• Journal of Korean Academy of Nursing
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• v.28 no.4
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• pp.893-907
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• 1998

The purpose of this study was to determine the effect of regular exercise during dexamethasone injection on the body weight, weight of hindlimb muslces, myofibrillar protein content and glutamine synthetase activity. 180-200g female Wistar rats were divided into four groups : control, exercise, dexamethasone injection (dexa), and exercise during dexamethasone injection(D+E) group. The dexa group received daily subcutaneous injection of dexamethasone at a dose of 4mg/kg body weight for 7 days. The exercise group ran on a treadmill for 60min/day(20minutes every 4 hours) at 10m/min and a 10$^{\circ}$grade. The control group received daily subcutaneous injection of normal saline at a dose of 4mg/kg body weight for 7 days. The D+E group ran on a treadmill for 60min/day(20minutes every 4 hours) at 10m/min and a 10$^{\circ}$ grade during dexamethasone injection. Body weight of the control group increased significantly from days of experiment, that of the dexa group decreased significantly from day 4 of the experiment resulting in a 82.4% decrease compared to the first day of the experiment. Body weight of the D+E group decreased significantly from day 5 of experiment resulting in a 81.77% decrease comprared to the first day of the experiment. Body weights, muscle weight and myofibrillar protein content of the plantaris and gastrocnemius decreased significantly and muscle weight of the soleus tended to decrease with dexamethasone injection. Glutamine synthetase activity of the hindlimb muscles increased significantly with the dexamethasone injection. The relative weight of the soleus was comparable to the control group and that of plantaris decreased significantly and that of gastrocnemius tended to decrease compared to that of the control in the dexa group. Body weight and muscle weight of the plantaris and gastrocnemius of the excrcise group were comparable to the control group, and the muscle weight of soleus showed a tendencey to increase. The relative weight of the soleus increased significantly and that of the plantaris and gastrocnemius were comparable to the control in the exercise group. Myofibrillar protein content of the soleus and plantaris increased significantly and there was no change of GS activity of the hindlimb muscles compared to the control in the exercise group. Body weight of the D+E group was comparable to the dexa group, muscle weight of the plantaris increased significantly and that of the soleus and gastrocnemius showed a tendency to increase. The relative weight of the hindlimb muscles increased significantly. Myofibrillar protein content of the soleus and plantaris increased significantly and that of the gastrocnemius tended to increase compared to the dexa group. Body weight and muscle weight of the plantaris and gastrocnemius of the D+E group did not recover to that of the control group. Muscle weight of the soleus recovered to that of the control group. The relative weight and of myofibrillar protein content of the hindlimb muscles recovered to that of the control group. From these results, it is suggested that regular exercise during dexamethasone injection might attenuate the muscle atrophy of the hindlimb muscles.

• Korean Journal of Poultry Science
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• v.14 no.2
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• pp.137-143
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• 1987

This study was carried out to compare the changes in the extractability, biological activity, and solubility of myofibrillar proteins and actomyosins during storage period at 4$^{\circ}C$ and -20$^{\circ}C$in pectoral. and leg muscle of broiler meat. 1. The results obtained are as fellows ; The extractabilities of myofibrillar proteins in pectoral and leg muscle were increased gradually to 7-days during storage at 4$^{\circ}C$ and decreased slightly during frozen storage at -20$^{\circ}C$. The extractabilities of actomyosins in pectoral and legmuscle were not greatly changed during cold storage and decreased gradually during frozen storage. 2. The Ca$\^$2+/-ATP ase activities of myofibrillar proteins in the both muscles were not greatly changed to 7-days during cold storage, and in the case of frozen storage, those were highest on the 2nd week, thereafter decreased with storage period. The Ca$\^$2+/-ATPase activities of actomyosins in pectoral and leg muscle were decreased sightly only frist day during cold storage and decreased gently during frozen storage. 3. Myofibrillar proteins in the both muscles were solubilized completely at 0.20M KCl in fresh meat, at 0.25M (pectoral) and 0.30M KCl (leg) in the cold storage, and at 0.30M KCl in the frozen storage. Actomyosins of both muscles were solubilized completely at 0.40M KCl in fresh meat, cold and frozen storage.

