freezing. In this study, microbial transglutaminase (MTGase) was used to improve the quality of fish mince gel products made from frozen-stored longtail southern cod (LSC). The gel strength of the gel product increased with the addition of MTGase and reached a plateau value of ~19 N mm beyond 300 U/kg of MTGase, at the same condition, T22 was reduced from 57.22 to 49.77 ms, T23 was reduced from 1,273.88 to 1,072.27 ms. As the MTGase addition increased from 0 to 400 U/kg, the hardness of the fish surimi gel increased from 14.52 to 21.36 N, and the microstructure changed from loose to dense, respectively. This study showed that MTGase could promote gelation to improve the quality of frozen-stored LSC fish mince gel, especially at 300 U/kg, which potentially can be utilized to produce good surimi gel products out of frozen-stored fish.

Kappa-carrageenan as an effective cryoprotectant on water mobility and functional properties of grass carp myofibrillar protein gel during frozen storage

The effect of kappa-carrageenan oligosaccharides was analyzed on the gelling abilities of grass carp myofibrillar proteins (MP) during 60 days frozen storage. Four gel treatments were prepared: control without additives (C), a positive control with sucrose: sorbitol (PC), and two batches with 1 and 2% of kappa-carrageenan (KC). All MP gels showed a significant decline in the functional and structural properties. Water holding capacity (WHC) and textural properties of control MP gel was significantly reduced due to oxidative changes, whereas weak cross-linking between amino acid molecules and denaturation of myosin observed. In contrast, PC and KC showed a significant control on the reduction of functional properties due to the enhanced inter/intra-molecular interactions and less formation of ice crystals. Addition of KC (2%) significantly restricted the decline in WHC from 95.45 to 75.47%, which is well associated with high hydrogen proton density. Besides that, low field nuclear magnetic resonance (LF-NMR) analysis exhibited a restricted increase in T22 relaxation time in samples added with KC (2%). Overall, MP gel with KC (2%) proved to be an effective alternative in comparison with PC and could be efficient in the production and commercialization of fish and other seafood products.

Molecular cloning and expression dynamics of UNC-45B upon heat shock in the muscle of yellowtail

As a myosin chaperone, uncoordinated-45B (UNC-45B) is expressed specifically in striated muscle tissues. It has been proved that overheat shock will lead to myosin denaturation, and that UNC-45B is involved in myosin assembly. Yellowtail was chosen for this study, as an important economic aquaculture fish worldwide. To establish the heat shock response of UNC-45B in yellowtail, cDNA cloning and expression analysis were carried out. The cDNA of yellowtail unc-45b was successfully cloned, and consisted of 3051 bp encoding 930 amino acid residues (ORF 2793 bp). Based on the sequence of yellowtail unc-45b, we designed original primers and an anti-peptide antibody for our study. Yellowtail were then exposed to short-term or long-term heat shock, and UNC-45B expression levels were determined by qPCR and western blot analysis. For short-term heat shock exposure, the fish were kept in water tanks at 25 °C (control group) and 30 °C (heat shock group) for up to 30 h. The mRNA and protein expression levels of UNC-45B increased markedly after 8 h and 24 h, respectively. To investigate the effects of long-term heat shock exposure, cultured yellowtail were sampled in summer and winter at sea surface temperatures of 30 °C and 14 °C. The expression of UNC-45B in both mRNA and protein levels was significantly higher in summer than in winter. Our results show that the increase in UNC-45B expression levels can reflect heat shock response sensitively, and it is suggested that UNC-45B can repair the denatured myosin during heat shock exposure in yellowtail. Moreover, we successfully detected the protein expression of UNC-45B in aquaculture fish species in native conditions by using western blot analysis for the first time. Therefore, we assume that UNC-45B can be regarded as a biomarker to predict heat shock resistance level. This would help in aquaculture production, in the selection of juveniles able to endure heat shock.

Effect of high pressure processing and heat treatment on the gelation properties of blue crab meat proteins

This study was carried out to evaluate the effect of high pressure processing (HPP) and thermal treatments on the gelling properties of proteins from blue crab meat. Crabmeat was pressurized at 100, 300, and 500 MPa (10 °C/5 min) with and without heating (90 °C/20 min) after the HPP treatment. Treated samples were analyzed by protein interactions, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and dynamic rheometry. Protein gelation after pressurization was based on physical interactions which were modified after HPP treatment; meanwhile, thermal gelation was based mainly on the formation of covalent bonds. DSC showed that pressure levels over 300 MPa reduced myosin denaturation temperature indicating protein unfolding. HPP treatment at 100 MPa led to a partial protein denaturation effect. FTIR results showed a reduction in the fraction of α-helix structure along with a development of β-sheet portion as a result of protein denaturation promoted by the application of pressure. The sweep temperature analysis indicated that the combination of treatments stabilized the protein network in the gels from blue crab meat. The combination of pressure (100 MPa) and heat (90 °C) treatments allowed obtaining gels from crabmeat proteins with optimal rheological properties.

