Hamm R, Gottesmann P
Z Lebensm Unters Forsch. 1985 Sep;181(3):210-6. doi: 10.1007/BF02425580.
Samples of bovine muscle (post rigor) were frozen at different temperatures between -5 degrees and -196 degrees C at different freezing rates, and thawed at room temperature. The activities of the mitochondrial enzymes lipoamide dehydrogenase, citrate synthase and beta-hydroxyacyl-CoA-dehydrogenase were determined in the supernatant of the tissue homogenates in phosphate buffer (total enzyme activity), as well as in the press juice of the intact tissue (enzyme activity in the sarcoplasma). Neither the temperature nor the rate of freezing (varying from 25.5 to 0.01 min/degrees C) showed a significant influence on the total enzyme activities. Freezing at -5 degrees and -10 degrees C (at different rates but without intracellular freezing) and thawing did not result in an appreciable release of enzymes. Below -10 degrees C the release of the three enzymes from their binding to the inner membrane of the mitochondrion into the sarcoplasmic fluid increased upon rapid freezing with decreasing temperature i.e. with increasing intracellular ice formation, whereas at slow freezing (with extracellular ice formation only) freezing below -20 degrees C did not cause further enzyme release. At freezing temperatures below -20 degrees C rapid freezing resulted in a significantly stronger release of the three enzymes than slow freezing. From these results it was concluded that the damage to mitochondrial membranes upon fast freezing is primarily a result of intracellular (and perhaps also intramitochondrial) ice formation, whereas the membrane damage during slow freezing is primarily due to dehydration caused by the migration of water from the muscle fibers into the extracellular space as a result of osmotic effects. Ion concentration in the nonfreezing fraction of tissue water seems to be only of minor importance for the disintegration of mitochondrial membranes.
取牛肌肉（宰后僵直）样本，在不同冷冻速率下于-5℃至-196℃的不同温度冷冻，并在室温下解冻。在磷酸盐缓冲液中组织匀浆的上清液（总酶活性）以及完整组织的压榨汁（肌浆中的酶活性）中测定线粒体酶硫辛酰胺脱氢酶、柠檬酸合酶和β-羟酰基辅酶A脱氢酶的活性。冷冻温度和冷冻速率（从25.5至0.01分钟/℃变化）均未对总酶活性产生显著影响。在-5℃和-10℃冷冻（不同速率但无细胞内结冰）和解冻未导致酶的明显释放。在-10℃以下，随着温度降低（即细胞内结冰增加）快速冷冻时，这三种酶从与线粒体内膜的结合释放到肌浆中的量增加，而在缓慢冷冻（仅细胞外结冰）时，低于-20℃冷冻不会导致进一步的酶释放。在低于-20℃的冷冻温度下，快速冷冻导致的三种酶释放比缓慢冷冻明显更强。从这些结果得出结论，快速冷冻时线粒体膜的损伤主要是细胞内（可能还有线粒体内）结冰的结果，而缓慢冷冻期间的膜损伤主要是由于渗透作用导致水从肌肉纤维迁移到细胞外空间引起的脱水。组织水未冷冻部分中的离子浓度对于线粒体膜的解体似乎仅具有次要重要性。
