Carp Actomyosin Research Articles

Effects of Microwave Radiation and Water Bath Heating on the Physicochemical Properties of Actomyosin from Silver Carp (Hypophthalmichthys molitrix)during Setting

Changes in the physical and chemical characteristics of actomyosin, isolated from silver carp (Hypophthalmichthys molitrix), induced by heating in a water bath and microwave oven were investigated. Ca2+-ATPase showed a heating-time-dependent decrease in activity, suggesting denaturation of myosin and dissociation of the actomyosin complex. The decrease in actomyosin solubility indicates the formation of protein aggregates. In addition, reactive sulfhydryl (R-SH) groups increased and total SH (T-SH) groups decreased with heating, indicating the formation of disulfide bonds through SH oxidation or disulfide interchanges. The differences of surface hydrophobicity (S0) showed microwave heating has an inhibitory effect on protein conformation changes. Fourier transform infrared confirmed the conformational changes of silver carp actomyosin. This study demonstrated that microwave heating can effectively depressed actomyosin structural changes during heating and provided useful information for surimi production. Practical Applications At present, there is lot of research about heat-induced gel from fish protein, but the way they used are traditional water bath or ohmic heating. Though reports of microwave heating on structure and the characteristics of fish protein are few, it is important for surimi gelation and microwave sterilization. We supposed microwave heating could influence the structure of fish protein and improve the quality of surimi. A preliminary study of microwave heating on actomyosin not only can enrich theory of heated induced protein gel also has important scientific value.

Chemical interactions and gel properties of black carp actomyosin affected by MTGase and their relationships

Partial least squares regression (PLSR) was applied to evaluate and correlate chemical interactions (–NH2 content, S–S bonds, four non-covalent interactions) with gel properties (dynamic rheological properties and cooking loss (CL)) of black carp actomyosin affected by microbial transglutaminase (MTGase) at suwari and kamaboko stages. The G′ and CL were significantly enhanced by MTGase and their values in kamaboko gels were higher than those in suwari gels at the same MTGase concentration. The γ-carboxyamide and amino cross-links, catalyzed by MTGase, were constructed at suwari stage and contributed to the network formation, while disulfide bonds were formed not only in suwari gels but also in kamaboko gels, further enhancing the gel network. PLSR analysis revealed that 86.6–90.3% of the variation of G′ and 91.8–94.4% of the variation of CL were best explained by chemical interactions. G′ mainly depended on covalent cross-links and gave positive correlation. CL was positively correlated with covalent cross-links, but negatively related to non-covalent bonds, indicating that covalent bonds promoted water extrusion, whereas non-covalent bonds were beneficial for water-holding.

Effect of iced-storage on the activity of cathepsin L and trypsin-like protease in carp dorsal muscle

Carps were stored in ice for 0, 2 and 4 days. The actomyosin was extracted from the ice-stored fish and the enzymatic activity of cathepsin L and trypsin-like protease in the extract was assayed. The two enzymes remained in the carp actomyosin despite intensive leaching during the extraction procedure. The activity of cathepsin L decreased slightly after 2 days of storage and remained relative constant thereafter, suggesting the enzyme was only slightly affected by the short term iced-storage. However the activity of the trypsin-like protease increased rapidly with iced-storage time, indicating that it might have been activated during the short term storage in ice.

Changes in Physicochemical Properties of Bighead Carp (Aristichthys mobilis) Actomyosin by Thermal Treatment

Physicochemical properties of actomyosin from bighead carp during heat-treatment were investigated. Turbidity, solubility, and surface hydrophobicity showed significant changes from 40–55°C (P < 0.05). Heat-treatment before 45°C could make actomyosin unfold, and the disulfide bonds were formed at temperatures above 45°C. Three enthalpy transitions at 41.2, 61.7, and 63.4°C were found in differential scanning calorimetry thermogram of bighead carp actomyosin. Storage modulus (G′) increased gradually and reached the first peak at 36.5°C and the second peak at 50°C. Myosin suffered conformation changes and lead to aggregation during the heating period.

