• Food Science of Animal Resources
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• v.41 no.4
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• pp.589-607
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• 2021

Meat proteolytic systems play a crucial role in meat tenderisation. Understanding the effects of processing technologies and post-mortem storage conditions on these systems is important due to their crucial role in determining the quality characteristics of meat and meat products. It has recently been proposed that tenderisation occurs due to the synergistic action of numerous endogenous proteolytic systems. There is strong evidence suggesting the importance of μ-calpain during the initial post-mortem aging phase, while m-calpain may have a role during long-term aging. The caspase proteolytic system is also a candidate for cell degradation in the initial stages of conversion of muscle to meat. The role of cathepsins, which are found in the lysosomes, in post-mortem aging is controversial. Lysosomes need to be ruptured, through aging, or other forms of processing to release cathepsins into the cytosol for participation in proteolysis. A combination of optimum storage conditions along with suitable processing may accelerate protease activity within meat, which can potentially lead to improved meat tenderness. Processing technologies such as high pressure, ultrasound, and shockwave processing have been reported to disrupt muscle structure, which can facilitate proteolysis and potentially enhance the aging process. This paper reviews the recent literature on the impacts of processing technologies along with post-mortem storage conditions on the activities of endogenous proteases in meat. The information provided in the review may be helpful in selecting optimum post-mortem meat storage and processing conditions to achieve improved muscle tenderness within shorter aging and cooking times.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.3
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• pp.405-411
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• 1994

Purified myofibrils were prepared from ante-mortem stress and control lots of Taiwan country chicken breast and thigh muscles at death and afler storage at $4^{\circ}C$ for 0, 1, 2, 3, and 7 days post-mortem. Sodium dodecyl sulfate polycrylamide gel electrophoresis (3.2%) and densitometer were used to examine the effect of ante-mortem stress and control storage of muscle on titin and nebulin. Results indicated that titin and nebulin were more rapidly degraded in the control and the ante-mortem stress light muscles than in the control and ante-mortem dark muscles of Taiwan country chicken. In contrast, nebulin was shown to be more resistance to degradation in the ante-mortem stress dark muscle than in the control light muscle.

• Food Science of Animal Resources
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• v.40 no.3
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• pp.415-425
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• 2020

It is believed that two main proteolytic systems are involved in the tenderization of meat: the cathepsins and the calpains. Many researchers consider the calpain system to be the major contributor to meat tenderness during post-mortem storage. However, the role and activity of cathepsins during post-mortem storage or low temperature meat processing is unclear, particularly for the tough meat cuts like brisket. Thus, the study was designed to investigate the effects of cold (refrigerated and frozen) storage and sous vide processing on the activities of cathepsin B, H, and L in beef brisket. There were no significant changes in pH and cathepsin H activity throughout the 18 d of storage at both temperatures. However, an increase in cathepsin B activity was observed during the first 4 d at both storage temperatures, but subsequently the activity remained unchanged. Cathepsins B and L were found to be more heat stable at sous vide temperatures (50℃ for 24 h, 55℃ for 5 h and at 60℃ and 70℃ for 1 h) compared to cathepsin H. Cathepsin B+L activity was found to increase after sous vide cooking at 50℃ for 1 h but decreased to about 47% relative to the uncooked control after 24 h of cooking. These results suggest that cathepsins B and L may contribute to the improved meat tenderness usually seen in sous vide cooked brisket meat.

• Food Science of Animal Resources
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• v.35 no.4
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• pp.524-532
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• 2015

The objective of this study was to investigate the effects of high post-mortem temperature application on development of pale, soft, exudative (PSE) turkey meat characteristics in terms of local slaughter conditions. Within this scope, it was targeted to obtain PSE-like muscles benefiting from different post-mortem temperature applications. Immediately after slaughter, turkey Pectoralis major (n=15) muscles were kept at various post-mortem temperatures (0, 10, 20, 30, and 40℃) for 5 h. pH values of 40°C treatment were lower than four other treatments (p<0.05). L* values, drip loss, cook loss, and thawing loss of 40℃ group were higher than the other groups (p< 0.05). Napole yield of 40℃ treatment indicated that high post-mortem temperature decreases brine uptake. Protein solubility of 40℃ group was lower than 0℃ group (p<0.05). Expressible moisture did not differ between 0 and 40℃ treatments. Hardness, gumminess and chewiness of 40℃ treatment were higher than 0℃ treatment. The results of this research showed that high post-mortem temperature treatment induced development of PSE-like turkey meat, with lower pH, paler color, higher technological and storage losses, and reduced protein solubility and texture.

