• Food Science of Animal Resources
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• v.36 no.3
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• pp.389-396
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• 2016

In order to attain heavier live weight without impairing pork or sensory quality characteristics, carcass performance, muscle fiber, pork quality, and sensory quality characteristics were compared among the heavy weight (HW, average live weight of 130.5 kg), medium weight (MW, average weight of 111.1 kg), and light weight (LW, average weight of 96.3 kg) pigs at time of slaughter. The loin eye area was 1.47 times greater in the HW group compared to the LW group (64.0 and 43.5 cm², p<0.001), while carcass percent was similar between the HW and MW groups (p>0.05). This greater performance by the HW group compared to the LW group can be explained by a greater total number (1,436 vs. 1,188, ×10³, p<0.001) and larger area (4,452 vs. 3,716 μm², p<0.001) of muscle fibers. No significant differences were observed in muscle pH_{45 min}, lightness, drip loss, and shear force among the groups (p>0.05), and higher live weights did not influence sensory quality attributes, including tenderness, juiciness, and flavor. Therefore, these findings indicate that increased live weights in this study did not influence the technological and sensory quality characteristics. Moreover, muscles with a higher number of medium or large size fibers tend to exhibit good carcass performance without impairing meat and sensory quality characteristics.

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

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.8
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• pp.1046-1053
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• 1999

The musculotendon model is presented to show the declines in muscle force and shortening velocity during muscle fatigue due to the repeated functional electrical stimulation (FES). It consists of the nonlinear activation and contraction dynamics including physiological concepts of muscle fatigue. The activation dynamics represents $Ca^{2+}$ binding and unbinding mechanism with troponins of cross-bridges in sarcoplasm. It has the constant binding rate or activation time constant and two step nonlinear unbinding rate or inactivation time constant. The contraction dynamics is the modified Hill type model to represent muscle force - length and muscle force - velocity relations. A muscle fatigue profile as a function of the intracellular acidification, pH is applied into the contraction dynamics to represent the force decline. The computer simulation shows that muscle force and shortening velocity decline in stimulation time. And we validate the model. The model can predicts the proper muscle force without changing its parameters even when existing the estimation errors of the optimal fiber length. The change in the estimate of the optimal fiber length has an effect only on muscle time constant in transient period not on the tetanic force in the steady-state and relaxation periods.

• Food Science of Animal Resources
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• v.37 no.5
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• pp.716-725
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• 2017

The objective of this study was to determine the relationship between composition of muscle fiber types and meat quality traits of eight major muscles from Hanwoo steers. Longissimus lumborum (LL), psoas major (PM), semimembranosus (SM), semitendinosus (ST), gluteus medius (GM), triceps brachii (TB), rectus abdominis (RA) and superficialis flexor (SF) muscles were obtained from 9 Hanwoo steers and subjected to histochemical analysis. There were significant (p<0.05) differences in fiber number percentage (FNP) and fiber area percentage (FAP) of fiber types among these 8 major muscles. SF had the highest FNP of type I (55.9%), followed by PM (46.4%), TB (45.4%), RA (38.5%), LD (36.8%), GM (36.0%), SM (22.2%), and ST (18.8%). FAP of type IIB ranged from 9.9% in SF to 58.7% in ST. Meat quality traits, including fat content, myoglobin content, collagen content, CIE $L^*$ and $a^*$, drip and cooking loss, sarcomere length and Warner-Bratzler shear force, were all significantly (p<0.05) different among these muscles. Due to such diversities among these 8 muscles, lack of correlations were found between fiber type composition and meat quality traits. These results suggest that correlation for each individual muscle should be used to improve meat quality and profitability of retail beef cuts.

• The Korean Journal of Physiology
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• v.4 no.2
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• pp.19-24
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• 1970

Since the discovery of the muscle spindle by Hassall (1831), an intensive studies of its anatomical and physiological characteristics had been undertaken. Recent morphological studies of Boyd (1962) demonstrated that the muscle spindles have two different intrafusal muscle fibers, nuclear bag and nuclear chain fiber, and these intrafusal fibers are under independent motor innervation by ${\gamma}_1$ and ${\gamma}_2$ motor neurone. Neurophysiological studies of Hunt and Kuffler (1951) showed regulatory effect of ${\gamma}$ motor neurone upon the excitability of the spindle afferents. Harvey and Mathews (1961) observed the dynamic and static characteristics of the two different spindle afferents, the primary and secondary ending. Furthermore, Mathews (1962) postulated the functional existance of two kind of ${\gamma}$ motor neurones, namely, the dynamic and static fusimotor fiber. Recent report of Kim and Partridge(1969) pointed out that the descending vestibular signals had increased the slope of the length-tension relationship in stretch reflex; Kim (1967) demonstrated that the descending vestibular impulses act upon the stretch reflex loop through the ${\gamma}$ motor pathway. These experimental evidences from the morphological and neurophysiological studies on the muscle spindles support the concept that the stretch reflex action of the skeletal muscle operates as a negative feedback control system. The author had discussed the way by which the f system participates in the control of stretch relfex feed back system. that was taken for a prototype of posture and movement.