Aggregation and structural changes of silver carp actomyosin as affected by mild acidification with d-gluconic acid δ-lactone

The structural changes and aggregation properties of silver carp actomyosin acidified with d-gluconic acid-δ-lactone (GDL) were investigated. Results showed that silver carp actomyosin underwent aggregation and formation of precipitate as indicated by turbidity and centrifugation coupled electrophoresis analysis. Circular dichroism indicated that myosin rod unfolded during acidification, resulting in a gradual decrease in α-helical content. The changes in tertiary structure of actomyosin under acidic conditions were demonstrated by second-derivative UV spectra and intrinsic fluorescence. Tyrosine residues were exposed to the surface of proteins when pH was decreased to 5.5, and were buried inside the protein aggregates with further reduction in pH. In contrast, more tryptophan residues were exposed to the polar environment with decreasing pH. 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide crosslinking experiments showed that the intensity of myosin heavy chain (MHC) bands decreased sharply with decreasing pH and the actin bands decreased more slowly, suggesting that MHC is the major protein component involved in the non-covalent cross-linking and formation of aggregates during acidification of silver carp actomyosin.

Acid-induced aggregation of actomyosin from silver carp ( Hypophthalmichthys molitrix)

Acid-induced denaturation and aggregation properties of silver carp actomyosin added with d-gluconic acid-δ-lactone (GDL) during incubation at chilled temperature (4 °C) were studied. Actomyosin underwent aggregation with decreasing pH, as evidenced by increased turbidity and decreased protein solubility in 0.6 M NaCl solution. Ca 2+-ATPase activity decreased continually with increasing incubation time in the presence of GDL, accompanied by an initial increase in surface reactive sulphydryl (SH) content, indicating the conformation changes of actomyosin during acidification. Protein solubility in selected solvents and electrophoresis analysis showed that the major myofibrillar proteins, particularly, myosin heavy chain and actin were involved in the formation of protein aggregates mainly through noncovalent bonds including hydrophobic interactions and hydrogen bonds during acidification. The slight decrease in total SH content during acidification suggested that disulphide bonds were also involved in acid-induced aggregation of silver carp actomyosin to a lesser extent.

Non-binding property of cathepsin L to myosin

Disodium pyrophosphate at 10 mM concentration, was effective in dissociating myosin and actin from actomyosin in walleye pollock ( Theragra chalcogramma) surimi and red bulleye ( Priacanthus macracanthus) surimi. After Sepharose 2B gel filtration, cathepsin L contained in the actomyosin was obviously non-binding to myosin. Actomyosin from carp ( Cyprinus carpio) muscle was not dissociated in pyrophosphate solution in the absence of MgCl 2 and it was successfully dissociated by 10 mM pyrophosphate in the presence of 2 mM MgCl 2. Cathepsin L in carp actomyosin was shown to be much more complicated than that in the above two surimis. After Sepharose 2B gel filtration, there were two activity peaks of cathepsin L in carp, one almost corresponding with actomyosin, the other obviously separated from actomyosin. Both of the peaks were non-binding to myosin.

Effect of pH on the gelation of walleye pollack surimi and carp actomyosin pastes

: The effect of pH on thermal gelation and transglutaminase (TGase; EC2.3.2.13)-induced suwari (setting) of surimi and actomyosin pastes was investigated. A strong and elastic gel was produced from walleye pollack surimi paste at pH 7.0 in the presence of Ca2+ using a two-step heating method. In contrast, walleye pollack actomyosin paste formed a weak gel under the same conditions as a result of the low concentration of endogenous TGase. In the presence of EGTA [ethyleneglycol bis(2-aminoethylether) tetraacetic acid], weak gels were formed at pH values of 7.0 and 6.0. Non-proteolytic modori (gel weakening) occurred extensively in the course of actomyosin gelation, but not in surimi gelation. Maximum TGase-induced myosin heavy chain cross-linking was observed at a slightly higher pH of 7.5 than at the optimal pH of endogenous TGase activity; the difference being derived from different substrates. Gelation of carp actomyosin paste at pH values of 5.5, 6.0, 6.5 and 7.0 was monitored by measuring storage modulus (G′) and loss modulus (G″). A weak gel was formed at all pH values, but a slightly rigid and less elastic gel was obtained at lower pH values. The addition of microbial TGase (MTGase) formed strong elastic gels at pH 7.0 and 6.5. MTGase cross-linked myosin heavy chains even at pH 5.5, but contributed neither to suwari response nor strong gel formation. Overall, results suggest that the optimal pH for the gelation of surimi paste from easy-setting fish species is a compromise between the pH-optima of TGase activity and of preferable actomyosin conformation for myosin cross-linking.

