菲律宾蛤仔肌原纤维蛋白热变性与闭壳肌脱壳的关联性

Correlation analysis between the thermal denaturation of myofibrillar proteins and adductor muscle shelling in Ruditapes philippinarum

为了探讨菲律宾蛤仔热处理后闭壳肌脱壳与肌原纤维蛋白热变性的关联,实验首先通过差示扫描量热仪(DSC)研究了闭壳肌蛋白的热变性规律,然后利用光学显微镜和电子显微镜观察了加热对闭壳肌微观结构的影响,以Ca^(2+)-ATPase活性、盐溶解度、SDSPAGE为指标研究了肌原纤维蛋白的热变性规律。新鲜的闭壳肌DSC结果显示,在50、60和78℃时共有3个吸收峰,闭壳肌在50和80℃加热5 min后对应的吸收峰消失,可能分别对应肌球蛋白和肌动蛋白发生了热变性。菲律宾蛤仔在沸水浴加热处理后,闭壳肌纤维呈现横向聚集和纵向收缩,由于收缩程度不同导致闭壳肌和外壳出现不同程度分离状态。肌原纤维蛋白加热处理(0.5 mol/L NaCl,45℃,5 min)后,Ca^(2+)-ATPase活性和盐溶解度快速下降,表明肌球蛋白发生了热变性。此外,肌动蛋白在变性前对肌球蛋白具有非常明显的保护作用。研究表明,使肌原纤维蛋白中肌球蛋白、肌动蛋白、副肌球蛋白同时变性,有利于脱壳的发生。本研究可为菲律宾蛤仔后续加工提供理论依据和数据支撑。

Frozen-cooked product is a common product form of Ruditapes philippinarum,with heating shelwith being a key processing technique.The basic principle of heating shelling relies on thermal contraction of the adductor muscle to separate the meat from the shell.Temperature is one of the crucial factors significantly affecting the protein in the adductor muscles of R.philippinarum.To inivestigate the correlation between adductor muscles decalcification and thermal denaturation of myofibrillar proteins in R.philippinarum following heat treatment,the thermal denaturation behavior of adductor muscle protein was initially investigated using a differential scanning calorimeter(DSC).Subsequently,the impact of heating on the microstructure of adductor muscles was observed using optical and electron microscopy.additionally,the thermal denaturation pattern of myofibrillar proteins was examined using Ca^(2+)-ATPase activity,salt solubility,and SDS-PAGE as indicators.The results showed that the DSC analysis of fresh adductor muscle revealed three absorption peaks at temperatures of 50,60 and 78℃.After heating for 5 minutes,the absorption peaks at 50℃ and 80℃ were no longer detectable,suggesting they likely correspond to the thermal denaturation of myosin and actin,respectively.Following boiling treatment,the adductor muscle fibers in R.philippinarum demonstrated lateral aggregation and longitudinal contraction.This morphological change resulted in varying degrees of separation between the muscle and shell due to differential contraction rates.A specific heating regimen for myofibrillar proteins(0.5 mol/L NaCl at 45℃ for 5 min)led to a marked decrease in Ca^(2+)-ATPase activity and salt solubility,indicating myosin thermal denaturation.Additionally,actin played a significant protective role over myosin before denaturation.The simultaneous denaturation of myosin,actin,and tropomyosin,which contributed to the facilitation of shelling.This study provided a scientific basis and data support for futher developing processing techniques for R.philippinarum.