• Journal of Korean Biological Nursing Science
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• v.1 no.1
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• pp.71-85
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• 1999

The purpose of this study was to determine the effect of periodic low-intensity exercise during hindlimb suspension on the mass, relative weight, myofibrillar protein content in soleus, plantaris and gastrocnemius muscles. To examine the effectiveness of periodic low-intensity exercise on mass, and myofibrillar protein content of hindlimb muscles, adult female Wistar rats were suspended(HS) and half of these rats walked on a treadmill for 45min/day(15 min every 4h) at 5m/min and a $15^{\circ}$ grade(HS-EX). Soleus wet weight was 33.51% significantly smaller(p<0.005) and relative soleus weight of hindlimb suspended rats was 31.96% smaller(p<0.005) compared with those of control rats following seven days of hindlimb suspension. Plantaris wet weight was 7.5% smaller(p<0.01) and relative plantaris weight was 11.83% smaller(p<0.05) compared with those of control rats following seven days of hindlimb suspension. Gastrocnemius wet weight was 11.31% significantly smaller(p<0.005) and relative gastrocnemius weight was 17.13% significantly smaller(p<0.005) compared with those of control rats following seven days of hindlimb suspension. Soleus wet weight while increased by relative soleus weight increased by 25.13%, 27.59% each through periodic low intensity exercise during hindlimb suspension(p<0.05, p<0.05). Plantaris wet weight and relative plantaris weight increased by 1.04%, 10.98%(p<0.05) each, and gastrocnemius wet weight and relative gastrocnemius weight increased by 1.98%, 12.02%(p<0.05) each through periodic low intensity exercise during hindlimb suspension. Wet weight of soleus, plantaris and gastrocnemius in HS-EX rats did not recover to control level. Myofibrillar protein content of soleus, plantaris and gastrocnemius was 48.24%, 40.85% and 37.33% significantly smaller(p<0.005) respectively compared with those of control rats following seven days of hindlimb suspension. Myofibrillar protein content of soleus, plantaris and gastrocnemius increased by 40.68%, 25.07% and 17.93%(p<0.005) each through periodic low intensity exercise during hindlimb suspension. Myofibrillar protein content of soleus, plantaris, and gastrocnemius in HS-EX rats did not recover to control level. The results suggest that periodic low intensity exercise can attenuate hindlimb muscle atrophy induced by hindlimb suspension.

• The Korean Journal of Food And Nutrition
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• v.6 no.2
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• pp.73-80
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• 1993

In order to examine food components of coho salmon and rainbow-trout, We analyzed the composition of protein, amino acids and total lipids. The coho salmon muscle contained about 19.3% of protein with the composition of 29.9% in sarcoplasmic protein, 56.3oA in myofibrillar protein 12.5% alkali soluble protein and 2.6% in stroma. Those of rainbow-trout contained 34.1%, 56.4%, 8.3% and 2.9%, respectively. The sarcoplasmic and myofibrillar protein were composed of 13 subunits in coho salmon, and 16 and 15 subunits in rainbow-trout. Judging from the contents of essential amino acids, both muscle proteins were complete proteins. The most remarkable feature of free amino acids was that a large amount of dipeptide anserine was present with fairly lower levels of 1 methyl histidine, taurine, histidine, alanine and glycine in both muscle extracts. The total fatty acids of coho salmon was composed of 31.49% polyenes, 43.79% monoenes and 24.73% saturates. The composition of total fatty acid of coho salmon muscle was not different from that of rainbow-trout muscle.

• Food Science of Animal Resources
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• v.20 no.4
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• pp.320-325
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• 2000

The diet had an effect(P<0.05) on the nutritional contents of ostrich meat during 4 month of frozen storage. As frozen storage increased up to 4 months, pJ, water holding capacity(WHC) and myofibrillar protein solu-bility($\mu$g/$\mu$l) were reduced (P<0.05), how-ever, increased drip loss(DL, %) was found in ostrich muscle from forage fed ostriches, This study suggests that forage fed ostriches, This study suggests that frozedn storage(-2$0^{\circ}C$)up to 4 months in ostrich FCL muscle (outside strip)could be reduced protein functionality, due to increase in DL. decrease in WHC, and markedly decrease in myofibrillar protein solubility($\mu$g/$\mu$l).

