Effects of high intensity ultrasound (HIU) on physicochemical properties of tilapia (Oreochromis niloticus) actomyosin in low NaCl concentrations were investigated. The protein content extracted in low NaCl concentrations (0.1-0.3 M NaCl) increased with increasing HIU intensity up to 20.62 W/cm2 (p < 0.05). The effect of HIU on actomyosin extractability in high NaCl concentrations (0.6 and 1.2 M NaCl) was less obvious. Ca2+-ATPase activity and total sulfhydryl (SH) group content decreased in both 0.2 and 0.6 M NaCl. HIU showed more pronounced effect on oxidation of the SH groups in 0.6 M NaCl, while the reactive SH content at 0.2 M NaCl increased after a prolonged exposure to HIU, suggesting conformational changes induced by HIU. Surface hydrophobicity of actomyosin in 0.6 M NaCl increased with increasing ultrasonic intensity and exposure time to a higher degree than that in 0.2 M NaCl. A greater absolute value of the zeta potential of actomyosin subjected to HIU were also observed. The HIU treatments decreased the turbidity of actomyosin incubated at 40 and 60 °C. A drastic increase in the solubility of myosin heavy chain (MHC) and actin with 0.2 M NaCl were evident when HIU treatments were applied, but degradation of MHC occurred in both 0.2 and 0.6 M NaCl. Based on particle size and microstructure, actomyosin in 0.6 M NaCl underwent more disruption by HIU than that in 0.2 M NaCl. HIU induced protein unfolding and protein dissociation, enabling better extraction in a lower NaCl concentration.

中文翻译：

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罗非鱼（尼罗罗非鱼）放线菌素的理化特性在低NaCl浓度下经受高强度超声处理。

研究了高强度超声（HIU）在低NaCl浓度下对罗非鱼（Oreochromis niloticus）肌动球蛋白的理化特性的影响。在低NaCl浓度（0.1-0.3 M NaCl）中提取的蛋白质含量会随着HIU强度的增加而增加，最高可达20.62 W / cm2（p <0.05）。在高NaCl浓度（0.6和1.2 M NaCl）下，HIU对放线菌素提取率的影响不太明显。在0.2和0.6 M NaCl中，Ca2 + -ATPase活性和总巯基（SH）基团含量均降低。HIU对0.6 M NaCl中的SH基团的氧化表现出更明显的影响，而长时间暴露于HIU后，在0.2 M NaCl中的反应性SH含量增加，表明HIU诱导了构象变化。放线菌素的表面疏水性为0。与0.2 M NaCl相比，随着超声强度和暴露时间的增加，6 M NaCl的增加程度更高。还观察到接受HIU的放线菌素的ζ电势的绝对值更大。HIU处理降低了在40和60°C孵育的放线菌素的浊度。当应用HIU处理时，明显可见肌球蛋白重链（MHC）和肌动蛋白与0.2 M NaCl的溶解度急剧增加，但在0.2 M和0.6 M NaCl中均发生MHC降解。根据粒径和微观结构，放线菌素在HIU中比在0.2 M NaCl中受到的破坏更多。HIU诱导蛋白质解折叠和蛋白质解离，从而可以在较低的NaCl浓度下更好地提取。还观察到接受HIU的放线菌素的ζ电势的绝对值更大。HIU处理降低了在40和60°C孵育的放线菌素的浊度。当应用HIU处理时，明显可见肌球蛋白重链（MHC）和肌动蛋白与0.2 M NaCl的溶解度急剧增加，但在0.2 M和0.6 M NaCl中均发生MHC降解。根据粒径和微观结构，放线菌素在HIU中比在0.2 M NaCl中受到的破坏更多。HIU诱导蛋白质解折叠和蛋白质解离，从而可以在较低的NaCl浓度下更好地提取。还观察到接受HIU的放线菌素的ζ电势的绝对值更大。HIU处理降低了在40和60°C孵育的放线菌素的浊度。当应用HIU处理时，肌球蛋白重链（MHC）和肌动蛋白与0.2 M NaCl的溶解度明显增加，但在0.2和0.6 M NaCl中均发生MHC降解。根据粒径和微观结构，放线菌素在HIU中比在0.2 M NaCl中受到的破坏更多。HIU诱导蛋白质解折叠和蛋白质解离，从而可以在较低的NaCl浓度下更好地提取。但是MHC的降解同时发生在0.2和0.6 M NaCl中。根据粒径和微观结构，放线菌素在HIU中比在0.2 M NaCl中受到的破坏更多。HIU诱导蛋白质解折叠和蛋白质解离，从而可以在较低的NaCl浓度下更好地提取。但是MHC的降解同时发生在0.2和0.6 M NaCl中。根据粒径和微观结构，放线菌素在HIU中比在0.2 M NaCl中受到的破坏更多。HIU诱导蛋白质解折叠和蛋白质解离，从而可以在较低的NaCl浓度下更好地提取。