Effects of temperature on the denaturation and aggregation of ( Lateolabrax japonicus ) myosin from sea bass surimi

This study aimed to investigate the effects of temperatures of 30–90°C on myosin denaturation and aggregation in sea bass (Lateolabrax japonicus) during setting. The result indicated that the myosin of sea bass began to form gels at 60°C, and surface hydrophobicity increased by around 8.9% at 40°C and reached its maximun at 60°C. During setting at 40°C and 60°C, the ratios of α‐helix of myosin reduced gradually and finally decreasing by 17.1% and 25.2%, respectively. Incubating at 90°C, α‐helix continued to transform into random coil. Association with the results of surface morphology, it further confirmed that the temperatures of 40°C and 60°C were two important denaturation and aggregation temperatures. At 90°C, myosin of sea bass formed a fine and dense gel network under the joint action of nondisulfide covalent bond, disulfide bond and hydrophobic interaction. PRACTICAL APPLICATIONS: The raw materials for marine surimi are becoming scarcer with marine overfishing and the increasing demand for surimi. Sea bass, an important economic mariculture fish in China, has white meat and less bone spur and is advantageous for the development of surimi products as raw materials. During heating of surimi, the change of myosin structure is a main important key to forming a gel network. This research revealed the changes of sea bass myosin from denaturation, aggregation to gel formation during heating and provided a theoretical basis for the processing of sea bass surimi.

Effect of Repeated Freezing-Thawing on Protein Fractions, Textural, and Functional Properties of Few Species of Freshwater Fishes (Indian Major Carps)

ABSTRACT The effects of repeated freezing-thawing on protein fractions and textural and functional properties of Indian major carps were assessed in the study. The loss of salt soluble proteins and water-soluble proteins was almost triple and double, respectively, due to freezing-thawing cycles compared to frozen storage alone. Electrophoresis pattern and Ca2+ATPase activity confirmed denaturation of myosin due to multiple freezing-thawing. The hardness of fillets, protein solubility, water-holding capacity, and emulsifying capacity decreased significantly (p < .05) with increased freezing-thawing cycles. The gel strength of Indian major carps subjected to multiple freezing-thawing cycles decreased up to ~44% at the end of five freezing-thawing cycles.

The characteristics of gelation of myofibrillar proteins combined with salt soluble Rhodotorula glutinis proteins by enzymatic crosslinking

Some microbial single-cell proteins are capable of producing synergistic crosslinking interactions with edible proteins by rational regulation. Herein, we reported that salt soluble proteins (RGP) extracted from Rhodotorula glutinis in an alkaline and saline system may combine with myofibrillar proteins (MP) by transglutaminase (TG) polymerization to form improvable irreversible thermal co-gels. The combination of MP, RGP, and TG, namely restructured MP gels, led to significantly enhanced water holding capacity (WHC), up to 90.76 ± 1.88% (% of retained water) and textural properties (hardness, springiness, and adhesiveness) as well as decreases of ‘gauche-gauche-gauche’ SS bonds and α-helix conformations and increases of ‘gauche-gauche-trans’ SS bonds and β-fold conformations, compared to MP and MP-RGP groups. Differential scanning calorimetry analysis validated that thermostability of myosins and actins from MP was reduced after using RGP, TG, and their combination, and unfolding and denaturation of myosin occurred easily during thermal co-gelation by TG and/or RGP.

The effect of fish freshness on myosin denaturation in flounder Paralichthys olivaceus muscle during frozen storage

The effect of fish freshness on myosin denaturation during the frozen storage of flounder muscle was studied. The muscle of instantaneously killed flounder was immediately stored at − 20 °C (pre-rigor mortis; day 0), or after storage at 0 °C for 2 days (rigor mortis) or 5 days (post-rigor mortis). Myosin denaturation in frozen stored muscle was studied by measuring Ca2+-ATPase activity, myosin solubility in the presence of salt (salt solubility), and monomeric myosin content. High ATPase activity was maintained in the day-0 samples of instantaneously killed flounder during the early phase of frozen storage. High salt solubility of myosin was also observed in these samples. However, the beneficial effect of frozen storage was lost when the storage period exceeded 2 months. There was no difference in myosin denaturation among the three groups of samples after 2 months of frozen storage. The myosin denaturation profile during the frozen storage of muscle was characterized by high salt solubility in the presence of Mg-ATP, even after ATPase inactivation, especially in the day-0 samples. The salt-soluble fraction contained a large amount of aggregated myosin, as revealed by (NH4)2SO4 fractionation. The monomeric myosin content was explained by Ca2+-ATPase inactivation in the frozen stored meat for all three groups. This study demonstrated that the high quality of flounder meat is maintained during short-term frozen storage, but that the beneficial effects of frozen storage are lost over longer periods of time.