• Food Science of Animal Resources
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• v.44 no.1
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• pp.51-73
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• 2024

This study investigated how birth weight differences in piglets affected carcass and muscle fiber properties as well as meat quality at slaughter. Within litters, piglets were grouped according to their birth weight as either normal (NBW; 1.62-1.73 kg) or low (LBW; 1.18-1.29 kg). At 5 weeks of age, NBW piglets were randomly transitioned to control (C) or isocaloric high fat diets derived from non-dairy (HF), while LBW piglets were randomly transitioned to high fat diets derived from non-dairy (HF) or dairy sources (HFHD). Piglets were reared in individual pens under standardized housing and feeding conditions. Live weight was recorded weekly, and pigs were slaughtered at 12 weeks of age. Hot carcass weights, dressing percentages, lean meat yield, and primal cut proportions were determined. The m. longissimus thoracis was collected from the right side of the carcass for measurement of physical and chemical properties of meat and muscle fiber characteristics. Results indicated that LBW pigs compensated for their live weight compared to NBW pigs at 6 weeks of age. The mean muscle fiber diameter of LBW-HFHD group is significantly higher than NBW-C and NBW-HF group, and the type I muscle fiber diameter is significantly higher than NBW-C group. Dairy fat inclusion in LBW pig diet reduced carcass back fat thickness. This increased the calculated lean meat yield to be comparable to that of NBW pigs fed a commercial diet. Incorporating dairy-sourced high-fat into LBW pigs' diets appears to be an effective strategy for producing carcasses equivalent to NBW pigs.

• Food Science of Animal Resources
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• v.21 no.2
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• pp.142-148
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• 2001

Comparisons in physicochemical characteristics of longissimus muscle between the Korean native pig(KNP: 75kg of slaughter weight and 240 days of age) versus Landrace(110kg of slaughter weight and 180 days of age) are as below. Compared with Landrace, KNP had a greater drip loss resulting from a lower muscle pH and water holding capacity, greater L*(lightness), a*(redness) and b*(yellowness) values in muscle color, and a greater L* value and smaller a* and b* values in attached backfat color. Tenderness were greater in the Korean native pig. Moreover, KNP had a greater number of muscle fibers and a smaller diameter of the fiber when examined by scanning electron microscopy. In sum, the Korean native pig, compared with Landrace, had a greater redness in meat color, a greater whiteness in fat color; the lower WHC and greater tenderness of the former apparently resulted from the lower slaughter weight rather than from a species difference.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.9
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• pp.1430-1438
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• 2019

Objective: This experiment was designed to determine the effects of coated cysteamine hydrochloride (CC) on muscle fiber characteristics, amino acid composition and transporters gene expression in the longissimus dorsi muscle (LDM) of finishing pigs. Methods: Two hundred and sixteen Duroc/Landrace/Yorkshire cross-bred male finishing pigs were fed with a corn-soybean basal diet supplemented with 0, 70, and 140 mg/kg cysteamine. Each group contained eight replicates of nine pigs per replicate. After 29 days, one pig was randomly selected from each replicate and slaughtered. Blood and LDM samples were collected and analyzed. Results: The results showed that supplemental dietary CC increased (p<0.05) the muscle fiber density. And CC supplementation also up-regulated (p<0.05) the expression of myosin heavy chain 1 (MyHC1) and MyHC2x mRNA levels, and down-regulated (p<0.05) MyHC2b expression in the LDM. Additionally, supplemental dietary CC reduced (p<0.05) the concentration of total cholesterol in the plasma and enhanced (p<0.05) the concentrations of essential amino acid and total amino acid in the LDM. The relative expression levels of chloramphenicol acetyltransferase 2, $b^{0,+}$ amino acid transporter, and $y^+$-L-type amino acid transporter 1 were upregulated (p<0.05) in the LDM when pigs were fed with the dietary CC of 70 mg/kg. Conclusion: Cysteamine supplementation could increase fiber density and distribution of fiber types. It also improved the deposition of protein in the LDM by up-regulated the expression of amino acid transporters.

• Food Science of Animal Resources
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• v.44 no.4
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• pp.758-778
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• 2024

This study assessed previous research aimed at mitigating the adverse effects of freeze-thawing on meat quality. Specifically, it focuses on assessing the physicochemical alterations in meat resulting from freezing, freeze-thawing, or technologies to minimize these alterations. Recent studies have focused on conventional freeze-thaw technology applicable across various livestock species and muscle types. However, recent research has indicated the necessity for developing freeze-thaw technology considering the unique characteristics of individual muscles. In this review, we summarize previous studies that have compared alterations in the physicochemical properties of primary muscles owing to freezing or freeze-thawing. Despite the introduction of various technologies to significantly reduce the adverse effects on meat quality resulting from freeze-thawing, it is essential to consider the unique characteristics (proximate composition, pH, and muscle fiber characteristics) of individual muscles or cuts to develop enhanced the freeze-thaw processing technology.

• Food Science of Animal Resources
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• v.27 no.4
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• pp.401-408
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• 2007

This study examined the histochemical and physiological characteristics during Korean native Ogol chickens (KNOC) development. The body weight, Pectoralis major and soleus muscle weights, and muscle samples were taken at hatching as well as at 3, 5, and 15 weeks of age. The fiber characteristics of the Pectoralis major and soleus muscles from the KNOC at hatching to 15 weeks of age were determined, and the deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein concentrations were measured from the left Pectoralis major muscles. A greater increase in body and muscle weights was detected between hatching and 3 weeks of age than during any other period. Moreover, the cross sectional area (CSA) of the fibers, as well as the total concentration of DNA, RNA, and protein also showed a greater increase betweenhatching and 3 weeks of age than during any other period. The KNOC breed is a dual purpose breed, however, the it has lower body and muscle weights than commercial meat type chickens or layer type chickens. Moreover, the KNOC breed has a small muscle fiber CSA of and a low nucleic acid concentration.