Postmortem Aging (postmortem + aging)

Distribution by Scientific Domains


Selected Abstracts


EFFECTS OF MUSCLE PROTEASES, ENDOGENOUS PROTEASE INHIBITORS AND MYOFIBRIL FRAGMENTATION ON POSTMORTEM AGING OF GOAT MEAT

JOURNAL OF FOOD BIOCHEMISTRY, Issue 3 2006
N.S. NAGARAJ
ABSTRACT The present study was conducted to evaluate the extent of postmortem proteolysis in longissimus dorsi, biceps femoris, semimembranosus and semitendinosus goat muscles on postmortem aging at an ambient (27C) temperature. The activities of calpains and calpastatin were determined after separation on a (diethylamino)ethyl,Sephacel column (Sigma, St. Louis, MO) and cathepsin (B, B + L and H) by carboxymethyl,Sepharose column (Sigma). The results showed that the decrease in calpain I and calpastatin activities was significantly higher than that of calpain II. Cathepsin B, B + L, H and cystatin were found to fall by 30,80% after 12 h, whereas cathepsin D decreased significantly in all the muscles. The disappearance of titin 1 and nebulin, and the appearance of a 30-kDa component were confirmed by Western blot analysis. The appearance of the 30-kDa component reported here explains the time-induced structural changes of myofibrils. The Z-line degradation had occurred by 6 h postmortem. Cathepsins are not stable compared to calpains during postmortem aging, and both enzymes may play a significant role in the proteolysis of myofibrillar proteins at ambient temperature. [source]


Relationship Between Fragmentation of Myofibrils and Liberation of Phospholipids from Z-Disks Induced by Calcium Ions at 0.1 mM: Mechanism of Tenderization of Pork and Beef during Postmortem Aging

JOURNAL OF FOOD SCIENCE, Issue 9 2003
K. SHIMADA
ABSTRACT We studied the myofibril fragmentation using porcine and bovine myofibrils to determine the mechanism by which myofibrils are fragmented during postmortem aging of meat. Both myofibril fragmentation and liberation of phospholipids from Z-disks were maximally induced by calcium ions at 0.1 mM. These phenomena showed identical dependencies on pH and temperature in the presence of calcium ions at 0.1 mM. All phospholipids in Z-disks, except for lysophosphatidylethanolamine, had affinity for calcium ions. Therefore, we concluded that liberation of calcium-phospholipid compounds from Z-disks causes weakening of the Z-disk structure, resulting in the myofibril fragmentation during postmortem aging of meat. [source]


Effects of boning method and postmortem aging on meat quality characteristics of pork loin

ANIMAL SCIENCE JOURNAL, Issue 5 2009
Chunbao LI
ABSTRACT This work investigated the effects of boning method and postmortem aging on pork loin color, shearing value and sensory attributes. Two experiments were assigned. In Experiment I, 30 Chinese native black pigs were slaughtered and their carcasses were divided into three groups: (i) hot-boning: carcasses were fabricated within 45 min postmortem just after dressing; (ii) cold boning at 24 h: carcasses were fabricated after chilling at 0°C for 24 h; (iii) cold boning at 36 h: carcasses were fabricated after chilling at 0°C for 36 h. In Experiment II, right sides of the second group in Experiment I were used and primal cuts were vacuum packed and aged for 1 day, 8 days and 16 days. Pork loins (Longissimus lumborum) were used for color measurement, shearing test, and sensory evaluation. Among three boning methods, cold-boning at 36 h postmortem had the advantages of giving muscles a better color, the lowest cooking loss and cooked shearing value, and the highest sensory tenderness, juiciness, flavor and overall liking. Postmortem aging could improve pork quality characteristics, but it is not the fact that the longer aging time is, the better pork quality would be. Eight days may be enough to obtain an acceptable sensory attribute. These results are meaningful for pork processing and pork consumption. [source]


