冷藏过程中虾夷扇贝横纹肌微观结构变化与肌原纤维蛋白稳定性

Microstructure Change and Myofibrillar Protein Stability of Patinopecten yessoensis Striated Adductor Muscle during Chilling Storage

为探讨虾夷扇贝横纹肌在冷藏期间微观结构和品质的变化,挑选活力良好的虾夷扇贝去壳,取横纹肌部分进行冷藏,分析冷藏期间其微观结构、ATP及其关联物含量、蛋白盐溶解性及肌原纤维蛋白ATPase活力的变化规律。结果显示:扇贝横纹肌在冷藏5 d后收缩明显、质地变硬、汁液流失严重,肌细胞中大量存在的线粒体发生了空泡样变,但横纹肌微观结构仍保持完整,经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳检测后未观察到蛋白的降解。冷藏5 d后横纹肌中ATP含量仍为1.07μmol/g,肌原纤维蛋白Ca^(2+)-ATPase活力从0.41μmol/(mg·min)升高到0.50μmol/(mg·min)。横纹肌肌肉蛋白在1.0 mol/L NaCl溶液中的溶解度始终仅约为60%,在匀浆液中添加ATP或在均质前溶液中添加乙二醇双(2-氨基乙基醚)四乙酸螯合Ca^(2+),可将横纹肌在0.4 mol/L NaCl中的蛋白溶解度从25%提高至70%。以上结果说明横纹肌硬化过程中肌动蛋白和肌球蛋白的结合能够激活肌球蛋白的ATPase活性,并对横纹肌盐溶解度产生影响。

In order to investigate the changes in the microstructure and quality of scallop(Patinopecten yessoensis)striated adductor muscle during chilling storage,live scallops with good vitality were shucked and then the striated adductor muscle was taken and stored at 4℃for 5 days.The pattern of changes in its microstructure,the contents of ATP and related compounds,salt-soluble protein content,and myofibrillar ATPase activity was analyzed.The results showed that the striated adductor muscle contracted obviously,and its texture became harder accompanied by high drip loss on day 5 of storage.The abundant mitochondria in the muscle become vacuolate.However,the microstructure of the muscle remained relatively intact and no myofibrillar protein degradation was detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE).After storage for 5 days,the ATP content remained at 1.07μmol/g,while the Ca2+-ATPase activity of myosin increased from 0.41 to 0.50μmol/(mg·min).The solubility of striated muscle protein remained at only about 60%in 1.0 mol/L NaCl,and at 25%in 0.4 mol/L NaCl,increasing to 70%when ATP was added to the homogenate or ethylenebis(oxyethylenenitrilo)tetraacetic acid was added to chelate Ca2+before homogenization.These results indicate that the binding of actin to myosin can activate myosin ATPase activity in vitro and affect the salt solubility of striated adductor muscle proteins.