• Journal of the Korean Society of Food Science and Nutrition
• /
• v.28 no.2
• /
• pp.292-298
• /
• 1999

Myofibril and actomyosin were prepared from red muscle and white muscle of fresh water fish and sea water fish, and their biochemical characteristics and SDS PAGE patterns of myofibril were compared. SDS PAGE analysis showed that electrophoretic patterns of myofibril were similar be tween white muscle and red muscle, while difference of 30kDa component of myofibril was detected between fresh water fish and sea water fish. When myofibril were treated with trypsin, difference in hydrolysis of heavy chain was observed between white muscle and red muscle. In activities of Ca ATPase, Mg ATPase, EDTA ATPase and ATPase activity pH curve, myofibrillar protein from fresh water fish showed higher specific activity than those from sea water fish.

• Journal of Life Science
• /
• v.7 no.4
• /
• pp.336-341
• /
• 1997

This study was conducted to investigate the effects of carcass grade on the hardness, myofibrillar fragmentations index, protein extractability and Mg-ATPase activity of myofibril and actomyosin obtained from 1, 2, 3 and D carcass grade)subgrade) in Korean native cow. Proximate component, hardness, chewiness, myofibril fragmentation index, protein extractability and Mg-ATPase activity if myofibril or actomyosin were not significantly different between 1st and 2nd carcass grade loin. The hardness and chewiness of 2nd carcass grade loin's were significantly lower than 3th grade loin's, but the myofibril fragmentation index, sarcoplasmic protein extractability and Mg-ATPase activity of myofibril were higher. The myofibrillar protein extractability and Mg-ATPase activity of actomyosin obtained from 3th carcase grade loin's were significantly higher than D grade loin's, but the hardness, chewiness and stroma protein extractability were lower. In conclusion, the degree of toughness in Korean native cow's loin was not significantly different between 1st and 2nd grade, but 3rd and D carcass grade were significantly higher, regardless of before and after aging.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.14 no.1
• /
• pp.82-87
• /
• 1985

Some biological activities showed as ATPase activity of myofibril, actomyosin and myosin extracted from chicken leg and pectoral skeletal muscle were investigated. The $Mg^{+2}$-ATPase activity at 0.05 M KCl were 0.82, 0.38 and 0.11 ${\mu}mole$ Pi/mg protein/min. in actomyosin, myofibril and myosin from pectoral muscle while 0.71, 0.32 and 0.08 ${\mu}mole$ Pi/mg protein/min. in actomyosin, myofibril and myosin from leg muscle. EDTA-ATPase activity at 0.6M KCl were 0.80, 0.42 and 0.40 ${\mu}mole$ Pi/mg protein/min. in actomyosin, myofibril and myosin from pectoral muscle. In case of leg muscle, that activity was noted as 0.69, 0.33 and 0.28 ${\mu}mole$e Pi/mg protein/min in proteins. ATPase activity of myosin from leg and pectoral muscle were inhibited in 10% at a higher concentration of $Mg^{+2}$ than molar concentration of EDTA, and the ATPase activity was increased to 400% compared with control at $10^{-3}M$ of $Ca^{+2}$. Actomyosin from pectoral muscle was solubilized at 0.1 M KCl above and that from leg muscle was solubilized at 0.15 M KCl above. In case of myosin, pectoral muscle was solubilized at 0.25M KCI above and leg muscle was solubilized at 0.30M KCl above.

• Korean Journal of Food Science and Technology
• /
• v.16 no.3
• /
• pp.353-357
• /
• 1984

The myofibril prepared from PSE (pale, soft, exudative) porcine meat was modified by reacting with succinic anhydride and the chemical and functional properties of modified myofibrils were investigated. $No\;Ca^{2+}-and\;Mg^{2+}-ATPase$ activity were observed irrespective of the degree of succinylation. Isoelectric point of the succinylated myofibril changed to around pH 3 from the pH 5 of unmodified myofibril. Salt soluble property was not affected by changing the salt concentration. The modified myofibril in aqueous solution did not coagulate during heating at $98^{\circ}C$ for 10 min. Water absorption ability was not improved but emulsion capacity was improved a little by succinylation.

• Animal Bioscience
• /
• v.34 no.11
• /
• pp.1849-1858
• /
• 2021

Objective: Tenderness is a very complex feature, and the process of its formation is very complicated and not fully understood. Its diversification is one of the most important problems of beef production, as a result beef aging is widely used to improve tenderness as it is believed to provide a homogeneous product to consumers. While few studies have evaluated the muscle structure properties in relation to tenderness from early post-mortem, there little to no information available on how the muscle nanostructure of beef carcasses changes during post-mortem ageing to determine the appropriate aging time for acceptable tenderness. Methods: Muscle nanostructure (myofibril diameter [MYD], myofibril spacing [MYS], muscle fibre diameter [MFD], muscle fibre spacing [MFS], and sarcomere length [SL]), meat tenderness and cooking loss [CL]) were measured on 20 A2 longissimus muscles of Bonsmara, Beefmaster, Hereford, and Simbra at 45_mins, 1, 3, and 7 days post-slaughter. Muscle nanostructure was measured using a scanning electron microscope, while tenderness was measured using Warner Bratzler shear force. Results: At 45 minutes post-slaughter, breed affected MYD and MYS only, while at 24_hrs it also affected MFD and MFS. On day 3 breed effected MFS and SL, while on day 7 breed effected tenderness only. As the muscles matured, both MYD and MYS decreased while CL increased, and the muscles became tender. There was no uniformity on muscle texture features (surface structure, fibre separation, muscle contraction, and relaxation) throughout the ageing period. Conclusion: Meat tenderness can be directly linked to breed related myofibril structure changes during aging in particular the MYD, spacing between myofibrils and their interaction; while the MFD, spacing between muscle fibres, SL, and CL explain the non-uniformity in beef tenderness.

