• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.523-528
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• 1998

To clarify the effect of life or death condition before cooling on the physicochemical properties of plaice, Paralichthys olivaceus muscle at the early period after death, the plaices were dipped in the refrigerated sea water ($0^{\circ}C$) either as alive or after anesthesia killing. These samples were stored at $0^{\circ}C$ sea water and the changes in rigor-mortis, ATP breakdown, content of ATP and its related compounds, breaking strength and lactate accumulation through storage were investigated. Acceleration of rigor-mortis, ATP breakdown and lactate accumulation were taster in the samples refrigerated as alive than in samples killed by anesthesia before cooling. ATP in samples refrigerated as alive showed little breakdown until 7.5 hrs but it was decomposed completely after 17.5 hrs storage. The breaking strength in muscle of plaice was 1736.2 $\pm$ 65.4 g immediately after killing. The breaking strength in samples dipped in refrigerated sea water as alive increased more rapidly and showed the maximum value over 7.5 hrs (2183.3$\pm$32.2 g), However, in case of samples killed by anesthesia before cooling, the value and time reached around the maximum breaking strength were 2126.3 $\pm$ 32.2 g and 12.5 hrs, respectively and then decreased until 30 hrs. From these results, it could be suggested that dipping in refrigerated sea water after anesthesia killing before cooling is more effective in maintaining freshness of fresh plaice muscle than refrigerating as alive.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.1
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• pp.23-30
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• 1995

This study was undertaken to clarify the effects of electrical stimulation on physicochemical and rheological properties of the plaice (Paralichthys olivaceus) muscle at early period after death. The plaices were electrically stimulated in seawater bath (110V/60Hz) for 15sec., 35sec., and 60sec. and killed instantly with spiking at the head. Killed samples were stored at $5^{\circ}C$, and the changes in rigor index, ATP breakdown, lactate accumulation, and breaking strength of muscle through storage were investigated. Electrical stimulation effectively accelerated rigor-mortis, lactate accumulation , and ATP breakdown. As the time of electrical stimulation was lengthened, the onset of rigor-mortis of all samples were accelerated Just after killing, and the amount of lactate was rapidly increased, But, significant differences were not observed in variance of rigor-mortis and lactate concentration. Electrically stimulated plaices showed decreasing in ATP to $4.58{\mu}mole/g$ for 15sec., $4.13{\mu}mole/g$ for 35sec., and $2.39{\mu}mole/g$ for 60sec. samples as compared with $5.5{\mu}mole/g$ of unstimulated samples. As the time of electrical stimulation was lengthened, ATP in samples were decomposed more rapidly. The rate constant of ATP breakdown were $0.244hr^{-1}$ for 15sec., $0.358hr^{-1}$ for 35sec., and $0.479hr^{-1}$ for 60sec.. The level of breaking strength in muscle of the plaice was $1050.30\pm50.23g$ immediately after killing. Values of breaking strength in samples electrically stimulated for 35sec. increased rapidly just after killing among all samples. However, the breaking strength was not increased through the whole storage time in samples stimulated for 60sec.. The value and time roaching to the maximum breaking strength for each samples stimulated electrically for 15, 35 and 60 second were $1264.43\pm35.76g$ and 2hr, $1357.68\pm22.50g$ and Ohr, and $1012.18\pm57.36g$ and Ohr. Breaking strength in all samples electrically stimulated decreased significantly (P<0.05) after reaching the maximum values.

• Journal of Fisheries and Marine Sciences Education
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• v.15 no.1
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• pp.57-66
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• 2003

The purpose of the present study was to investigate physicochemical changes in olive flounder and korean rockfish muscle subjected to the cold brine, and to find the optimal immersion condition. Effects of various immersion conditions in a sliced raw fish quality were investigated in the rigor index, breaking strength, ATP related compounds, and lactate accumulation in the muscle. The onset of rigor-mortis was accelerated by the increase of immersion time. Also, the time reaching full rigor was shortened remarkably too. However, the rigor index of samples immersed in the cold brine decreased more than that of samples killed instantly. Rigor index was the highest in samples killed instantly, followed by 2.5 min, 5min, 7.5 min, 10 min and 15 min in order. Breaking strength of all samples immersed in the cold brine decreased significantly after reaching the maximum values. The content of ATP related compounds in olive flounder, korean rockfish were $12.0{\mu}mole/g$ and $8.3{\mu}mole/g$, respectively. However, ATP decreased in the samples immersed in the cold brine. The content of ATP was lower, at the optimal condition and then it was increased. Also, lactates increased, at the optimal condition and then it decreased, in contrast with the ATP. The results suggested that the optimal immersion condition of olive flounder and korean rockfish was at -${12.5}^{\circ}C$ for 5min.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.2
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• pp.69-73
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• 2003

