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Molecular mechanism of meat tenderization during post-mortem aging

宰后老化过程中肉嫩化的分子机制

基本信息

批准号：
02403025
负责人：
TAKAHASHI Koui
金额：
$ 13.44万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1993
项目状态：
已结题

项目摘要

1. alpha-Connectin, which forms very thin filaments in myofibrils, was non-enzymatically split into beta-connectin and a 1,200-kDa subfragment during post-mortem ageing of meat. The splitting was induced by the binding of calcium ions to the beta-connectin portion of alpha-connectin, and reached a maximum at 0.1 mM Ca^<2+>. The 1,200-kDa subfragment was about 0.34 mum apart from the Z-disk, and bound to alpha-actinin. 2. Nebulin filaments which adhere to thin (actin) filaments, were fragmented into 200-, 180-, 40-, 33- and 23-kDa subfragments during post-mortem ageing of meat. All the subfragments except the 180-kDa one were released from myofibrils. The fragmentation of nebulin filaments was non-enzymatically induced by the binding of calcium ions to the 200-, 40- and 23-kDa subfragments, and reached a maximum at 0.1 mM Ca^<2+>.3. The rate of the post-mortem translocation of paratropomyosin from the A-I junction region of sarcomeres onto the thin filaments in the A-band, where rigor linkages had been formed, agreed well with the rate of increase in length of rigor-shortened sarcomeres : The sarcomere lengths were found to be maximum at 1, 7 and 10 days post-mortem in chicken, pork and beef, respectively. Those rates are quite consistent with the well-known periods required for post-mortem ageing to tenderize chicken, pork and beef. 4. Phospholipids existed in the Z-disk of skeletal muscle myofibrils, and constituted its amorphous matrix. The content of phospholipids was about 1 g per 100 g of myofibrillar proteins. The phospholipids were released from the Z-disk in a precise agreement with the Z-disk weakening during post-mortem ageing of meat. On the other hand, the amount of alpha-actinin remained unchanged during post-mortem ageing of meat, indicating that calpain does not take part in the post-mortem weakening of Z-disks. 5. These results powerfully support the "Calcium theory of meat tenderization" which I have proposed, and object the assumption t

1.α-连接蛋白在肌原纤维中形成非常细的细丝，在肉的死后老化过程中被非酶促分裂成β-连接蛋白和1，200-kDa的亚片段。这种分裂是由钙离子与α-连接蛋白的β-连接蛋白部分结合引起的，在0.1 mM Ca^<2+>时达到最大值。1，200-kDa的亚片段是约0.34妈妈除了Z-磁盘，并结合α-辅肌动蛋白。2.粘薄（肌动蛋白）丝，被破碎成200-，180-，40-，33-和23-kDa的亚片段在死后的肉老化。除180-kDa的一个外，所有的亚片段都从肌原纤维释放。钙离子与200、40和23 kDa亚片段的结合可以非酶促地诱导星云蛋白丝的断裂，并在0.1 mM Ca^<2+>时达到最大值。死后易位率的副肌球蛋白从A-I交界区的肌节到A带的细丝，在那里已经形成了严格的联系，同意严格缩短的肌节长度的增加率：在鸡，猪肉和牛肉，分别在死后1，7和10天的肌节长度被发现是最大的。这些速度与众所周知的鸡、猪肉和牛肉死后老化所需的时间相当一致。4.磷脂存在于骨骼肌肌原纤维的Z盘中，构成其无定形基质。磷脂含量约为1g/100 g肌原纤维蛋白。磷脂从Z-盘中释放出来，与肉死后老化过程中Z-盘弱化的精确一致。另一方面，α-辅肌动蛋白的量保持不变，在宰后老化的肉，表明钙蛋白酶不参加宰后弱化的Z盘。5.这些结果有力地支持了我提出的“肉嫩化的钙理论”，反对了肉嫩化的假设。