Effect of Microbial Transglutaminase on Thermal Gelation of Carp Actomyosin Sol

Effect of Microbial Transglutaminase on Thermal Gelation of Carp Actomyosin Sol

Role of SH&lt;sub&gt;a&lt;/sub&gt; in the Polymerization of Myosin Heavy Chain during Ice Storage of Carp Actomyosin

Role of SH&lt;sub&gt;a&lt;/sub&gt; in the Polymerization of Myosin Heavy Chain during Ice Storage of Carp Actomyosin

Responsibility of Myosin Rod for the Dimer Formation of Myosin Heavy Chain through SS Bonding during Ice Storage of Carp Actomyosin

Responsibility of Myosin Rod for the Dimer Formation of Myosin Heavy Chain through SS Bonding during Ice Storage of Carp Actomyosin

Carp Natural Actomyosin: Thermal Denaturation Mechanism

ABSTRACTStructural changes of actomyosin, the major protein of muscle, on heating have been estimated on ATPase activity. We investigated carp actomyosin molecule changes on heating based on biophysical and biochemical techniques. Actomyosin molecules began to unfold at ∼30°C. Hydrophobic amino acid residues and SH groups, which had been inside the molecule, emerged to the surface. Because of hydrophobic interactions and disulfide bonds, actomyosin molecules formed aggregates. At &gt; 40°C, a part of myosin molecules was dissociated from actin filaments. Thus, dissociated myosin and the myosin‐lacking molecules co‐existed. In addition, fragmentation of actin filaments was observed, which was associated with the dissociation of myosin molecules. At ≥ 60 °C actomyosin molecules formed larger aggregates, in which no filamentous shape was observed. This aggregation occurred mainly by formation of SS bonds.

Some specific features of the thermotropic gelation of carp actomyosin

AbstractThis paper is devoted to the study of the heat treatment regime affection on the rheological properties of the actomyosin (AM) thermotropic gels of the muscle tissue of carp. It is shown, that systems containing AM undergo several conformational transitions during heating. These transitions make the essential contributions into the gelation process since they predetermine the dissociation, reassociation and aggregation of AM, i.e. they determine in the end the nature of the physicomechanical properties of the spatial network. The two‐ or three‐staged heat treatment of the AM dispersions at narrow temperature intervals was found to be optimal in order to obtain the more elastic thermotropic gels.

Surface Tension, Spinnability, and Gelation of Denatured Carp Actomyosin Preparation.

Actomyosin preparation was treated by denaturating agents. When NH2C(=NH)NH2HSCN was added to actomyosin preparation in water or 0.6M KCl, surface tension and spinnability showed the maximum around 3M, decreased at 6M and decreased farther at 8M. When CO(NH2)2 was added to actomyosin preparation, surface tension and spinnability showed the maxima at 2M and around 8M. It was suggested from the great changes of surface tension and spinnability that structure change (unfolding) of actomyosin was induced with the treatments by these denaturating agents. When actomyosin preparation in water or 0.6M KCl was treated by NH2C(=NH)NH2HSCN or CO(NH2)2 and dialysed against water to remove the denaturating agent, 6M-treatment pro-duced firm gel, 4M-treatment produced medium gel, and 8M-treatment produced soft gel. It was concluded that the local unfolding of actomyosin molecule by 6M-treatment was more favoured for the gelation of actomyosin than the complete unfolding by 8M-treatment. When actomyosin preparation was treated by NH2C(=NH)NH2HSCN and dialysed against 0.6M KCl in place of water, the gel made by 6M-treatment was softer than the gels made by 4M- and 8M-treatments.

Application of high pressure to food processing: Textural comparison of pressure- and heat-induced gels of food proteins.

Hydrostatic pressure of 1000 to 7000 kg/cm2 was applied on fresh hen egg white and yolk, carp crude actomyosin, a paste of rabbit meat, and a suspension of soy protein at 25°C for 30 min. Gels that stand under their own weight maintaining their shapes were obtained at 6000 kg/cm2 for the egg white, 4000 kg/cm2 for the egg yolk, 2000 kg/cm2 for the carp actomyosin and the rabbit meat, and 3000 kg/cm2 for the soy protein. These pressure-induced gels generally kept their original color and flavor, and were glossy and soft in comparison with heat-induced gels. According to textural measurements, the gels tended to increase in hardness and to decrease in adhesiveness with an increase in the pressure applied. However, they had large extensibility and were not fractured by a high stress.

Viscoelasticity of carp actomyosin solution during heating.

