• 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.

• Food Science of Animal Resources
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• v.39 no.2
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• pp.197-208
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• 2019

The aim of this study was to investigate the relation of sensory quality traits of cooked beef to fresh meat quality and histochemical characteristics, especially muscle bundle traits, in the longissimus thoracis muscle of Hanwoo steers. Cooking loss negatively correlated with softness, initial tenderness, chewiness, rate of breakdown (RB), and amount of perceptible residue (AR) after chewing (p<0.05), and drip loss showed negative correlation with RB and AR (p<0.05). All the attributes of tenderness exhibited negative correlation with the Warner-Bratzler shear force value (p<0.05). Marbling score and the intramuscular fat (IMF) content showed positive correlation with all the organoleptic characteristics, including tenderness attributes, juiciness, and flavor (p<0.05). Regarding histochemical characteristics, muscle fiber size did not have a significant correlation with all the sensory quality traits, although the area percentage of type I fiber was related with softness, initial tenderness, and chewiness (p<0.05). On the contrary, the characteristics of muscle bundle were related to all the sensory tenderness attributes (p<0.05), and the sensory tenderness increased with smaller muscle bundle size (p<0.05). These results suggest that the IMF content and bundle characteristics can be used as indicators for explaining the variations in sensory tenderness in well-marbled beef.

• Journal of Oral Medicine and Pain
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• v.20 no.1
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• pp.171-183
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• 1995

This study was carried out to investigate the relationship between tensed mandibular positions, muscle tenderness and EMG activity, respectively, and between range of motion of the neck and sternocleidomastoid muscle tenderness. Under stressful conditions, most of people take several types of behavioral patterns. Two of them observed frequently are clenching of teeth and grasping of fist. Prolonged clenching or grasping should increase electromyographic activity of associated muscle, especially muscles of mastication and neck muscles and will cause hyperfunction, dysfunction and muscle pain. So it is necessary to relate EMG activity with muscle pain. The author performed routine clinical examination in 47 patients with Temporomandibular Disorders, especially for presence or absence of muscle tenderness. Mandibular rest position was used as a baseline reference position and two more position in which EMG activity was taken were rest postion with grasping of fist and teeth clenching position. BioEMG of Biopak system (Bioresearch Inc, USA) was used for measuring of integrated EMG in masseter, anterior temporalis, anterior belly of digastic muscle and sternocleidomastoid muscle. To measure of the range of neck motion. CROM(Cervical-Range-of Motion, USA) was used. The obtained results were as follows : 1. EMG activity of all muscles except in masseter was higher in grasping of fist than those in rest position and there were significant correlation in EMG activity between the two position except in anterior belly of digastric muscle. 2. When comparing EMG activity between tender and non-tender muscle, all examined muscles did not show any significant difference. From this data, we could conclude that EMG activity was generally not changed with tenderness, of couse, it might be dependent with degree of muscle tenderness. 3. Number of tender points in examined muscles was also not significantly different between in patients with masticatory muscle disorders and in patients with internal derangement. 4. Cervical posture and range of motion of the neck was not differed significantly between in patients with and in patients without tenderness of sternocleidomastoid muscle.

• Food Science of Animal Resources
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• v.40 no.1
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• pp.34-43
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• 2020

The objectives of this study was to compare palatability changes of the longissimus thoracis (LT) and vastus lateralis (VL) muscles of Hanwoo steers from different beef quality grades (1⁺ and 1) during 28 d of wet-aging in order to improve the utilization of the VL muscle as a steak. The VL muscle showed a higher collagen content and a lower intramuscular fat content than the LT muscle (p<0.05). As expected, the Warner-Bratzler shear force value was greater in the LT 1 grade (LT-1) muscle than the LT-1⁺ muscle (p<0.05); whereas no difference was observed between the grades in the VL muscle at 24 h postmortem. Compared to 0 d of aging, tenderness scores significantly increased after 14 and 21 d of aging in the LT and VL muscles, respectively (p<0.05). Additionally, there was no difference in tenderness score between the VL-1⁺ aged for 21 d and the LT-1 at 24 h postmortem, although tenderness score was greater in the LT than the VL at each period (p<0.05). Moreover, the VL-1⁺ steak exhibited a higher tenderness score than the VL-1 steak at 21 and 28 d of aging (p<0.05). On the other hand, the effect of aging time on juiciness and flavor in the VL muscle was somewhat limited unlike the LT muscle. Taken together, the VL muscle requires a longer aging time than the LT muscle to improve consumer preference. Considering the tenderness, using a higher quality grade for aging is more useful in the VL muscle.