• Korean Journal of Food Science and Technology
• /
• v.6 no.4
• /
• pp.199-208
• /
• 1974

An attempt was made to study on new method for the extraction of the regulatory proteins from myofibrils, and the procedures for the preparation of desensitized actomyosin and for complete extraction of troponin-tropomyosin complex were developed. When myofibrils were treated through the procedures developed in this study, actomyosin obtained had no Ca-sensitivity, indicating that Ca-sensitizing protein factor had been removed completely from myofibril. Consequently, it was concluded that the procedures developed in this study were convenient to test whether Ca-sensitizing proteins has been removed or not. When Mg-activated ATPase activity of myofibril were measured, the myofibrillar ATPase turned into the actomyosin type ATPase with the progress of the treatment. This result was interpreted to show that the regulatory proteins of the myofibril seems to play a cementing role on the structure of myofibril. When supernatant containing the regulatory proteins were fractionated with $(NH_4)_2SO_4$ saturation solution, regulatory proteins, ${\alpha}-actinin$ and troponia-tropomyosin complex, could be obtained and they showed their typical phyoislogical activity which modify the actin-myosin interaction. The amount of troponin-tropomyosin complex in myofibril was 72 mg per g myofibril. This result was in good agreement with the results reported by many investigators, and therefore it was concluded that our procedures for the extraction of troponin-tropomyosin complex were desirable to study on the quantitative analysis of troponin-tropomyosin complex.

• Korean Journal of Food Science and Technology
• /
• v.20 no.3
• /
• pp.371-379
• /
• 1988

To investigate on the biochemical characteristics of myofibrillar proteins between cold(pollack, salmon) and warm current fish (yellow corbina, shark), myofibrils and actomyosin were prepared, and their biological activities, effect of temperature on the myofibrillar ATPase activities and SDS-polyacrylamide gel electrophoretic patterns of myofibrils were compared. SDS-polyacrylamide gel electrophoretic analysis showed that electrophoretic patterns of myofibril vary from fish to fish. Difference in KCl concentration dependency of myofibrillar ATPase activities and ATPase activity- pH curve were found among fish species. Myofibrillar proteins from cold current fish showed higher specific activity at low temperature $(5^{\circ}C-10^{\circ}C)$ than those from warm current fish.

• Korean Journal of Food Science and Technology
• /
• v.18 no.3
• /
• pp.173-180
• /
• 1986

To investigate on the biochemical characteristics of muscle fiber, myofibrils and actomyosins were prepared front red muscle and white muscle, and their ATPase activities and SDS-polyacrylamide gel electrophoretic patterns were compared. Also biochemical characteristics of bovine muscle were compared with those of chicken muscle for the detection of species characteristics. SDS-polyacrylamide gel electrophoretic analysis indicated that red muscle contained nlore 30K component of myofibril than white muscle. Differences in KCI concen-tration dependency of actomyosin ATPase activities and ATPase activity-pH cone were observed, when bovine muscle were compared with chicken muscle.

• Food Science of Animal Resources
• /
• v.42 no.5
• /
• pp.849-860
• /
• 2022

The myofibril protein (MP) isolate-saccharide graft reactions was prepared using the Maillard reaction with saccharides. The effects of various saccharides on protein functionality and quality of the Maillard reaction were investigated and compared with those of MP. The grafting degree of the MP isolate-saccharide graft reaction was significantly higher in the reducing sugar-treated groups (lactose, glucose, fructose, and palatinose). The browning intensity of the MP isolate-saccharide graft reaction with fructose, sucrose, and erythitol was higher than that observed in the control reaction (p<0.05). MP that reacted with reducing sugars (glucose, fructose, palatinose, and lactose) had fainter bands than MP that reacted with non-reducing sugars (sucrose, erythitol, trehalose, sorbitol, and xylitol). MPs conjugated with glucose exhibited higher protein solubility. The palatinose and lactose treatments were maximum in water binding capacity, though no significant difference in oil binding capacity among the saccharide treatments was observed. The emulsion stability of the MP isolate-saccharide graft reaction with palatinose and erythitol was higher than that of the control reaction. Therefore, reducing sugars have good protein functionality in the MP isolate-saccharides graft reaction.

• Korean Journal of Food Science and Technology
• /
• v.6 no.2
• /
• pp.79-85
• /
• 1974

To obtain further information concerning the nature myofibrillar proteins in a food system, an investigation has been conducted to compare the change in the biochemical property of the myofibril with the changes in the morphological structure of the myofibril. When myofibrils were prepared with 0.16 M KCl-0.04 M Tris-HCl, the band pattern was clear and distinct. There was a uniform thickening of A-band, a sharp appearence of Z-lines and a wide I-band. The band pattern of myofibrils was changed as the composition of extraction solution was changed. Also the ATPase activity of myofibril changed as the length of sarcomere changed. When myofibrils were treated with a low concentration of trypsin, myofibrils turned in the contracted state. With the progress of prolonged trypsin treatment, most of myofibrils exhibited a pattern of alternating light and dark bands, supercontracted pattern. Although myofibrils exhibited a supercontracted band pattern, the ATPase activity of myofibril continued to increase with the progress of trypsin treatment. An assumption was made that tropomyosin may be located in Z-line and that troponin-tropomyosin complex can inhibit the ATPase activity of myofibrils through the structural alternation of myofibril.