The steady and dynamic shear rate behaviors of carp actomyosin solution were measured during incubation at 40°C. The maximum steady shear viscosity was observed around 35 min, while the maximum dynamic rigidity was observed around 2h. The hysteresis loop area increased for 2h, and thereafter it remained almost unchanged till 6h where the dynamic rigidity decreased. Therefore we deduce that during the incubation, the network structure would develop also in the carp actomyosin solution as in the hen or rabbit myosin solution, but the network structure of carp actomyosin solution would be so weak as to be broken down even during the repeated measurements of dynamic behaviors. The actomyosin solution at pH 5.8 exhibited the lowest viscoelasticity. The solution at pH 6.8 exhibited the highest dynamic rigidity. The solution at pH 7.8 exhibited the highest stress in the shear rate scan measurement. These results were explained by the fact that the actomyosin solution at pH 5.8 existed near the isoelectric point, and the network structure at pH 6.8 would be different from the network structure at pH 8.8. In the temperature scanning experiment the dynamic rigidity began to increase around 40°C the maximum was observed around 61°C, The peak value around 61°C was high at pH 5.8 and pH 6.8, and low at pH 7.8.

Separation of cathepsin d-like proteinase and acid thiol proteinase of squid mantle muscle

1. 1. When the proteinases of the squid mantle muscle were extracted in the presence of dithiothreitol (DTT), the acid proteinase activity increased, indicating that the squid mantle muscle contains a considerable amount of the acid thiol proteinase. 2. 2. The crude extract hydrolyzed neither α-N- benzoyl- d, l-arginine-ϱ-nitroanilide (BAPA) nor azocasein, thus refuting the presence of cathepsins B and L in the mantle muscle. 3. 3. The cathepsin D-like proteinase and the acid thiol proteinase were separated by Sephadex A-50 column chromatography. 4. 4. Each of the above partially purified proteinases was able to degrade carp actomyosin at pH 2.5 and 5.0, respectively.

Studies on the freeze denaturation of squid actomyosin.

Denaturation of squid actomyosin during frozen storage was studied by measuring solubility, viscosity, and ATPase activity, and by ultracentrifugal analysis and SDS-electrophoresis. The additive effect of sodium glutamate, well-known for its cryoprotective effect on the freeze denaturation of carp actomyosin, was also checked. When solutions (0.6 M KCI) or suspensions (0.05 M KCI) of the isolated squid actomyosin were stored at -20 ??, the solubility, reduced viscosity and ATPase activity decreased with the length of frozen storage. The ultracentrifugal patterns showed that aggregation proceeded during frozen storage. Evidently, sodium glutamate prevented the freeze denaturation of squid actomyosin, as in the case of carp actomyosin. When the mantle muscle of squid was freeze-stored at -20 ?? and extracted with 0.6 M KCI, the amount of soluble actomyosin extractable from the frozen meat and the ATPase activity of the actomyosin were decreased only slightly even after a long freezing period. This differed from the results with isolated actomyosin.

キハダマグロおよびコイのアクトミオシンからトリプシン消化によるＨメロミオシンの調製と性質

Actomyosin (AM), when submitted to tryptic digestion, yielded fragments which remained bound to actin. The fragments were separated from actin by high concentration of ATP-Mg and collected in the supernatant by centrifugation When digestion of AM was conducted at 25°C for 10 min using trypsin in an amount of 1/200 (w/w) relative to AM, the enzymatically active fragments were isolated from yellowfin tuna AM. In the case of the enzymic activity of the fragments from carp AM was reduced even when the amount of trypsin was varied from 1/200 to 1/10, 000 (w/w) relative to AM. The fragments thus obtained were characterized by its enzymic activity, actin-binding properties, and chromatographic profile on Sephadex G-200. The proteolysis at 10°C instead of 25°C for 10 min using trypsin in an amount of 1/200 (w/w) relative to AM, was found to be favorable in priparing the enzymatically active fragments from carp AM. The fragments were further purified by salting with (NH4)2SO4 in the presence of 10mM ATP-Mg and then characterized by its enzymic activity, kinetic parameters (Vmax and Ka) of ATPase in actin activation, chromatographic profile on Sephadex G-200, and sedimentation constant It was thus shown that these fragments from yellowfin tuna and carp AM's were similar to heavy meromyosins from rabbit and skipjack tuna myosins, which have already been reported.

Formation of Polymeric Molecules of Protein Resulting from Intermolecular SS Bonds Formed during the Gel Formation of Carp Actomyosin by Heating

Formation of Polymeric Molecules of Protein Resulting from Intermolecular SS Bonds Formed during the Gel Formation of Carp Actomyosin by Heating