• The Journal of Korean Physical Therapy
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• v.6 no.1
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• pp.61-74
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• 1994

This study was carried out to determine effects of electrical stimulation on the soleus, target muscle of the sciatic newt, of white rat normal muscles. The biometric, histochemical, ultrastructural observations were made. The following results were obtained. A daily electrical stimulation of the skeletal muscle of the normally-functioning rat caused an increase of girth and weight of the muscle fibers for 2 weeks. No noticeable change was observed afterwards. More specifically, the density of volume of the red muscle fiber increased. whereas the density of the white muscle fiber decreased. The electrical stimulation group(experimental group) showed hypertrophy of the muscle fibers and narrowing of the space between perimysium and endomysium. Normally, glycogen granules are accumulated regardless of classification of muscle fibers. In addition, the NADH-TR reaction results were in agreement with the biometric findings, in that the red muscle fibers significantly increased. The ultrastructural observations revealed that mitochondria was formed in the red muscle fiber parallel to the muscle fibers of normal muscle, while mitochondria was observed in the sarcomere region of the white muscle fiber. However, activation of mitochondria took place in the sarcolemma region of the muscle fiber, and generation of mitochondria was observed in the sarcomere region of the white muscle fiber.

• Food Science of Animal Resources
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• v.31 no.5
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• pp.676-683
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• 2011

The aim of this study was to compare the physicochemical changes of hot-boned chicken breast and leg muscles. Chicken breast and leg muscles from 56 broilers were excised within a 15 min post-mortem (PM) and stored at $20^{\circ}C$. Physicochemical traits were determined at 0.5, 6, 12, and 24 h PM. The ultimate pH of leg muscle was higher than that of breast muscle (p<0.05). The content of glycogen in the breast muscle was relatively higher than that in the leg muscle until 6 h PM (p<0.05). R-values showing rigor mortis of breast and leg muscles were completed after or before 6 h PM. Breast muscle had less cooking loss than leg muscle (p<0.05). Drip loss did not significantly differ between breast and leg muscles with the exception of that at 6 h PM. The sarcomere length of leg muscle was relatively longer than that of breast muscle (p<0.05). The MFI of leg muscle was significantly lower than that of breast muscle (p<0.05). The shear force of leg muscle was lower than that of breast muscle at 6 and 12 h PM (p<0.05); however, that of both muscles did not significantly differ at 24 h PM.

• Food Science of Animal Resources
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• v.29 no.1
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• pp.55-61
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• 2009

The objective of this study was to examine the effects of high and low chilling temperature on the water-holding capacity (WHC) and tenderness of hot-boned breast meat of broiler chickens. Breast meat was obtained from 32 broiler chickens within 15 min post-mortem (PM), and then divided into two groups. One group was chilled at $-1^{\circ}C$ and the other group was stored at $30^{\circ}C$ for 3 hr, and then all the samples were chilled at $2^{\circ}C$ until 24 hr PM. During the storage, their physicochemical characteristics were tested at 15 min, 3 hr and 24 hr PM. These included pH, R-values, cooking losses, sarcomere length, MFI, and shear force of the breast meat, none of which was different (p>0.05) between the two temperature treatments at $-1^{\circ}C$ and $30^{\circ}C$. However, sarcomere length was shortened more at $-1^{\circ}C$ than at $30^{\circ}C$, MFI was larger at $30^{\circ}C$ than at $-1^{\circ}C$, drip loss was greater at $30^{\circ}C$ than at $-1^{\circ}C$, and WHC was lower at $30^{\circ}C$ than at $-1^{\circ}C$(p<0.05). In brief, in terms of yield and tenderness, broiler breast meat stored at $-1^{\circ}C$ was superior to that stored at $30^{\circ}C$.

• Food Science of Animal Resources
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• v.36 no.6
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• pp.819-828
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• 2016

Muscle fiber characteristics account for meat quality and muscle fibers are mainly classified into three or more types according to their contractile and metabolic properties. However, the majority of previous studies on bovine skeletal muscle are based on myosin ATPase activity. In the present study, the differences in the characteristics of muscle fibers classified by the expression of myosin heavy chain (MHC) among four bovine skeletal muscles such as longissimus thoracis (LT), psoas major (PM), semimembranosus (SM) and semi-tendinosus (ST) and their relationships to beef quality were investigated. MHCs 2x, 2a and slow were identified by LC-MS/MS and IIX, IIA and I fiber types were classified. PM, which had the smallest size and highest density of fibers regardless of type, showed the highest myoglobin content, CIE $L^*$, $a^*$, $b^*$ and sarcomere length (p<0.05), whereas ST with the highest composition of IIX, showed high shear force and low sarcomere length (p<0.05). The correlation coefficients between muscle fiber characteristics and meat quality showed that type IIX is closely related to poor beef quality and that a high density of small-sized fibers is related to redness and tenderness. Therefore, the differences in meat quality between muscles can be explained by the differences in muscle fiber characteristics, and especially, the muscles with good quality are composed of more small-sized fibers regardless of fiber type.