EFFECTS OF MUSCLE PROTEASES, ENDOGENOUS PROTEASE INHIBITORS AND MYOFIBRIL FRAGMENTATION ON POSTMORTEM AGING OF GOAT MEAT

JOURNAL OF FOOD BIOCHEMISTRY, Issue 3 2006
N.S. NAGARAJ
ABSTRACT The present study was conducted to evaluate the extent of postmortem proteolysis in longissimus dorsi, biceps femoris, semimembranosus and semitendinosus goat muscles on postmortem aging at an ambient (27C) temperature. The activities of calpains and calpastatin were determined after separation on a (diethylamino)ethyl,Sephacel column (Sigma, St. Louis, MO) and cathepsin (B, B + L and H) by carboxymethyl,Sepharose column (Sigma). The results showed that the decrease in calpain I and calpastatin activities was significantly higher than that of calpain II. Cathepsin B, B + L, H and cystatin were found to fall by 30,80% after 12 h, whereas cathepsin D decreased significantly in all the muscles. The disappearance of titin 1 and nebulin, and the appearance of a 30-kDa component were confirmed by Western blot analysis. The appearance of the 30-kDa component reported here explains the time-induced structural changes of myofibrils. The Z-line degradation had occurred by 6 h postmortem. Cathepsins are not stable compared to calpains during postmortem aging, and both enzymes may play a significant role in the proteolysis of myofibrillar proteins at ambient temperature. [source]


Relationship Between Fragmentation of Myofibrils and Liberation of Phospholipids from Z-Disks Induced by Calcium Ions at 0.1 mM: Mechanism of Tenderization of Pork and Beef during Postmortem Aging

JOURNAL OF FOOD SCIENCE, Issue 9 2003
K. SHIMADA
ABSTRACT We studied the myofibril fragmentation using porcine and bovine myofibrils to determine the mechanism by which myofibrils are fragmented during postmortem aging of meat. Both myofibril fragmentation and liberation of phospholipids from Z-disks were maximally induced by calcium ions at 0.1 mM. These phenomena showed identical dependencies on pH and temperature in the presence of calcium ions at 0.1 mM. All phospholipids in Z-disks, except for lysophosphatidylethanolamine, had affinity for calcium ions. Therefore, we concluded that liberation of calcium-phospholipid compounds from Z-disks causes weakening of the Z-disk structure, resulting in the myofibril fragmentation during postmortem aging of meat. [source]


Actions of cathepsins on troponin T during postmortem aging of porcine muscle

ANIMAL SCIENCE JOURNAL, Issue 4 2010
Shin-ichi KITAMURA
ABSTRACT In this study, we examined the contribution of the cathepsins (cathepsin D and crude cathepsins containing cathepsins B and L) to troponin T degradation during postmortem aging. The action of cathepsin D on troponin T was examined at various pHs (pH 4.0,6.5). The degradation of intact troponin T was observed at pH 4.0, but not observed at pH 5.5 and 6.5. As a result of the degradation of troponin T, the 30 kDa fragment was not generated in any pH condition. The action of the crude cathepsins on troponin T was also examined at various pHs (pH 4.0,6.5). The intact troponin T was degraded at pH 4.0 and the 30 kDa fragments were observed. These 30 kDa fragments disappeared during further incubation. On the other hand, at pH 5.5 and 6.5, the intact troponin T was degraded and the 30 kDa fragment was accumulated. These results suggested that the cathepsin D scarcely contributed to the degradation of troponin T during postmortem aging, but crude cathepsins containing cathepsins B and L were partially involved in the degradation of troponin T and the generation of 30 kDa fragments. [source]


Effects of boning method and postmortem aging on meat quality characteristics of pork loin

ANIMAL SCIENCE JOURNAL, Issue 5 2009
Chunbao LI
ABSTRACT This work investigated the effects of boning method and postmortem aging on pork loin color, shearing value and sensory attributes. Two experiments were assigned. In Experiment I, 30 Chinese native black pigs were slaughtered and their carcasses were divided into three groups: (i) hot-boning: carcasses were fabricated within 45 min postmortem just after dressing; (ii) cold boning at 24 h: carcasses were fabricated after chilling at 0°C for 24 h; (iii) cold boning at 36 h: carcasses were fabricated after chilling at 0°C for 36 h. In Experiment II, right sides of the second group in Experiment I were used and primal cuts were vacuum packed and aged for 1 day, 8 days and 16 days. Pork loins (Longissimus lumborum) were used for color measurement, shearing test, and sensory evaluation. Among three boning methods, cold-boning at 36 h postmortem had the advantages of giving muscles a better color, the lowest cooking loss and cooked shearing value, and the highest sensory tenderness, juiciness, flavor and overall liking. Postmortem aging could improve pork quality characteristics, but it is not the fact that the longer aging time is, the better pork quality would be. Eight days may be enough to obtain an acceptable sensory attribute. These results are meaningful for pork processing and pork consumption. [source]