High-concentration soy protein isolate was subjected to ultrasonication for viscosity reduction to assist the process of limited enzymatic hydrolysis. Ultrasonication (20 kHz, 10 min, 160 W/L) effectively reduced the viscosity of soy protein isolate at a comparatively high concentration of 14 % (w/v) and promoted the limited enzymatic hydrolysis (controlled degree of hydrolysis of 12 %) with a higher peptide yield than that of the conventional method. The correlations between substrate viscosity and peptide yield, as well as the viscosities of the resulting hydrolysates, were studied. The findings revealed positive correlations between the viscosities of the substrate and hydrolysate, underscoring the potential impact of altering substrate viscosity on the final product. Furthermore, the utilization of ultrasonic viscosity reduction-assisted proteolysis has shown its capability to improve the functional and physicochemical properties, as well as the protein structure of the hydrolysate, while maintaining the same level of hydrolysis. It is worth noting that there were significant alterations in particle size (decrease), β-sheet content (increase), β-turn content (increase), and random coil content (increase). Interestingly, ultrasonication unexpectedly impeded the degradation of molecular mass in proteins during proteolysis, while increasing the hydrophobic properties of the hydrolysate. These findings aligned with the observed reduction in bitterness and improvement in emulsifying properties and water-holding capacity.

中文翻译：

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超声降粘作用对有限水解度大豆分离蛋白水解的影响：功能特性和蛋白质结构的变化

对高浓度大豆分离蛋白进行超声波处理以降低粘度，以协助有限酶水解过程。超声波处理（20 kHz，10 分钟，160 W/L）有效降低了浓度较高的 14 % (w/v) 大豆分离蛋白的粘度，并促进了有限的酶水解（控制水解度为 12 %）。与传统方法相比，肽得率更高。研究了底物粘度和肽产量以及所得水解产物的粘度之间的相关性。研究结果揭示了底物和水解产物的粘度之间存在正相关性，强调了改变底物粘度对最终产品的潜在影响。此外，利用超声波降粘辅助蛋白水解已显示出其能够改善水解产物的功能和理化特性以及蛋白质结构，同时保持相同的水解水平。值得注意的是，颗粒尺寸（减少）、β-折叠含量（增加）、β-转角含量（增加）和无规卷曲含量（增加）均发生了显着变化。有趣的是，超声波处理出乎意料地阻止了蛋白水解过程中蛋白质分子质量的降解，同时增加了水解产物的疏水性。这些发现与观察到的苦味减少以及乳化性能和保水能力的改善相一致。