• Korean Journal of Food Science and Technology
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• v.21 no.2
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• pp.173-179
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• 1989

The influence of the storage temperature and time after slaughter on the thermal denaturation of PSE porcine muscle protein was studied by differential scanning calorimetry and by measuring the solubility of the sarcoplasmic proteins. In the DSC therodiagram a decrease of the endotherm enthalpy of the myosin plus sarcoplasmic proteins in PSE muscle could be observed with an increase in the storage temperature and time of post mortem. Storage temperature at $20^{\circ}C$ during the first four hours of post mortem resulted in relatively slight denaturation of myosin plus sarcoplasmic proteins in PSE muscle. Storage temperature above $25^{\circ}C$ caused to increase the denaturation of muscle proteins. The minimal drip loss in PSE muscle could be observed, when the muscle was cooled to $2^{\circ}C$ as quickly as possible post mortem. However, when stored for several hours of post morte at a temperature between $32^{\circ}C-38^{\circ}C$, the drip loss reached the level established for PSE muscle. The paleness of PSE muscle could be prevented to some extent by rapid chill to $20^{\circ}C$ post mortem. The more the muscle proteins in the PSE muscle become denatured during the early storage period of post mortem, the more the drip loss increases. With the increase in the denaturation of myosin plus sarcoplasmic proteins in PSE muscle with regard to temperature of post mortem, there was a corresponding decrease in the solubility of the sarcoplasmic proteins in PSE muscle.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.1002-1006
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• 2007

Twenty four broilers (Ross) and 24 ducklings (Cherry berry) aged 45days were stunned and killed by conventional neck cut to evaluate the meat characteristics and fatty acid composition of breast meat. Breast meats were removed from each carcass at different post-mortem times. After complete processing, the breast meats were then placed in a polythene bag and kept in a cold storage room at $4^{\circ}C$ for 7 days. The pH of meat samples at different post-mortem times, and meat characteristics and fatty composition at different storage times were evaluated. No significant differences were found in pH at different post-mortem times except at 30 min postmortem, where duck breast showed significantly lower pH than chicken breast. As expected, duck breast meat had significantly higher redness (a*), but lower lightness (L*) value compared to chicken breast. During whole storage time, the a* value remained constant in duck breast. Cooking loss (%) was higher in duck breast compared to chicken breast during the whole storage time. Shear force decreased with increasing storage time in both chicken and duck breast meat, moreover, it decreased rapidly in duck breast compared to chicken breast. The TBARS values increased with increasing storage time in both duck breast and chicken breast meat and was significantly higher in duck breast. The fatty acids (%) C14:0, C16:0, C16:1, C18:2 and C18:3 were significantly higher while C18:0 was significantly lower in duck breast compared to chicken. SFA was increased, while USFA and MUSFA decreased only in duck breast during the 7 day storage time.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.566-572
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• 1996

The relationship between the myofibrillar fragmentation and zeugmatin during post-mortem aging was in vestigated by indirect immunofluorescence method using antizeugmatin Antiserum as a measure of meat tenderization. The antizeugmatin antiserum was prepared using bands separated by SDS-PAGE and reacted specifically with zeugmatin, showing no cross-reactivity with the other myofibrillar proteins. By the indirect immunofluorescence method, this antiserum stained the fresh myofibrillar However, the fluorescence intensity decreased with post-mortem time and almost disappeared within 24 hr of storage, in parallel with the myofibrillar fragmentation. It was therefore concluded that zeugmatin can be conveniently used as a measure of meat tenderization during post-mortem aging by immunoflurescence method.

• Korean Journal of Food Science and Technology
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• v.9 no.4
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• pp.295-305
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• 1977

The procedures for the Preparation of regulatory proteins of myofibrill were developed and postmortem changes in the regulatory proteins of myofibrill were investigated. Both the physiological property and molecular shape of ${\alpha}-actinin$ from pre-rigor muscle did not differ from those of ${\alpha}-actinin$ from post-rigor muscle. On the other hand, although tropomyosin of myofibril changed negligibly during the post-mortem storage of muscle, troponin of myofibril changed remarkably.

• Korean Journal of Poultry Science
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• v.42 no.4
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• pp.347-352
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• 2015

This study was first conducted to investigate the effect of post-mortem storage time of chicken meat on the quality of chicken breast, and to determine whether the current grading rule that is 'using the chicken meat within 2 day post-mortem (PM)' is appropriate or not at meat processing plants. Different methods such as freshness, lightness ($L^*$), total number of microbes, 2-thiobarbituric acid reactive substances (TBARS), shear force and cooking loss were performed. Forty samples of different PM time (0~4 day) of chicken meat were stored in the refrigerator ($3^{\circ}C$). As a result of comparing the chicken meat of 2 day and 3 day PM, torrymeter value was 6.9 and 7.0, respectively. The other values are also as follows: lightness ($L^*$) 60.22 and 60.51, total number of microbes 4.20 and $4.31log_{10}CFU/g$, TBARS value 0.056 and 0.071 mg MDA/kg, shear force 1.43 and $1.59kg/cm^2$, and cooking loss 17.24 and 15.66%, respectively. As a result, these two groups were not significantly different (P<0.05). TBARS value of the chicken meat of 4 day PM was 0.088 mg MDA/kg which is significantly higher compared to 2~3 day PM (P<0.05). Thus, the result of the study suggests that using the chicken meat within 3 day PM is also possible. If the grading rule that is 'using the chicken meat within 2 day post-mortem (PM)' is changed to 3 day PM, it will allow processing plants and distributors to more flexibly use or distribute chicken meat.

• 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 $30^{\circ}C$.