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

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.10a
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• pp.113-124
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• 2004

• Food Science of Animal Resources
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• v.35 no.6
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• pp.841-846
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• 2015

This study was investigated to determine the effect of microbial transglutaminase (MTG) with or without red bean protein isolate (RBPI) on the porcine myofibrillar protein (MP) gel functionality at different pH values (pH 5.75-6.5). Cooking yield (CY, %), gel strength (GS, gf), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) were determined to measure gel characteristics. Since no differences were observed the interaction between 1% RBPI and pH, data were pooled. CY increased with the addition of 1% RBPI, while it was not affected by pH values. GS increased with increased pH and increased when 1% RBPI was added, regardless of pH. There were distinctive endothermic protein peaks, at 56.55 and 75.02℃ at pH 5.75, and 56.47 and 72.43℃ at pH 6.5 in DSC results, which revealed decreased temperature of the first peak with the addition of 1% RBPI and increased pH. In SEM, a more compact structure with fewer voids was shown with the addition of 1% RBPI and increased pH from 5.75 to 6.5. In addition, the three-dimensional structure was highly dense and hard at pH 6.5 when RBPI was added. These results indicated that the addition of 1% RBPI at pH 6.5 in MTG-mediated MP represent the optimum condition to attain maximum gel-formation and protein gel functionality.

• Food Science of Animal Resources
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• v.31 no.5
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• pp.727-730
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• 2011

The effects of various NaCl levels (0, 0.3, and 0.6 M) and pH values (pH 5.0, 5.5, 6.0, and 6.5) on the emulsifying and gelling properties of pork myofibrillar protein (MP) were assessed. The emulsion stability index (ESI), emulsifying activity index (EAI), and creaming index were measured at a 1:20 ratio of MP to corn oil. The EAI and ESI of pork MP showed maximum values at pHs 6.0 and 6.5 and at 0.3 M NaCl, resulting in better emulsion properties. Additionally, the cooking yield (CY) and gel strength (GS) of emulsified MP gel were measured at an MP: corn oil ratio of 1: 2; GS increased with increasing levels of salt. At 0.6 M NaCl, GS decreased with decreasing pH from 5.5 to 6.5. GS and gelling properties were optimal at pH 5.5 in 0.6 M salt. The highest CY was observed at 0.6 M NaCl, regardless of the pH value. However, increasing pH increased CY at salt levels of 0 and 0.3 M. These results indicate that NaCl and pH profoundly affected the emulsified MP system. Future work will be conducted on the rheological properties of the pork emulsified system as affected by adding non-meat protein.

• Food Science of Animal Resources
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• v.35 no.1
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• pp.50-57
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• 2015

Fish sarcoplasmic protein (SP) is currently dumped as waste from surimi industry and its recovery by practical method for being the non-meat ingredient in meat industry would be a strategy to utilize effectively the fish resource. This study was aimed to apply pH treatment for fish SP recovery and evaluated its effect on pork myofibrillar protein (MP) gel. The pH values of fish SP were changed to 3 and 12, and neutralized to pH 7 before lyophilizing the precipitated protein after centrifugation. Acid-treated fish SP (AFSP) showed about 4-fold higher recovery yield than that of alkaline-treated SP and water absorption capacity was also about 1.2-fold greater. Because of the high recovery yield and water absorption capacity, AFSP was selected to incorporate into MP with/without microbial transglutaminase (MTG). The effects of AFSP and MTG on the physicochemical and rheological characteristics of MP and MP gel were evaluated. MTG induced an increase shear stress of the MP mixture and increase the breaking force of MP gels. MP gel lightness was decreased by adding AFSP. MP gel with MTG showed higher cooking loss than that without MTG. A reduction of cooking loss was observed when the AFSP was added along with MTG, where the insoluble particles were found. Therefore, AFSP could be contributed as a water holding agent in meat protein gel.