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

• Animal Bioscience
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• v.34 no.4
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• pp.743-750
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• 2021

Objective: The objectives of this study were to explore the expression patterns of myosin heavy chain (MyHC) genes of different skeletal muscles from Chinese cattle, and to investigate the relationship between myofiber characteristics and meat quality of M. longissimus lumborum (LL), M. psoas major (PM), and M. semimembranosus (SM) from Chinese Luxi and Qinchuan cattle. Methods: Three major muscles including LL, PM, and SM from Chinese Luxi cattle and Chinese Qinchuan cattle were used in this study. The myofiber characteristics were measured by histochemical analysis. The MyHC isoforms expression was evaluated by real-time quantitative polymerase chain reaction. Quality traits including pH value, meat color, cooking loss, Warner-Bratzler shear force (WBSF) and sarcomere length were determined at day 5 postmortem. Results: PM muscle had higher pH value, a* value, sarcomere length and lower WBSF value compared to LL and SM muscles (p<0.05). Numbers of type I myofiber and the relative expression of MyHC I mRNA in PM muscle were higher than those of LL and SM muscles (p<0.05). Myofiber diameter of PM muscle was lower than that of LL and SM muscles, regardless of myofiber types (p<0.05). Conclusion: According to the stepwise linear regression analyses, tenderness was influenced by myofiber characteristics in all three examined muscles. Tenderness of beef muscles from Qinchuan and Luxi cattle could be improved by increasing numbers of type I myofiber.

• Molecules and Cells
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• v.45 no.12
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• pp.923-934
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• 2022

Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) have great potential in applications such as regenerative medicine, cardiac disease modeling, and in vitro drug evaluation. However, hPSC-CMs are immature, which limits their applications. During development, the maturation of CMs is accompanied by a decline in their proliferative capacity. This phenomenon suggests that regulating the cell cycle may facilitate the maturation of hPSC-CMs. Aurora kinases are essential kinases that regulate the cell cycle, the role of which is not well studied in hPSC-CM maturation. Here, we demonstrate that CYC116, an inhibitor of Aurora kinases, significantly promotes the maturation of CMs derived from both human embryonic stem cells (H1 and H9) and iPSCs (induced PSCs) (UC013), resulting in increased expression of genes related to cardiomyocyte function, better organization of the sarcomere, increased sarcomere length, increased number of mitochondria, and enhanced physiological function of the cells. In addition, a number of other Aurora kinase inhibitors have also been found to promote the maturation of hPSC-CMs. Our data suggest that blocking aurora kinase activity and regulating cell cycle progression may promote the maturation of hPSC-CMs.

• Animal Bioscience
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• v.36 no.9
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• pp.1435-1444
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• 2023

Objective: This study was conducted to evaluate Raman spectroscopy technique as a noninvasive tool to predict meat quality traits on Braford longissimus thoracis et lumborum muscle. Methods: Thirty samples of muscle from Braford steers were analyzed by classical meat quality techniques and by Raman spectroscopy with 785 nm laser excitation. Water holding capacity (WHC), intramuscular fat content (IMF), cooking loss (CL), and texture profile analysis recording hardness, cohesiveness, and chewiness were determined, along with fiber diameter and sarcomere length by scanning electron microscopy. Warner-Bratzler shear force (WBSF) analysis was used to differentiate tender and tough meat groups. Results: Higher values of cohesiveness and CL, together with lower values of WHC, IMF, and shorter sarcomere were obtained for tender meat samples than for the tougher ones. Raman spectra analysis allows tender and tough sample differentiation. The correlation between the quality attributes predicted by Raman and the physical measurements resulted in values of R² = 0.69 for hardness and 0,58 for WBSF. Pearson's correlation coefficient of hardness (r = 0.84) and WBSF (r = 0.79) parameters with the phenylalanine Raman signal at 1,003 cm^-1, suggests that the content of this amino acid could explain the differences between samples. Conclusion: Raman spectroscopy with 785 nm laser excitation is a suitable and accurate technique to identify beef with different quality attributes.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2000.06a
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• pp.123-123
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• 2000

• Food Science of Animal Resources
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• v.44 no.4
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• pp.861-872
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• 2024

The aim of this study was to determine the effects of sous-vide cooking temperature on the triceps brachii of black goats. Triceps brachii of black goats (12 months) were sous-vide cooked at 55℃, 60℃, and 65℃. The samples were examined for color, scanning electron microscope photographs, sarcomere length, fiber cross-sectional area, cooking yield, shear force, sensory evaluation, and aromatic profile. The results showed that CIE a^*, CIE b^*, and chroma increased with increasing sous-vide cooking temperature. However, the cooking yield significantly decreased with increasing sous-vide cooking temperature, and the shear forces of the 60℃ and 65℃ samples showed no significant differences. For sensory evaluation, the 60℃ sample showed the highest scores for flavor, texture, and off-flavor. Furthermore, the 60℃ sample showed the significantly lowest value of octadienone (aroma characteristics of metallic) intensity (p<0.05). Therefore, sous-vide cooking of triceps brachii of black goats at 60℃ is effective in reducing off-flavor and improving tenderness.