• Physical Therapy Korea
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• v.21 no.3
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• pp.28-37
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• 2014

The purpose of this study was to investigate the effects of smartphone use on muscle fatigue and tenderness in the cervical erector spinae (CES) and the upper trapezius (UT) and on the cervical range of motion among subjects with and without neck muscle pain. The subjects were 30 smartphone users in their 20 s who -were assigned to either an experimental group with neck muscle pain or a control group without neck muscle pain. Muscle fatigue and tenderness in the CES and the UT as well as the subjects' cervical range of motion were measured before and after 20-min smartphone sessions in a sitting position. In a between-group comparison of muscle fatigue, the experimental group showed a significantly greater decrease in median frequency in the CES and the right UT after smartphone use (p<.05). Regarding the assessment of muscle tenderness after smartphone use, the experimental group showed a statistically significant decrease in the pressure-pain threshold (PPT) in all muscles (p<.05), whereas the control group showed a significantly decreased PPT in the right CES and the UT (p<.05). The assessment of the cervical range of motion revealed a statistically significant reduction in the cervical flexion-extension and left lateral flexion in the experimental group (p<.05) after smartphone use. However, there was no significant change in the cervical range of motion in the control group (p>.05) after smartphone use. When compared with the control group, the experimental group demonstrated greater changes in cervical extension, lateral flexion, and rotation, except for cervical flexion (p<.05). In conclusion, when smartphone users have pre-existing neck muscle pain, the use of a smartphone further increased muscle fatigue and tenderness in the neck and reduced PPT and the cervical range of motion.

• Journal of Oral Medicine and Pain
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• v.18 no.1
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• pp.31-43
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• 1993

To evaluate the correlationship between sign/symptoms of craniomandibular disorder(CMD) and possible contributing occlusal factors, the author analyzed craniomandibular index(CMI), clinical dysfunction index(CDI) and occlusal index(Oi) obtained from 88 subjects (32 males, 56 females, mean age 28.7) consisted of 49 CMD patients(15 males, 34 females, mean age 28.7) and 39 non-CMD patients (17 males, 22 females, mean age 24.5). The obtained results were as follows : 1. There was very high significant correlation bebween CMI and CDI in total subjects (r=0.83, p<0.01) 2. There was very low correlation between working-side interference and TMJ noise which was observed as a statistically significant value(p<0.05). And also there ws very low correlation between nonworking side interference and muscle tenderness, CDI, dysfunction index(DI), palpation index(PI) which were observed as statistically significant value (p<0.01) 3. There was very low correlation between as ymmetry of tetruded contact position(RCP)-intercuspal position(ICP) slide and muscle tenderness, TMJ tenderness, TMJ noise, CMI, DI, PI which were observed as statistically significant values(p<0.05) 4. In general there was low correlation between Oi and muscle tenderness, CDI, CMI, DI, PI which were observed as statistically significant values (p,0.05). But Oi had a relatively higher correlation with muscle tenderness, PI than whith CDI, DI.

• 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.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.965-970
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• 2008

The objective of this study was to examine the relationship between instrumental tenderness parameters and histochemical characteristics in the porcine longissimus dorsi muscle, and to investigate a comparison between tenderness parameters such as the Warner-Bratzler shear-force (WBS) and texture profile analysis (TPA). A negative relationship between WBS and fiber area was observed. However, there was no significant relationship between hardness and muscle fiber area. The percentage of fiber type IIb exhibited a positive correlation with hardness. There was a negative relationship between the type IIa composition percentage and hardness. This study showed that some muscle fiber characteristics were related to WBS and TPA parameters, especially hardness.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.1
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• pp.111-116
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• 2002

This study investigated quantitative changes in the spaces between and within myofibrils and the impact of high and low voltage electrical stimulation on muscle ultrastructure as seen in electron micrographs. In addition, the relationships of these spaces and the impact to meat tenderness were investigated. The degradation of myofibrils during aging appeared to be localized across the muscle fibre. Structural deterioration of muscle fibres was evident 1 day post-mortem, involving the weakening in the lateral integrity of the myofibrils and Z-disc regions. Meat tenderisation, as shown by objective measurements, coincided with these increases in degradation, as assessed by the sum of the gaps between and within myofibrils. The results showed that the total size of gaps between and within myofibrils can be used as an indicator of meat tenderization during aging, but that ultrastructural alteration in electrically stimulated muscle had little relationship with meat tenderness.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1677-1679
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• 2002

This experiment was carried out to evaluate the tenderness of meat and it''s correlation with other carcass traits of Hanwoo steers. The significantly (p<0.01) higher mastication and shearing were observed in boiled meat than in the raw meat but the coefficient of variations were greater in raw meat than in boiled meat. The correlation between raw and boiled meat for shearing and penetration were positive and significant (p<0.01). Negative and significant correlations were observed between mastication and eye muscle area (p<0.05) and also between shearing and cooking loss (p<0.01) in raw meat whereas, penetration in raw meat was positively and significantly (p<0.05) correlated with age of the steers. Shearing in boiled meat negatively and significantly correlated with age (p<0.05), carcass weight (p<0.01), back fat thickness (p<0.01) as well as muscle score (p<0.01). The pH was not significantly correlated with tenderness in both raw and boiled meat. There were possibilities that the tenderness of boiled meat could be predicted from the raw meat.