To improve the sensory quality of sliced raw fish, the effect of cold brine temperature on the texture properties was investigated. Fishes were immersed in cold brine by various condition and killed instantly by spiking at the head. The onset of rigor-mortis was accelerated by decrease of immersion temperature. Also, the time reaching full rigor was shortened remarkably too. However, the rigor index of samples immersed in the cold brine decreased more than that of samples killed instantly. Rigor index was the highest in samples killed instantly, followed by $0^{\circ}C,\;-5^{\circ}C,\;-10^{\circ}C,\;-12.5^{\circ}C,\;-15^{\circ}C\;and\;-20^{\circ}C$ in that order. The breaking strength of samples immersed in the cold brine increased slowly but did not increase through all the conditions in the samples. Breaking strength of all samples immersed in the cold brine decreased significantly after reaching the maximum values (p<0.05). The lactate content of muscle was increased by the decreased brine temperature, however ATP content decreased. Minimum lactate and maximum ATP content in fish muscle showed at $-12.5^{\circ}C$. Those results demonstrate that optimal temperature for improvement of sliced raw fish quality by cold brine was $-12.5^{\circ}C.$

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.3
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• pp.435-441
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• 2015

Relationships among different stress parameters (lairage time and blood level of lactate and cortisol), meat quality parameters (initial and ultimate pH value, temperature, drip loss, sensory and instrumental colour, marbling) and carcass quality parameters (degree of rigor mortis and skin damages, hot carcass weight, carcass fat thickness, meatiness) were determined in pigs (n = 100) using Pearson correlations. After longer lairage, blood lactate (p<0.05) and degree of injuries (p<0.001) increased, meat became darker (p<0.001), while drip loss decreased (p<0.05). Higher lactate was associated with lower initial pH value (p<0.01), higher temperature (p<0.001) and skin blemishes score (p<0.05) and more developed rigor mortis (p<0.05), suggesting that lactate could be a predictor of both meat quality and the level of preslaughter stress. Cortisol affected carcass quality, so higher levels of cortisol were associated with increased hot carcass weight, carcass fat thickness on the back and at the sacrum and marbling, but also with decreased meatiness. The most important meat quality parameters (pH and temperature after 60 minutes) deteriorated when blood lactate concentration was above 12 mmol/L.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2002.05a
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• pp.17-25
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• 2002

Application of electrical stimulation in the red meat species (eg. beef and sheep) processing has been erratic around the world and this may reflect an incomplete knowledge of how to optimise the technology. Although it is well established that stimulation increases the rate of post-mortem glycolysis other biochemical and biophysical effects have been implicated with the use of this technology. On the basis of currently available knowledge, this mini-review seeks to examine the current theories about the effect of stimulation on post-mortem muscle. The classical view that stimulation prevents muscle from shortening excessively during rigor development has been expanded to include the possibility that it also results in physical disruption of muscle structure. The interaction of these effects with the acceleration of the rate of proteolysis through activation of the calpain protease system has not been comprehensively reviewed in the past. As a result of conclusion driven, this article highlights several areas that may prove fruitful for further research. The challenge for further development of electrical stimulation systems is optimisation of the activation of the enzyme systems in parallel with manipulation of chilling regimes so as to ensure rigor mortis is achieved at temperatures which minimise shortening. The potential of regional stimulation of sections of the carcass to achieve this outcome is worthy of study given the different fibre composition of muscles and temperature gradients.

• Animal Bioscience
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• v.36 no.2_spc
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• pp.374-384
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• 2023

Skeletal muscle metabolism regulates homeostatic balance in animals. The metabolic impact persists even after farm animal skeletal muscle is converted to edible meat through postmortem rigor mortis and aging. Muscle metabolites resulting from animal growth and postmortem storage have a significant impact on meat quality, including flavor and color. Metabolomics studies of postmortem muscle aging have identified metabolisms that contain signatures inherent to muscle properties and the altered metabolites by physiological adaptation, with glycolysis as the pivotal metabolism in postmortem aging. Metabolomics has also played a role in mining relevant postmortem metabolisms and pathways, such as the citrate cycle and mitochondrial metabolism. This leads to a deeper understanding of the mechanisms underlying the generation of key compounds that are associated with meat quality. Genetic background, feeding strategy, and muscle type primarily determine skeletal muscle properties in live animals and affect post-mortem muscle metabolism. With comprehensive metabolite detection, metabolomics is also beneficial for exploring biomarker candidates that could be useful to monitor meat production and predict the quality traits. The present review focuses on advances in farm animal muscle metabolomics, especially postmortem muscle metabolism associated with genetic factors and muscle type.

• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.57-62
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• 1993

The influence of the storage temperature at $15^{\circ}C$ on the biochemical and structural changes in the red muscles (M. sternomandibularis) of korean native cattle postmortem were studied. The results obtained were summarized as follows; 1.5 to 2 hours postmortem the pH-value had dropped to $6.7{\sim}6.8$, after 18 or 20 hours at $15^{\circ}C$ it had reached its final pH-value (5.5). The irreversible loss of extensibility, i.e. the onset of rigor mortis, arose at $15^{\circ}C$ between 9 and 10 hours postmortem at pH 6.1 to 6.0 and R-value between 1.05/1.10. The complete loss of extensibility postmortem was reached after 18 to 20 hours at pH 5.5/5.6. Muscle and sarcomere length of korean native cattle were contracted about 20% and 15%, respectively at $15^{\circ}C$. Meat of korean native cattle had the highest shear force (4.7 kg) on 1 day after slaughter. The tenderness was increased with the ripening period prolonged and was highest at the end of the 9 day ripening period.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.3
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• pp.447-456
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• 2014

The use of electrical stimulation (ES) as a management tool to improve meat quality and efficiency of meat processing is reviewed. The basis of the efficacy of ES is its ability to fast track postmortem glycolysis, which in turn stimulates myriad histological, physical, biochemical, biophysical and physiological changes in the postmortem muscle. Electrical stimulation hastens the onset and resolution of rigor mortis thereby reducing processing time and labor and plays a vital role in improving meat tenderness and other meat quality traits. However, ES may have negative impacts on some meat quality traits such as color stability and water holding capacity in some animals. Electrical stimulation is not an end in itself. In order to achieve the desired benefits from its application, the technique must be properly used in conjunction with various intricate antemortem, perimortem and postmortem management practices. Despite extensive research on ES, the fundamental mechanisms and the appropriate commercial applications remained obscured. In addition, muscles differ in their response to ES. Thus, elementary knowledge of the various alterations with respect to muscle type is needed in order to optimize the effectiveness of ES in the improvement of meat quality.

• Journal of Animal Science and Technology
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• v.48 no.6
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• pp.921-932
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• 2006

Management to improve beef tenderness is always been a historical idea, but during the recent past it has become an issue of prime importance to the meat scientists and the industries as well. Variation in tenderness is the prime explanation for consumer’s dissatisfaction for the concern meat. It has been well documented that both postmortem proteolysis and sarcomere length have significant effect on meat tenderness and its consistency. Electrical stimulation and tenderstretch techniques have been used by a number of countries to underpin carcass quality assurance schemes focused on eating quality. The mechanism(s) by which the postmortem interventions improve tenderness (or prevent toughness) has not been fully elucidated. However, it is evident that electrical stimulation accelerates the development of rigor mortis so that prevention of cold shortening is possible and ageing commences at higher temperatures. On the other hand, tendersretch appears to prevent meat toughness via placing tension of the myofibrils and connective matrix during rigor development. Previous findings indicated that electrical stimulation and tenderstretch improved beef tenderness even for fattened cattle under moderate chilling conditions. Recent studies demonstrate beef tenderness to be one of the most important factors determining satisfaction levels of Korean beef consumers. There are number of studies which reported that electrical stimulation and tenderstretch techniques improved Hanwoo tenderness and color. It is believed that the techniques are mostly useful wherein controls of carcass size, fatness and/or chilling regimes are not easy such as Korean beef industry. However, Korean beef industry is one such area where postmortem intervention techniques have not been adopted so far. Taking into consideration of the Korean beef industry, wherein carcass size and fatness varies the post-slaughter intervention technique could be the most feasible measurement to ensure eating quality. The manuscript attempts to highlight the current knowledge aiming primarily towards the assurance of beef tenderness.